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Post by GO30 on Jul 15, 2024 10:22:52 GMT 12
Im thinking rural here but Im sure the same applies wherever its batteries not just battery.
Balancing them.
Just ran into a lectronic battery balancer gizmo which spurred a discussion. In rural I have 2 x 2 12V 200ah Gels sitting as a 24V bank. Very rare to see the bank drop below 90%.
The thinking, based on sweet fuck all actual knowledge, is maybe as we dont push them they may get a bit relaxed and out of whack.
Whats the thoughts about these balancing black boxes, are they real and worth fitting or are they more, to use a term that will be thrashed silly today, a bit of a conspiracy thing?
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Post by fish on Jul 15, 2024 11:36:51 GMT 12
Couldn't comment without knowing what the black box is and exactly how it works.
I don't think there is any way to balance the batteries once they are all connected up into one big lump.
If they are good quality and nothing is wrong with each cell, then they will stay at the same voltage as they are all getting the exact same charge and discharge.
All I know is you need to get them balanced before putting them into service.
I did that by taking my 3 x 12v PbC's and sitting them on a mains powered charger to the end of the absorption charge (as in overnight or 24 hrs or something). Checked they all had the same resting voltage 24hrs after charging. To be honest that was a basic warranty check before putting them into service, to check supplied quality.
I think once they are in service, to balance them you need to take them out of service, disconnect them all and charge them to completion individually. But I'd be more interested why you would need to do that, rather than just doing it.
PS, don't quote me as I'm by no means an expert, that is just my understanding.
Second thought, you could give them a very high voltage 'balancing charge' with low current, as in like 15.5v or something. I'd be very cautious doing that with gels - I'd be very cautious doing that with any battery but esp not gels. The extra high voltage pushes through to each cell (not the proper technical term, but the one I'm going with). Again, the big question is why do you want to or need to do that?
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Post by Fogg on Jul 15, 2024 16:26:32 GMT 12
All I know about balancing is that when wiring up a parallel bank you should connect the ultimate positive and negatives from across opposite ends of the bank. Rather than across one battery.
Make sense?
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Post by GO30 on Jul 15, 2024 17:47:22 GMT 12
Don't know if I need to or should do or what. Asking around gives many varied responses so it could be one of those 'ask 100 and the average is probably about right' sort of things.
In a way Yes Mr Fogg, that does. Back in concrete today so I will check when back in nature on Wednesday.
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Post by GO30 on Jul 15, 2024 17:49:40 GMT 12
Couldn't comment without knowing what the black box is and exactly how it works. Many know what they are but most suggest the contents are magic.
Back up the voltage, I know a man who may just know...stand by
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Post by ComfortZone on Jul 15, 2024 18:18:05 GMT 12
Im thinking rural here but Im sure the same applies wherever its batteries not just battery. Balancing them. Just ran into a lectronic battery balancer gizmo which spurred a discussion. In rural I have 2 x 2 12V 200ah Gels sitting as a 24V bank. Very rare to see the bank drop below 90%. The thinking, based on sweet fuck all actual knowledge, is maybe as we dont push them they may get a bit relaxed and out of whack. Whats the thoughts about these balancing black boxes, are they real and worth fitting or are they more, to use a term that will be thrashed silly today, a bit of a conspiracy thing? Don't know anything about these balancing black boxes (link?) but thoughts from my recent experience. CZ runs a 12V system fed by 4 x 6V batteries, ie series/parallel combination. They have been getting tired over the last year and during haulout the system crashed. Testing found both batteries on the negative side had dropped cells, those on positive are fine and have been hooked up in series to keep systems running until I fork out for new batteries. Sparky said this was a little unusual as his experience was those on the positive side usually die first. My suggestion, without any science, would be every 3 to 6 months swap the batteries round, ie change over positive and negative connections from your battery bank to your switchboard which would effectively balance them.
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Post by Fogg on Jul 16, 2024 3:40:21 GMT 12
See pic below. You could make it work by simply attaching both the +ve and -ve loads to the top battery only but this would create uneven draw biased towards the top batteries. By separating the +ve and -ve loads to opposite ends of the bank - as shown in this pic - you ensure balanced flows. I can’t see the need for a gadget if you do this.  |
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Post by BatteryGuy on Jul 16, 2024 7:53:38 GMT 12
Im thinking rural here but Im sure the same applies wherever its batteries not just battery. Balancing them. Just ran into a lectronic battery balancer gizmo which spurred a discussion. In rural I have 2 x 2 12V 200ah Gels sitting as a 24V bank. Very rare to see the bank drop below 90%. The thinking, based on sweet fuck all actual knowledge, is maybe as we dont push them they may get a bit relaxed and out of whack. Whats the thoughts about these balancing black boxes, are they real and worth fitting or are they more, to use a term that will be thrashed silly today, a bit of a conspiracy thing? Balancing is a necessary evil whenever you have cells in series and want to prolong the overall life of the pack. In your case you have 2s2p battery pack. Technically as each battery has 6 cells you actually have a 12s2p pack. The parallel cells will always be at the same SoC and they self balance. But the series cells will not be without some balancing. In a small correctly built and cabled AGM stack like a 2s I personally think balancing is a waste of money. When charging, 2 of the batteries in each of the 2 parallel packs will be getting pushed harder than the other simply due to internal characteristics being different. So that battery will be having its life shortened. But also inside the battery a single cell will be being pushed harder than the rest of the cells, that cell will be having its life shortened. TLDU: for your configuration, don't waste your money. |
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Post by sloopjohnb on Jul 16, 2024 10:40:25 GMT 12
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Post by GO30 on Jul 16, 2024 13:34:47 GMT 12
See pic below. You could make it work by simply attaching both the +ve and -ve loads to the top battery only but this would create uneven draw biased towards the top batteries. By separating the +ve and -ve loads to opposite ends of the bank - as shown in this pic - you ensure balanced flows. I can’t see the need for a gadget if you do this. View AttachmentI do like that, it makes lots of sense. I'm series and parallel so will check how I set it up.
I do like Sloops simplicity. He can choose whether I'm referring to his drawing or him   |
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Post by Battery Guy on Jul 17, 2024 21:12:02 GMT 12
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Post by GO30 on Jul 19, 2024 12:35:32 GMT 12
Not sure what's going on Battery Guy but all I see is a blank post. That could easily be at my end,you're not the only one my machine is trying to cancel 
If I 'quote' you then flick it from preview to BBCode I see this -
If I copy and paste into a browser I get a chart of the worlds population growth. That's a tad random
Wowww....I can't even quote his quote without it going all stealth. To not put the BBCode into a quote do we see it now? Ah ha, excuse the niggle sussing on the fly chaps. The last 'quote' was pure code not inside anything else this time and it does not show up. So now I'm thinking it's something to do with the coding when something is quoted. The same quote but the quotie bots at each end removed
["/post/24141/thread" timestamp="1721207522" author="Battery Guy"]
Better but not quite but does seem to confirm the niggle is quote code related. I shall dive deeper elsewhere. 
Anyway,
Here's how I'm currently wired
Not sure what I can do with that except maybe swapping the top 2 for the bottom 2 occasionally.
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Post by Cantab on Jul 19, 2024 13:12:59 GMT 12
Some would say the black wire should go to the bottom negative.
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Post by fish on Jul 19, 2024 13:37:56 GMT 12
I can't see Battery Guy's last post either.
Agree with Cantab's comment on the negative position. It would balance the inherent resistance in the vertical blue wires. Currently the bottom two batts have to overcome more resistance than the top two.
What's with the fuse? that looks like a random spot for one?
Linking back to the original post, have you worked out if you actually need to balance your batteries? Is one at a different resting voltage to the rest?
The question around the black box sounds as much like consumerism and good advertising than anything else.
I.e. something has told you you need the black box. You haven't identified an issue with the batts or a problem you are trying to solve, but are trying to decide to spend money on something you have no apparent actual need for?
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Post by GO30 on Jul 19, 2024 13:58:49 GMT 12
Some would say the black wire should go to the bottom negative. Yes I can see where you are going with that and it makes sense. On to that this arvo.
No one Mr Fish. But I was sussing something and battery balancers popped up. I chatted to our in house sparky about them and if I needed one. He wasn't too sure how or why either so we thought we'd ask the audience, preferably people who deal/rely on with batteries, like boaters.
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