Yellow Top question

[Blue Fury 10+ year member]

Taken straight from the 1st-optima-batteries.com FAQ section:

"Question: Can I hook an OPTIMA in parallel with a different battery?

Answer: No, when hooking batteries together in parallel, they should be of the same type and similar age."

Is this really the case? I read about a lot of people running a yellow top and some other battery. What bad could happen?

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[gotparts90 10+ year member]

I talked to the engineers when I used to work for johnson controls and they said best to match all the batteries down to the model and lot number. other people will say different but I guess those people must have done more extensive testing. If you do just get an isolator. If you use an isolator when at rest they will not be connected.

 

[Blue Fury 10+ year member]

But driving is what Ill be using my car for mostly..

what bad could happen?

 

[grassroots 10+ year member]

the only thing "bad" thing that i could see happening is that if they had different float voltages, one would try to balance the other out and visa versa and it would essentially shorten the life span of the batteries. at least this is what i have heard... i personally run a yellow top up front and an HC200 in the cab and have been for almost two years now without an issue...

 

[BassAddictJ 5,000+ posts]

the only thing "bad" thing that i could see happening is that if they had different float voltages, one would try to balance the other out and visa versa and it would essentially shorten the life span of the batteries. at least this is what i have heard... i personally run a yellow top up front and an HC200 in the cab and have been for almost two years now without an issue...

correct. the main issue is one battery pulling energy off the other battery to balance out. this is most likely going to happen if one battery is more particularly drained than the other. if you have a more than adequate charging system then this wont be an issue. One well respected alternator builder told me "not to even bother with an isolator" since my charging system would more than adequate for what i was running.

commonly you'll see 2 different types and sizes of bats off a stock alty (no isolator), ussually there isn't an issue, and if there was, it takes a bit of time before it is noticeable. if you have a semi stock setup like this avoid going full tilt with your rpm's low, it helps when the stock alty is pumping out as much as it can during full tilt. i've done that for years on semi stock electrical and never had any issues. i'd imagine it takes months to years for damage to be noticed, and thats if it'll happen.

you always could play it safe and get a solenoid that can handle 400amps (or less amperage if you aren't completely nuts like some of us) and put it inline between the batteries on the power wire. solenoids are switches than when you turnthe car off it'll seperate the connection of the power wires on either side of it, thus disconnecting the batteries from each other when the car is off.....

 

[Blue Fury 10+ year member]

200A alt hooked up already, big 3 in 1/0, NSB 90 in back with 1/0 from front to back.

 

[jco1385 5,000+ posts]

i run a YT and a Orbital together and zero problems

they probably want you to buy a second YT