Diffrence in red and yellow top for audio

[_DjScrew_ 5,000+ posts]

different batteries sometimes cancel eachother out trying to regulate the voltage to the same between the 2, so an isolator will protect burnout by not letting that occur.
I have a nice heavy duty isolator Im not using I can sell ya for $40 if you decide to use one. I was gonna put it in my car but the car is on its last legs so im not gonna waste the money in upgrading the power in it.

ah ic, so if i was to run a yellow top under the hood and 2 in the back, would i need an isolator? -- sorry for the false informations dytboi

 

[dleccord 5,000+ posts]

so the majority of the people use an isolator if there are two different brands? (ie optima and kirkland?)

 

[headless 10+ year member]

two batteries with identical resting voltages (such as the ones being discussed in this thread which are all 12.6v resting voltages) will not discharge into eachother because of a lack of an isolator. The concept that 2 batteries wired in parralel with no load on them would discharge eachother defies the laws of electricity. Self discharge is a real thing, but it would occur to any battery regardless as to weather it's wired in parrallel with another one. One battery would charge the other if it was failing, causing both to be discharged, but that is not a blanket statement but a situation where you had a destroyed battery ANYWAY that managed to take the other one with it. On the plus side, yellow top batteries can be deep discharged without ill effect, so even if your front battery does die horribly, draining your rear mounted yellowtop with it, your yellowtop will not be harmed.

Long story short, isolators are only necessary when you are PUTTING A LOAD ON THE BATTERIES while the alternator cannot charge them (read: when the engine is not running). Merely having 2 batteries plugged into eachother is not going to cause them to drain any more than they drain anyway as a result of self discharging.