Battery Drain..need help
08-02-2015, 07:55 AM
#1
Thread Starter
Battery Drain..need help
Hey guys. I've been having this horrible battery drain for a while now. If I don't drive the car for about a week the battery isn't strong enough to turn over. I bought a brand new battery on 3-31-15 from Honda. I've done the battery drain test and really nothing has been the culprit. I do have a comptech supercharger. I also read that the keyless entry can cause this drain? Can someone elaborate on that? The car is in a shop rite now getting the bumpers redone. I should have it back in a few days. Please any suggestions would be appreciated. I've posted this all over the place and haven't gotten an straight answer. Thank you.
08-02-2015, 09:11 AM
#2
Something as simple as the trunk light staying on when it's closed will case real problems. Any non-OEM electrical accessories?
Keyless entry system, alarm system, radio battery, etc. all have parasitic draws on the battery. Regular car batteries are built to start the car -- high amperage draw for a few seconds -- not long term deep discharge. If you let a car battery get to the point of dead more than a few times it'll never recover, that's the realm of deep discharge batteries.
Measure your battery voltage after the car has sat overnight. Anything below 12v is real trouble.
Open the battery caps and add enough distilled water to just cover the plates.
Any dry plates? Dry plates are dead plates.
Charge the battery 24 hours (at least 12) and add distilled water to the fill marks.
Charge another 12-24 hours (driving time counts).
Let sit overnight.
Measure the voltage again. Hopefully it's come back.
-- Chuck
Keyless entry system, alarm system, radio battery, etc. all have parasitic draws on the battery. Regular car batteries are built to start the car -- high amperage draw for a few seconds -- not long term deep discharge. If you let a car battery get to the point of dead more than a few times it'll never recover, that's the realm of deep discharge batteries.
Measure your battery voltage after the car has sat overnight. Anything below 12v is real trouble.
Open the battery caps and add enough distilled water to just cover the plates.
Any dry plates? Dry plates are dead plates.
Charge the battery 24 hours (at least 12) and add distilled water to the fill marks.
Charge another 12-24 hours (driving time counts).
Let sit overnight.
Measure the voltage again. Hopefully it's come back.
-- Chuck
08-02-2015, 09:58 AM
#3
Thread Starter
The only non oem part is a iPhone cable hooked up
To the oem radio. After the car is off it stays "live" for 20 minutes.. The other non oem part is a relay that powers the water pump for the supercharger after cooler.. But I tested the battery with that unplugged and did a batt drain test. Doing the battery drain test I noticed when I pulled the fuse for the keyless entry it dropped a lot. But I thought it was normal. Once I get the car back I'll fully charge the battery , test it, pull the keyless fuse and see what happens. I've read that the keyless entry drains it to the point of killing the battery.
To the oem radio. After the car is off it stays "live" for 20 minutes.. The other non oem part is a relay that powers the water pump for the supercharger after cooler.. But I tested the battery with that unplugged and did a batt drain test. Doing the battery drain test I noticed when I pulled the fuse for the keyless entry it dropped a lot. But I thought it was normal. Once I get the car back I'll fully charge the battery , test it, pull the keyless fuse and see what happens. I've read that the keyless entry drains it to the point of killing the battery.
08-02-2015, 01:57 PM
#4
The G51 battery in these cars have about 35 useful amp-hours. One amp draw for one hour is an amp-hour. The parasitic draws add up in the background. 24 hours with a 500ma load sucks 1/3 of the battery capacity. A week burning 28 amp-hours (4 amp-hours a day) only takes a draw of 166ma.
There's also the alternator to consider. But it's rated at 105 amps (closer to 50a duty cycle) which should keep the battery up to charge.
The starter itself really uses little power. If it draws 600 amps (and it doesn't!) and you crank it for 6 seconds that's 3600 amp-seconds -- or one (1) amp hour. But it needs a lot of amps all at once.
Check your "at rest" battery voltage. (No use/charge for at least 12 hours.) Its key to the chart above.
-- Chuck
There's also the alternator to consider. But it's rated at 105 amps (closer to 50a duty cycle) which should keep the battery up to charge.
The starter itself really uses little power. If it draws 600 amps (and it doesn't!) and you crank it for 6 seconds that's 3600 amp-seconds -- or one (1) amp hour. But it needs a lot of amps all at once.
Check your "at rest" battery voltage. (No use/charge for at least 12 hours.) Its key to the chart above.
-- Chuck
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08-06-2015, 04:42 AM
#8
BatteryTender will keep the battery up. I use one periodically during winter storage. But it doesn't solve the battery drain problem, just disguises it. My Fords are infamous for depleted batteries. If I park at the airport for a couple of weeks I disconnect the battery with a $10 switch on the negative terminal. On the S2000 be sure to have your radio code!
If you leave a battery on charge all time you risk "boiling" it try. Check the electrolyte lever periodically to ensure this isn't happening. Defective charger boiled both my boat batteries dry one summer!
-- Chuck
If you leave a battery on charge all time you risk "boiling" it try. Check the electrolyte lever periodically to ensure this isn't happening. Defective charger boiled both my boat batteries dry one summer!
-- Chuck
08-07-2015, 12:20 PM
#9
Thread Starter
The problem was the relay on the water pump for my supercharger. The car is at Formula H with Vinny working on it. I ran out and got a replacement relay so as soon as he hooks it up he will let me know. He's 99% sure that is the issue.
