45W Fridge voltage drop

[TijuanaKez]

Hey there,

I've been setting up solar in a little getaway camper van.

I have a 120W panel, and 2 x 130AH deep cycle batteries in parralell connected via a solar charge controller.
Mini fridge arrived yesterday, but when I hook it up and the compressor kicks in, I see the voltage on the charge controller drop slowly over then next few seconds till it drops under 10.5V and the charge controller battery protection shuts it off.
As soon as the fridge load is shut off, the battery voltage instantly reads ~13V again with the panel connected.

What could be happening?

The solar charge controller can auto detect and switch between 24/12V automatically. Would I be better off putting my batteries in series for 24V?

[littleharbor]

Sounds like you have the fridge connected to the load output on the controller. Do not use it. Connect directly to the batteries.
You have 230 amp hours of batteries. You should have 25 to 30 amps of charging power. One 120 watt panel is about 7 amps, at best.
If you want to run the refer 24/7 you will need at least 4-5 panels.
What size wires are you using to and from the controller?
What size wire are you using to power the fridge?
Is this a 12 volt fridge? 120 volt with inverter.
Is your battery bank healthy and fully charged when you are trying to power up your fridge?
Can you post any pictures of your system and battery wiring?
If your fridge will run on 24 volts and you don't need 12 volt anywhere else then, Yes wire them in series. Do not leave solar panels connected to the controller. Disconnect them first and only reconnect them after reconnecting the 24 volt battery.

[TijuanaKez]

Sounds like you have the fridge connected to the load output on the controller. Do not use it. Connect directly to the batteries.
You have 230 amp hours of batteries. You should have 25 to 30 amps of charging power. One 120 watt panel is about 7 amps, at best.
If you want to run the refer 24/7 you will need at least 4-5 panels.
What size wires are you using to and from the controller?
What size wire are you using to power the fridge?
Is this a 12 volt fridge? 120 volt with inverter.
Is your battery bank healthy and fully charged when you are trying to power up your fridge?
Can you post any pictures of your system and battery wiring?
If your fridge will run on 24 volts and you don't need 12 volt anywhere else then, Yes wire them in series. Do not leave solar panels connected to the controller. Disconnect them first and only reconnect them after reconnecting the 24 volt battery.

Hi, thanks for the reply.
I didn't realise fridge should be connected directly to batteries. Ofcourse, this way I would have to monitor the battery voltage manually to make sure they aren't over discharged by the fridge right?
It's only a small 12VDC 50L fridge, max power consumption is rated at 45W, but i imagine this would be only when set to lowest temp and is not already in a cold state.
I'm on a shoe string budget, so I'm using the red and black wire from 15A mains cable which I have a 100M roll of. Any thicker gauge would not fit into the terminals on the charge controller.
One thing I already know I'm doing wrong is using 2 different batteries (I originally believed I'd be receiving a second 130AH battery of the same type/age but it didn't happen)
I bought one 130AH battery very cheap second hand but less than 6 months old, and I've now connected a second 105AH battery I already had in parallel. I know this is not ideal for the health of the batteries, but buying 2 new batteries is way out of my shoe string budget, so it's my only choice for now.

I have some LED lights, 12V cig lighter macbook charger, and want to be able to charge 5V usb things like phones and portable speakers etc as well as the fridge.
Do I really need 4-5 panels for this? I'm going to connect the fridge through an Amp/watt meter to see what its power use is under normal conditions but i'm hoping it's no where close to 45W.

Thanks.

[littleharbor]

If you have no funds to correct your issues just continue on with what you have. The best thing you can do at this point is get more panels. Your batteries won't last too long being mismatched. get a set of matching fresh 6 volt Golf cart batteries , although I really think you need a minimum of four of them. Your charge controller should give you some info as to the state of charge of your batteries albeit not very accurate. It will tell you when your relatively full and dead, pretty well.