Which would you choose?

 

Bronze Member
Username: Titanbk

Mansfield, CT USA

Post Number: 85
Registered: Sep-05
I know nothing about a battery isolator except I should probably get one which would be the better buy? Looking for quality. Do all of you with 2 batteries use an isolator?

http://cgi.ebay.com/Stinger-200-Amp-Battery-Relay-Isolator-5-50-Ship-SR200_W0QQi temZ5868161304QQcategoryZ50552QQrdZ1QQcmdZViewItem

or

http://cgi.ebay.com/ebaymotors/HUGE-200a-DUAL-BATTERY-ISOLATOR-GUARD-BRAND-NEW_W 0QQcmdZViewItemQQcategoryZ33573QQitemZ8039336089QQrdZ1
 

Silver Member
Username: Fandim

Reno, Nevada United State...

Post Number: 729
Registered: Jun-05
They're two totally different types. With the latter, you're going to see like at least .4-.7 volt loss, just in that connection, however, it will completely isolate the batteries, and they wont even be on the same circuit, so to speak.

With the first one, you're going to need a 12v switch for it (significantly more than your decks remote turnon can provide, mind you), and when it's turned on, your batteries will be in parallel. No significant voltage loss is associated with this type, as it's more of just a really big relay. (assuming that's how you're wiring them, and not going for a 24v setup)

The second type is probably more effective overall, as you cant forget to flip a switch, etc.. and also will let you effectively use a normal starter battery under the hood, and a deep cycle just for the audio.. (Whereas doing this with the relay type, your starter battery could still see voltage dips even when the car is running in a high wattage situation and become permanently damaged - in turn hurting your alternator, and deep cycle battery both).

If you're going to go for the first - you *should* still at least use two of the same battery type, if possible.

Seth
 

Bronze Member
Username: Titanbk

Mansfield, CT USA

Post Number: 86
Registered: Sep-05
excellent write up seth, thank you. But do I need an isolator? I am running right now without one and it seems to do okay. I was using a visonik v900hc and just bought an orion 2500d and with the visonik my voltage was dropping to dangerous levels like under 11 on hard bass hits. I have 2 batteries and a 200 amp alternator. whats causing the voltage drop?
 

Silver Member
Username: Fandim

Reno, Nevada United State...

Post Number: 730
Registered: Jun-05
Well, the visionik claims 1000w x2 @2ohms, and it's class AB. So if it's 65% efficient, it's actually pulling in the neighborhood of 3075 watts or so, and the rest is being turned into heat.

So at 14.4 volts, the Visionik is pulling 213 amps by itself at peak usage. The orion, produces it's RMS wattage at 13.8 volts, and is 80% efficient (roughly) so it pulls about 226 amps at peak usage, but produces 500 more watts.

You're not running them both at the same time are you?

Even if not, though... At peak draw, it's pulling more current than your alternator produces max, and that's excluding your vehicles electrical system draw.. So that's why you're noticing large voltage drops.

A couple more questions..

What kind of batteries are you using? Are they deep cycle?

You might want to consider a couple of Optima Yellow Tops, as they maintain a 12v charge throughout nearly all of their discharging cycle.. This can help HUGE amounts.. Since your amps wont be pulling max constantly, this will at least ensure you'll keep things at 12v or higher, and your alternator should be able to recharge them pretty well between max surges..

Also - if your batteries arent deep cycle and you're dropping their voltage, chances are they're damaged irrepairably, and causing a large drain on your alternator all by themselves (which can end up destroying your alternator, too.)
 

Silver Member
Username: Fandim

Reno, Nevada United State...

Post Number: 731
Registered: Jun-05
pardon - in the previous post I said it pulls 3075 watts, what I meant, was, it pulls the amperage it would take to produce that amount of watts if it were 100% efficient.

Also, to answer your question - I also run multiple batteries, and I dont have them isolated. I have them for the exact thing you're trying to fix - to regulate my voltage from dipping dangerously low, as my alternator dosnt kick on until 900ish RPM, so it dosnt take long at all to cause a serious voltage drop on a normal battery, even at a long red light.. But having more than one yellow top in parallel gives me more than enough juice to maintain a 12+ volt charge for a pretty decent amount of time.. (If you're going to be running your system with the car off, though, you'll definately want an isolator.)
 

Bronze Member
Username: Titanbk

Mansfield, CT USA

Post Number: 87
Registered: Sep-05
well right now I only have an optima red top and cheaped out at napa and got the "equivalent" to the optima yellow top but I am going to have to go with 2 yellow tops I know this. And if I dont need a isolator then screw that it will just make things more complicated then they have to be. I only have 4 guage cables for all my cables, including my big 3, should I go with a smaller guage? I am hopeing the orion will jump me up over 150dbs this season.
 

Bronze Member
Username: Titanbk

Mansfield, CT USA

Post Number: 89
Registered: Sep-05
grrrrr it said that last post didnt show up, whats up with this forum lately.
 

Silver Member
Username: Fandim

Reno, Nevada United State...

Post Number: 736
Registered: Jun-05
red tops will die quickly in that situation.. I actually destroyed a red top in less than 3 weeks, when I didnt realize they wernt also deep cycle..

About the other version of the deep cycle battery - that should be ok in terms of at least not destroying your battery...

Do this. Unhook the red top after driving without your car audio for a little while.. (20+ minutes to let it get really charged). Then disconnect it, let it sit for 3-4 hours, and then use a voltage meter and see what it reads at.

It should be above 12.5 volts, if it's not - you have a damaged battery that's acting as a constant drain on your deep cycle battery, as your deep cycle will have a higher voltage, and be trying to bring up the other batteries voltage to match it, which the red top wont hold..in effect wasting all that transferred electricity.
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