This is a parallel install being talked about. And if a series string of cells, in a parallel array, has a high impedance cell, that forces the other strings to work harder to carry the slacker's load, and ages the other strings till they are all as bad as the worse one, which usually continues to get worse, and then the race to the bottom is on.
About to buy an AGM battery bank. Anything new or economical I should consider?
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Some other engineers here recently installed several new AGM batteries at a solar site. They tried hard to make the wiring to all batteries equal. For fun I went up and measured the charge currents to each battery on a sunny day. The currents were (rounded to the nearest quarter-amp) 6.5 A, 6A, 8A, 6A, 4A, 8A, 3A, 8A, 5A, 8A, 8A, and 7A. These are all new batteries wired in a way that they thought would make the currents equal. It showed me first hand why parallel cycled batteries is a bad idea.
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It can be done but one needs to know how to wire the loom and understand the why in detail. If ones does not get the loom correct, some batteries in the bank will receive more charge, others will be discharged harder, resulting in a unbalanced battery bank. Without going into protracted detail, a unbalanced battery bank is self-destructive. Then there are variables that the best loom cannot factor out. The only way to deal with the variables is higher battery maintenance or accepting a shorter battery life span.
On the other hand, a series loom is almost .. almost idiot proof.
Last edited by Falsa_Nominis; 03-28-2018, 05:00 PM.Leave a comment:
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Some other engineers here recently installed several new AGM batteries at a solar site. They tried hard to make the wiring to all batteries equal. For fun I went up and measured the charge currents to each battery on a sunny day. The currents were (rounded to the nearest quarter-amp) 6.5 A, 6A, 8A, 6A, 4A, 8A, 3A, 8A, 5A, 8A, 8A, and 7A. These are all new batteries wired in a way that they thought would make the currents equal. It showed me first hand why parallel cycled batteries is a bad idea.Leave a comment:
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Some other engineers here recently installed several new AGM batteries at a solar site. They tried hard to make the wiring to all batteries equal. For fun I went up and measured the charge currents to each battery on a sunny day. The currents were (rounded to the nearest quarter-amp) 6.5 A, 6A, 8A, 6A, 4A, 8A, 3A, 8A, 5A, 8A, 8A, and 7A. These are all new batteries wired in a way that they thought would make the currents equal. It showed me first hand why parallel cycled batteries is a bad idea.Last edited by sdold; 03-27-2018, 12:27 PM.Leave a comment:
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I actually managed 981w of PV on the roof. so I should be ok there. I didn't know you couldn't parallel batteries. Damn. I actually came here to ask what you guys thought of 2 big lifeline 255AH 12v batteries over 4 Crown 220AH 6V batteries.
So, what do you recommend for ~500/600AH at 12V for an AGM battery bank?
I actually built a battery system with 4 x 12V 50Ah AGM type batteries all wired in parallel. They have lasted a couple of years but then again I rarely use them. If I did use them daily I would have probably replaced them with 2 x 6V 232Ah FLA type and would have spent less money and gotten a better battery system. Usually the first set of batteries are used as a learning curve and will not perform as expected.
Building an AGM battery system with a high AH rating may be difficult since the selection of high AH low voltage (4V or 6V) cells is not very big or probably cheap.Leave a comment:
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Never ever parallel batteries. Like Mike said you just signed your batteries death warrant. If you need 600 AH, buy 600 AH cells. They will not be 12 volt batteries. Either 4 or 6 volt batteries. A 12 volt 600 AH battery would weigh around 500 pounds. That is why you cannot find large 12 volt batteries over 200 AH.
FWI a 12 volt 600 AH battery needs 60 to 80 amps of charge current and that translates to 700 to 1000 watts of panels. Good luck finding a place to place all those panels.
Forget the Balancer, lead acid batteries self balance.
So, what do you recommend for ~500/600AH at 12V for an AGM battery bank?Leave a comment:
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I can appreciate this. But they will be self contained inside a van. I'd like to avoid outgassing fumes, even though I hear they're not much of an issue, and vanagon guys have dealt with it forever. What steps can I do to maintain a 6 battery bank (3 parallel in 2 series) at 660AH? I've heard AGMs are pretty maintenance free. I'll definitely by charging them off the alternator while driving, and thinking about getting a balancer as well.
Cheers
FWI a 12 volt 600 AH battery needs 60 to 80 amps of charge current and that translates to 700 to 1000 watts of panels. Good luck finding a place to place all those panels.
Forget the Balancer, lead acid batteries self balance.
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CheersLeave a comment:
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No, they are not.
What is the benefit for AGM when compare with GC?
https://www.samsclub.com/sams/durace...prod3590228.ip
GC aka Golf Cart is just a marketing name to indicate the battery is a HYBRID battery and is neither a Deep Cycle or Cranking battery. It is somewhere in between. That is why they call it a HYBRID. The Sam's battery is a low end DEKA GC battery.Last edited by Sunking; 03-22-2018, 03:50 PM.Leave a comment:
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No, they are not.
What is the benefit for AGM when compare with GC?
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Generally, neophytes to solar, destroy their first bank of batteries. Better to fry a cheap learner set of flooded batteries ($400), than expen$ive AGM batteries. ($900)Leave a comment:
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