Battery low issue

[Dan_A]

Hi!

I just got a 2020 Tahoe from CarMax a few weeks ago. I just got it back on Saturday from the dealer, where I had them do a complete look-over, 36k mile service, new tires, etc. I went to start it yesterday and it wouldn’t start. I got a “battery low” message on the instrument panel. I put a meter on the battery and it only showed 7.68 volts. I ended up jumping it and put the charger on overnight. They did a battery check during the service and it checked out ok. Needless to say, it was disconcerting to see this happen.

Would anyone have and ideas how this happened? If something was inadvertently left on, wouldn’t there be an auto-shutoff feature to prevent situations like this? They replaced the tires because, although plenty of tread, there was a lot of cracking, indicating the car may have been standing for a period during the lockdowns. Could that have damaged the battery? Being a 2020 it could possibly have been original battery. The car has 37k miles.

Any ideas???

Thanks for any help!

Dan

 

[Onlyone]

The battery is bad. Replace it. I’m sure it’s the factory battery that just gave up. 7.68 volts is dead.

 

[WillCO]

A 3 year old battery is highly likely to be ready to go. I'm sure that's all it is.

The battery swap on these is a pretty easy DIY with the exception that some of the aftermarket batteries are large enough to make a very snug fit. If you take care to buy a new one with the same dimensions as the OEM you can have it in there inside of 15 minutes.

 

[Dan_A]

Great thanks! When popping the hood to jumpstart I noticed an empty spot for a second battery. Is that for redundancy, or maybe when towing? I would hate to buy a second one to have “just in case” and have it go bad from non-use. Or maybe it gets charged by the alternator in parallel with the primary battery, so maybe it would be good to have for redundancy?

Thanks a lot! I really appreciate all the advice and information

 

[tom3]

I think that second tray is either for a diesel or a police spec vehicle. Not sure you can parallel two batteries without some switching control. I'd try to keep the vehicle powered up while swapping the batteries too if possible. Seems like bad things happen sometimes if you just unhook the battery for a while.

 

[swathdiver]

Hi!

I just got a 2020 Tahoe from CarMax a few weeks ago.

Hi Dan,

That's very likely the original battery and if she was not driven a lot, the battery plates have sulfated and can either be cleaned up with a tender or just replace it with a new battery.

These vehicles depend on a proper functioning electrical system. If you make multiple short trips and or let it sit for weeks at a time the battery will become depleted. To learn how the system works, look up Regulated Voltage Control and Electronic Power Management.

When mine sits, I put a battery tender on it. For yours, get one made for AGM batteries.

 

[Dan_A]

Hi Dan,

That's very likely the original battery and if she was not driven a lot, the battery plates have sulfated and can either be cleaned up with a tender or just replace it with a new battery.

These vehicles depend on a proper functioning electrical system. If you make multiple short trips and or let it sit for weeks at a time the battery will become depleted. To learn how the system works, look up Regulated Voltage Control and Electronic Power Management.

When mine sits, I put a battery tender on it. For yours, get one made for AGM batteries.

Hey thanks a lot! I am just guessing it sat a lot during the lockdowns, because I had to have the tires replaced because they had good tread but a lot of cracking, indicative of a lot of sitting.

Hey I really appreciate your help and insight!

Take care -

Dan

 

[B-train]

Great thanks! When popping the hood to jumpstart I noticed an empty spot for a second battery. Is that for redundancy, or maybe when towing? I would hate to buy a second one to have “just in case” and have it go bad from non-use. Or maybe it gets charged by the alternator in parallel with the primary battery, so maybe it would be good to have for redundancy?

Thanks a lot! I really appreciate all the advice and information

You van definitely add another battery in parallel if you like. It is there for police vehicles and other commercial applications that call out 2 batteries. I have a 2008 and 2017. Both have the extra tray available, so I added one in my 2008 yukon that I use for overlanding.

It was very easy to install and now I have much more reserve available should I need it. There are ways to isolate them from each other so you don't end up with 2 dead batteries if something goes haywire, but it seems a bit over complicated for me to want to tackle.

 

[SpyShops212]

Get the platinum AGM battery from AutoZone so if it goes bad in 3 years from now you could go to any AutoZone and replace it. AutoZone will even change it for you. The battery does come with 3 year warranty so if it goes bad before, no matter where you’re at in the US you can get it replaced. My mistake was letting the dealer change my battery and paying $220 only to have it fail when I was out of town and could not bring back to dealer. I needed it right away so I ended up paying an additional $270 at Autozone. The dealer Delco Gold battery only lasted 11 months because I constantly clean my truck almost every day so it runs out more often but never dies. Now I have a AGM which is meant to be discharged and charged more often also has a hour or more reserve. You don’t need the dual battery unless your a TLC, camper, or have an intense sound system. The dual battery setup will cost you over $700 to add.

 

[WillCO]

I think that second tray is either for a diesel or a police spec vehicle. Not sure you can parallel two batteries without some switching control. I'd try to keep the vehicle powered up while swapping the batteries too if possible. Seems like bad things happen sometimes if you just unhook the battery for a while.

+1. If you have a battery tender or a jump device that plugs into the cigarette lighter, plug it in while you swap the battery. It will keep the systems from fully losing power and may save you a headache or two if something fails to restart or restarts when you'd rather it hadn't.