battery keeps running down

vasyachkin

Disabled Account
2007-12-31 1:16 am
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.
 
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.
 

vasyachkin

Disabled Account
2007-12-31 1:16 am
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

Disabled Account
2007-12-31 1:16 am
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 ?
 

Flyin11

Member
2007-09-26 1:29 pm
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....
 

vasyachkin

Disabled Account
2007-12-31 1:16 am
luka said:
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

what makes you think that i will use a second battery ? i would put all the amps on one side of the relay and battery & alt on the other.

bulldogfreddy said:
Isn't the 7700 DC and not AC.

its 12V DC ... why would i need AC ?

djQUAN said:
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?

i know they shouldnt ... but they apparently do. if you check the specs for your household electronics like TV etc they all pull about 5 watts when "off"

im currently using two JL Audio Slash series amps, two Pioneer Premier PRS amps and two audiocontrol crossovers. and i have a 2000W rockford fosgate subwoofer amp that i did not install yet.

Flyin11 said:
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....

you seem to be confusing voltage and current. you cannot test for current by touching two wires like that or i would have done it myself. instead i dont really know what current my amps may be pulling but my estimate (from the time it takes them to kill the battery) its about 1/10th of an amp.
 
If you want to try to find the device drawing current, disconnect the negative battery terminal and insert an automotive headlamp in series between the battery and the terminal. Then connect your multimeter (set to DC volts) across the headlamp. When there is high current draw (more than a few amps), the lamp will light. For low current, the lamp won't light but you will be able to read voltage drop across it with the multimeter.

Ideally, you'd want to see 0v across the headlamp but you'll probably see a few millivolts. If you see a significant drop across the headlamp, begin removing one device at a time from the system until you find the one causing the current draw.

If you remove all of the amps from the circuit and there is no change, the amps are not causing the problem unless they have an intermittent fault.

You'll have to remove the hood/trunk/dome lamps or do whatever it takes to have them remain off during testing to prevent them from drawing current.
 

vasyachkin

Disabled Account
2007-12-31 1:16 am
Perry Babin said:
If you want to try to find the device drawing current, disconnect the negative battery terminal and insert an automotive headlamp in series between the battery and the terminal. Then connect your multimeter (set to DC volts) across the headlamp. When there is high current draw (more than a few amps), the lamp will light. For low current, the lamp won't light but you will be able to read voltage drop across it with the multimeter.

Ideally, you'd want to see 0v across the headlamp but you'll probably see a few millivolts. If you see a significant drop across the headlamp, begin removing one device at a time from the system until you find the one causing the current draw.

If you remove all of the amps from the circuit and there is no change, the amps are not causing the problem unless they have an intermittent fault.

You'll have to remove the hood/trunk/dome lamps or do whatever it takes to have them remain off during testing to prevent them from drawing current.

your advice makes sense. but i have been putting off the purchase of a good multimeter. mine is worth like 5 bucks and not accurate enough for this type of thing imho. plus it would be quite a hassle to connect the system through a light bulb ... but i agree that your plan would work with a half-decent multimeter and the willingness to do it.

how do you connect wires to a light bulb ? did you buy like a socket for it in radio shack or something ?

my plan is to wait until MLK holiday is over and then call the store

7700

to find out if they got the switch in stock ... i think to simply install this switch would be simpler than to find out whats wrong ... worst case scenario is it will accomplish nothing ... but how likely is this scenario ?
 

Flyin11

Member
2007-09-26 1:29 pm
vasyachkin said:


you seem to be confusing voltage and current. you cannot test for current by touching two wires like that or i would have done it myself. instead i dont really know what current my amps may be pulling but my estimate (from the time it takes them to kill the battery) its about 1/10th of an amp.

Yeah, I know all that...I guess doesn't matter. I mean if you test the voltage on your battery when the car is off the meter still reads 12.5 or around there so your battery is still putting out juice like that so it makes sense that since I would have the power wire or any wire connected to it it still puts current through it. As long as the amps only turn on with the remote wire when I turn the radio on it's all fine...