MOTORHOME LiPo CHARGING QUESTION

[Wheels66]

Is it possible to have LiPo coach batteries on your 12v system charged by:

1. Solar
2. Shore power
3. Engine alternator
4. installed coach generator

1 and 2 are pretty clear, I’m not so sure with 3 and 4.

What components would be required?

New to the forums so please be gentle “there are no stupid questions, only inquisitive idiots”.

 

[Bobert]

Is it possible to have LiPo coach batteries on your 12v system charged by:

1. Solar
2. Shore power
3. Engine alternator
4. installed coach generator

1 and 2 are pretty clear, I’m not so sure with 3 and 4.

What components would be required?

New to the forums so please be gentle “there are no stupid questions, only inquisitive idiots”.

All 4 are possible 1 is done with a charge controller 2 and 4 can be done with a victron multiplus. 3 is the most difficult and the solution varies a lot depending upon how much amperage you want.

 

[SeaGal]

Is it possible to have LiPo coach batteries on your 12v system charged by:

Do you already have LiPo batteries? If not:-

a) you'll find more options for charging LiFePO4 batteries.
b) Unlike LiPo, LiFePO4 chemistry has a negative temp co-efficient, so won't catch fire if your charging mechanism fails. Personally I wouldn't want LiPo's near where I sleep, but YMMV.

 

[justinm001]

4 is the same as 2, just depends on inbound wiring and using a transfer switch or not.

3 is complicated. DC to dc converter is usually best.

 

[Wheels66]

Thank you all. If the the coach already has the ability to charge the SLAB battery from shore power, the generator and the alternator, what components would need to be be swapped to be able or add the solar? Am I basically looking at replacing the transfer switch and any other conversion components?

 

[HRTKD]

Shore power and generator should go through a transfer switch already. The feed from the transfer switch would then go to an inverter/charger that handles charging the batteries from those two sources. The solar input can be independent of the inverter/charger but there are all-in-one systems that include solar. As stated already a couple of times, the charge from the alternator needs to go through a DC-DC charger.

Without a complete understanding of your existing system, everything but the transfer switch would be replaced.

 

[Wheels66]

Shore power and generator should go through a transfer switch already. The feed from the transfer switch would then go to an inverter/charger that handles charging the batteries from those two sources. The solar input can be independent of the inverter/charger but there are all-in-one systems that include solar. As stated already a couple of times, the charge from the alternator needs to go through a DC-DC charger.

Without a complete understanding of your existing system, everything but the transfer switch would be replaced.

Thank you for the explanation. Would I also need to completely rewire the fuse box, or would I tie into it?

 

[HRTKD]

In my camper I used the existing fuse box. I had to disconnect the existing AC-DC converter. Check out all the big wires going into and out of the fuse box and make sure you understand what they are doing.

 

[TheBreeze]

Another option for your alternator question is a Li-BIM, to replace your existing BIM. I use this and it works great:

 

[justinm001]

Another option for your alternator question is a Li-BIM, to replace your existing BIM. I use this and it works great:

This just connects then disconnects the alt every 15 minutes. The thought is it gives the alternator time to cool down. Doesn't seem very safe.

 

[TheBreeze]

This just connects then disconnects the alt every 15 minutes. The thought is it gives the alternator time to cool down. Doesn't seem very safe.

No problems after 15k miles. I'd submit that's a good shake down. Not trying to promote. Just sharing an option/experience.

 

[justinm001]

No problems after 15k miles. I'd submit that's a good shake down. Not trying to promote. Just sharing an option/experience.

I'm sure it works fine for most cases. I just wouldn't want my batteries going full charge to 0 then back every 15 minutes and don't want my alt getting red hot then cooling and back.

 

[RvNaut]

3 of the 4 are easy.. charging Li from the vehicle alternator present challenges. Unless you are on the move a lot, why bother.

this diagram might help you understand some aspects..

 

[justinm001]

3 of the 4 are easy.. charging Li from the vehicle alternator present challenges. Unless you are on the move a lot, why bother.

this diagram might help you understand some aspects..

Because typically you're using power while traveling especially in an RV. It's very normal for us to have a movie on or something and AC all running while driving. I could see in a Trailer with propane fridge and such you wouldn't really need it but I'd still think you would want to cool that thing whole driving in the summer so if you're boondocking the camper isn't 100+ while you're setting everything up. Especially if you have an underrated AC unit.

 

[Wheels66]

Many thanks for the info and insights. Doing some research I found this diagram, but still don’t see where the coach generator would feed into the system. Ideas or thoughts?

 

[justinm001]

You would need a transfer switch where the shore goes in then it'll pick shore or generator.

Victron quattro inverters have 2 inputs and is a built in transfer switch

 

[medic149]

Thank you for this thread.

We are looking at living full-time in a motorhome starting next year and I am anxious to switch to solar in a motorhome. After installing an entire 48v system at our off-grid cabin, I need to do MORE lol.

Does anyone know if it is possible to disconnect the ability of the engine's alternator from charging the house batteries? It just seems like it would be easier to eliminate the alternator charging.

Thanks!

Andy

 

[HRTKD]

Thank you for this thread.

We are looking at living full-time in a motorhome starting next year and I am anxious to switch to solar in a motorhome. After installing an entire 48v system at our off-grid cabin, I need to do MORE lol.

Does anyone know if it is possible to disconnect the ability of the engine's alternator from charging the house batteries? It just seems like it would be easier to eliminate the alternator charging.

Thanks!

Andy

Sure, you just have to track down the wiring coming from the alternator. I did that on my camper. No charge from the tow vehicle is used on the house batteries. If you have a generator, you'll have to take into account the voltage and amperage that it requires to start and continue to run.