On Star draining the battery

[The_Yeti]

I pulled the fuse on my Onstar awhile ago. Don't use it and I heard about the drain before.

[HummerJim]

OnStar is a VERY common source of battery drain on the H2 and I pulled my fuse as soon as the complimentary free OnStar service was completed! There's a picture of that fuse in a previous post or someone with good photography skills can post another.

[[__--MUD--__]]

I've always had some serious doubts about the onstar module draining battery. I've never once seen someone post actual data numbers on excessive amperage usage. Its a cell phone...and you have a battery 200x the size of whats in a cell phone. It doesn't put out any more transmitting power than a regular cell phone. No way its going to kill a healthy battery in a day or even a week.

When you jump start a car, there are all kinds of electronice operating at voltages below normal operating requirements. After your battery gets fully charged up, you should disconnect it- let it sit for 15-20 minutes then hook it back up. This allows the correct voltage for everything to fire up and go operational.

[smileynialley]

MUD that was my thoughts also, but it's hard to ignore.
Battery is fine all year long.
OnStar is activated - Battery dies and drains itself everytime it's left standing.
OnStar disconnected - battery is back to normal.

[HUMTECH]

What sometimes happens is when your onstar is not activated it may wake the module up and search for a signal. When the onstar module wakes up it can draw between 250mA to 400mA which at that rate of 400mA would take approx 1 and a half days to drain a battery enough to cause a no start. Also there is typically around 35 to 50 mA draw from all other components which could take your total draw to 450mA. Now add in a remote start or other aftermarket devices and you may get up over 500mA or more. That can drain a battery overnight.

[cashville]

Yep, before I removed the fuse, 2 days without driving the H2 it was a sure thing the battery would be dead, right after I removed the fuse the problem was gone.

[HummerMann]

I had this problem after I didn't renew my OnStar service. If it sat for three days in the garage the battery would be dead. The dealer told me exactly what Hum Tech said that I should deactivate the OnStar with the fuse because it can draw current while it continually searches for a signal. I pulled the fuse on the OnStar and I've never had the drained battery problem since!