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Forum Index : Other Stuff : New 2nd hand batterys.
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Wombat Regular Member  Joined: 27/05/2011 Location: AustraliaPosts: 72 |
Hi all. I'm back and you missed me I know... ahahaha 
Well. I was playing with somw small 12V 7Ah batterys and was aching over rejuvenating them. And now I've just acquired 52X 12V 26Ah gell cells. OMG! That's a lot! So I've given up on the little ones (except for a few of the best one), and now have a major task ahead of me. I had over 100 units to choose from. Some dead, others reading low. Picked the ones reading over 13V. they range from 13.04 to 13.14 unloaded. I will first build a shelf for them, then connect 48 off for 24V and charge then with my 24V inverter/charger. My main concern is how to keep a eye on so many batterys! Oh they are all identically aged BP26-12 SLA's. I've downloaded then data sheet but they do not state charging or float voltages! The pain, the pain.. I would like to eventually use them in a 48V configuration stringing 4 in series 12 times (saving 6 for other things). So much cabling, or buss bar.. rambling again! 
Something I would really like is a circuit to check each battery to prevent individual overcharging and/or a shorting/dieing battery. Something similar to what the guys with Ultracaps are doing. I have no idea where to start and any and all suggestions/ideas will be greatly appreciated. Russ  |
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mac46 Guru  Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hello Russ, It would be by far, better to recharge these batteries each one at a time. bring them back to full charge and then recheck after a perriod of a few days to see how they are. Ganging them up together will subject the weakest battery to failure, possible fire, short, and the entire bank will only recharge at the rate of the weakest battery/ batteries. That is a great find, be patient and treat them as indivuals first. Mac46 I'm just a farmer |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yes I agree with Mac, you need to charge and test each battery separately. After a charge, let each battery sit for an hour, and then test with a good load, like a couple of 50 watt 12v down lamps. Write down the no load voltage, then apply the load and write down the new voltage reading, then keep them loaded for 10 minutes and measure the voltage again. If the voltage hasn't changed, then you need to test for longer or use a bigger load, we want to see a measureable difference of several hundred millivolts or more, but not too much. Its important to apply the same test to all batteries, and give them a top up with the charger when done You then have the data on each cell to match them up with simmilar cells. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hey Russ, Trev has just that sort of circuit you'r asking about...look into his posts in (EV)of this forum. He has a equalizing circuit that sounds just like what you want. also, be safe around these batteries, protect you'r eyes at all times. You may also want to check into the "desolphinators"...I have had some positive results. Have fun with all those batteries. Mac46 I'm just a farmer |
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| Wombat Regular Member Joined: 27/05/2011 Location: AustraliaPosts: 72 |
Giday Mac46 & Gizmo, thanks for your input. These batterys have been sitting for some time before I got to them, so they 'should' be quite good. When I finish the shelving, (need space to put them!) I'LL do as suggested and charge them individually. I have a large 100W 12V torch I can use for testing. This part alone will take over 8 1/2 hours! So It's going to take some time before there ready to go. Mac, yes, I found Trev's post and is an interesting read. I've started looking around at BMS shunt controllers and the like. They seem all to be low voltage, but I think I can come up with something. Even if it's some sort of voltage controlled relay to disconnect a string when a battery is showing a fault. I have a few desulphators already on my 720Ah 24V bank and are now doing fine thank to VK4AYQ Bob's assistance. I'LL get back with some data when available. Much to do, sleep to be had, etc,etc. 
Regards Russ |
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| Wombat Regular Member Joined: 27/05/2011 Location: AustraliaPosts: 72 |
No sleep yet, busy reading... 
Charge shunting sounds interesting... with a disconnect fail safe? Hmmm.. Can anyone find spec sheet for a 'IR 92-0182'? I've looked everywhere and can only find Chinese suppliers of these things. I'm not even sure what they are! Some sort of heavy duty transistor, mosfet or something... I have a few of them and would love to see then switch some big currents. Well, back to reading. Russ |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Talking about batteries. Our local member (federal) Ken Wyatt kept asking his constituents for suggestions how to improve things, so I asked him to comment on the following: Telecom batteries ex exchanges last 20 years but are replaced after ten AND not sold to us but to China. Reason: Web states that batts were found dumped in the bush with Telstra markings (??) leading to complaints so the local scrap yards are no longer allowed to sell them to the public. Will let this forum know what his research says. Even if federal approval is granted we have another hurdle: scrap yards have done away with retail ops at least my favourite one in Welshpool (WA) and sacked the staff as they can sell everything to China, so they do not have to bother with us littlies. This is even a bigger hurdle UNLESS those batts are auctioned off and one of us can buy a complete pallet as we cannot force the yards to employ staff. Saw a backyard dealer breaking batts (illegal, as the H2SO4 leaks into the env.)and casting diver's weights from the recovered lead and many years ago a fully clad one with sledge hammer was seen allowing the acid to simply seep in a commercial yard. I have a romantic love affair with scrap yards! Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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| Wombat Regular Member Joined: 27/05/2011 Location: AustraliaPosts: 72 |
I hate it when you half type a reply... and then somehow...??? delete it!!! 
So! I'LL try again... |
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| Wombat Regular Member Joined: 27/05/2011 Location: AustraliaPosts: 72 |
I remember now... Yes... Images on TV... Battery's in the bush!!! Must say, I wasn't impressed when I saw that... ...come to think of it... Ive been very cautious with acid from when etching PCB's with hydrochloric and sulfuric acids in the 70's. I have quite the battery haven here now. Recently adopted another 66 x Vision 6FM55's There 12V 55Ah's. That's 3630Ah @ 12V! Crazy!
So that's... 118 Battery's now!!! That's CRAZY!!! 
This is seriously getting out of hand! And if/when I stumble across more,.. Dom,.. You'll be the first to know!
I like your affinity with scrapyards, I feel the same.
Mac46, you mentioned Trev. And yes... I've been following his exploits with great interest. If he came out with a 12V version of "Relativities", he would find a customer here! (price permitting) **## (Ya listenen Trev?) 
And I also need at least 6 switchmode chargers for them. Thinking... a 2, 4, 6 and 12A switchable, with programmable cycle and Standby voltage charger. Is that 2 or 3 stage? Hmmm? Basically, I need to do what Trev is doing, but for 12V! Russ... on the run! hahahaha |
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| Wombat Regular Member Joined: 27/05/2011 Location: AustraliaPosts: 72 |
I've been cheating with charging my battery's. After they've rested for a couple of days... I measure the standing voltage of each. Place then in order of lowest to highest. Then charge then in batches of 6 to 12 in parallel. I only have 2 x 12v desulphators, so I place then towards to "lower" end of the scale and also charge from the "low" end. Theorize being, more desulphting and charge for the more flat battery's, therefor..., balancing.
It works. (for me!  ) (DO NOT PRACTCE THIS AT HOME!, NO FORESEEABILITY TAKEN!)
The battery's are only 0.1V max difference to start with anyway. To buy a welder now to build the shelf needed for the 66 newies... Here we go! Here we go! Drunk with battery's... I shake my head in disbelieve!
Keep running Russ! hahaha... |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Wombat, Most desulphinators I know of will do their work best with fully charged batteries, (in the float stage), but you can just leave them on 24-7 as long as they don't overcharge the batteries. You should "exercize" the batteries, put a light load on them for an hour or so and then recharge them right away...either in groups of 6 to 10 or 12 batteries or as the entire bank. With that many batteries it may be best to make two or three individual banks, this should help you keep track of things. (Also), if you do not have "Fuses" in the system then now is the time to install them. You have a great amount of stored power there, it only takes one mistake. Mac46 I'm just a farmer |
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