: ONSTAR has a Back-up Battery....

Smokin' SRX
04-06-11, 10:32 AM
Just found out our SRX (and other GM's) have a Back-up battery! It is a long-life, lithium cell,located in our Onstar module. If main battery is damaged (as in a crash) the back-up can power an Onstar Crash Notification call to get help. I can't locate any other data, but I assume it could help find the SRX, in case of theft, where the thieves cut the battery cables, to thwart ONSTAR from finding the vehicle and tipping the Police. Based on my calculations, knowledge of lithium cells from my work, and description of battery, I'm guessing it would only work an hour, at most, under these conditions. Cannot find exact batt specs at this time. But beware, because.....

When we work on our SRX to change/upgrade bulbs, wiring add-ons, etc, DO NOT disconnect the main battery with the key/eng ON, OR while Retained Power is working!! (you know how radio still plays with key/eng OFF, for 10-15 minutes or till drivers door is opened to terminate.) Likewise DO NOT test your upgrades till you have re-connected main battery.

If you cause a power drain, with main batt disconnected, the lithium, mini-back-up battery is irreparably drained and will need replacing! You will get the RED lite on the OnSTAR mirror (instead of normal green) indicating SERVICE REQUIRED. It may turn Green after a drive, (nature of lithium batts to bounce back) with main batt reconnected, but do not trust it. Back-up power may be incapable of an ONSTAR call, in event of an accident. Dealer must replace it. Costs may apply.

I found some data from our Rippy, on other Caddy cars, during a Google search. Maybe he or other Dealer members can add.....

Never knew. And my daughter was recently rescued via an ONSTAR Crash Notification. Her Chevy was totaled but she had relatively minor injuries and Ambulance/Police found her quickly and accurately, and I was also notified, all thx to Onstar!


04-06-11, 06:36 PM
This is good to know. I wonder why they didn't make this a "rechargeable" lithium on a constant trickle charge. That way, if it does drain down it would automatically recharge itself.


Smokin' SRX
04-07-11, 08:17 AM
Good question. Perhaps the big price diff in the 2 ? Both at build time and replacement?? I will be looking at the Green dot in all my family's GM cars now.....


10-25-12, 09:07 AM
To disable ONSTAR all a thief has to do is put tinfoil around the antenna.

Mike Grasso
10-25-12, 12:38 PM
To disable ONSTAR all a thief has to do is put tinfoil around the antenna.

Thanks for sharing that tidbit of info, I'm sure a lot of bad guys will like it when they Google....