Does the house battery charge when the engine is running??

[JVL]

Hi - I'm a newbee here - thanks in advance for your insights and advice!I

I made the mistake of leaving the van (2023 Jayco Swift 20T) at home for several days, not connected to short power, and with the (12V compressor) fridge running (inverter was off). I thought the solar panel could keep up with the fridge load and keep the battery charged, and I've now learned it can't. Bit of a disappointment there...

When we took a trip last week and ended up having to camp without power for a night, the battery was just over 10V in the morning, and the fridge was warm.

I don't know what the battery voltage was when we left for that trip, but we did drive for about 4 hours before camping. I was surprised the battery hadn't been fully charged while driving. Obviously the solar panel will charge the battery somewhat whenever the sun is out, but I expected faster charging when the engine was on too.

Am I mistaken that the battery should charge when the engine is running???

btw - When we got home I checked that the battery and other charging systems still appear to be working fine. With a full battery charge from short power, the fridge will in fact run all night on battery only. So, although I may have damaged the battery some by fully discharging it, this is really a question of whether the battery should charge while the engine is running.

Thanks!

 

[Kevin Cooper]

Welcome to the forum.
Without knowing exactly what the voltage was before the trip and when you turned off the engine, there really is no way to answer the question for sure. We also do not know what kind and number of batteries you have.
Having said that. With engine off, take a reading of voltage at the house battery. Fully charged and settled voltage on LA batteries is 12.6 volts. Guessing lead acid. Then start the engine and take another voltage reading. Should be around 14.4 volts. If so, the alternator is charging the house battery. If you do not have a clamp on DC ammeter, you should consider one, or else install a shunt meter on the negative at the battery. Mine bluetooths to my phone. I ran our two batteries down to nothing, and started the engine and was getting 55 amps for a short while. I suspect that the 4 hours was not long enough to fully charge the battery with the refrigerator running.

 

[JVL]

Thanks so much for the great suggestions and information! I really like the BT shunt suggestion - I didn't know they made such things.

My van has 2 100AH batteries mounted underneath, which are fairly hard to get at. I'll need to get some heavy-duty ramps or something to make access easier (any suggestions??).

Thanks again!

 

[Kevin Cooper]

I tried to find the shunt I bought and use. It is no longer available. The prices on the others are 2-10 times the one I have.

 

[Jimer]

I would guess that you ran the batteries down with Fridge left on. I turn mine off if not using on the road or plugged into power. Your engine, shore power, and generator should all charge your batteries. My solar will keep my batteries charged as long as I don't leave anything on or running.

 

[Mr_Mango]

My van is the 2023 20D model, which has the larger 12v refrigerator/freezer (I think, than the 20T).

In the summer, longer days with clear skies, and temp setting at low for both refrigerator and freezer, running 24/7, the solar is able to maintain battery voltage (charging to 12.7-12.8v by sundown). In winter, shorter days and more frequent cloudy skies, solar had difficulty and have to plug into (residential) house power.

I use a Victron Smart Shunt (300a version) to monitor the batteries via bluetooth.

House batteries should be charging off van’s alternator while driving. If not, there could be issue with BIM, which is located underneath enclosed in metal box (probably midway between propane tank and batteries. (Yes, it is cramped underneath, but I’m a smaller guy, so I have no problem crawling underneath without lifting).

I recently swapped out the heavy AGM batteries for equivalent LiFePo batteries. The battery trays do tilt down to ease removal of the batteries.

 

[JVL]

This is all great information - thanks so much!! This is my first real RV, so steep learning curve and this is a great help - just learned what a BIM is, and that the battery trays tilt!! Great forum, and great contributors!!

I can see that Lipo batteries are in my future, but not quite yet...

Thanks again!

 

[Mr_Mango]

This is all great information - thanks so much!! This is my first real RV, so steep learning curve and this is a great help - just learned what a BIM is, and that the battery trays tilt!! Great forum, and great contributors!!

I can see that Lipo batteries are in my future, but not quite yet...

Thanks again!

I am 1st-time owner, as well. Although, I have the Entegra version, the models are identical to Jayco’s Swift. And, not much going on in the Entegra forum for Class B. So, I frequent this site.

I’ve learned a lot from the seasoned RV owners on here….and, inspired to take on the lithium upgrade by posts in here.

Enjoy!!

 

[JVL]

The manual I got for the Swift was an Entegra manual, which confused me at first, but made sense once I saw that Jayco owns Entegra. More surprizing was when we were shopping we also looked at the Thor Tellaro, which sure looked to us to be the same Entegra van also...

 

[Schiel1]

Keep in mind. If you run AGM batteries down to 12 volts (50%) more than 2-3 times they will most likely be shot. I did it at 11.7 volts, 3 times and killed them. I now I have Lithium batteries.