Community Forums

flyboy013 · 10-13-2019, 10:16 AM

Once the chassis battery is charged, how long should it maintain an acceptable voltage without needing to be charged via the charge bridge?

I have a 2018 MADP on a Spartan chassis. I find that after I’ve driven the coach for several hours, the chassis battery will be at 12.8 volts and will fall below 12.5V after about 15 hours at which time the charge bridge will kick in and charge the battery for a configurable 60 minute period. The charge bridge will then kick in about every 6 hours as the battery voltage drops back down below 12.5v volts and then is charged back up to 12.8 volts.

I have found that when I do the occasional boondocking, I often have a low chassis battery warning by morning time as the voltage has dropped even further below the 12.5 volts mark. My car can sit for months without being charged and starts right up, but the coach only maintain it state of charge for a day (give or take). So the charging of the chassis battery doesn’t seem right.

I’ve previously looked at parasitic draws and found that the Spartan Control Module (SCM) was drawing an excessive amount of current. The SCM has been replaced but I haven’t yet check for what the parasitic draw now is.

So how often should the charge bridge be kicking in? Silverleaf only allows me to configure the duration for a maximum of 60 minutes. This seems like a short period of time. Should it be longer and if so, how to I make it longer short of putting a wedge in the “battery boost” momentary switch?

ewlee · 10-13-2019, 02:22 PM

I saw your post this morning, figured someone would chime in before this. I am away from the coach right now and not able to look at the Silverleaf. My limits are set differently from yours. When the lightning bolt is illuminated, both coach and chassis batteries are being charged at the same voltage which is usually around 13.4V. The relay will stay engaged for 60 minutes then release. My chassis batteries will float for about 45 minutes, then the relay will latch again. This is because the latch voltage is anything below 12.8. This was set at factory pickup and I never changed it since. What I don't remember is where in Silverleaf to change the settings.This is just what mine does and may or may not be correct. If your voltages are not the same when the lightning bolt is displayed, your relay is bad. Maybe someone else will chime in that can look at their Silverleaf control screen.

flyboy013 · 10-13-2019, 02:43 PM

Thanks for the reply. According to Silverleaf the default is for the charge bridge to kick in when voltage drops below 12.5 for 30 seconds. The configuration is in the auto gen configuration. I can have it kick in at a higher voltage which would have the charge bridge kick in more often, but what I’m really trying to understand is what’s normal? How long can you be disconnected from power and still have a decent voltage. Hours, days, or weeks? Or do you just not disconnect for long?

My charge bridge was bad and I replaced it a few days ago.

10 fan · 10-13-2019, 09:59 PM

I don't have or know anything about Silverleaf. As far as the boost switch I installed a latching relay to keep mine connected when using AC off batteries when driving. Also a led indicator light so I know it's on.