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Connecting two inverters to one battery bank off grid

gnoeld

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Apr 11, 2022
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I am assuming I can connect a 3000 watt and a 5000 watt inverters to the bank separately. If I am correct is it best to connect them to a distribution block or to the batteries in two different locations on the bank?
 
Yup, no problem.
As long as they can support the output, many small inverters are fine.
 
My question is similar. I have very large lead acid battery bank and want to hook up two separate hybrid inverters so i can get enough solar to charge them up. I assume I can just hook both up to the buss bars from the battery bank. These are very different inverters and the AC output not connected in any way. One also will have grid AC input as back up.
Thank you
 
My question is similar. I have very large lead acid battery bank and want to hook up two separate hybrid inverters so i can get enough solar to charge them up. I assume I can just hook both up to the buss bars from the battery bank. These are very different inverters and the AC output not connected in any way. One also will have grid AC input as back up.
Thank you
Yes, no problem.
Just make sure that the total charging is not over the rating for the battery.
 
Yes, no problem.... I'm not sure about that statement. As an example I have one DEYE Sun 5000 and a Growatt SPF 5000ES; right now the battery bank is hooked to the Growatt, but would like both inverters connected to the mentioned bank. Problem is the battery only has one comm cable that came with the batteries (6 x Pylontech US3000C and 1 x US5000). I need both inverters to receive the data from the BMS, but how do I do that?

And why do I want to have both inverters connected to the battery bank? well, simply because I would like both inverters to manage the battery bank when charging and when discharging; that way (in theory), the battery bank should be able to deliver more power when the solar PV is not present and I don't want to draw any power from the grid.

And splitting the batteries so part of them feed one inverter while the rest feed the other does not seem to be a good idea....
 

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Connecting multiple loads to the same battery bank is common place. (No problem)
But I don't think that you will be able to have communication with both AIO's. I doubt that they use the same protocol.
Communication is too problematic, anyway.
It's better if you learn how to set up your own parameters for your batteries. You will end up with a better performing system.
But if that's just not your thing. You have to choose which one to communicate with. And try to match the parameters on the other.
 
My question is similar. I have very large lead acid battery bank and want to hook up two separate hybrid inverters so i can get enough solar to charge them up. I assume I can just hook both up to the buss bars from the battery bank. These are very different inverters and the AC output not connected in any way. One also will have grid AC input as back up.
Thank you
Lead acid needs absorption to get to full charge. As a lead acid battery gets closer to 100% charge, the internal resistance of the battery increases and the charge rate will slow down. Adding another charging source will not speed up the absorption charge. 100% full charge needs to be reached to prevent sulfation and reduced capacity. Equalization (depending on whether flooded, gel, AGM and manufacturer recommendations) should be performed as required. Absorption takes time, it is common to see absorption mode be entered early in the day and still never reach full charge before the sun goes down and charging ceases. Then overnight loads drop the SOC and the process repeats the next day and the battery never reaches full charge.

One method used it to split the lead acid bank allowing one half to be used while the other half is in absorption or EQ. Then switch banks and charge the other bank to full charge.

If the bank never reaches 100% on a regular basis, the lead acid bank will suffer greatly from sulfation and have reduced capacity. Eventually the bank will start dipping below 50% SOC due to the reduced capacity and the problem snowballs from there.

Lead acid works very well for something like a UPS system where the battery is held at 100% SOC and only used when needed. LFP does not like staying at 100% SOC for extended time frames but works very well in a solar system where the SOC is commonly below 100% SOC and does not require hitting 100% full charge.
 
I am assuming I can connect a 3000 watt and a 5000 watt inverters to the bank separately. If I am correct is it best to connect them to a distribution block or to the batteries in two different locations on the bank?
if you make very sure the are not connected to the same AC Panel , no problem

if your intention is 120/240 2 phase, you need the same inverter that can be paralleled, otherwise you will blow one of them
 
Thanks houseof ancients, in my case I live in Europe and only have single phase 230 V AC. I thought of using a splitter box so one cable leaves the battery bank, one cable ===>splitter box====>two cables, one for each inverter.
 
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