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Guest

Fri Feb 01, 2019 8:45 pm   



I have decided to take some advice from here, which is usually a good idea. I am not going to build the charging system for the main system, there is too much out there that is too far beyond me. I am not learning to do software and USB interfaces and all that shit. So that part of it is settled.

After some research he has decided on a 24 volt main system. Invertors are a bit more efficient obviously, the wire gauges are half what they would be at 12, and going to higher voltages really gets into diminishing returns. It might not even be Tesla batteries, there are alternatives. Plus he already ordered the PV panels and is next going to deal with the mounting and the tilting mechanism, which is not my job.

So, since so much runs off 12 volts these days I intend to build a regulator for that and have recommended that he get a regular lead acid battery for that, preferably deep cycle.

What I intend to do, and the crux of my question is, if I build the regulator to put out something like 14.8 volts, can I just dump that into the battery with no filtering ? AND, would it be advantageous to do so ?

Years ago I read about a battery desulfider. From what I gleaned the thing puts out an AC current to the battery and that somehow makes it better. They claimed it knocked the sulfides off the plates or whatever.

Any filtering I have to do for the 12 volt devices will be easier with (after) the aid of the storage battery of course.

I designed some lighting controls and they are of course PWM and I am going to put them at about 25KHz to make sure they're inaudible. That wiring will be all over the place so I think that is a good move. However this charger deal is going to be stashed in the back of this thing and I can use 25Hz, 30Hz, 60Hz, whatever.

Whatever is best for the battery, and this will be a lead acid. The charger will limit current to a reasonable level and shut down at what, 13.8 ? Whatever.

I noticed over the years that cars that charged at a higher voltage had a better charge. With an old battery this would require the periodic addition of water but on a maintenance free newer one it can take it. I've had cars that charged at like 14.3 and they were able to start but not much else. But then my van, well I lived with the olman and we couldn't smoke pot in the house. This thing charged at about 15.8. We sat in that thing (I had easy chairs n shit in there, house speakers, this was the young Man cave) for six hours partying and it started up just fine in the morning. We had the interior lights on and the stereo, used the lighter. Other vehicles it seemed if you left the headlights on for three hours you needed a jump start. So I want a nice healthy charge on that battery.

Someone in the other thread mentioned like a week long blizzard ? Well I want to get as close as possible to being able to handle that, but if a blizzard there will be practically no solar coming in. So one of the enhancements will be possibly to charge the main batteries off the engine alternator. We intend to install a second alternator for this. What's more in the cold the vehicle heater will assist whatever else goes in there, propane of course.

Anyway, my main question again, is it good for a lead acid battery to charge it with pulsed current ? Is it bad ? Does it simply not matter ? That is my question for today.


Thanks.


Guest

Fri Feb 01, 2019 8:45 pm   



On Friday, February 1, 2019 at 2:17:20 PM UTC-5, jurb...@gmail.com wrote:
Quote:
I have decided to take some advice from here, which is usually a good idea. I am not going to build the charging system for the main system, there is too much out there that is too far beyond me. I am not learning to do software and USB interfaces and all that shit. So that part of it is settled.

After some research he has decided on a 24 volt main system. Invertors are a bit more efficient obviously, the wire gauges are half what they would be at 12, and going to higher voltages really gets into diminishing returns.. It might not even be Tesla batteries, there are alternatives. Plus he already ordered the PV panels and is next going to deal with the mounting and the tilting mechanism, which is not my job.

So, since so much runs off 12 volts these days I intend to build a regulator for that and have recommended that he get a regular lead acid battery for that, preferably deep cycle.

What I intend to do, and the crux of my question is, if I build the regulator to put out something like 14.8 volts, can I just dump that into the battery with no filtering ? AND, would it be advantageous to do so ?

Years ago I read about a battery desulfider. From what I gleaned the thing puts out an AC current to the battery and that somehow makes it better. They claimed it knocked the sulfides off the plates or whatever.

Any filtering I have to do for the 12 volt devices will be easier with (after) the aid of the storage battery of course.

I designed some lighting controls and they are of course PWM and I am going to put them at about 25KHz to make sure they're inaudible. That wiring will be all over the place so I think that is a good move. However this charger deal is going to be stashed in the back of this thing and I can use 25Hz, 30Hz, 60Hz, whatever.

Whatever is best for the battery, and this will be a lead acid. The charger will limit current to a reasonable level and shut down at what, 13.8 ? Whatever.

I noticed over the years that cars that charged at a higher voltage had a better charge. With an old battery this would require the periodic addition of water but on a maintenance free newer one it can take it. I've had cars that charged at like 14.3 and they were able to start but not much else. But then my van, well I lived with the olman and we couldn't smoke pot in the house. This thing charged at about 15.8. We sat in that thing (I had easy chairs n shit in there, house speakers, this was the young Man cave) for six hours partying and it started up just fine in the morning. We had the interior lights on and the stereo, used the lighter. Other vehicles it seemed if you left the headlights on for three hours you needed a jump start. So I want a nice healthy charge on that battery.

Someone in the other thread mentioned like a week long blizzard ? Well I want to get as close as possible to being able to handle that, but if a blizzard there will be practically no solar coming in. So one of the enhancements will be possibly to charge the main batteries off the engine alternator.. We intend to install a second alternator for this. What's more in the cold the vehicle heater will assist whatever else goes in there, propane of course.

Anyway, my main question again, is it good for a lead acid battery to charge it with pulsed current ? Is it bad ? Does it simply not matter ? That is my question for today.


Speaking from relative ignorance on pulsed charging, but I have never seen any indication that pulsed DC would harm a lead acid battery. In fact, I have see reports that in general, pulsed charging of batteries can be good. It seems the pulsing provides some time for the electrolytes to diffuse and prevent some of the concentrations from causing problems in charging.

I will say the voltage you charge the battery to, and that is the battery voltage, not the voltage at the other end of the cable, is well documented and is a function of battery temperature. Overcharge and you will harm the battery, maintenance free or not.

Rick C.

- Tesla referral code - https://ts.la/richard11209

Jasen Betts
Guest

Sat Feb 02, 2019 12:39 am   



On 2019-02-01, jurb6006_at_gmail.com <jurb6006_at_gmail.com> wrote:
Quote:
I have decided to take some advice from here, which is usually a
good idea. I am not going to build the charging system for the main
system, there is too much out there that is too far beyond me. I am
not learning to do software and USB interfaces and all that shit. So
that part of it is settled.

After some research he has decided on a 24 volt main system.
Invertors are a bit more efficient obviously, the wire gauges are half
what they would be at 12, and going to higher voltages really gets
into diminishing returns. It might not even be Tesla batteries, there
are alternatives. Plus he already ordered the PV panels and is next
going to deal with the mounting and the tilting mechanism, which is
not my job.

So, since so much runs off 12 volts these days I intend to build a
regulator for that and have recommended that he get a regular lead
acid battery for that, preferably deep cycle.


I'd say no. just tap the 24V stack at 12V and take the 12V from the
lower battery.

then fit a buck converter with feedback to maintain the lower battery
at the mid-point voltage of the whole stack.

This also gives the option of running mis-matched batteries in the
stack.

--
When I tried casting out nines I made a hash of it.

Robert Baer
Guest

Sat Feb 02, 2019 8:45 am   



jurb6006_at_gmail.com wrote:
Quote:
I have decided to take some advice from here, which is usually a good idea. I am not going to build the charging system for the main system, there is too much out there that is too far beyond me. I am not learning to do software and USB interfaces and all that shit. So that part of it is settled.

After some research he has decided on a 24 volt main system. Invertors are a bit more efficient obviously, the wire gauges are half what they would be at 12, and going to higher voltages really gets into diminishing returns. It might not even be Tesla batteries, there are alternatives. Plus he already ordered the PV panels and is next going to deal with the mounting and the tilting mechanism, which is not my job.

So, since so much runs off 12 volts these days I intend to build a regulator for that and have recommended that he get a regular lead acid battery for that, preferably deep cycle.

What I intend to do, and the crux of my question is, if I build the regulator to put out something like 14.8 volts, can I just dump that into the battery with no filtering ? AND, would it be advantageous to do so ?

Years ago I read about a battery desulfider. From what I gleaned the thing puts out an AC current to the battery and that somehow makes it better. They claimed it knocked the sulfides off the plates or whatever.

* Not claim..more like fact.
The idea is the charge/discharge current chemically tears apart the
sulfides, so they can be formed into chemically useful lead sulphate.
Sulfide is used to describe any of three types of chemical compounds
that contain sulfur. Sulfite is sulfur dioxide, or SO2.

Quote:

Any filtering I have to do for the 12 volt devices will be easier with (after) the aid of the storage battery of course.

I designed some lighting controls and they are of course PWM and I am going to put them at about 25KHz to make sure they're inaudible. That wiring will be all over the place so I think that is a good move. However this charger deal is going to be stashed in the back of this thing and I can use 25Hz, 30Hz, 60Hz, whatever.

Whatever is best for the battery, and this will be a lead acid. The charger will limit current to a reasonable level and shut down at what, 13.8 ? Whatever.

I noticed over the years that cars that charged at a higher voltage had a better charge. With an old battery this would require the periodic addition of water but on a maintenance free newer one it can take it. I've had cars that charged at like 14.3 and they were able to start but not much else. But then my van, well I lived with the olman and we couldn't smoke pot in the house. This thing charged at about 15.8. We sat in that thing (I had easy chairs n shit in there, house speakers, this was the young Man cave) for six hours partying and it started up just fine in the morning. We had the interior lights on and the stereo, used the lighter. Other vehicles it seemed if you left the headlights on for three hours you needed a jump start. So I want a nice healthy charge on that battery.

Someone in the other thread mentioned like a week long blizzard ? Well I want to get as close as possible to being able to handle that, but if a blizzard there will be practically no solar coming in. So one of the enhancements will be possibly to charge the main batteries off the engine alternator. We intend to install a second alternator for this. What's more in the cold the vehicle heater will assist whatever else goes in there, propane of course.

* Re-think.. There may be MORE light available during a blizzard than a
foggy day.

Quote:

Anyway, my main question again, is it good for a lead acid battery to charge it with pulsed current ? Is it bad ? Does it simply not matter ? That is my question for today.

* Limit the pulsing and you are OK. Just like DC chargers run between
constant voltage and constant current, one puts limits on those values.
A highly sulphated battery will require a large voltage (i have seen
up to 100V needed) to get a decent current,so think a (semi) constant
current AC source.
A variac, and capacitor in series for the AC charge/discharge
component, and a diode across the battery to limit overall discharge
will do the job.

Perhaps pick C/20 for slow,normal use; add voltage limit when
charging rises to nominal value, NO limit if baaaad battery.

Quote:


Thanks.


Mike
Guest

Sat Feb 02, 2019 11:45 am   



On 2/1/2019 11:17 AM, jurb6006_at_gmail.com wrote:
Quote:
I have decided to take some advice from here, which is usually a good idea. I am not going to build the charging system for the main system, there is too much out there that is too far beyond me. I am not learning to do software and USB interfaces and all that shit. So that part of it is settled.

After some research he has decided on a 24 volt main system. Invertors are a bit more efficient obviously, the wire gauges are half what they would be at 12, and going to higher voltages really gets into diminishing returns. It might not even be Tesla batteries, there are alternatives. Plus he already ordered the PV panels and is next going to deal with the mounting and the tilting mechanism, which is not my job.

So, since so much runs off 12 volts these days I intend to build a regulator for that and have recommended that he get a regular lead acid battery for that, preferably deep cycle.

What I intend to do, and the crux of my question is, if I build the regulator to put out something like 14.8 volts, can I just dump that into the battery with no filtering ? AND, would it be advantageous to do so ?

Years ago I read about a battery desulfider. From what I gleaned the thing puts out an AC current to the battery and that somehow makes it better. They claimed it knocked the sulfides off the plates or whatever.

Any filtering I have to do for the 12 volt devices will be easier with (after) the aid of the storage battery of course.

I designed some lighting controls and they are of course PWM and I am going to put them at about 25KHz to make sure they're inaudible. That wiring will be all over the place so I think that is a good move. However this charger deal is going to be stashed in the back of this thing and I can use 25Hz, 30Hz, 60Hz, whatever.

Whatever is best for the battery, and this will be a lead acid. The charger will limit current to a reasonable level and shut down at what, 13.8 ? Whatever.

I noticed over the years that cars that charged at a higher voltage had a better charge. With an old battery this would require the periodic addition of water but on a maintenance free newer one it can take it. I've had cars that charged at like 14.3 and they were able to start but not much else. But then my van, well I lived with the olman and we couldn't smoke pot in the house. This thing charged at about 15.8. We sat in that thing (I had easy chairs n shit in there, house speakers, this was the young Man cave) for six hours partying and it started up just fine in the morning. We had the interior lights on and the stereo, used the lighter. Other vehicles it seemed if you left the headlights on for three hours you needed a jump start. So I want a nice healthy charge on that battery.

Someone in the other thread mentioned like a week long blizzard ? Well I want to get as close as possible to being able to handle that, but if a blizzard there will be practically no solar coming in. So one of the enhancements will be possibly to charge the main batteries off the engine alternator. We intend to install a second alternator for this. What's more in the cold the vehicle heater will assist whatever else goes in there, propane of course.

Anyway, my main question again, is it good for a lead acid battery to charge it with pulsed current ? Is it bad ? Does it simply not matter ? That is my question for today.


Thanks.

Pick a reputable battery vendor. Go to their website and look up the
specs on the battery you'll buy.
It will give you temperature compensation curves and maximum
charge/discharge currents.
Conventional wisdom suggests that you want to use no more than half of
the rated capacity. Multiply that by the bad weather you need to ride out.
By the time you're done with that, you'll decide that you can't afford
enough solar panels to provide excess peak current to the batteries.
But you do need to limit the total charge according to the
manufacturer's curves.
Automotive alternators provide pulsed current at varying frequencies.
If it were me, I'd provide some filtering. Makes it easier
to instrument.

Pay careful attention to the battery configuration. Little things matter.

Make sure you're measuring the voltages right at the batteries.
If you have a bunch of batteries in parallel, you might wire them up
like this:

+ ---------------------
B B B B B
- ---------------------

But those resistances add up to make a significant difference in
currents per battery.

Might be better to wire them up like this:

+ ---------------------
B B B B
---------------------- -

Batteries don't charge on volts.
They charge on current. Volts is a result.
You MUST build (or buy) a MPPT solar charge controller.
Solar panels are closer to current sources where it matters. MPPT
modifies the
pulse width to achieve maximum average current, then throttles
back as the target voltage is achieved.
We used a shunt regulator to limit the charge voltage,
mostly because the wind generator component got very
unhappy when you unloaded it in a high wind.

You don't have to use exotic algorithms. Perturb and observe
is plenty good.

It's trivial to achieve on a PIC processor, but I expect
that an arduino would be a better choice today.
Add bluetooth and you can control/log on a smart phone.

Most interesting system I'd ever heard of used solar
to disassociate water into hydrogen and oxygen.
Storage was a barrel full of water with a concentric
inverted barrel inside. The gas raised the smaller
barrel. You put a few bricks on top to regulate the pressure.

They used Hydrogen Fuel cells for electricity and
burned the Hydrogen for heat and cooking.

Such a system has significant risk of explosion, but
it seemed to do the job without a lot of batteries.

Carl
Guest

Sat Feb 02, 2019 5:45 pm   



jurb6006_at_gmail.com wrote:
Quote:
I have decided to take some advice from here, which is usually a good
idea. I am not going to build the charging system for the main system,
there is too much out there that is too far beyond me. I am not learning
to do software and USB interfaces and all that shit. So that part of it
is settled.

After some research he has decided on a 24 volt main system. Invertors
are a bit more efficient obviously, the wire gauges are half what they
would be at 12, and going to higher voltages really gets into diminishing
returns. It might not even be Tesla batteries, there are alternatives.
Plus he already ordered the PV panels and is next going to deal with the
mounting and the tilting mechanism, which is not my job.

So, since so much runs off 12 volts these days I intend to build a
regulator for that and have recommended that he get a regular lead acid
battery for that, preferably deep cycle.

What I intend to do, and the crux of my question is, if I build the
regulator to put out something like 14.8 volts, can I just dump that into
the battery with no filtering ? AND, would it be advantageous to do so ?

Years ago I read about a battery desulfider. From what I gleaned the
thing puts out an AC current to the battery and that somehow makes it
better. They claimed it knocked the sulfides off the plates or whatever.
* Not claim..more like fact.
The idea is the charge/discharge current chemically tears apart the
sulfides, so they can be formed into chemically useful lead sulphate.
Sulfide is used to describe any of three types of chemical compounds that
contain sulfur. Sulfite is sulfur dioxide, or SO2.


More info than you ever wanted to know:
https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

--
Regards,
Carl Ijames


Guest

Sat Feb 02, 2019 10:45 pm   



On Saturday, February 2, 2019 at 3:55:15 PM UTC-5, jurb...@gmail.com wrote:
Quote:
Not to be an asshole, but I am top posting to reply to all. Thanks.

"Speaking from relative ignorance on pulsed charging,.."

You admitting that is noteworthy...

" I have see reports that in general, pulsed charging of batteries can be good..."

That's pretty much what I've gleaned over the years. a car alternator for example is not filtered in any way and it is pretty much pulsed, though sine type waves, at anywhere from like 2KHz to who knows. I was kinda thinking that a lower frequency would be better, but I am not sure of that. I must also admit ignorance on the subject but it looks like I won't be ignorant for long.

"...and is a function of battery temperature..."

Yes, I heard about that. But a car now, the way it thermally tracks is in cold weather it will apply a higher charging voltage, once it all warms up it tapers off some. The reference voltage is not the output, it is off a separate set of tops of a three phase full wave bridge. so it is also partly current and partly voltage regulated. I thin it would maybe be a good idea to charge like that, since it has been working for the last forty years.


I would not use anything about the way a car charges a battery to be an example of doing it "right". While a typical car battery lasts some four years or so, properly maintained lead acid batteries last 20 years. I worked for a railroad once and they had batteries in service for at least 20 years before they would find need to remove them.

In particular, you should actually measure the temperature of the battery, not the ambient temp. The battery will get warm from use.


Quote:
"I'd say no. just tap the 24V stack at 12V and take the 12V from the lower battery. "

You're talking using a battery balancer. I am not so sure I want to do that. The balancer, as efficient as it may be it actually just partly shorting out the top battery. I think with the batteries in parallel we would get more capacity in the end. The ONE regulator would be doing the charging, the batteries, especially more than one would do most of the filtering. I dunno, it IS an option but I am not sure it is right for this project.


I'm not sure why that would be better than just a 24 to 12 volt converter. Isn't it really the same thing?


Quote:
"* Not claim..more like fact.
The idea is the charge/discharge current chemically tears apart the sulfides, so they can be formed into chemically useful lead sulphate. "

Sounds like we just saved the cost of a choke. The only problem is the peak current of the chopper(s). Actually just one 100 amp MOSFET should do it, no ?


Of all the battery chargers I've opened up, I've never seen either a separate choke or a capacitor in them. They have a transformer, a diode or two and a big honkin transformer. I suspect they only put out pulsed DC. I've never scoped one though.


Quote:
"* Re-think.. There may be MORE light available during a blizzard than a foggy day. "

Re-think is right, just what wavelengths of light do these things run off of ?


I'm not sure that is very relevant. Even if you get some light, it won't be much. I've been snow bound for a while, but I've never been in a week long blizzard though. I have been in more than a week of heavy overcast though. In fact, I think this past year we had so many overcast and rain days that they outnumbered the sunny days. Mid-Atlantic states.


Quote:
" A highly sulphated battery will require a large voltage..."

But that should never happen right ? Or at least for a long long time...

"Automotive alternators provide pulsed current at varying frequencies. If it were me, I'd provide some filtering. Makes it easier to instrument. "

I think I can pick that up anyway. If there IS, which seems to be, an actual advantage to pulsed current I will deal with it. Might have to do some math but if anyone could do it it would pay minimum wage. Just a resistor and a filter will give me a smooth enough voltage I think, and a series resistor, low value as it may be would serve to set the maximum current. I just want to keep it down at like 0.1 ohm. We do not want to waste power. So whatever voltage I get would have to be scaled by amplification. No sweat.


Averaging won't give you RMS, but if the waveform is consistent it can be calibrated accurately. It may take a long sample time or synchronous samplings to minimize artifacts of not having whole periods in a single average.


Quote:
"Most interesting system I'd ever heard of used solar
to disassociate water into hydrogen and oxygen. "

HA, one day a friend of mine comes over with a water separator, but it had the H and O2 unseparated. Could have blown up the house. Edumacated him a bit about making like tubes or something to collect the gases of each electrode separately, and then they are pumped into tanks... But the house did not fly to Kansas so we OK.

" Perturb and observe ..."

Right up my alley.

"More info than you ever wanted to know: "

I will be reading that soon. Probably be back with questions. Damn answers, more than half the time you get an answer and you got at least a new question. Dammit.

Thanks all. I think we are going to git-r-done.


Good luck.

Rick C.

+ Tesla referral code - https://ts.la/richard11209


Guest

Sat Feb 02, 2019 10:45 pm   



Not to be an asshole, but I am top posting to reply to all. Thanks.

>"Speaking from relative ignorance on pulsed charging,.."

You admitting that is noteworthy...

>" I have see reports that in general, pulsed charging of batteries can be good..."

That's pretty much what I've gleaned over the years. a car alternator for example is not filtered in any way and it is pretty much pulsed, though sine type waves, at anywhere from like 2KHz to who knows. I was kinda thinking that a lower frequency would be better, but I am not sure of that. I must also admit ignorance on the subject but it looks like I won't be ignorant for long.

>"...and is a function of battery temperature..."

Yes, I heard about that. But a car now, the way it thermally tracks is in cold weather it will apply a higher charging voltage, once it all warms up it tapers off some. The reference voltage is not the output, it is off a separate set of tops of a three phase full wave bridge. so it is also partly current and partly voltage regulated. I thin it would maybe be a good idea to charge like that, since it has been working for the last forty years.

>"I'd say no. just tap the 24V stack at 12V and take the 12V from the lower battery. "

You're talking using a battery balancer. I am not so sure I want to do that.. The balancer, as efficient as it may be it actually just partly shorting out the top battery. I think with the batteries in parallel we would get more capacity in the end. The ONE regulator would be doing the charging, the batteries, especially more than one would do most of the filtering. I dunno, it IS an option but I am not sure it is right for this project.

Quote:
"* Not claim..more like fact.
The idea is the charge/discharge current chemically tears apart the sulfides, so they can be formed into chemically useful lead sulphate. "


Sounds like we just saved the cost of a choke. The only problem is the peak current of the chopper(s). Actually just one 100 amp MOSFET should do it, no ?

>"* Re-think.. There may be MORE light available during a blizzard than a foggy day. "

Re-think is right, just what wavelengths of light do these things run off of ?

>" A highly sulphated battery will require a large voltage..."

But that should never happen right ? Or at least for a long long time...

>"Automotive alternators provide pulsed current at varying frequencies. If it were me, I'd provide some filtering. Makes it easier to instrument. "

I think I can pick that up anyway. If there IS, which seems to be, an actual advantage to pulsed current I will deal with it. Might have to do some math but if anyone could do it it would pay minimum wage. Just a resistor and a filter will give me a smooth enough voltage I think, and a series resistor, low value as it may be would serve to set the maximum current. I just want to keep it down at like 0.1 ohm. We do not want to waste power. So whatever voltage I get would have to be scaled by amplification. No sweat.

Quote:
"Most interesting system I'd ever heard of used solar
to disassociate water into hydrogen and oxygen. "


HA, one day a friend of mine comes over with a water separator, but it had the H and O2 unseparated. Could have blown up the house. Edumacated him a bit about making like tubes or something to collect the gases of each electrode separately, and then they are pumped into tanks... But the house did not fly to Kansas so we OK.

>" Perturb and observe ..."

Right up my alley.

>"More info than you ever wanted to know: "

I will be reading that soon. Probably be back with questions. Damn answers, more than half the time you get an answer and you got at least a new question. Dammit.

Thanks all. I think we are going to git-r-done.

Mike
Guest

Sun Feb 03, 2019 1:45 am   



On 2/2/2019 12:55 PM, jurb6006_at_gmail.com wrote:
Quote:
Not to be an asshole, but I am top posting to reply to all. Thanks.

"Speaking from relative ignorance on pulsed charging,.."

You admitting that is noteworthy...

" I have see reports that in general, pulsed charging of batteries can be good..."

That's pretty much what I've gleaned over the years. a car alternator for example is not filtered in any way and it is pretty much pulsed, though sine type waves, at anywhere from like 2KHz to who knows. I was kinda thinking that a lower frequency would be better, but I am not sure of that. I must also admit ignorance on the subject but it looks like I won't be ignorant for long.

"...and is a function of battery temperature..."

Yes, I heard about that. But a car now, the way it thermally tracks is in cold weather it will apply a higher charging voltage, once it all warms up it tapers off some. The reference voltage is not the output, it is off a separate set of tops of a three phase full wave bridge. so it is also partly current and partly voltage regulated. I thin it would maybe be a good idea to charge like that, since it has been working for the last forty years.

"I'd say no. just tap the 24V stack at 12V and take the 12V from the lower battery."

You're talking using a battery balancer. I am not so sure I want to do that. The balancer, as efficient as it may be it actually just partly shorting out the top battery. I think with the batteries in parallel we would get more capacity in the end. The ONE regulator would be doing the charging, the batteries, especially more than one would do most of the filtering. I dunno, it IS an option but I am not sure it is right for this project.

"* Not claim..more like fact.
The idea is the charge/discharge current chemically tears apart the sulfides, so they can be formed into chemically useful lead sulphate. "

Sounds like we just saved the cost of a choke. The only problem is the peak current of the chopper(s). Actually just one 100 amp MOSFET should do it, no ?

"* Re-think.. There may be MORE light available during a blizzard than a foggy day."

Re-think is right, just what wavelengths of light do these things run off of ?

" A highly sulphated battery will require a large voltage..."

But that should never happen right ? Or at least for a long long time...

"Automotive alternators provide pulsed current at varying frequencies. If it were me, I'd provide some filtering. Makes it easier to instrument."

I think I can pick that up anyway. If there IS, which seems to be, an actual advantage to pulsed current I will deal with it. Might have to do some math but if anyone could do it it would pay minimum wage. Just a resistor and a filter will give me a smooth enough voltage I think, and a series resistor, low value as it may be would serve to set the maximum current. I just want to keep it down at like 0.1 ohm. We do not want to waste power. So whatever voltage I get would have to be scaled by amplification. No sweat.

"Most interesting system I'd ever heard of used solar
to disassociate water into hydrogen and oxygen. "

HA, one day a friend of mine comes over with a water separator, but it had the H and O2 unseparated. Could have blown up the house. Edumacated him a bit about making like tubes or something to collect the gases of each electrode separately, and then they are pumped into tanks... But the house did not fly to Kansas so we OK.


I got sucked into a discussion of Brown's gas by a guy who was
generating it to run his car. Free energy...right...
So, one night, he forgot to turn off the generator in the trunk.
Next morning, when he tried to start it, it exploded the air filter and
blew the
valve cover completely off. He was undeterred, despite a mathematical
analysis
showing that he was doing nothing more than spending money to wear out
his engine.
Quote:

" Perturb and observe ..."

Right up my alley.

"More info than you ever wanted to know:"

I will be reading that soon. Probably be back with questions. Damn answers, more than half the time you get an answer and you got at least a new question. Dammit.

Thanks all. I think we are going to git-r-done.


This thread is a basic design review.
If I were the project manager, I'd be biting my tongue
and sending you home with homework...
Everything is a tradeoff. Even if more is better for that
function, it may not be better than having less here and using
that extra resource to make something else more better. Might
be overall optimization of cost, time to market, reliability...

If the project is a solar panel with a switching buck regulator to charge
24V lead acid batteries, there are some things that you might not have
thought about. Depending on your total architecture, buck may not
be enough, but don't worry about that at this point.

The time to think about them is BEFORE you start spending money
buying stuff.

The most costly, biggest, most fragile part of the system is
the solar array. You want to maximize the number of electrons
it produces per dollar/meter/whateverparameter.

So, get yourself a graph of the voltage/current curves for your
panels parameterized by insolation level.
On each curve, find the point where volts times current is maximum.
Put a dot on each curve at those points. Draw a curve thru those
points and call it the maximum power line.
Draw a horizontal line at 30 Volts...round numbers.
Below that 30V line, you get zero output capable of charging the
fully charged 24V battery.

At this point, you're probably formulating your response on how
I'm full of shit and... Bite your tongue and hang in there.
There will be plenty of time to fine tune the numbers.
This is the concept phase...just bear with me.

For maximum power output, you want the output voltage/current
of the panel to be RIGHT ON THAT LINE. That means you MUST filter it.
You adjust the buck converter to make that happen. You just dither the
pulse width around that point of the curve...perturb and observe...

That's the concept. As a practical matter, you can consider the battery
voltage to be pretty constant in the short term. You measure the charge
current and optimize that with the pulse width. That automagically makes
the panel voltage track at maximum. That works for all insolation
levels above the 30V line. Panel current does not equal
charge current. The peak charge current can be several times
the panel output current for discharged battery and lotsa sun.
That 100A FET may have to be a 400A FET capable of higher voltage.

By the time you're done with that, you will have learned that you
do need an inductor and a capacitor on each end of it...well there's a
diode on the bottom end.

If you plot insolation over the course of a year at the location,
you'll also realize how little time the solar voltage stays over 30V
in the winter. And how much more battery you need and how much bigger
the solar panels need to be. And start thinking how to redesign
the switcher to deliver some charge below 30V of solar output.

And you won't have spent a dime yet.
And I haven't mentioned pulse charging at all.
You can tweak that anywhere you want by varying the
size of the bottom cap.

++++++++++++++++++++++++++++++++++++++++
I spent most of my career as project manager for test systems
designed to be used by inexperienced users. I spent a lot of
effort to reign in the excessive cleverness of the engineers
where it added no value to the end user but made the system
more difficult to use.

You're building a system to be used by someone else.
It's unlikely that you could spend enough time to experience
all the diversity that nature has to offer.

You do not want to build a system that causes the other guy
grief. Or sets him on fire. Or lets his water system freeze.

I stand my my assessment that you can buy a better charge
controller than you can build and for less money than
you're gonna spend building it. Time is money. Get a job
at minimum wage and buy him a controller. You'll still
be money ahead.

I've done what you're doing many times. It rarely
ended up cheaper.

Are we having fun yet?


Guest

Sun Feb 03, 2019 3:45 am   



On Saturday, February 2, 2019 at 6:31:45 PM UTC+11, Robert Baer wrote:
Quote:
jurb6006_at_gmail.com wrote:
I have decided to take some advice from here, which is usually a good idea. I am not going to build the charging system for the main system, there is too much out there that is too far beyond me. I am not learning to do software and USB interfaces and all that shit. So that part of it is settled..

After some research he has decided on a 24 volt main system. Invertors are a bit more efficient obviously, the wire gauges are half what they would be at 12, and going to higher voltages really gets into diminishing returns. It might not even be Tesla batteries, there are alternatives. Plus he already ordered the PV panels and is next going to deal with the mounting and the tilting mechanism, which is not my job.

So, since so much runs off 12 volts these days I intend to build a regulator for that and have recommended that he get a regular lead acid battery for that, preferably deep cycle.

What I intend to do, and the crux of my question is, if I build the regulator to put out something like 14.8 volts, can I just dump that into the battery with no filtering ? AND, would it be advantageous to do so ?

Years ago I read about a battery desulfider. From what I gleaned the thing puts out an AC current to the battery and that somehow makes it better. They claimed it knocked the sulfides off the plates or whatever.
* Not claim..more like fact.
The idea is the charge/discharge current chemically tears apart the
sulfides, so they can be formed into chemically useful lead sulphate.
Sulfide is used to describe any of three types of chemical compounds
that contain sulfur. Sulfite is sulfur dioxide, or SO2.


It was probably a battery desulphater.

Sulphides don't show up in lead-acid batteries. Sulphides are chemical compounds containing sulphur atoms. Sulfides contain negatively charged SO3 groups, and sulphates contain negatively charged SO4 groups. You can oxidise sulphur in sulphides to get sulfites and sulphates, but it does soak up oxygen.

<snip>

--
Bill Sloman, Sydney


Guest

Sun Feb 03, 2019 4:45 am   



On Sunday, February 3, 2019 at 7:55:15 AM UTC+11, jurb...@gmail.com wrote:
Quote:
Not to be an asshole, but I am top posting to reply to all. Thanks.

"Speaking from relative ignorance on pulsed charging,.."

You admitting that is noteworthy...

" I have see reports that in general, pulsed charging of batteries can be good..."

That's pretty much what I've gleaned over the years. a car alternator for example is not filtered in any way and it is pretty much pulsed, though sine type waves, at anywhere from like 2KHz to who knows. I was kinda thinking that a lower frequency would be better, but I am not sure of that. I must also admit ignorance on the subject but it looks like I won't be ignorant for long.

"...and is a function of battery temperature..."

Yes, I heard about that. But a car now, the way it thermally tracks is in cold weather it will apply a higher charging voltage, once it all warms up it tapers off some. The reference voltage is not the output, it is off a separate set of tops of a three phase full wave bridge. so it is also partly current and partly voltage regulated. I thin it would maybe be a good idea to charge like that, since it has been working for the last forty years.

"I'd say no. just tap the 24V stack at 12V and take the 12V from the lower battery. "

You're talking using a battery balancer. I am not so sure I want to do that. The balancer, as efficient as it may be it actually just partly shorting out the top battery. I think with the batteries in parallel we would get more capacity in the end. The ONE regulator would be doing the charging, the batteries, especially more than one would do most of the filtering. I dunno, it IS an option but I am not sure it is right for this project.

"* Not claim..more like fact.
The idea is the charge/discharge current chemically tears apart the sulfides, so they can be formed into chemically useful lead sulphate. "

Sounds like we just saved the cost of a choke. The only problem is the peak current of the chopper(s). Actually just one 100 amp MOSFET should do it, no ?


That came from Robert Baer, who is a Baer of very little brain. Don't rely on it.

--
Bill Sloman, Sydney


Guest

Sun Feb 03, 2019 5:45 am   



>"That came from Robert Baer, who is a Baer of very little brain. Don't rely on it."

See, what that should have been is "Wrong, check it out, [and whatever] can't you do that ?

T^T <you don't know what that means YET, no threat but...


Guest

Sun Feb 03, 2019 10:45 am   



On Sunday, February 3, 2019 at 2:50:33 PM UTC+11, jurb...@gmail.com wrote:
Quote:
"That came from Robert Baer, who is a Baer of very little brain. Don't rely on it."

See, what that should have been is "Wrong, check it out, [and whatever] can't you do that ?

T^T <you don't know what that means YET, no threat but...


If you had bothered reading the post I'd put up three minutes earlier, you could have found out what I'd thought was wrong with Robert Baer's post - which is that he doesn't know the difference between sulphates, sulphites and sulphides, or at least not enough about the difference to say anything worth posting.

Repeating the exercise just for you would have been a waste of bandwidth, and here I am doing it anyway. You aren't as dim as Robert Baer, but your other defects are still irritating.

--
Bill Sloman, Sydney


Guest

Wed Feb 06, 2019 8:45 pm   



Without significant chemistry knowledge, your post is near gibberish. Not 100% on me, I know A LITTLE BIT. I could very quickly sim up what I know about chemistry.

I know about atoms, take or give electrons you get ions, give or take neutrons to get isotopes, give or take protons and you got a different substance.. Got ionic and covalent bonds and I ain't no expert on that either. But I don't claim to be. I know a little about ph and what makes ph, some things about properties, reacting with light or similar EM. I know hwy blue LEDs are more expensive, but not EXACTLY why they have a higher junction drop.

If I forgot to mention a few things listing them would not take more text than ^ that up there. Oh, I read somewhere how to make LSD25 but have never tried it and have no intention of doing it. More useless knowledge.

So you partly explained about the difference between a sulphate, ide, ite whatever. I guess it could be considered interesting. The question however was if AC is good for the battery.

Thusfar the general consensus seems to be yes. what frequency ? Well what frequency works ? A car alternator. It will be pulsing at maybe 3K up to who knows. Might be interesting to put a freq counter on one. Maybe I will.

The other thing is the charging parameters. I am recommending two new and same deep cycle marine batteries. I will not fuck with charging the main batteries, but the 12 volt subsystem I will. It will be a combination regulator and charger. Since the battery likes pulses I will give it pulses. I'll figure out the feedback loop somehow. This approach should save time, money, space and maybe a little bit of those spunky electrons, which shall be at issue.


Guest

Thu Feb 07, 2019 6:45 pm   



On Wednesday, February 6, 2019 at 2:01:03 PM UTC-5, jurb...@gmail.com wrote:
> Without significant chemistry knowledge, your post is near gibberish. Not 100% on me, I know A LITTLE BIT. I could very quickly sim up what I know about chemistry.

He didn't make it any easier to understand by using multiple spellings and poor wording. It was almost as if he didn't want anyone to understand what he was saying.


Quote:
I know about atoms, take or give electrons you get ions, give or take neutrons to get isotopes, give or take protons and you got a different substance. Got ionic and covalent bonds and I ain't no expert on that either. But I don't claim to be. I know a little about ph and what makes ph, some things about properties, reacting with light or similar EM. I know hwy blue LEDs are more expensive, but not EXACTLY why they have a higher junction drop.

If I forgot to mention a few things listing them would not take more text than ^ that up there. Oh, I read somewhere how to make LSD25 but have never tried it and have no intention of doing it. More useless knowledge.

So you partly explained about the difference between a sulphate, ide, ite whatever. I guess it could be considered interesting. The question however was if AC is good for the battery.


Yes, well, if you are trying to sound smart it's always good to change the topic to one you are pretty sure no one else in the conversation knows.


> Thusfar the general consensus seems to be yes. what frequency ? Well what frequency works ? A car alternator. It will be pulsing at maybe 3K up to who knows. Might be interesting to put a freq counter on one. Maybe I will.

I don't think the frequency is so important as long as it isn't very high. Remember, this is about atoms moving about in a liquid, so that takes time.. I would say 1 kHz is the high end for this and I would not say 60 Hz it too low, but of course this is a gut feel and not based on anything I've read.


> The other thing is the charging parameters. I am recommending two new and same deep cycle marine batteries. I will not fuck with charging the main batteries, but the 12 volt subsystem I will. It will be a combination regulator and charger. Since the battery likes pulses I will give it pulses. I'll figure out the feedback loop somehow. This approach should save time, money, space and maybe a little bit of those spunky electrons, which shall be at issue.

It's been a while since I read this thread. Why are you designing any of this rather than using off the shelf units?


Rick C.

-- Tesla referral code - https://ts.la/richard11209

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