Best way to charge a battery stored in the back of the SUV ?

truck2trail

Original poster
Member
Apr 5, 2012
39
For reasons that are long and complicated, I'd like to carry a spare battery in the back/trunk of my TB. How could I keep it charged up as we go along ? Plug it into the cigarette lighter on the back of the separator between the two front seats ?
 

STLtrailbSS

Member
Dec 4, 2011
1,617
You can just run it inline with your trucks battery. about 25-30ft of wire and a few terminals will keep you a full battery. I have an extra but its a hicap to power my amplifiers.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
How about running it off the trailer connector and the red wire?
 

CaptainXL

Member
Dec 4, 2011
2,445
truck2trail said:
For reasons that are long and complicated, I'd like to carry a spare battery in the back/trunk of my TB. How could I keep it charged up as we go along ? Plug it into the cigarette lighter on the back of the separator between the two front seats ?

You will need to run some 2 gauge wire in parallel from the original battery to the slave. Stick with the same amp/hr ratings.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
truck2trail said:
For reasons that are long and complicated, I'd like to carry a spare battery in the back/trunk of my TB. How could I keep it charged up as we go along ? Plug it into the cigarette lighter on the back of the separator between the two front seats ?


Are you planning to use it as an automatic back-up starter battery?
 

meerschm

Member
Aug 26, 2012
1,079
If you want it as a spare for the car it is in, you need an isolator. otherwise it will discharge with the one up front
 

Steveinfl

Member
Dec 6, 2011
62
Would you ground to the rear frame or join grounds ( run two wires) to the original battery? Or do both.
 

CaptainXL

Member
Dec 4, 2011
2,445
Steveinfl said:
Would you ground to the rear frame or join grounds ( run two wires) to the original battery? Or do both.

You could just ground to the frame at the battery since the battery up front it grounded to frame as well.

Isolators have three terminals. Two for the positive terminals of each battery and the other for the alternator. Grounds are connected to nearby sheetmetal or frame.
 

truck2trail

Original poster
Member
Apr 5, 2012
39
Wooluf1952 said:
Are you planning to use it as an automatic back-up starter battery?

That's one reason. Saved my bacon the other day when we had left the car at an airport for 3 weeks.

Another is to connect my high pressure air pump to it

Another is to parallel it with my inadequate (but can't make it any bigger on the frame) trailer battery when we are "boondocking" over night in the cold cold winter.
 

truck2trail

Original poster
Member
Apr 5, 2012
39
CaptainXL said:
You could just ground to the frame at the battery since the battery up front it grounded to frame as well.

Isolators have three terminals. Two for the positive terminals of each battery and the other for the alternator. Grounds are connected to nearby sheetmetal or frame.

Huh ? All three terminals are +ve ?
 

X5rdman

Member
Dec 31, 2012
20
You should not have a battery in the same compartment as the passengers, it can put out harmful fumes. You would need a special box ventilated to the outside of the TB.
 

CaptainXL

Member
Dec 4, 2011
2,445
X5rdman said:
You should not have a battery in the same compartment as the passengers, it can put out harmful fumes. You would need a special box ventilated to the outside of the TB.

Not a problem with AGM batteries.

AGM batteries only need to be vented to atmosphere, they do not need to be in a sealed box vented to the outside like wet batteries, and can be mounted on their sides or ends if needed.
 

meerschm

Member
Aug 26, 2012
1,079
my folks had a '67 ford econoline which had the battery under the driver's seat (about a foot and a half left of the engine, which was between the two front seats)

when the alternator over-drove the battery and ran it a bit dry, you could smell that something was wrong.

it did not kill me, but what did we know way back then?

I would at least put in in a plastic box to catch the acid if it gets excited. They are pretty cheap at the boat section of your local store, if no where else.
 

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