I have a 12v Refrigerator. Has two ends to hook up to battery. I have a 400w solar system w/ charge controller , 4 agm 12v 100ah batteries in parallel with a 3,000w inverter....which battery do I hook my frig up to? Or does it matter...dumb question probably!
12v refrigerator
- Thread starter Grey Fox
- Start date
Rednecktek
Solar Wizard
In a perfect world your batteries are all connected to some sort of bus bar, fuse block, or other central point. That central point would then go off to feed any of your 12v devices.
Ok..
So hook the busbar up to the last battery in the bank....where I connect the inverter?
Rednecktek
Solar Wizard
How are your batteries currently connected? A quick MS Paint sketch or photo will be fine.
When you have batteries in parallel you shouldn't be connecting anything to a single battery. Best case is a common bus bar, worst case would be Batt-1 Pos and Batt-4 Neg if you don't have a common connection point.
The worst thing you can do would be to connect all the batteries together and connect your loads to the same battery. That will imbalance and really mess with your batteries lifespan and capacity quickly.
When you have batteries in parallel you shouldn't be connecting anything to a single battery. Best case is a common bus bar, worst case would be Batt-1 Pos and Batt-4 Neg if you don't have a common connection point.
The worst thing you can do would be to connect all the batteries together and connect your loads to the same battery. That will imbalance and really mess with your batteries lifespan and capacity quickly.
No.
Thank you...now I am really confused...I have all kinds of friends living off grid but none with a busbar....I run everything through my inverter...but I did buy this 12v refrigerator 6.1cuft....so...I guess a busbar is what I need. Thought this was going to be easy....my charge controller pos to 1st battery pos....charge controller neg to 1st battery neg.....then pos to pos and neg to neg fo r batteries2,3 4....then inverter pos to battery 4 and neg to battery 4....can't take pic now.
Rednecktek
Solar Wizard
Aaaahhhh, ok. There's your problem. Your batteries are wired up in a way that the batteries aren't charging or discharging evenly. Your battery with the charge controller are getting all the charge first and only passing a little power to the next battery, and a little less to the 3rd battery, and almost mothing to the 4th battery.
Your 4th battery is trying to feed the inverter load, asking for help from the other batteries and getting a little from battery 3, and a little less from battery 2.
Your charge controller will see that battery 1 is full when your inverter battery is crying for help. That unbalances the batteries pretty badly and short cycles the middle batteries, deep drains the inverter battery, and keeps the 1st battery mostly full.
Ok, hopefully that explains the basic concept. You've got to get all those batteries talking to a common point, all your Pos together and all your Neg together. From that common point ALL your loads get connected.
The easiest way is like Pic 1 above where you bring everything to a common point (bus bar) and go from there.
If you don't have access to a bus bar, the next best option would be to connect your charge controller to Batt-1 Pos and Batt-4 Neg, and connect the inverter/fridge/lights/loads to Batt-1 Neg and Batt-4 Pos. That's not ideal but it will be better than what you have now.
Your 4th battery is trying to feed the inverter load, asking for help from the other batteries and getting a little from battery 3, and a little less from battery 2.
Your charge controller will see that battery 1 is full when your inverter battery is crying for help. That unbalances the batteries pretty badly and short cycles the middle batteries, deep drains the inverter battery, and keeps the 1st battery mostly full.
Ok, hopefully that explains the basic concept. You've got to get all those batteries talking to a common point, all your Pos together and all your Neg together. From that common point ALL your loads get connected.
The easiest way is like Pic 1 above where you bring everything to a common point (bus bar) and go from there.
If you don't have access to a bus bar, the next best option would be to connect your charge controller to Batt-1 Pos and Batt-4 Neg, and connect the inverter/fridge/lights/loads to Batt-1 Neg and Batt-4 Pos. That's not ideal but it will be better than what you have now.
Thank you...
Rednecktek
Solar Wizard
Don't panic, we all learn somehow.
Bluedog225
Texas
- Joined
- Nov 18, 2019
- Messages
- 2,999
You may need to run some numbers to keep from over discharging the batteries. Don’t go below 50%.
Some other members here have had some unacceptably high current drain when using 12 volts on Tri mode type RV refrigerators DC, AC and propane. With those types, propane is by far the most efficient. A dedicated 12 volt only refrigerator seems to be very efficient (refrigerant type, not Pelletier).
Yup, this mess is a learning experience.
Let’s start with pictures of what you have.
Pictures of the batteries and wiring.
Pictures of the cooler
Pictures of solar
We like pictures.
Let’s start with pictures of what you have.
Pictures of the batteries and wiring.
Pictures of the cooler
Pictures of solar
We like pictures.
Ok....it will take a little bit..thanks
Thank you so very much for your help. I am moving into our cabin in about 1 month so I rewired my batteries and inverter as you suggested....not the best but better. That will give me time to get bus bars set up and ready to use in our cabin. Now I will either buy them or make them...any suggestions.
Rednecktek
Solar Wizard
Of course I see this right after I leave the house for the weekend and have to use my phone.
Stand by, someone should be posting a diagram shortly.
Stand by, someone should be posting a diagram shortly.
Not in a big hurry...enjoy..get to me laterOf course I see this right after I leave the house for the weekend and have to use my phone.
Stand by, someone should be posting a diagram shortly.
Zwy
Emperor Of Solar
Start with this thread. https://diysolarforum.com/threads/calculation-of-parallel-string-battery-currents.37937/
If done properly, the 4 batteries will remain in balance.
I liked it so much I adopted Example 9 for my LFP large bank.
Similar threads
