Originally Posted by LARufus
The house battery in our van is not able to hold a charge, I believe it may be original-2005. Since we brought it home last week have been keeping it plugged in which I assume is charging van Battery and house battery. If not plugged in toggle switch on dash has to be flipped (learned this the hard way) or will drain van battery.
We plan to mostly camp at campgrounds where 30a hookups are available.
How important is it to change this 4d battery? I donít want to ruin the agm van battery as it is a 2020. Is it okay to leave van plugged in when in storage?
Kinda depends. Do you have a charging isolator, or a separator relay such as the Surepower model? Also does you van have a inverter or a converter? That info should be in your manual.
It's hard to say w/o looking at your layout but guess that toggle switch is a way to force the separator to stay open or closed. If you set it to stay open (like you are saying), plugging into shore power and starting the charger will only allow the house battery to charge. In 2005 SMB was using Surepower separators on many of their builds.
I would just replace the house battery with the same AH size that is in there. Make sure the new battery is also physically sized the same if it's in a tight fit box and has the same type power lugs. When you drive, the alternator should be charging both batteries if everything is working correctly. When in storage it's best to trickle charge but if the on board charger is high amp, just periodically charge the whole system. It's best to daily monitor a higher amp charge rather than setting it to on for long periods of time. Most high amp chargers are automatic and ramp down but I'd never take a chance leaving it charging for weeks. With a standalone low amp trickle charger (sometimes called a maintenance charger) you can use those to supply a very light charge while the van is in storage.
There are also ways to permanently remove the house battery altogether but would require more info on your particular DC system.
I'm curious to how your fridge is working without a house battery when you turn off the vehicle before hooking to shore power.