How Low Should Voltage Drop On XS D3400 During Storage?

[Sutliff]

I fried batteries on a bit higher than that voltage. It's really up to you how much of a big deal you want to place on it. I've cooked my batteries, others have run for years without issue. YMMV

And as for the combo of things making a draw: Yeah it's entirely possible for that to drag down your resting voltage a bit. Little draws add up. I noticed mine changed when I got an aftermarket alarm

Interesting on the alarm, but it does make sense as it is constantly monitoring sensors, etc., ... especially if you had perimeter, & if you had it activated.

I suppose the only question I have left, & I thank you greatly for what you have shared already is: What can I do if I want to tune the charging voltage down a little? ... & right along with that, ... within the next month ... well, probably my Memorial Day Weekend project ... I will be adding a D975 to the trunk ... when charging both BATTs, I would probably want the higher voltage, no? I guess I do not know how the voltage(s) are going to go/react once a second BATT is added to the system. I am going to take both my front POS & NEG - which run to the back anyway, & take them away from the DIST BLKs for the amps, & put right on BATT, then run 1/0 POS & NEG off the D975 to the DIST BLKs for the amps. That's how I should do it, right?

PS: I have to admit that I also had to look up "YMMV". Ugh, ... I am too old!

[SnowDrifter]

Number of batteries doesn't have any effect on charge voltage

As far as reducing: call up your manufacturer and ask for either a lower voltage regulator or just go to a full external reg

[Sutliff]

Got it.