Do I need an Isolator?

[Hirschblazin 10+ year member]

I have heard so many different responses from different people, i wanna hear what you all have to say... I have 2 Hawker Genesis batteries in the back of my blazer, and an Autolite Platinum under the hood... I have heard that since these batteries are soo similar, an isolater would be pointless, then I have also heard that I still should have an isolator.//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

I need Opinions!!

thanks!

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[1 Loud Explorer 10+ year member]

i was told its good to have one. its like a circuit protector for you amp when running multiple batteries. or something like that.

 

[audioholic 5,000+ posts]

There are isolators, and there are relays. An isolator does just that, isolates the front and rear batts 100%, for charging and discharging. A relaying isolates the front and rear batts when the ignition is turned off, and connects them when it is turned on. Each type has its benefits and drawbacks.

Isolators' benefits include allowing completely different batt types/sizes/ages/conditions between the front and rear, and of course the ability to run the stereo with the engine off with no conern for draining the engine's batt. The drawbacks include the price, higher than a relay by about double usually, and obviously more expensive than running nothing at all. Usually around $100. An isolator also adds a slight resistance to the circuit. Older isolators use to suffer relatively large voltage drains (a volt or more), but newer ones display much less resistance. Still, more than running nothing at all.

Relays work by making or breaking the circuit between the front and rear batts, triggered off a signal wire from the ignition. When the ignition if off, the relay's contacts are open, and the rear batts are isolated from the front. This allows engine-off play time with no concern for draining the engine's batt. When the ignition is turned on, the circuit is made between the front and rear batts, and they charge/discharge as one large battery. This has the advantage over an isolator of allowing the capacity of the batt(s) under the hood to be included in the stereo's consumption, when the engine/ignition is turned on. The disadavantage is, because the batts are much of the time wired directly together in parallel, the batts must be of very similar type/size/condition to allow for an even charge/discharge, and not promote parasitic discharge due to varying internal resistances. A relay is the medium priced choice, at around $50-75.

Last option is runing no isolation device at all. This is like the relay description above when the circuit between front and rear batts is made, all batts are wired together in parrallel and act as one large batt. The advanatge of this is, obviously, the cost. Zero dollars brings it in as the cheapest option. The disadvantage is, like the relay setup, all batts in the circuit must be very similar for optimum performance. The other disadvantage to no isolation device is that you can run your engine starting battery dead while playing your stereo with the engine off, leaving you stranded and wishing you'd opted for choice number one or two.

 

[audioholic 5,000+ posts]

i was told its good to have one. its like a circuit protector for you amp when running multiple batteries. or something like that.

No.

 

[taintedplay 10+ year member]

i have some interstate battery up front. getting two of ryans huge cd batts in the back. is it worth an isolator?

 

[Hirschblazin 10+ year member]

Thanks for the detailed response!

So if i plan on not playing much with my car off what would you suggest?

 

[audioholic 5,000+ posts]

Thanks for the detailed response!So if i plan on not playing much with my car off what would you suggest?

I always like to suggest using a relay or isolator. To me it just means less chance of problems down the road. But if you really dont play the stereo with the engine off much, the option of just wiring the batts all together in parallel would probably work out okay for you.

Just make sure you fuse correctly. Remember, the wiring will have a power source (battery) at BOTH ends, so a fuse will be required at BOTH ends of the power wires between the front and rear batts.

 

[Xprime4 10+ year member]

I'm glad i bought one. First it help with battery lifetime and you can play your stereo at high volume without worrying about your front batt being too low

 

[mcsoul 10+ year member]

I'm glad i bought one. First it help with battery lifetime and you can play your stereo at high volume without worrying about your front batt being too low

I worry about running my system off battery only power for long periods because I would not want to feed my amps low voltage.

 

[Xprime4 10+ year member]

I worry about running my system off battery only power for long periods because I would not want to feed my amps low voltage.

well if you don't run full tilt with car off , it can't be that harmful. I monitor my voltage so it does drop under 11.3 (random number I feel safe with //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif ). I can get descently loud without starting the car.

Plus if i need to charge the read batt, i only start the car 5sec then shut it off. Since the isolator connect the two batt, the rear one can have a little quick charge