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Aux Battery Saver Issues

13K views 10 replies 7 participants last post by  pablo_fil  
I wonder if your 12V battery is no longer holding its charge very well. My 38 at the moment only does a topup every 24 hours, and these usually last about 20 minutes, just like yours seem to. I don't yet have the latest update to force 6 topups a day, and it's very rare for me to see more than one topup a day. I have auto top-up battery-saver enabled. I have once gone as long as 42 hours without a topup, I think this was a glitch! I expected a topup, and the voltage suggests I ought to have got one.

My 12V is usually between 12.6V & 12.5 volts or a bit below when the topup starts.
If my 12V is at 12.6V, the daily topup then lasts 20 minutes.
If my 12V is at 12,47V, the daily topup lasts 1 hour.
If my 12V is at 12.43V, the daily topup lasts 1 hour 20 minutes.

So it looks like when the topup test is done, the voltage is used to decide how long to topup. M battery has been flattened to 8.4V twice now, and is probably damaged. I've seen a plot from a Kona in good condition, and that sat at almost exactly 13.0V between the 6 topups per day it was doing. So I'd expect a battery in good condition to be at or near 13V between topups, not dropping from 12.9 down to 12.6 like mine does between topups. I suggest yo get a new battery. Yuasa do some I believe, but note that the Delkor that Hyundai fit is a plain lead-acid, NOT an AGM battery! AGMs want a different charging voltage than plain lead-acid I believe.