battery keeps running down

[vasyachkin]

ok i dont even have a subwoofer in yet and my battery is already dying on me

i have four amplifiers and two electronic crossovers installed but they're all relatively low power - two 300W class AB amps for treble and two 600W class D amps for midrange. there is no bass in the system yet.

every 2 weeks or so i would try to start the car and it would be dead. i thought that ain't so bad so i just bought new booster cables (longer and thicker) to make jump starting the car less of a hassle ...

problem is now its dead every time i try to start it ... so i need a new game plan lol.

im thinking of putting a remote controlled relay/switch in the trunk to disconnect everything in the trunk from 12V power when i leave the car ... problem is i dont know if such switches exist ? i would need to connect it to my zero gauge power cable and have it rated at least 250 amp (because thats the fuse rating on the subwoofer amp that i already bought).

alternatively i could buy a pair of batteries and put them in the trunk ... but im not sure if this would even work since my weak 90 amp alternator would probably not be able to charge them up and i don't have the money right now to upgrade the alternator.

any ideas what i could do ? im at the point where i can't even use the car because of this mess ...

PS: my battery is about a year old but i it has been heavily abused. that is it has been run down completely about 10 times in that year.

[Perry Babin]

The battery is probably damaged. Normal batteries can't survive too many times being drained completely.

The first thing you need to do is have your battery load tested. Auto-zone will do it for free (if I'm not mistaken).

[Jonny Hotnuts]

I have had amps in the past that would have something go wrong and cause a constant current draw even if the amp was not on.

My batteries would go dead after a few days if the truck was not started, even with a fresh battery.

Perry was correct about the battery now being likely shot after being run to zero a few too many times but I will be willing to bet that you have an amp that is causing your woes that is the root of your problem and even with a new battery you will see the same problem in the future.

[I Am An Idiot]

Midway down the page Pac-200

[vasyachkin]

thanks for the responses.

yes i figure the battery is probably damaged but i will not test it since it will not prove anything (just because battery is damaged does not mean it is the problem).

the PAC-200 seems like what i need.

question - is there any reason you recommend this particular unit ? is this a reputable company ? this unit looks a lot like the stinger 200A relay ... i have some stinger stuff and its quality is merely decent. is there any information at least on what size this relay is ?

200A continuous rating is very nice! but 300A peak is worrying me ... i don't know how much current an amp pulls when its initially connected to power ... when i put in the sub amp the five amps will have a total of 400+ amps worth of fuses in them so when they're initially connected to 12V i am afraid they will momentarily draw as much or more

im also not sure if putting two relays in parallel would be of any use since one would always make contact just before the other and most of the energy of that contacting would then end up in one of the relays ...

what do you think ?

[vasyachkin]

i think i found something better

blue sea magnetic latch series

more specifically the 7700 model

the thing draws zero current in either closed or open position because its a latching switch. it has a built in lever which allows it to be operated remotely or manually which could be convenient. it also has silver alloy contacts.

to me the important advantage is the fact that it draws no current itself. the PAC-200 on the other hand, when closed, draws 1 ampere which is more than the amps themselves draw when they're not doing anything useful.

in other words if without PAC-200 it would take a week for my battery to die then with it (closed) it would take just one day. i would then either have to use the switch every time i get out of the car (annoying) or connect it to service wire. i don't want to use the service wire for a number of reasons.

problem is 7700 costs $130 ... i wonder if its worth it ?

[luka]

Hi

Still, problem will be still there and it will get only worse. And you will have one battery that is empty everytime, not good for battery nor your alternator

[bulldogfreddy]

Isn't the 7700 DC and not AC.

[djQUAN]

you might want to check your amps and/or wiring because car amps should not draw any current when off.

what equipments are you using?

[Flyin11]

Sorry to butt in but if you use a voltage meter and check the voltage coming to your amps by touching the power and ground wires and it reads voltage does this mean that it's still drawing current when the power is off on the amps? I get a reading on the voltage meter and have for quite sometime so I don't think it's a issue but just thought I'd ask being as we are talking about current draw with the power off and I hope I'm not in any danger. Note that one amp is also connected to a cap but it didn't make any difference as I got a reading from my Alpine when it was by itself as well. Or, are you guys referring to current coming out your speaker leads? I just thought it was natural to have a amperage reading if you touch the terminals like that....