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Forum Index : Electronics : Effects of battery charging
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readyakira Senior Member  Joined: 17/07/2008 Location: United StatesPosts: 114 |
So I've been watching topics on the battery charging and different batteries. My question is if I have 100ah battery and charge at 4amp what is the big difference from charging at say 20a? I know that they like the bigger charge rate but why? Don't you think Free/Renewable energy should be mandatory in new buildings? |
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| davef Guru  Joined: 14/05/2006 Location: New ZealandPosts: 499 |
Just takes about 5 times longer to charge it 4 Amps. You have to be more careful that you terminate the higher charge rates as the battery gets full. I would hold charge rates down at C/10, ie 10A, although I have seen lead-acid charged at pretty high rates as you suggest. I am unsure as to whether or not they would "like" the higher charge rates. I would think it would place the plates under more stress at the higher rates. Search for <battery Bible> |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
High Ready I have found as Davef has said that 10% capacity charge is a good round the mark charge rate, but you still must be careful near the end of charge as the voltage across the battery gets a bit high. If you use a solar regulator in line it will make sure the high volts for the battery isn't exceeded and will allow a higher charge rate for initial charge up to the capacity of the controller, This is extremely important for gell cells and SLA batteries. Make sure you don't put more amps through the controller than its rating or the magic smoke will escape. I use a 20 amp controller on a 16 amp charger and it really works well, much cheaper than the 300 dollar I was quoted for a voltage controlled charger of the same output. The problem with fast charging is it heats the plates and they shed some of the active material each time you do it, and that shortens the battery life by up to fifty percent, I have also found that a desulphator is a big advantage for keeping the battery healthy and it reconstitutes the sulphate on the plates without boiling hell out of the battery. All the best Bob Foolin Around |
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SSW_squall Senior Member Joined: 20/03/2010 Location: AustraliaPosts: 111 |
Hey Bob, what desulphator are you using?? Is it just the Silicon chip kit or some thing larger?? I think the 48v 600Ah forklift battery bank i have need to be desuphated, as it is 2nd hand, although in reasonable condition. But i reckon the SC design is too small for what i want, because the 2v cells are quite large it will take a fair amount of energy just to overcome the capacitance of the plates. AB Einstein: Everything should be made as simple as possible, but not one bit simpler |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi AB Im guessing you might have seen this before but if not heres a home build for you to ponder over. 2010-05-26_000648_desulfator.pdf Its rather old now but might get your creative thoughts going. Pete. Sometimes it just works |
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| SSW_squall Senior Member Joined: 20/03/2010 Location: AustraliaPosts: 111 |
Thanks Pete, I'll have to read through that article closely... It look like the same basic topology as the SC design at a glance I did find a high power design and related info: High power desulphator Which does at least amp up the danger if nothing else?? Just wondering if anyone has tried anything on this kind of power scale?? AB Einstein: Everything should be made as simple as possible, but not one bit simpler |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
HI SSW I am using a commercial unit available in Malaysia www.infinetumstore.com they are a good little unit in 12 and 24 volts however they are a bit slow on big batteries I have 4000 ah at 24 volts and use four of them placed around the bank. These where discarded emergency SLA lighting standby batteries, they have now come up to full capacity. I don't use equalizing charge as there seems to be no need to damage the batteries by over-boiling them, initially i used a 12 v desulphator across lazy cells and once they where within .2 volts I left it for another month now all batteries are within .1 volts on 12 volt group. I had a bigger unit for doing 32 volt systems but it was a bit savage on smaller batteries these ones are a bit to small but if left on do a real good job over time approx 3 months. Somewhere in my files I have a circuit for a bigger unit which I was going to build but these have done the job so no need to burn my fingers. I have punished them in my testing as I was looking at being an Australian distributor so I wanted to know they stand up, I put the 12 volt one on 24 volts and also connected them reverse polarity and no magic smoke escaped. The Jaycar ones you have to be real careful with or smoke gets out. The circuit Pete gave you is a good starting point if you dont mind burnt fingers. All the best Bob Foolin Around |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi SSW The circuit you have is a later model of the 32v one I had and is used for a short time to blast the sulphate but I have found that the smaller units left on is a better solution. This circuit will revive or blow up a dead battery but long term use will do more damage than good, it would be useful for initially reviving a fork lift battery that is badly sulphated. I have tried a little inverter welder I got on ebay as a charger and due to the switching frequency it desulphates as well, and you can adjust the amps as well high for short term and low for long term charge. All the best Bob Foolin Around |
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Bub73 Senior Member Joined: 10/12/2009 Location: United StatesPosts: 116 |
The circuit Pete posted is the one I use with a few minor changes; it has worked well for me; I'm just now trying to lay it out on strip board. I like to keep several around for reclaiming old battery's as it takes a long time for good results; up to a month and I leave one on my 12 volt bank all the time. Bob |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Bob I think it is a bit smaller in output than the ones I use but on long term use that's not a problem, good to see you are having good results on your battery bank, what size is it? I feel that all deep cycling battery banks should have a desulphator to maintain the optimum performance as long as possible, our batteries are very expensive and the the most neglected thing in our system. All the best Bob Foolin Around |
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| Bub73 Senior Member Joined: 10/12/2009 Location: United StatesPosts: 116 |
Bob; just a small 12 volt main bank now 4 Decka golf cart battery's with a backup bank of reclaimed what ever we find. My brother recently picked up a couple 10000cc farm tractor battery's that had been left sitting discharged for some time one is coming back nicely the other very slowly. I just finished 2 lawn tractor battery's and another automotive; had some that didn't make it we will save these up as trade ins for more cart battery's Bob |
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| SSW_squall Senior Member Joined: 20/03/2010 Location: AustraliaPosts: 111 |
Cheers BobVK4AYQ (and others), really good info... 4000Ah is quite a large bank, if you can manage to desulphate that then i don't have anything to worry about?! I agree with your comments about leaving the various unit connected or not. I'll have to give some of these circuits a go some time, after i get some other other projects out of the way AB Einstein: Everything should be made as simple as possible, but not one bit simpler |
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| readyakira Senior Member Joined: 17/07/2008 Location: United StatesPosts: 114 |
that desulphator circuit hard to build and tune? The toroid I think is what scares me the most :P Don't you think Free/Renewable energy should be mandatory in new buildings? |
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| Bub73 Senior Member Joined: 10/12/2009 Location: United StatesPosts: 116 |
The circuit Pete posted is easy to build no tuning needed; Unless you have a scope and want to play also they will run self powered. I'm trying to lay it out on strip board now so it will be even easier. I had to order the fet from hong kong when they get here I'll test the layout and if its ok I'll post it to the forum. Bob |
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| readyakira Senior Member Joined: 17/07/2008 Location: United StatesPosts: 114 |
is there any fets that are comparable? or is that what makes these so challenging? I thought they would be one of the harder small circuits to build. Don't they work on resonance? Doesn't that have a usually small window? I played with it a bit when I messed with HHO. I have a Pulse width modulator circuit I had built that I could adjust 2 signal's width and frequency and it was a mutha to make it just right so you saw an increase in output. Do you have a link to his circuit? Don't you think Free/Renewable energy should be mandatory in new buildings? |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Ready, Go back a page or two and you will find a post with a PDF of the circuit. Pete. Sometimes it just works |
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| Bub73 Senior Member Joined: 10/12/2009 Location: United StatesPosts: 116 |
Just click the link in Pete's post read the pdf file it contains the circuit and lot of info on how it works. |
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| Bub73 Senior Member Joined: 10/12/2009 Location: United StatesPosts: 116 |
Bob Isaiah has a Goodall twin 300 amp hot shot booster for jump starting airplanes would this be good to hook up to the 10000 amp tractor battery to try to break up the sulfate. it is flat and we are starting reclaiming.The goodall uses what looks like 4 of the car generators to make two separate 300 amp systems and yes it is heavy!! Isaiah on Bubs computer'  ' |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Isiah I haven't had much luck desulphating with any power source that has rectifiers as I believe the power is to smooth due to the diode effect, so car type alternators will charge OK but not much good to desulphate unless you boil hell out of the battery and that is destructive. A better compromise is a brush style generator as it mechanically rectifies the power and tends to be spiky on the dc, its not the answer to desulphating but works better than an alternator. The high energy spike generated by a a dedicated unit is the best way to go. And there is a specific frequency that works better on each battery, but I have never found a way to work it out easily, the frequency range I have tried is 10K to 30K the higher frequency tends to work better on smaller batteries and the lower frequency on large batteries SLA and FLOODED gell cells work better around 15K. The original one I had was 5K for doing large glass case cells on 32 volt and 48 volt lighting plants with a six to one pulse ratio, also used it on 110 volt systems by cell division doing one group at a time. I now believe the smaller units are better as they are self powered and you leave them on the battery, slow on a heavily sulphated battery but have the ability to keep a battery in good condition rather than a king hit every few months. All the best Bob PS The lighting plants that had brush type generators gave a lot less trouble with sulphating than the later versions that where alternators with diode bank rectifiers. Foolin Around |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Bob, I have noticed that many RE solar systems fall over with sulphated battery cells. [Bulged sides on the cells] The solar is very smooth DC from the MPPT. A lot of care is taken by the manufacturers to keep the ripple low. Systems with inverter/chargers, and AC coupling have 100HZ current ripple, and these systems still have problems with battery sulphation. I have noticed that windmill systems with wild rectified AC charge a battery better. Gordon. become more energy aware |
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