Fri Feb 08, 2019 12:45 am
>"He didn't make it any easier to understand by using multiple spellings and poor wording."
It could have been worse but I think if I find a wiki on it, it will be better.
>" It was almost as if he didn't want anyone to understand what he was saying. "
Well it's hard to shoot someone 10,000 miles away. I'm pretty good but not that good.
>" I would say 1 kHz is the high end for this and I would not say 60 Hz it too low..."
Well I guess I'll take that. A car alternator is much higher but nobody ever claimed it keeps the sulphwhatevers off the plates.
>"Why are you designing any of this rather than using off the shelf units? "
We are doing that on the main 24 volt system. I am handling the 12 volt subsystem. I have some ideas on exactly how I want the charger/regulator to behave.
Also it is work. I could search the internet and tell him what to buy and gain like a 12 pack out of it. I'd rather handle it, lead acid will not be a big problem.
Another thing is that what I've done so far, and no there is not an off the shelf solution, I don't know what to charge for it. It is not all that technical, just some PWM running some power MOSFETs, but what do you all charge for that say, per hour ? I also have to build it and I don't really know what to charge for that.
Anyway, there will probably be a second alternator on it, isolated from ground and in series with the original. The original can charge the 12 volt system and the stacked one can charge the 24 volt system. And it will be separate except for when the engine is running. I'll either come of the IGN line in the vehicle or run a relay off it for that. Being an alternator, the 24 volt system is automatically isolated except when the engine is running, it cannot discharge the batteries. Also, if he happens to run the vehicle battery too low he'll have the option of actually jump starting it off the 12 volt system with the flip of a switch. We don't really anticipate that but better to have it and not need it.
So I don't know, I think it is 35 components, simple PWM, four independent channels. Outputs to a string of LEDs and can sink (they are common anode) around 20 amps per channel. Three dual OP AMPs, four power MOSFETs and a bunch of penny ante shit. There have been four revisions. One his order, the others were overlooks on my part.
I got maybe ten hours into it but I am sure a real pro could do it in half the time.
What is fair ?
Fri Feb 08, 2019 4:45 am
On Friday, February 8, 2019 at 4:43:31 AM UTC+11, gnuarm.del...@gmail.com wrote:
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.
I spelt sulphur as sulfur once in that short post. That probably counts as typo - it's conflict between the English spelling I grew up with an Noah Webster's corruption that Americans use (and I get to see quite frequently).
If you think the wording was poor, demonstrate how you would have done it better.
> > 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.
If somebody tells you that there are are sulphides in a battery, you can work out that they don't know what they are talking about, which detracts from the credibility of their other claims.
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.
The distinction between sulphides, sulphites and sulphates is very elementary chemistry. This is a largely university educated group, and I'd expect most people who post here would know the difference.
Thus far 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.
I did a conductivity-measuring circuit once that generated a frequency output - about 2.4kHz for tap water (300 microSiemens) to about 50kHz for 2% NaoH at 85C (300 milliSiemens). That signal went through the water.
The conductivity of water isn't about atoms moving through the water, but about ions. It's frequency dependence is captured by
which tends to give a 45 degree phase shift over a large frequency range.
What happens at the positive and negative plates of a lead acid battery during charge and discharge is even more complicated, and someboyd blithering about "atoms" clearly hasn't got much insight into it.
> It's been a while since I read this thread. Why are you designing any of this rather than using off the shelf units?
Probably because he thinks he can. Building stuff always looks cheaper than buying it, and until you figure in the cost of getting it to work.
I spent six years in the Nijmegen University science faculty workshop, and a lot of the job was persuading academics to go out and buy what they needed, rather than wasting out time reinventing the wheel for them.
Bill Sloman, Sydney