Parasitic draw test

[Chester11]

Hey folks:

Here is the culprit: 09 Honda CRV with a hard to start if left setting for a 3-5 days or more. It basically goes around town, and has an aftermarket remote starter. My theory is that the battery just wasn't getting charged up during short trips after being run down by the remote start hardware.

I replaced the small stock battery (51R) with a size 24 about 2 years ago, and last summer I replaced the AC condensor coil and associated relay. (The relay was burned out, probably from the compressor short cycling).

Testing the battery now after a few days sitting - it only showed about 12.4 volts - which starts it. System shows about 14.6 volts running. (I think the spec is about 14.6)

I hooked up a multimeter in-series with the battery, and expected to see a pretty big draw from the remote starter. It only shows about .02 to .03 amps at rest. (My manual shows the spec is 25 milliamps). While trying to figure out the meter, the highest I saw was .04 amps for a few seconds once everything calmed down and went to sleep.

I pulled the relays under the hood, and tested voltage drop across the fuses. The only fuse that shows voltage drop was number 23 - which is listed as backup. (I learned that this runs a lot of items, including the multiplexer, and a few modules). Even pulling that fuse only drops the amp draw to a steady .01 amps.

I really feel like I'm chasing my tail. (I could only reach about half of the under dash fuses with the meter leads, and found none with a voltage drop - and with a low battery, figured it was pointless anyway). So, I cleaned the grounds near the negative cable, and may have the battery load tested. The remote starter has a couple in-line fuses, that I may pull those just to see what happens. (The wiring is wrapped pretty nicely, it's not a best buy hack job - so I can't tell what they tapped into, and didn't want to go yanking.)

Any suggestions? I'm leaning toward battery.

 

[zrxkawboy]

The battery sounds like a reasonable suspect...your troubleshooting sounds good. One thing you could do is go to a parts store; many offer free testing of your battery/starter/charging system.

 

[Rand]

bandaid the issue with a solar battery charger if you cant put a plug in maintainer on it?

 

[brianl703]

If you connect a charger to the battery (one that shows current draw), and let it fully charge, does the current draw on the battery ever drop to zero? If not the battery has a problem, maybe a shorted cell. I had a battery that I believe had a shorted cell and it would be fine as long as you drove the car every day. Let it sit for a few days and it wouldn't start. The clue was when I checked the voltage after sitting for a few days it went down to about 10V. That's five 2 volt cells working and one shorted one, making 10V. And a shorted cell may not necessarily be completely shorted, it might just drain itself over the course of several days, like this battery was doing.

 

[CharBaby]

How long have you had this remote starter?
I suspect that it is the aftermarket remote engine starter(RES).

 

[Chester11]

How long have you had this remote starter?
I suspect that it is the aftermarket remote engine starter(RES).

Basically since the car was new - I think it was put on in 2010. The car was driven pretty steady until 2020 (15 minute trips at least 4-5 times a week).

If it matters, it's a Diehard Advance battery. (Wasn't cheap either).

 

[ZeeOSix]

Testing the battery now after a few days sitting - it only showed about 12.4 volts - which starts it. System shows about 14.6 volts running. (I think the spec is about 14.6)

I hooked up a multimeter in-series with the battery, and expected to see a pretty big draw from the remote starter. It only shows about .02 to .03 amps at rest. (My manual shows the spec is 25 milliamps).

If the parasitic current is within spec at 25 mA, and the charging voltage is also within spec, then it's gotta be the battery going south. Doing short infrequent trips don't help either.

If you have a battery charger, fully charge the battery, then check the voltage a couple days later without driving or disturbing the car (don't open doors, etc). Is the battery voltage still 12.4 volts or higher?

 

[CharBaby]

Basically since the car was new - I think it was put on in 2010. The car was driven pretty steady until 2020 (15 minute trips at least 4-5 times a week).

If it matters, it's a Diehard Advance battery. (Wasn't cheap either).

Without testing/diagnosing we really won’t know. However I have seen way too many parasitic draw issues & draining down perfectly good batteries due to aftermarket RES systems…even years later I always suspect them. And I have been correct more often than not even if this isn’t the case in your particular situation.

 

[repairman54]

Without testing/diagnosing we really won’t know. However I have seen way too many parasitic draw issues & draining down perfectly good batteries due to aftermarket RES systems…even years later I always suspect them. And I have been correct more often than not even if this isn’t the case in your particular situation.

2X That's why most shop manuals ask right up front if any aftermarket stuff has been installed.

 

[Chester11]

Thanks all - while I have the paneling off, I'll pull the remote start fuses, charge the battery and see what happens over a couple days.

 

[CharBaby]

Please keep us posted as we’ll be waiting. Even if it’s a few months.

 

[Chester11]

My friends at Advance say the battery is fine. I didn't get a good look at their tester, but it looked fancy. Pretty much expected I guess.

I

 

[Fabulous50s]

Easy test is to disconnect the battery after your trip. Wait the normal 3-4 days and then check the voltage, reconnect and see if it starts the car normally. I suspect it will.

How are your setting up your meter for the amp draw? What type/brand of meter is it?

 

[Chester11]

Easy test is to disconnect the battery after your trip. Wait the normal 3-4 days and then check the voltage, reconnect and see if it starts the car normally. I suspect it will.

How are your setting up your meter for the amp draw? What type/brand of meter is it?

Harbor Freight freebie (Centech?) hooked up in series - set to 10a.

 

[wtd]

A bad alternator can cause a parasitic draw. Have you tested that?

 

[Chester11]

A bad alternator can cause a parasitic draw. Have you tested that?

It's putting out 14+ volts under load (defroster / seat heater / high beams). Seems to be in spec or very close.

 

[kschachn]

It's putting out 14+ volts under load (defroster / seat heater / high beams). Seems to be in spec or very close.

The alternator output was good on my old BMW as well but it was causing a 4A parasitic draw when off.

 

[brianl703]

The alternator output was good on my old BMW as well but it was causing a 4A parasitic draw when off.

I had an alternator that was causing a parasitic draw. Figured out what was happening because, after the car had been off and sitting for a while, it was the warmest part under the hood.

 

[Fabulous50s]

So is your battery good?

Keep your meter on it and pull fuses until the draw goes away.

In you first post it looked like you had a nice and low draw, which is normal but the battery wouldn't turn over the car after a few days.

 

[Chester11]

So is your battery good?

Keep your meter on it and pull fuses until the draw goes away.

In you first post it looked like you had a nice and low draw, which is normal but the battery wouldn't turn over the car after a few days.

Advance says it's good. I put it on a trickle charger last weekend after cleaning the terminals and sanding down the grounds. It seems to hold a charge. It started yesterday pretty normally.

I'm going to throw a meter on it again this weekend.