House battery voltage under draw?
I have a new (to me motor home) and an upgrade from my old one. In my old RV, I had to check the house battery voltage manually. With the new rv, I have a switch on the wall. However, when I check t...
Forum Discussion
theoldwizard1 wrote:pianotuna wrote:
Hi tommymsw,
The batteries have never been fully charged. They need to get to 14.8 volts. Driving for 9 or 10 hours for a few days might get the job done.
It is almost impossible to fully charge a house battery bank by simply driving, especially if they are deep discharge batteries ! This has been discussed many times before.
The only way to get a 100% charge on a deep discharge battery bank is by using a top quality multi-stage charger and depending on their state of charge, it could take more than one day.
You don't need a multi-stage charger at all. You just need a single voltage charger set to the specified Absorption Voltage for the battery being charged.
The battery will go through its Bulk and Absorption stages (it might skip the Bulk stage if it is already high enough in SOC to do that) All that is then needed is to put the battery on a maintenance charge.
Beware of automatic chargers though, which mostly seem to shut off before the Absorption stage is complete. Often at about 97% SOC. This is where the multi-stage converter comes in handy (but is not essential) The PD gets to about 97% and drops to 13.6 and stays on, in hopes that the battery will get that 97-100 part done while in Float.
The best way is with the single stage at Vabs and with an ammeter, note when the battery is not absorbing any more amps, indicating it is full at 100%. Then you do the switch over to a Float charge.
