Community Forums

asgweb · 08-13-2020, 10:48 PM

My fridge is 1.8 amps. 700 watts of solar. 4 six-volt batteries. 40 amp mppt charger. 2000 watt inverter. Im running a swamp cooler constant 3 amps And the fridge starts up good but after about 3 hours when it restarts it kills the inverter. Not sure if its low voltage or too many watts, but I've still got like 12.2 volts. Maybe my batteries are weak. My inverter is next to the batteries with 2 ot cables. I hope this makes sense. Any ideas are appreciated.

Mr_D · 08-13-2020, 10:56 PM

12.2 volts is just under 50% charge but still should run your fridge. I have 1220 amp hr of battery but still get near 12.2 by morning with my Jenn Aire residential refer.

twinboat · 08-14-2020, 12:10 AM

If your starting with 12 .7 volts or more and are down to 12.2 volts, in 3 hours, with the inverter shut down, your batteries are overdue for replacement.

Your draw is 5 amps per hour for 3 hours or 15 AHs.
4, 6 volt batteries should give you 400 AH.

757driver · 08-14-2020, 08:18 AM

Quote:

Originally Posted by asgweb

My fridge is 1.8 amps. 700 watts of solar. 4 six-volt batteries. 40 amp mppt charger. 2000 watt inverter. Im running a swamp cooler constant 3 amps And the fridge starts up good but after about 3 hours when it restarts it kills the inverter. Not sure if its low voltage or too many watts, but I've still got like 12.2 volts. Maybe my batteries are weak. My inverter is next to the batteries with 2 ot cables. I hope this makes sense. Any ideas are appreciated.

What inverter do you have? Does it have a LBCO (low battery cutout) setting? Perhaps it is set too high and is causing your inverter to shut down.

Sweetbriar · 08-14-2020, 09:03 AM

When I first installed a residential fridge my two batteries I had at the time were older and of marginal performance AND the DC power 2 gauge cables between the batteries and inverter were on the small side for what I was demanding of the configuration. At around 12.2 or so volts the start surge of my fridge would drag the battery volts down below inverter minimum and cause a fault. The surge is somewhat quick and the voltage drop is hard to see with a digital meter but you might be able to catch it with an analog meter. I replaced the two tired batteries with four and increased the cables to 4/0 gauge. All has been good ever since.

asgweb · 08-14-2020, 04:12 PM

it's an Edecoa 2000 watt/4k peak. It's been a good inverter, not sure if it's really 2k watts. I can't set the shut off but it's set at like 11 volts.

hclarkx · 08-14-2020, 04:54 PM

Quote:

Originally Posted by asgweb

it's an Edecoa 2000 watt/4k peak. It's been a good inverter, not sure if it's really 2k watts. I can't set the shut off but it's set at like 11 volts.

Well aged batteries do have more internal resistance and the voltage will drop more than on new ones when a load is thrown on (with a bit of surge). And the batteries being down around 50% state of charge exacerbates this problem with even more internal resistance. The tip-off is the problem occurring some time after drawing energy out of the battery. As other's have said, try to capture the battery voltage during fridge start-up.

astrocamper · 08-15-2020, 03:27 PM

I would want to know your cable size and length between batteries and inverter. Voltage drop can be considerable. The cables that come with some inverters are grossly undersized.

Lead Acid batteries are better in your four battery configuration of two 6 volt batteries in series and the pair in parallel. That should work if the batteries a good.

Pappion · 08-18-2020, 01:38 PM

Hmm, maybe a Super Capacitor could help with the surge.

It would be easier to use LifeP04 Battle Born batteries. Good surge power and constant voltage output for 90% of discharge.

https://batteryuniversity.com/learn/...supercapacitor
https://www.amazon.com/MAX-Ultracapa...4&sr=8-14&th=1

asgweb · 08-25-2020, 08:15 PM

Quote:

Originally Posted by 757driver

What inverter do you have? Does it have a LBCO (low battery cutout) setting? Perhaps it is set too high and is causing your inverter to shut down.

It's an Edecoa. It has a low battery shut off the is not adjustable butI think is set at 10.5 volts.

757driver · 08-26-2020, 08:59 AM

Quote:

Originally Posted by asgweb

It's an Edecoa. It has a low battery shut off the is not adjustable butI think is set at 10.5 volts.

If your LBCO is set to 10.5v that is fine and not your problem.

asgweb · 08-31-2020, 05:21 PM

Turns out it was the heat sensor breaker. Just kinda cheap. Replaced it with a better one and it works great. probably replace all of them. I also bought a 3K watt inverter but not sure I need it.

asgweb · 08-31-2020, 05:23 PM

Quote:

Originally Posted by Sweetbriar

When I first installed a residential fridge my two batteries I had at the time were older and of marginal performance AND the DC power 2 gauge cables between the batteries and inverter were on the small side for what I was demanding of the configuration. At around 12.2 or so volts the start surge of my fridge would drag the battery volts down below inverter minimum and cause a fault. The surge is somewhat quick and the voltage drop is hard to see with a digital meter but you might be able to catch it with an analog meter. I replaced the two tired batteries with four and increased the cables to 4/0 gauge. All has been good ever since.

Just wonder how many amps your fridge is and how many watts your inverter is. Thanks.