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Generator issues

Agotte3

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Joined
Dec 1, 2022
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5
Hello,

I am having issues with my generator off switch. It was working great and then the installer came to add a second inverter which started to throw codes. I have disconnected said inverter and running off my first one. The issue I am having now is that every time I charge my batteries with my generator and then turn it off my batteries automatically drain by 40%. What could be the issue??
 
Going to need more information. What is determining the state of charge? Type of battery? Sizes of each component would help, maybe a photo or two..
 
Hello,

I am having issues with my generator off switch. It was working great and then the installer came to add a second inverter which started to throw codes. I have disconnected said inverter and running off my first one. The issue I am having now is that every time I charge my batteries with my generator and then turn it off my batteries automatically drain by 40%. What could be the issue??
If you are using voltage as your state of charge indicator, and the batteries are connected to a load, when the charging stops, the batteries will sag in voltage making the soc show a lower point.
 
There is charge voltage on the inverter which I then use a chart for my batteries to determine the percentage. My batteries are lithium. My generator is 30Amp.
 

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If you are using voltage as your state of charge indicator, and the batteries are connected to a load, when the charging stops, the batteries will sag in voltage making the soc show a lower point.
But is it normal to drop dramatically? I wasn’t having this issue a week ago. When turning off the switch I would lose about a percent but now it’s 40%
 
Depends on the load on them. You could also have some bad connections causing issues. Get an IR camera and look for hot spots. Or use your hand to see if anything is warm…
 
There is charge voltage on the inverter which I then use a chart for my batteries to determine the percentage. My batteries are lithium. My generator is 30Amp.
The bussbars in your picture are brass, known to cause hot spots and other issues…
 
It is also possible the batteries were depleted quite low, and the generator was outputting enough to show a higher voltage, but the batteries hadn’t yet reached a higher state of charge.
 
But is it normal to drop dramatically? I wasn’t having this issue a week ago. When turning off the switch I would lose about a percent but now it’s 40%
That would make me suspect a battery issue such as in a bank of batteries where one is not performing (perhaps BMS trip) in parallel with another. 2 batteries in parallel can hide one not working. Or it simply could be that the SOC had not caught up to the voltage.
 
There's a whole bunch of things that can go wrong here. You have to start from one point and work all the way back.

Issues:
*Lithium Battery: How many cells? Is it balanced? You could have one or two cells reading much higher than the others and not allowing a full charge.

*You're using voltage to determine the SOC of the battery pack. What is determining that voltage? Have you double checked to make sure each measurement is accurate? It would suck if your inverter is reading 51 volts while a good multimeter reads 54 volts.

*When checking SOC (using voltage) on a lithium battery, you must allow it to rest for at least 30 minutes to get a decently accurate reading. Charge/discharge hysteresis can throw off any measurement, especially if you go from a state of high charge amps to a state of high load draw.

*We need numbers, like how much load you're putting on the battery and the capacity of the battery bank. Drawing a 50 amp load from a 50aH battery bank is a very different thing then drawing that same 50 amp load from a 500aH bank.
 
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