i have been searching this subject for days now. i have been able to find how to hook an isolator up, but how do i know what size isolator i need? i have a 95 nissan pickup 4x4. i am installing a second battery to run all of my accessories. ie....lights and siren, stereo, and multipule scene lights. i have considered upgrading my alternator, however that is very costly. the second battery that i have is a deep cycle gel. it has a phenomonal amp hour rating, i'm not positive of what it is right now. this is not your regular everyday gel cell battery either. my thing is, sometimes i leave my engine running with accessories on, however i would like to have the option of running some of my gear without the engine running.
any suggestions/directions would be great. to match up an isolator, does it go by what the second battery has to supply in amps, or does it go by what comes into the second battery amp wise. i'm considering a 90 amp isolator.
the majority of my warning lights are led, so amp draw shouldn't be a significant issue. thanks a lot, i am enjoying taking in all of the knowledge on this site. thanks.
when choosing an isolator, you need to consider how much equipment will be connected to the second battery. get an idea of how much current it will all draw, and choose an isolator with a higher amperage rating than that. thats it. if you pull more current through your isolator than it is rated, just like a fuse, it will burn up.
ok, so if i decided to run my amp off my second battery, and let's say my amp draws 60 amps, i would obviously have 30 amps to play with right? (if i use a 90 amp isolator) my amp has 2- 30 amp fuses in it. an average siren would draw say 15 amps running. that would leave me with 15 amps to "play with". so as long as all of my other accessories do not draw more than 15 amps i should be safe?
now say, when i'm running lights and siren to a call, with my stereo on, but not "pounding" obviously, the amp would draw a lot less amperage correct?
i'm thinking that a 90 amp isolator could be basically the smallest i could run.
Your probably right on that if all your electronics draw that much. does your siren really draw 15? that seems like alot to me for a siren.
as for the amp with 2 30 amp fuses, 60 amps is the most it can possibly draw, and, keep in mind that is only for a short period of time. you are also correct that the less volume your amplifier is outputing, the less current it draws.
hmmmmm. i'm going to be switching to a unitrol 9000 siren. according to federal, they suggest a 20amp fuse to be used.
so i guess that as long as i don't run everything at once, i should be ok.
thanks a lot for the advice. isolators aren't cheap, and with me having another baby on the way, i have to play mr. cheap skate. i just don't want to get burned. or burnt up!!
I did a simmilar thing with my 99 Tahoe PPV, which came factory with the dual battery option. In the case of the PPV, left and right batteries were simply paralelled.
What I chose to do was use was an automated disconnect on one battery. I just searched for one online, and was unable to find the exact model I used, ( I believe that it was a FedSig or SoundOff product) What it did was when the voltage dropped below a preset level, it simply disconnected the battery from the system.
I did this only on one battery though. So, when it is sitting with lights and sounds flying, but engine off, and the batteries drain down, one disconnects and the systems continue to run off the other battery untill it goes flat. At this point, I turn the key, hit the reset button on the disconnected battery and start the truck.
Another system that I created for a friend was a little more in depth. 97 F150. Single battery. I had done a LOT of custom sound system work for him, which he enjoyed showing off, usually running his battery flat doing so. I installed a Code Alarm CA670 remote system (remote start, keyless entry, security) This particular system has the option for remote start from an onboard system, ie, pushbutton or factory remote (swap the trunk open to pulse the CA and start the car instead, etx) Then I installed a
Soundoff AltAlert and instead of flashing a light or buzzer, it simply started the truck. He could leave the truck with sterio on (controlled by an aux switch) and it would run the battery down, and when it got low, the truck would autostart and recharge for 10min and turn back off till the voltage dropped again. As a safety, there was a switch that would change the AltAlert output to a light in the window instead of starting the truck.
The system worked great until the security system side of the CA started to flake out.
Not quite what you had in mind to start, but its a similar solution to what you are after.
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Chris
StreetFX
i'm currently looking at a cole heresy product that is basically an isolator and a battery protector in one. i'm still unsure on what i want to do here. too many options.......