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Power depletion problem..5 parallel Li04 50ah?

Brettxxx4

New Member
Joined
Apr 20, 2024
Messages
74
Location
Locust nc
So I’m not sure why, but I have a bank of five same type batteries that can’t seem to keep a simple modem and router overnight without depleting. I’m not sure I have it hooked up right. But I’m open to suggestions and questions.
 

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Are those batteries really in parallel? Can’t tell from the pictures, but we’ll give you the benefit of the doubt. They certainly won’t share current equally with that wiring mess. When you clean it up see if you can use equal length wires to a busbar, ideally with individual battery fuses, breakers, disconnects.

What’s the quiescent DC current of your inverter with all loads off? What’s the DC load when the modem and router are on?

What modem? What router?

I hope you have a clamp-on DC ammeter. You can see if all batteries are charging/discharging about equally and find anomalies.

How long does it take to fully charge the bank in the daytime? How do you know when/if it’s fully charged?

It’s likely that one or more of your batteries has become unbalanced and useful capacity has declined. See all the threads in this forum about using a bench power supply to charge and balance the batteries individually.

2.4KWH ought to be enough to get you through the night but the devil is in the details.
 
If it's a regular 12V router which consumes <1A i don't see how that will flatten those batteries assuming they're topped up.

Instinct tells me
- one of the batteries in parallel is draining the others.
- you're not getting the batteries charged enough
- inverter self consumption high?
 
Yeah, unless something is very wrong, that many batteries should hold electronics load for days...

Lets pull everything out and check connections.
 
Heres more pictures. I used the ampmeter but im. Ot sure what im looking for. It was not under a load

The batteries are the same and not terribly old.
 

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Ok, looks like some corrosion on some terminals, the crimps look pretry bad, but they shouldnt be causing your issues.
Cable layout isnt neat, but appears correctly routed.
I would shut everything down, and take one terminal apart, at a time clean everything with stainless steel brush, and reassemble.
See if problems go away.
I see several different types of batteries.
Are they used?
You migjt want to take them all apart and measure the voltage at each battery.
 
So I tried to make those wire connections myself. But I think I might end up purchasing factory made ones for AWG with terminal ends.
 
I have tried the ones they bundle with lugs, and they work ok, but nowhere near as versitle as the big one.
 
These batteries are different sizes, but should that make a difference? They are both LiFePO4 12.8v 50ah
 

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OK, I put new wires on the batteries only connected four of them . And still overnight. It seemed like they went from a full charge to under 12v just charging a modem which looks like it draws a 10th of an amp. I’ll show you some tests with the DC amp meter I can follow the path of 2 A as it’s hooked up in parallel and the final draw is 8 A see pictures. What am i doing wrong ?
 

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With 8.7 amps on the last cable going into the inverter, means you are consuming around 100 watts.

Either there is another load on the system or the inverter itself has very high self consumption.
 
Everything appears correct now.
However, it looks like you wired the solar panels in series, but have a combiner box in the drawing.
Can you show us what is in the combiner box, and what charge controller you have?
 
4 x 50 Ah batteries gives you 2500 watt hours so if the system is consuming 100 watts continuously then that is 25 hours of runtime.
 
Sorry, I see you have 5 50 Ah batteries. So that's 3200 watt hours. Or 32 hours of runtime at 100 watts.
 
With 8.7 amps on the last cable going into the inverter, means you are consuming around 100 watts.

Either there is another load on the system or the inverter itself has very high self consumption.
Yes, I temporarilyhooked up a oscillating fan to draw some apps so I could measure the amps .
 
OK, here’s my next test. You guys are correct I I put a temporary load on that last one. But it’s 10 AM this morning is cloudy anyway but to do a good test I just shut off the breaker to the solar panels. So if things go like they have been then By 5 PM today I should be getting an error alert on my inverter to say the voltage is lower than 12 V from my 4. 50ah batteries.
 

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