Battery Loosing Charge

**TeamRSX** · 05-02-2008, 12:49 PM

I was looking for some assistance with my battery loosing its charge.

First off i have a 2005 rsx-s and have installed a carputer with amp in my car.

I have my main power from my battery which is 8awg wire to a 60a fuse. The power then runs to my power distrobution block which i have output to my amp and computer again using 8awg wire.

About 3 weeks ago i was having the same problem. i came out one morning and my battery wouldn't start. I have very low voltage and needed a boost to start the car. This probably had to due that i had killed my battery 4-5 times while installing the system.

So, i ended up replacing the battery and with this new battery it has 85amps and 500CCA and have been running it for 3 weeks with out problem and last night the car wouldn't start.

I checked the volts and was reading just under 11 volts.

I have checked my amplifier and computer power and acc with the car off and on and is fine.

For my amp, when the car is off the ACC is 0 and power is just over 12 volts. Same thing with my computer acc and power.

With the car on the ACC line will also read over 12 volts now. Normal.

I checked the volts on my battery with the car off and reads around 12.4 (but this will drop if i leave the car off. With in a 3-4 hours it will be too low to start).

When i check the battery volts with the car on it reads around 14.3 volts.

So, i know the alternator is charging the batter and the battery is fine as its brand new.

I can't find any voltages draining my battery whiles its off, but the weird thing is it was fine for almost a month.

I am wondering if i am supplying the battery with too many AMPS and can't hold the charge. As my amp alone requires 50a fuse, computer requires 20a fuse, but not sure if a bigger battery with more amps would help.

A lot of ppl tell me to get a capacitor to put between my amp and power wire which will keep the charge, but have no experiece with them.

Not sure if a bigger battery would help like a deep cycle or maybe a capacitor, but a capacitor seems more like a temp fix.

Any suggestions?

If you need more info let me know.

**CarComp** · 05-02-2008, 01:40 PM

Forget capacitors. I have the alumapro 15 farad thing. Its useless for carputering. Its just good for a big old BUUUUUHHHHHH from your subwoofers. A cap won't do anything for your computer turn on either. If I were you, invest in a second battery. You can get a deep cycle, put it in your trunk, and use a hellraisor http://www.hellroaring.com/ battery isolator to keep it charged correctly. You didn't mention how your carpc is powered. I know that when I leave my inverter on, it will run down the battery.

Do this.. Get a multimeter and hook it up between your battery+ and carputer. If you see any amperage while its off, there is your issue. Some motherboards draw minute power while in complete "off" mode as well as keep usb powered. Put a hard switch on your carputer for when you won't be using it (like overnight). A relay can be used here.

**TeamRSX** · 05-02-2008, 01:57 PM

Originally Posted by CarComp

Forget capacitors. I have the alumapro 15 farad thing. Its useless for carputering. Its just good for a big old BUUUUUHHHHHH from your subwoofers. A cap won't do anything for your computer turn on either. If I were you, invest in a second battery. You can get a deep cycle, put it in your trunk, and use a hellraisor http://www.hellroaring.com/ battery isolator to keep it charged correctly. You didn't mention how your carpc is powered. I know that when I leave my inverter on, it will run down the battery.

Do this.. Get a multimeter and hook it up between your battery+ and carputer. If you see any amperage while its off, there is your issue. Some motherboards draw minute power while in complete "off" mode as well as keep usb powered. Put a hard switch on your carputer for when you won't be using it (like overnight). A relay can be used here.

I power my carpc with a dsatx. By default when the computer shuts down it will turn off the 5 volt rails, so dont think its from the motherboard. I have checked the volts when the car is off for both the amp and dsatx and volts are good.

I also have a kill switch for my dsatx which will kill power when i turn it off. I have this connected to the ignition and then connected to my dsatx. I turn the switch off when the car is not running just to make sure nothing is getting power from my computer. My amp turns off when the ignition is turned off.

I have a mulimeter which i have been using to check the volts, but not sure how to check the amps or if there is a setting on the mulitmeter to check.

I have checked all my devices when the car is off. I am supplying power to 12v for my lilliput and 5v for my usb powered hub and slim usb dvd through the molex and are all reading 0 volts when car is off.

Its kinda getting fustrating, but i have to check the amps to make sure it is not drawing anything as you mentioned.

I was thinking of getting a deep cycle batter as my main battery, but from reading i hear its not a good idea and should just get one for a second battery with a battery isolator which i have no experience with.

First thing i will have to do is check my amps.

Also, next to my battery i have a 60a fuse which then connects to my fused power distro block which has a 60a fuse for my amp and a 20a fuse for my dsatx.

I have tried taking out my main fuse next to the battery and it still drains. So, could i have a short somewhere? maybe i'm using too many amps for my battery and cant hold the charge.

I also have a kill switch for my dsatx to kill power to my computer if soemthing happends. I have this connected to my ignition in my harness and then connect it to my dsatx. I turn this switch off when the car is off just to make sure nothing is getting power from my carputer. I dont have a kill switch for my amp, but its connected to the ignition so it will turn off when the ignition drops.

**rijk** · 05-02-2008, 02:56 PM

Doyou have a brainstem, then set the 01 (low voltage) higher in voltage (11.2), also be sure the 5 volt rail goes off (sett 22 to 1). If you don't do that it will drain it in 4 hours, main alarm went of, because the battery was to low. It was lower than 7 volt (minimum voltmeter in the car)

Also use the VVINHIGHTHRESH 02, set this to 11.8 volts this way, your battery can recuperate. Set 15 (Vturnon) to 1
Set shut down time (TIMER1EE) 10 to 30 seconds (100030), set TIMETOKILL 11 to 90 seconds (110090)

I had a secend battery and diode-bridge in the 12 volt to the dsx12vd.

After removing the second battery and getting rid of the diode-bridge and switch of the 5 volt rail no more dead battery. Be sure to hook up the wire that tells the dsx your mobo is on or off.
After i used the settings above the mobo was switched of bij the dsx while i was installing som stoftware, and the car had more than inoth power to start. M2 has given me a flat battery when installing software.

if you don't have the brainstem, set your pods all the way to the right (clockwise) but don't overturn them! this way your timer1ee is short and your lowvolts is high (12 volts)

hoop this does the job for you.

ps the + and - of the dsx are always hooked up to my battery. only the remote is connected to the alarm and the ignision.

**TeamRSX** · 05-02-2008, 03:09 PM

Originally Posted by rijk

Doyou have a brainstem, then set the 01 (low voltage) higher in voltage (11.2), also be sure the 5 volt rail goes off (sett 22 to 1). If you don't do that it will drain it in 4 hours, main alarm went of, because the battery was to low. It was lower than 7 volt (minimum voltmeter in the car)

Also use the VVINHIGHTHRESH 02, set this to 11.8 volts this way, your battery can recuperate. Set 15 (Vturnon) to 1
Set shut down time (TIMER1EE) 10 to 30 seconds (100030), set TIMETOKILL 11 to 90 seconds (110090)

I had a secend battery and diode-bridge in the 12 volt to the dsx12vd.

After removing the second battery and getting rid of the diode-bridge and switch of the 5 volt rail no more dead battery. Be sure to hook up the wire that tells the dsx your mobo is on or off.

if you don't have the brainstem, set your pods all the way to the right (clockwise) but don't overturn them! this way your timer1ee is short and your lowvolts is high (12 volts)

hoop this does the job for you.

I do have a brainstem and have configured only a few settings.

By default it turns off the 5v rail. I have checked this and is correct
I have low volts set to 10.0volts
i have vturnon disabled. Will enable this
I have set the timer to 1 second. Shuts down immediately.

The reason why i didn't think it was the dsatx because when i turn the car off and check the vin voltages it reads 0, so didn't think much of it.

I did want to change a few settings, so i will go by what you mentioned above and see if that helps.

Thanks for elaborating on the dsatx settings for the brainstem.

**rijk** · 05-02-2008, 03:59 PM

ok, if you want to go for a second battery,
i have this one to the little battery witch powers my m2 for standby:
http://stroomwereld.nl/N_frame.html?...roomwereld.nl/

it makes sure your car battery can't be draind by the second battery

**TeamRSX** · 05-06-2008, 10:32 PM

Ok, so i was looking further into the battery drain. I also made a post of clubrsx regading how constant current can be running in the car while its off whithout drianing the battery. I was told no more than 0.07a. Anything more and it will drian your battery.

So, i finally ended up getting a multimeter that reads amp. I set it to 10a on the multimeter, disconnect the negative terminal on my battery. Put the black end of the multimeter to the negative terminal i just removed and the red end of the multimeter to the battery terminal.

When i do this it will tell me the amount of current amps and i'm reading 1.87a.

It was late and didn't have much time to check, but i did take out the two fused in my power distro block for the dsatx and amp and the amps didn't go down. I even removed the main fuse by my battery and the amps didn't go down. Weird becasue i wasn't having a draining issue until i installed the carpc.

I do have an alarm and autostart, but the draining wasn't there prior to the carpc. Could a short drain the battery? But if there was a short something wouldn't work or a fuse would be blown.

Any suggestions? Not exactly sure what else in the car would be on in order to receive this amount of current while the car is off.

**TeamRSX** · 05-06-2008, 10:40 PM

Originally Posted by CarComp

Forget capacitors. I have the alumapro 15 farad thing. Its useless for carputering. Its just good for a big old BUUUUUHHHHHH from your subwoofers. A cap won't do anything for your computer turn on either. If I were you, invest in a second battery. You can get a deep cycle, put it in your trunk, and use a hellraisor http://www.hellroaring.com/ battery isolator to keep it charged correctly. You didn't mention how your carpc is powered. I know that when I leave my inverter on, it will run down the battery.

Do this.. Get a multimeter and hook it up between your battery+ and carputer. If you see any amperage while its off, there is your issue. Some motherboards draw minute power while in complete "off" mode as well as keep usb powered. Put a hard switch on your carputer for when you won't be using it (like overnight). A relay can be used here.

I do have a kill switch for my dsatx which is tied into the acc line on the dsatx to the ignition on my harness. I usually turn it off overnight. Are relays better to use?

When you say use a multimeter to check amps for carputer and put it between battery+ and carputer. Do you mean connect the red end of the multimeter to the main power comming from my battery and connec the black end of multimeter to power for carputer thats comming out of fused power distrobution block so they are in series?

Becasue what i did is test amperage from the battery and even with the carputer fuse out it didn't go down. I will try this also so i can rule out the computer and will do the same thing with my amp. Check amperage directly from the device.

**CarComp** · 05-07-2008, 01:39 PM

If your battery is low to begin with (below nominal charge), your alternator will NEVER charge it up fully since you use the alternator's output power for your engine, lights, carputer etc. Normal (non carputer'ed) cars don't have this problem b/c the battery is only used for a short minute to start. Well, not NEVER, if you get out on the highway for an hour or two that might charge it up fully. But thats usually not happening.

I've had this "where did my battery charge go" problem for awhile now. I've found that hooking up a small motorcycle maint charger at night to top off the battery works wonders for weird problems like this.

To use a multimeter to test for amperage from your car battery, first make sure EVERYTHING in your car is off. If anything is on, you might blow the multimeter fuse. Hook up the multimeter in series with your car battery. You will have to unhook the positive terminal on the battery. The multimeter goes there similar to the following.

(BATT+)-----(MULTIMETER)-----(CAR)

Nothing will be hooked to the ground. The multimeter is going to act like a paddle wheel in a creek, measuring the flow of water (current), not how hard its pressing against the wheel (volts).

With everything off, you can get your baseline constant draw. By putting the multimeter between the battery and the car, you can see the overall picture. Then you can start testing "downstream components" such as your carputer, stereo amps, etc. Find out where the current IS drawing, and where it IS NOT. This eliminates things to worry about. Until you find out where it isn't drawing, you won't be able to eliminate anything. You have to test to each device that uses the current. Testing a wire that goes to your amps and carputer doesn't tell you if its the amps or carputer. Get it?

**TeamRSX** · 05-07-2008, 02:03 PM

Originally Posted by CarComp

If your battery is low to begin with (below nominal charge), your alternator will NEVER charge it up fully since you use the alternator's output power for your engine, lights, carputer etc. Normal (non carputer'ed) cars don't have this problem b/c the battery is only used for a short minute to start. Well, not NEVER, if you get out on the highway for an hour or two that might charge it up fully. But thats usually not happening.

I've had this "where did my battery charge go" problem for awhile now. I've found that hooking up a small motorcycle maint charger at night to top off the battery works wonders for weird problems like this.

To use a multimeter to test for amperage from your car battery, first make sure EVERYTHING in your car is off. If anything is on, you might blow the multimeter fuse. Hook up the multimeter in series with your car battery. You will have to unhook the positive terminal on the battery. The multimeter goes there similar to the following.

(BATT+)-----(MULTIMETER)-----(CAR)

Nothing will be hooked to the ground. The multimeter is going to act like a paddle wheel in a creek, measuring the flow of water (current), not how hard its pressing against the wheel (volts).

With everything off, you can get your baseline constant draw. By putting the multimeter between the battery and the car, you can see the overall picture. Then you can start testing "downstream components" such as your carputer, stereo amps, etc. Find out where the current IS drawing, and where it IS NOT. This eliminates things to worry about. Until you find out where it isn't drawing, you won't be able to eliminate anything. You have to test to each device that uses the current. Testing a wire that goes to your amps and carputer doesn't tell you if its the amps or carputer. Get it?

Thanks for the info.

Last night i checked the amps by disconnecting the negative terminal on the battery and put the multimeter in seriers to check amps.

I then did it again, but this time put the multimeter as you suggested between the battery + and carputer. It reads 1.50a. I have taken out the main fuse by my battery which then goes into my fused distro block for my amp and pc. So, after i pulled that fuse i was still reading 1.50. Actually it dropped to 1.47.

So, this tells me the amp and carputer are not draining the car, but something else. This is weird becasue i was not having a problem with draining until after i installed the pc.

I know the battery and alternator are ok, because last night i left the battery + disconnected to see if the battery would hold the charge from the alternator and it did. Woke up this morning checked my battery with the battery + off and it read 12.53. When i put the battery + back on i can see it draining, slowly but sherly.

When i turn the car on my battery reads around 14.2, when i turn the car off the voltage goes to 12.6 and if i keep the battery + off the battery will hold the charge.

I guess i will have to start pulling fuses to see what is draining. Could a bad ground or short casue battery draining?