dual battery set up

paul2005tb

Silver Supporter
#1
My major summer modification is to install dual batteries so that I can have AC power via a 2kW inverter. The plan :
primary control circut
1) locate the battery isolator/relay next to the rear fuse box, connect to ACC+12 at the rear fuse box.
2) place a switch in the center console that is run in series with the rear ACC that powers the isolator so that I can fully isolate the starter battery from the backup battery.

power circuit
3) place the 2nd dual back up battery behind the rear seat in the back.
4) have the inverter on the floor behind the front passenger seat at the foot of the rear seat

Ill have photos soon.
 

littleblazer

Gold Supporter
#2
My inverter (1.5kw) mounted under the passengers seat. I didn't do dual batteries though. The size needed to run for any period of time was too large for me to sacrifice the space.

Instead of a switch to isolate though why not use an actual isolator with a time delay and voltage monitoring?
 

Reprise

Lifetime VIP Supporter
#3
Subscribing. Curious to see how well this works, especially the charging circuit for the aux battery.

Had a longer reply typed out, but will file it away for now. I may learn something here... :lightbulb: :thumbsup:
 
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paul2005tb

paul2005tb

Silver Supporter
#4
Why didnt I get the time delay circuit. Well to be honest i was unable to really understand it and the simple mechanical isolators were inexpensive and from what I have read they are incredibly reliable. Of course as I learn more I can always upgrade my system once it is place.

My thinking on the wiring is that I really only need 0 gauge for the (+) and (-) connection to the inverter from the backup battery. All of the charging of the batteries can go over 4 gauge wire.

I am thinking of putting a second primary circuit switch that is powered off of the backup battery so that in the case that my main battery is drained I can start the car from the backup. In that mode the backup will charge up the main underthehood battery and I can start the car. I know this is not the best way to do it since Im effectively charging the drained battery with the backup rather than starting the car with the backup. But it allows me to avoid putting the isolator under the hood and running a 0/2 gauge wire the full length of the vehicle. There are pros and cons to every simple solution.
 

djthumper

Administrator
#9
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paul2005tb

paul2005tb

Silver Supporter
#10
Well, once you start a job like this the scope grows and grows, Ive now decided that Im going to install a separate dedicated fuse panel for the back up battery. I am also now thinking of removing one of the rear seats, Im leaning towards removing the driverside rear seat (the longer one) and leaving only the jumper seat, rear passenger side.

Has anyone made the choice to remove one or both (left and right rear) seat modules ? Why did you do it, pros and cons ?
 
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paul2005tb

paul2005tb

Silver Supporter
#11
I would suggest using a battery with a vent tube that could be extended thru the cargo floor to reduce gases produced when charged.
I realize this is the fool proof safe solution, but Im going to offer that if you monitor your battery health and you do not leave your battery charging when it is fully charged then you dont need to vent the back up battery. My solution with a control switch to stop the charging is perfectly safe. I could add a vent tube but Im not convinced it is necessary.
 

djthumper

Administrator
#12
Unless you shut off all charging then it is kind of worthless to run devices on the secondary battery while you are driving. That should be the only time you are charging anyhow. If you go with the ISOPWR that I used it will not charge until it is below a certain voltage and it only charges while the vehicle is operating.
 

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