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Need some troubleshooting help [SOLVED!]

100 Proof

"Please Lord, don't let me do something stupid."
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Feb 14, 2021
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I'm helping a friend imstal and configure a solar system for his camper. He has installed the following components so far:

- Three 100-amp Battleborn batteries wired in series for a total of 300 amps at 12 volts nominal. -540 watts of Z-Amp solar panels on the roof.
-A Victron 50 amp charge controller.
-A 3000 watt Victron inverter with the built-in transfer switch.
-The 12-volt side is all wired up with 2/0 cables through a T-class fuse to the batteries with a total one-way length of approximately 30 in.

The A/C side of this appears to operate nominally when he's plugged into shore power and everything is coming through the transfer switch. However, when he tries to run A/C loads from the inverter when the shore power is disconnected, it seems to overload the system. He's getting an error message that says there's system ripple. I've read the Victron documentation regarding ripple, and his situation does not seem to be consistent with what they describe as the problem.

Specifically, when he tries to run the microwave off of the battery bank, with the bank at about 13.4V, it fires up for about 15 or 20 seconds, then the system errors out with the ripple message and the inverter drops offline. At that point, the battery bank voltage drops to just over 10 volts for several seconds, then it appears to reset and jumps back up to the mid 13s. It seems like somehow the BMSs are being overloaded, even though the total draw is well within the specifications of the battery bank.

I've successfully built other similar systems with other brands of batteries and h/w without issues. I'm perplexed. What else should we be looking at?

100 Proof
 
Three 100-amp Battleborn batteries wired in series for a total of 300 amps at 12 volts nominal.
Sounds like wired in parallel not series otherwise voltage would be 36V.

Assuming this is wired in parallel, how exactly are they connected? In a balance manner or loads connected to one end (+ and - from one battery)? Any pics?

I would expect a 300Ah battery bank with 3x 100A BMSs to power a microwave. Curious as to where you are seeing ripple error, on the inverter?
Is that a Multiplus 3000VA model?
 
Three 100-amp Battleborn batteries wired in series for a total of 300 amps at 12 volts nominal.
That would be parallel, not series. Please confirm. And it’s 3 100 amp hour, not 100 amp.

The 12-volt side is all wired up with 2/0 cables
The wires are too small. 3000W / 12V / 90% = 278A. You need 4/0 for that much current. You should also have a 400A Class T fuse.

How are the three batteries wired in parallel? Post a picture showing how it’s all connected.

Also note that A/C is air conditioning. Alternating current is AC.
 
That sounds like one or more of the the BMS is shutting down, how many amps are being pulled when it shuts down? If the wiring is not balanced you could be pulling more amps on one battery causing it to trip and then it over loads and trips the other two. I would get the 2/0 changed to 4/0 and start by checking amperage on each battery and see what each is doing when it shuts down.
 
If the wire size is too small your inverter will (in highly technical terms) starve and do weird things.
 
Dump the inverter for 2000W with the battery and solar you have. But you will not run air conditioner with what you have for battery, or wire, or solar. or 2000w inverter.
 
The a/c units on an rv use a tremendous amount of amperage to start. You can overcome that by putting an “easy start” on the a/c unit(s) but with only 300ah of batteries you won’t be able to run it for long
 
First, thank you all for jumping in!

OK. Yes I , meant wired in Parallel. I wrote that on my phone in a hurry last Sunday. Sorry
Yes, It is a Multiplus 3000VA model.
The + and - are wired from either end of the parallel string, not the same battery.
The "rippple" error shows up in his Victron phone app for the inverter.
No, he is not running air conditioning, just alternating current (AC) loads.
He is not trying to pull 3,000 Watts, just the microwave. He went with a bigger inverter so as to not run it near the max capacity.
 
I have a Multiplus 12/3000 that I recently installed and it works great. The gut check test was the microwave and it passed with flying colors. I have a 560 Ah battery bank using 4s2p 280 Ah cells.

Did you run one 2/0 to the inverter or two? The Multiplus supports two and that's what I did. No hot spots anywhere in my system.

It sound like your batteries are not wired right. They should each have equal access to the common bus bars where the inverter also connects to. If you have wire going from one battery to the next, that's your problem. Run equal length cable from each battery to the bus bars.

You won't pull 3000 continuous watts with that Multiplus. It's rated for 2400 watts. The 3000 is volt amps.
 
The outer batteries will get more charge/discharge current.

Are you actually using the chassis as a high current return path?
Nope. There is a 2/0 cable going from the batteries directly to the inverter.
 
As a follow-up, the problem has been solved! Upon further investigation, we found two of his three Battle Born batteries were exhibiting some odd results. After call to Battle Born, they wanted the batteries back, and determined that they had bad BMS's. They sent my friend two new batteries. Yesterday, after making sure the batteries were charged within .1 volts of each other, we put it all back together. Everything worked perfectly!

Thanks to everyone who jumped in with advice! You're all the best!

100 Proof
 
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