Batteries in parallel and series

Mike134 wrote:

wa8yxm wrote:
Oh and balancing is only important when you are sucking hundreds of amps (or pushing) and even with a 2000 watt inverter at max load you won't bother the batteies the way you have 'em.

So what happens if the batteries on say the left provide 34% of the power (33+33+34=100 percent) as they discharge the voltage will drop every so slightly and the other one of the other two will provide that extra percent. So all batteries will be so close to each other in State of Charge the difference will not be something you can measure.

Now at around oh say 500 amps. THEN you might be able to notice differences.

Sounds like you've seen a phone companies power supply room as I have. There are literally hundreds of batteries connected in series parallel to give you 48V. Doesn't seem to be any issues of the batteries being "balanced" If I'm the OP don't lose any sleep about it. Your system will work fine.

X2!

Yeah, there are lots of obsessed folks that have NEVER seen a REAL battery "powerhouse" in use.. Worked for a place that had a dedicated "battery room" for their multiple 25Kw three phase "UPS" units (they also had redundant UPS units that would auto change over in case of a fault).. The battery room was 20'x30' and there certainly was not ANY "balancing" going on there.. The UPS system not only ran the computer room mainframe but the lighting and A/C units that were needed to keep the mainframes cool (mainframe was on a "false floor").

The huge UPS system was in place to give the 50KW three phase Diesel gen time to start and stabilize before transferring from UPS to gen under power outages.

Doubt the typical "RVr" is gonna draw enough or charge enough to cause enough "imbalance" to cause any "measurable" damage to their system to warrant obsessing over this subject.

wa8yxm wrote:
Oh and balancing is only important when you are sucking hundreds of amps (or pushing) and even with a 2000 watt inverter at max load you won't bother the batteies the way you have 'em.

So what happens if the batteries on say the left provide 34% of the power (33+33+34=100 percent) as they discharge the voltage will drop every so slightly and the other one of the other two will provide that extra percent. So all batteries will be so close to each other in State of Charge the difference will not be something you can measure.

Now at around oh say 500 amps. THEN you might be able to notice differences.

Sounds like you've seen a phone companies power supply room as I have. There are literally hundreds of batteries connected in series parallel to give you 48V. Doesn't seem to be any issues of the batteries being "balanced" If I'm the OP don't lose any sleep about it. Your system will work fine.

OP, the diagram you have is correct. The next diagram that Old Biscuit posted is exactly the same. #2 and #4 of The diagrams that pianotuna linked too are also effectively the same. The only "better" way is a buss bar (#3 that pianotuna linked to.) For most uses you will never see any difference between using bus bar and the diagram you originally posted.

I have my set of four wired unbalanced interconnected with 2/0 and periodically 160 amps for the inverter.
Only lasted 10 years with all in the same sad shape at the end time. Could they have lasted longer? I have doubts it would have been significant.

wa8yxm wrote:
Oh and balancing is only important when you are sucking hundreds of amps (or pushing) and even with a 2000 watt inverter at max load you won't bother the batteies the way you have 'em.

So what happens if the batteries on say the left provide 34% of the power (33+33+34=100 percent) as they discharge the voltage will drop every so slightly and the other one of the other two will provide that extra percent. So all batteries will be so close to each other in State of Charge the difference will not be something you can measure.

Now at around oh say 500 amps. THEN you might be able to notice differences.

w8xyxm that is simply not true. There are more than a few real life tests that show it makes a difference. The way the batteries charge is the issue due to their internal resistance. Using the OP's method causes an imbalance so batteries do not charge equally.

Oh and balancing is only important when you are sucking hundreds of amps (or pushing) and even with a 2000 watt inverter at max load you won't bother the batteies the way you have 'em.

So what happens if the batteries on say the left provide 34% of the power (33+33+34=100 percent) as they discharge the voltage will drop every so slightly and the other one of the other two will provide that extra percent. So all batteries will be so close to each other in State of Charge the difference will not be something you can measure.

Now at around oh say 500 amps. THEN you might be able to notice differences.

.

capacitor wrote:
Correct. That is what I drew. Is there a “better” way?

Yes.

For truly balanced wiring for an odd number of 12 volt batteries (or 2 six volts in series x three) only method number three will work.

http://www.smartgauge.co.uk/batt_con.html

The person was refering to "Balanced" hookups

Your diagram shows you did it that way.. he just could not read your diagram
Since it was "Different" from his.. You drew it right. The only question is did you do it right.

Someone suggested the inverter may have an issue. either it is hooked up backwards or wrong or it has a short.. I will admit your symptoms do fit a circuit breaker tripping.

I had/(still have) a 2000 watt inverter but the circuit breaker was only 80 amps (that's about 200 amps) so it hooked direct to the batteries via a fuse.

Thanks for the link. I see the “better” way is a buss bar.