Caravan mppt controller

[JZac75#]

Hello forum members,
I have just joined your forum as it was recommend to me to question I asked a friend ( I have liked 240 or 12 volt knowledge).
Before we escaped lock down in June 2021 in Victoria ( only returned to VIC. 2 weeks ago ), on recommendation, I had a mppt controller and lithium battery installed in the caravan with 2 Anderson plugs installed on the caravan and one on the tow vehicle. 1 Ando on the van is for the solar panels.
My question is: can I have the caravan continually connected to the vehicle while travelling and therefore charging the house battery, we may not have used the house battery in van for awhile because we where connected to 240v in a c/park for days. Will the mppt controller stop the battery from overcharging the van house battery while travelling for 4/6 hours. Hope that made sense?
I ask this I was recently told it would damage the battery as I hadn’t drawn down the stored charge in the house battery  before hand! Thank you John

[cods4]

I'm guessing the anderson connection to the van is connected directly to the battery or alternator so it will be providing 13.7v or whatever to the lithium battery in the caravan?

Without seeing a drawing of the full system and knowing the exact battery and charge controller. I'd suggest it is definitely possible that the charging voltage from the vehicle could be too high for the battery and might overcharge it resulting in quicker wear of the battery.

I'd recommend you try to rely primarily on the solar panel to charge the battery and only connect to the towing vehicle when you really need to, I.e if the battery is low and there's no sun to charge it.

The charge controller should be configured to charge your battery using the correct voltages etc. Whereas the vehicle alternator is not designed to charge a lithium battery

[JZac75#]

Thanks for the reply cods4,

I’ll keep advise in mind when towing, only connect to tow vehicle after been free camping for some days and relied on the house battery.

We have a 20amp Atem Power dc to dc battery charger and 120 lithium battery.
Just found the box and it states it has over charge protection, but will work on your advise.

Thanks John

[JZac75#]

Forgot to add it’s a: 20Amp Atom Power dc to dc MPPT charger.
Thanks John

[Renate]

Usually I have the house and the truck systems separate.
I do have a tie relay that I can activate if need be.
I might turn it on for a while if I've been up late draining the house battery and I have to drive somewhere before sunrise.
Still, I usually have a good idea of how my systems are going.