NO YOU SHOULD ALWAYS ISOLATE. WITH EITHER BATTERY ISLATOR OR A HIGH AMP RELAY. if you dont isolate is some fashion when the car is off not being used the batteries will drain each other especially if they are two different makes models etc. or one has less voltage. preferable the rear or second one on the chain from alt.
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Jon
Installer/Help Technician
---coral springs florida---
mecp certification is not always needed. I have it and it has not helped me out at all. my experience out shines it.
While I do agree the batteries should match and be the same age, etc, the idea that an isolator is "always" necessary is BS. There is absolutely no reason to use an isolator unless you want to make sure you do not drain your primary battery if operating the vehicle with the engine off. Placing dual or any other combination of batteries in parallel will not harm anything as long as your alternator can keep up with charging them, especially if you always operate with the engine running.
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Support the12volt.comRight now I'm runnuing some standard starter battery(Don't recall immediately what it was) and an Optima Yellow Top in the trunk no isolator. So far I have had no problems that I'd have noticed with anything, just curious, any warnings on that before hand?
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1998 Monte Carlo w/
Eclipse CD8454
2xRockford 5.25" Power 2-way T152C
2xRockford 6"x9" Punch 3-way FRC4369
1xMemphis 16-MCH1300 5-channel
2xKicker 12" L5 Solobaric-2 Ohm