Second battery wiring without isolator

[rujoesmith]

Im thinking of adding a second battery but don't want to buy an isolator if i don't have to. Could I have the relay connect the two batteries when the car is on, and then disconnect them when the car is off? Will this work in the same way an isolator does?

imgur: the simple image sharer

Also, is it unhealthy for the battery to be drained completely? I listen to the stereo with the car off alot.

Thanks!

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[Spl4200]

You won't need it

 

[brian84corvette 10+ year member]

i have 4 batterys in my burb - all of them are hooked together all the time. no problems. just use a fuze on the + runs if one battery is in the rear

 

[phemps 10+ year member]

Ive never used an isolator. There really is no point when playing it with the car on, and why play with it off and sacrifice the extra voltage?

 

---------- Post added at 03:00 AM ---------- Previous post was at 02:59 AM ----------

 

not to mention the alternator is what you want to be supplying your amps current first and foremost

 

[brian84corvette 10+ year member]

i had a yellow top optima one time as a under hood battery - and my viechle had the slightest electrical drain with engine off- im talking hardly anything - but it would always completely drain my yellow top - was so bad i ended up hooking a manual cut off switch to it. got it from harbor freight for like $5

and i could just literly turn off that battery manualy to keep it from draining dead over night.

was in my 84 vette = worst corvette ever made / possibly worst car ever made also lol.

 

[phemps 10+ year member]

i had a yellow top optima one time as a under hood battery - and my viechle had the slightest electrical drain with engine off- im talking hardly anything - but it would always completely drain my yellow top - was so bad i ended up hooking a manual cut off switch to it. got it from harbor freight for like $5and i could just literly turn off that battery manualy to keep it from draining dead over night.

was in my 84 vette = worst corvette ever made / possibly worst car ever made also lol.

What exactly was draining it though? that shouldn't happen regardless of setup. unless say you had a bank with a bad battery in the back bringing them down