2021 Yukon Denali - Correction, the "40w pulling the battery down" was misread of clamp meter

[DuraYuk]

No

Rule of thumb is 100mili amps needs to be looked at. But every car is different. And the tolerance range is different. Your denali has tons of modules that stay awake.

If it were mine unless I was actually seeing issues like a no start I wouldn't be bothered to be looking so deep.

 

[Fless]

I'd put an ammeter wired inline with the negative battery terminal and let everything go to sleep (just don't start it or turn anything on with this setup; the meter can't take a lot of current). Very few clamp meters are accurate at these low draw values. It's best to measure directly in Amps or milliamps.

I'd venture a guess that your "totally asleep" draw is less than 50mA. If it's much more than that, I would dig deeper.

 

[tagexpcom]

Once I discovered my clamp meters are way inaccurate I started measuring overall voltage drop over the week.

It's 12.4v -> 12.1v (~0.4v drop in 7 days). This is ~30% discharge of the 80ah battery and my calculations yield ~140ma (0.14a) average battery drain over the 7 days based on 30% discharge.

Interestingly, I see this same pattern on my 2004 Cadillac SRX - e.g. 12.3v -> 11.9v after 7 days of sitting - e.g. a 0.4v drop.

So I'm thinking that the Yukon is in a similar range of battery drop as my old car which I've been driving weekly for several years - and so I'm making a mountain out of mole hill.

It's weird - after buying this used rig, for A LOT of $, I find I'm overly alert about things as I don't have a history with the vehicle and it's been 19yrs since my last purchase. So far (7 weeks and 1,500miles) it's all looking great so I'm looking forward to relaxing a bit soon