2nd batt won't stay charged

dyohn the amps r powered from the side of the isolator where the second battery is.. so it would go front batt. - isolator - 2nd batt. - then to my amps...  the battery held a charge just fine before i put itin my truck.. i have had to charge it once as my circuit breaker triped when i didn't have my subs in my truck.. so it drained after about a month.. .but i recharged it and it held a charge and that was about 3 weeks ago.. but i happen to be a very hard user on stereo equipment.. as i do have the volume up most of the time.. so this may be causing my 2nd batt not to charge..

thanx haemphyst but it is virtually impossible for me to have 2 identical batteries in my truck.. i don't have the room for a full size optima where my 2nd battery is... oh ya and the money i happen to be a college student so money is tight.. im sure u guys know how that goes

Haemphyst is (as usual) correct.  Even the Stinger propaganda that must have come with that isolator recommends identical batteries.  Having mis-matched batteries causes circulating currents between them as they try to equalize with each other, and one will inevitably be parasitically drained by the other.  Also, since your audio gear is on the downstream side of the isolator, it is possible that something in that setup is simply draining the 2nd battery every time the vehicle sits with the engine off.  Do you ever operate the stereo with the engine off?

I vaguely remember college...

There's nothing inherently wrong with using an isolator in your circuit.. if the trunk battery isn't staying charged then you might want to look for problems elsewhere. As suggested, check to make sure that something isn't draining the trunk battery when the engine is off. I would also suggest measuring charging voltage at each battery when the engine is running.

Having a different battery on each side of the isolator isn't a problem either.. however, if you have more than one battery in the trunk (ie - you're running a battery bank) it IS important to make sure that not only are these batteries the same size but also do the best you can to get batteries with the same date code. Best is to get some from the same manufacturing run.

I *am* making an assumption here.. the assumption that when the engine is running and the batteries are connected together that charging system voltage doesn't drop below around 13.5 vdc... at least not for long. As long as the batteries are seeing 13.5 vdc they aren't discharging. 

What I'm attempting to say is that using an isolator with two different types of batteries (say, a starting battery and a deep cycle battery) is extremely common and very trouble free. If you are having problems, it's likely you *have* a problem.

Jim

What I'm attempting to say is that using an isolator with two different types of batteries (say, a starting battery and a deep cycle battery) is extremely common and very trouble free. If you are having problems, it's likely you *have* a problem.

This says it all.....it's been a tested, tried, and true solution for YEARS to needing more juice, and making sure you can start your rig when it's time to go home. Get a good deep cycle for the second battery, or better yet a kinetik power cell. If you have the isolater hooked correctly....your problem should be solved!  Good luck

If your charging system voltage holds around 13.5vdc or better then your alternator is holding up.. what I was thinking of was wiring, connection, or isolator problems not allowing the second battery to charge.

Jim

so i took my battery to the shop i bought it from and they called stinger and stinger is trying to pull some shhh saying that the battery is out of warranty according to that date code on the battery.. which makes no since as i bought that damn thing only 10 months ago and it has a 24 month warranty.. so hopefully the shop can get this figured out cause i don't want to be screwed out of a battery..  

on the same side as the second battery i have a stinger 1 farad cap (got it dirty cheap that the only reason i use it)... could this be draining power from the battery?? is it possible that i did not hook the cap up right with the initial charging of the cap?? that is that only thing left that i can think of that would cause the battery to go dead... during some bass hits the voltage on the cap will drop into the 12 volt range but its only at high volumes so most of the time the charging stays about 13.5 volts...

WRT the battery age.. probably the shop had the battery sitting around for a year+ before they sold it.. I can go into the local BJ's club and see batteries there over a year old, but being sold as new.

As for the second battery, first you need to determine *why* the battery goes dead. Is it being charged - is it being drained - is it bad? Until you determine this it'll be hard to fix any possible problems. If the cap's ok it's not discharging the battery.

Gotta go to work...

Jim