shanepotter

Alright guys im back again with more problems. A few months back i went out to start my s2000 after sitting for around a week. Put the key in the ignition, hit the start button and nothing. No power no lights, nothing. So i thought to myself, well its time for a new battery. So off to the store i went, bought a new battery and the car fired right up. I drove it around for the day and parked it in the garage. Just 2 days after replacing the battery i went outside to start my car and it cranked over for a second but failed to start. So i thought maybe my alternator is bad? Nope had its tested and it seems to be fine. After thinking about it i decided my car must be drawing power from somewhere, keep in mind im not an electrical guy so i took it to a specialist my father knows well. After leaving it with him over night he told me its drawing from my eps module and that i can buy a new one and replace it very easily. A week later my new eps module came in the mail and i installed it the following night. After installing it i let the car sit for a few days and the same problem occurred.

So before i take it back to the specialist and get charged shop fees i would just like to see if this problem has occurred to anyone else and if so what was the culprit?

windhund116

Do a parasitic draw test.

https://www.youtube.com/watch?v=KF1gijj03_0

Chuck S

Yep, Eric knows his stuff. Parasitic draw, even in the 500ma range will severely deplete the battery is a few days. This is especially important if the car is not driven regularly. 500ma x 24 hours is 12 amp hours and the typical car battery has about 50 amp hours available. 4 days of this draw will kill the battery. Starting batteries are not designed for deep discharge and you only get a few on them before the battery is damaged beyond repair.

Anything aftermarket is a prime suspect. Alarms specifically. Our S2000s have 3 leads in the fuse box for power. Always on, ignition on, lights on leads. Avoid the always on if you don't need it. You need it for an alarm, and the factory alarm and wireless lock/unlock system is always on too.

The "cigarette" lighter power outlets on my Fords are always on so I'm careful to disconnect my GPS and radar receivers when switching off. The S2000 outlet is ignition controlled so not a problem but something else could be.

As Eric points out a volt meter is your battery's best friend. Testing right after a charge or discharge is misleading. I prefer to test after a 12-24 hour "rest period" with the battery completely disconnected. Remove the negative cable!



-- Chuck

shanepotter

Hhhmmmmm well, im really not good with electrical stuff but il give it a shot with my multi meeter. I beleive the guy from the shop said its was like a 250ma power draw and that if i drive the car everyday it wont be a problem but regardless i would like to have the problem fixed.

windhund116

250mA (0.25 amp) is quite a draw. Best to find out what is doing that.

shanepotter

Ya it kills the battery pretty fast. I have been taking the terminal off over night and what not. Gonna have to find time this week to run a parasitic draw test. Thanks for the help.