I have 4 100ah 12v Global Power lifepo4 batteries in series that I use in my travel trailer 48v solar setup. These batteries are limited to 4 in series or 4 in parallel according to their documentation. I understand why the bms would limit the voltage to 48v. My question is why are the number of batteries limited in parallel? If amperage is the problem than 4 sets of batteries in series should be able to be paralleled together to create a 400 ah 48v battery bank. Yet the document reads 4 parallel or 4 series. I would sure like to know why.
Questions about series parallel battery limitations.
- Thread starter Bobert
- Start date
There are a few threads on this issue. Here's one:
diysolarforum.com
My opinion/preference is that if you need 48 volts, then build an actual 48 volt battery. Don't put four 12 volt batteries in series. I suspect that over time, you may find that one or more of your 12 volt batteries isn't getting charged right. The first battery in the series to hit a battery or cell high voltage limit will cause the other three batteries in the series to no longer get charged. In the short term, that's not a big deal. Long term, that could be a real problem. You will need to periodically verify that all four batteries are at similar states of charge. A battery balancer system could address this problem, but that's adding more complexity to a system.
As far as the limit on parallel connections, I don't see the problem. There was a paper put out by a BMS vendor (Orion?) that said parallel was bad, but there are many forum members that disagree with the conclusions in that paper. There are a lot of us on the forum that are running parallel batteries without any issues.
Why cant I run more than 4 lifepo4 batteries in parallel?
Looking at Chins or Ampere Time batteries from amazon (12v200ah models) and they both say 4s4p MAX. Why is this? How would the batteries even know if I set up for example 16 units all in parallel for a massive reserve bank? Our Lifepo4 batteries can be connected in parallels and in series...
diysolarforum.com
My opinion/preference is that if you need 48 volts, then build an actual 48 volt battery. Don't put four 12 volt batteries in series. I suspect that over time, you may find that one or more of your 12 volt batteries isn't getting charged right. The first battery in the series to hit a battery or cell high voltage limit will cause the other three batteries in the series to no longer get charged. In the short term, that's not a big deal. Long term, that could be a real problem. You will need to periodically verify that all four batteries are at similar states of charge. A battery balancer system could address this problem, but that's adding more complexity to a system.
As far as the limit on parallel connections, I don't see the problem. There was a paper put out by a BMS vendor (Orion?) that said parallel was bad, but there are many forum members that disagree with the conclusions in that paper. There are a lot of us on the forum that are running parallel batteries without any issues.
I would have preferred to buy or build a 48v battery but I have very limited space that just perfectly fit the batteries that I bought. Not really enough space to be able to see small wires. I was concerned about the batteries walking away from each other especially as they have a reputation for not being well balanced internally. To alleviate my concerns in this area I purchased a 48v lifepo4 battery balancer.There are a few threads on this issue. Here's one:
Why cant I run more than 4 lifepo4 batteries in parallel?
Looking at Chins or Ampere Time batteries from amazon (12v200ah models) and they both say 4s4p MAX. Why is this? How would the batteries even know if I set up for example 16 units all in parallel for a massive reserve bank? Our Lifepo4 batteries can be connected in parallels and in series...
My opinion/preference is that if you need 48 volts, then build an actual 48 volt battery. Don't put four 12 volt batteries in series. I suspect that over time, you may find that one or more of your 12 volt batteries isn't getting charged right. The first battery in the series to hit a battery or cell high voltage limit will cause the other three batteries in the series to no longer get charged. In the short term, that's not a big deal. Long term, that could be a real problem. You will need to periodically verify that all four batteries are at similar states of charge. A battery balancer system could address this problem, but that's adding more complexity to a system.
As far as the limit on parallel connections, I don't see the problem. There was a paper put out by a BMS vendor (Orion?) that said parallel was bad, but there are many forum members that disagree with the conclusions in that paper. There are a lot of us on the forum that are running parallel batteries without any issues.