My Old man has a daily driven 2018 Cadillac ATS with start/stop. It has a single AGM in the trunk, a group 94 AC Delco AGM rated at 80AH and 800 CCA.
When I recently put my 40 amp capable Meanwell rsp-500-15 on it when set at 14.7v, it took 40 amps for about 20 seconds before tapering to about 5 amps within 5 minutes. So nowhere near fully charged.
I'd estimate it would have required 2 more hours for amps to taper below 0.4a @14.7v, but My dad was going somewhere and I removed the Meanwell before it got there. I also could not get the trunk light to turn off, I saw no trigger switch anywhere, and estimated that was 0.6 amps worth of load in the figures above.
I expected it to take 40 amps for a bit longer than it did, but if it sucked up 40 amps for 20 seconds, well one does not really brake for longer than that, and some websites say that every 25 amps the alternator makes, sucks up one engine HP so say the VR asks for 14.8 when braking, and the engine is only then asked to make 50 amps just for the battery.
I wonder just how long the battery will last in such usage, hovering in the 90% charged range, with little chance of a deep cycle.
