How to change battery locations in a Motorhome

[WVPete]

I am planning to add lithium and install them in a basement compartment. This means I have to re-run the wires that used to go to the Lead Acid in the rear, up to the new location.

My question is: has anyone actually done this work? If so, do you have any advice as to how to begin? There are a ton of wires that I can barely see, running into an area I can barely access going to who knows where. They are all bundled tightly with zip ties. I am worried if I cut the zip ties, I'll have a mess of wires hanging everywhere.

From what I can tell, I have three large red wires and one large black wire running from the batteries. I think one goes to the electric bay, one to the inverter and a black to the inverter. I'm not sure where the other red one goes but obviously, I have to figure that out.

I am only talking about house batteries and I'm not asking how to hook everything up. I'm just wondering if anyone has figured out the wiring mess in a coach like mine (2005 Dutch Star). Believe me, if I lived near a center that could do this work, I would be very happy to pay someone. Of course, what a missed learning experience! Any advice would be appreciated.

As of right now, my plan is to remove one wire at a time and see where it goes. I am not sure how feasible this is, but that's all I know to do.

[dvspl]

The wiring is very much dependent upon what make/model motorhome you have and what equipment (including options) are installed. In my motorhome, there are 5 connections at the house battery. One to the negative terminal which leads to ground. Four to the positive terminal that go to: battery disconnect/converter; leveling jacks; generator start; aux start solenoid. The easiest way to do this is with an electrical schematic for your coach. I'm guessing you don't have that or you wouldn't be asking. I think your plan to trace each wire individually is the best option, though probably the hardest!

[WVPete]

Originally Posted by dvspl

The wiring is very much dependent upon what make/model motorhome you have and what equipment (including options) are installed. In my motorhome, there are 5 connections at the house battery. One to the negative terminal which leads to ground. Four to the positive terminal that go to: battery disconnect/converter; leveling jacks; generator start; aux start solenoid. The easiest way to do this is with an electrical schematic for your coach. I'm guessing you don't have that or you wouldn't be asking. I think your plan to trace each wire individually is the best option, though probably the hardest!

Thanks for this information! I forgot about the Generator starting current. That explains the extra red wire.

I have a wiring diagram for the Spartan end of the coach, but I believe these wires are all labeled "customer" on the diagram, meaning, Newmar did this and there is no further information.
Thanks again.

[WVPete]

Originally Posted by WVPete

Thanks for this information! I forgot about the Generator starting current. That explains the extra red wire.

I have a wiring diagram for the Spartan end of the coach, but I believe these wires are all labeled "customer" on the diagram, meaning, Newmar did this and there is no further information.
Thanks again.

I just realized, the generator starting power would have nothing to do with the house batteries. That comes from the chassis batteries. So, still and unexplained wire!

[computerguy]

May want to look at my post. I did a solar and lithium upgrade.
I talk about moving the batteries in post 49.
A little long but it is pretty detailed and might be a good read for you. Also, that was over 5 1/2 years ago and I am still using it and going strong.

[Olyteddy]

It seems like you would just need to run cables sized for the ampacity of your new battery pack & join them to the existing wiring. You could use a shunt to do the connecting & that would add current measuring capabilities.

[WVPete]

Originally Posted by Olyteddy

It seems like you would just need to run cables sized for the ampacity of your new battery pack & join them to the existing wiring. You could use a shunt to do the connecting & that would add current measuring capabilities.

I have ordered a crimping tool so I can make my own cables. There is one cable run that will be longer than anything I have now, so I either need a new cable or need to join two. I have a shunt operating at present but will need to move it. I'll get there eventually. I just need to figure out all the wires.
Thanks!

[WVPete]

Originally Posted by computerguy

May want to look at my post. I did a solar and lithium upgrade.
I talk about moving the batteries in post 49.
A little long but it is pretty detailed and might be a good read for you. Also, that was over 5 1/2 years ago and I am still using it and going strong.

Oh! That IS long! But, I am going to reed it. Thanks for posting it. I'm glad for any information I can get

[SJ-Chris]

As someone above also mentioned....you don't need to know which wire goes to what part of your RV. As long as you connect all the old positives to the new positive, and all the old negatives to the new negative, everything should work.



YES, you will need to consider the impact on added wire length depending on your application (so that you can size accordingly).


Make sure you are properly shielding/covering all your connections so that you never get a short.


Good luck!
Chris

[WVPete]

Originally Posted by SJ-Chris

As someone above also mentioned....you don't need to know which wire goes to what part of your RV. As long as you connect all the old positives to the new positive, and all the old negatives to the new negative, everything should work.



YES, you will need to consider the impact on added wire length depending on your application (so that you can size accordingly).


Make sure you are properly shielding/covering all your connections so that you never get a short.


Good luck!
Chris

Update: The batteries are in and working. As Chris and others mentioned, I just tried to keep track of which wires came from where. In doing so, I learned a bit about my system.

The job is physically hard. Maybe not for a 20 year old, but I'm 68. So the hard part is getting under the RV, reaching up to the existing cables and pulling them free from the old battery compartment (and keeping the labels on them!). Then, I pulled the wires up to the compartment where the inverter is. I was able to pull the wires through the shielding.
After that, the biggest problem was to route wires that used to go from the old batteries to the electric bay (with the A/C power and BIRD unit etc) to the new location in the Inverter area. I was trying to find a way to route those and was going to bore a hole through a wall and try to fish the wire through an area that has no access. (This particular spot is where my water and sewer tanks are, about 50 inches wide or so.) But as I looked, I wondered if they would reach the inverter area without modification. So, when I pulled the old wires through the shielding, I attached a rope to the ends of each one. I was then able to pull the wires from the electric bay to the inverter area. There was not much wire sticking into that compartment but there was enough to bolt the ends to the shunt and a switch where they needed to do. So that hard part was done.

I hooked up all the battery monitor wires, the charge controller wires, the temperature sense wires etc. Then I had to turn things on and re-program the Xantrex inverter for the new charge profile. That was an easy job.

Next I had to reprogram the Morningstar MPPT solar charge controller. To do that, I had to connect to my computer. It has a serial connector and I had bought an adapter to connect serial to USB a year or so ago. I went to hook it up and the connections were both male. Fortunately, in my electrical box left from the previous owner in 2016, there was a mini gender changer. (Very handy if one has trouble knowing how to identify). So..I got hooked up.

Pete, a guy working for Morningstar had sent via email, directions how to proceed with this process. He gave really great step by step instructions. Without them, I never would have known what to do. So it was not long and the solar charge controller was re-programmed too.

Now the only thing left for me to do is to deal with the alternator charging the lithium issue. I do have some questions regarding that.

1. Can I assume that if my lithium batteries are charged up, driving the motorhome will not harm the alternator because it only has to keep them topped off?

2. I am considering putting an on/off switch in the wire labeled "solenoid" on the BIRD unit. I would turn it off when driving and the solenoid would not connect the two battery banks. When not driving, I turn it back on and the solenoid could connect the battery banks to keep the chassis batteries charged. Is this idea valid, or am I missing something?
If anyone could answer those questions, it would be really helpful. I am hoping my adventure here will be helpful to someone trying this project. The days that were hard were a bit physically taxing but not really a big deal. People can do this on their own.
Thanks,
Pete

[computerguy]

Originally Posted by WVPete

...
1. Can I assume that if my lithium batteries are charged up, driving the motorhome will not harm the alternator because it only has to keep them topped off?

2. I am considering putting an on/off switch in the wire labeled "solenoid" on the BIRD unit. I would turn it off when driving and the solenoid would not connect the two battery banks. When not driving, I turn it back on and the solenoid could connect the battery banks to keep the chassis batteries charged. Is this idea valid, or am I missing something?
If anyone could answer those questions, it would be really helpful. I am hoping my adventure here will be helpful to someone trying this project. The days that were hard were a bit physically taxing but not really a big deal. People can do this on their own.
Thanks,
Pete

1) Yes. But the problem is there will be times the batteries are not full and will take whatever the alternator can generate.

2) That is basically what I did in my thread I pointed you to earlier. Mine has a BCC not a BIRD so the wiring is different.

[WVPete]

Originally Posted by computerguy

1) Yes. But the problem is there will be times the batteries are not full and will take whatever the alternator can generate.

2) That is basically what I did in my thread I pointed you to earlier. Mine has a BCC not a BIRD so the wiring is different.

Computerguy,
Thanks for pointing that out again. I found your link in that old post. That was a pretty long and confusing saga, but it looks like you got it worked out. Since mine is a BIRD, I will have to logic it out and hopefully come up with a similar solution.

You said the lithium batteries would take everything that is thrown at them. This aspect is a difference from lead acid that I have to get used to. I was freaked out yesterday when my battery monitor said I was at 100% and the amps going in was still at 120. I am used to the amps going down instead of the batteries taking it all. Anyway, I think my Tristar battery monitor is still calculating what "full" it and the amps did shortly drop off to about 1.5 or 2, keeping up with power draw. It's a whole new ball game with these. I'm hopeful it is worth it!!
Thanks for your help.
Pete

[dssl]

Originally Posted by WVPete

Update: The batteries are in and working. As Chris and others mentioned, I just tried to keep track of which wires came from where. In doing so, I learned a bit about my system.

The job is physically hard. Maybe not for a 20 year old, but I'm 68. So the hard part is getting under the RV, reaching up to the existing cables and pulling them free from the old battery compartment (and keeping the labels on them!). Then, I pulled the wires up to the compartment where the inverter is. I was able to pull the wires through the shielding.
After that, the biggest problem was to route wires that used to go from the old batteries to the electric bay (with the A/C power and BIRD unit etc) to the new location in the Inverter area. I was trying to find a way to route those and was going to bore a hole through a wall and try to fish the wire through an area that has no access. (This particular spot is where my water and sewer tanks are, about 50 inches wide or so.) But as I looked, I wondered if they would reach the inverter area without modification. So, when I pulled the old wires through the shielding, I attached a rope to the ends of each one. I was then able to pull the wires from the electric bay to the inverter area. There was not much wire sticking into that compartment but there was enough to bolt the ends to the shunt and a switch where they needed to do. So that hard part was done.

I hooked up all the battery monitor wires, the charge controller wires, the temperature sense wires etc. Then I had to turn things on and re-program the Xantrex inverter for the new charge profile. That was an easy job.

Next I had to reprogram the Morningstar MPPT solar charge controller. To do that, I had to connect to my computer. It has a serial connector and I had bought an adapter to connect serial to USB a year or so ago. I went to hook it up and the connections were both male. Fortunately, in my electrical box left from the previous owner in 2016, there was a mini gender changer. (Very handy if one has trouble knowing how to identify). So..I got hooked up.

Pete, a guy working for Morningstar had sent via email, directions how to proceed with this process. He gave really great step by step instructions. Without them, I never would have known what to do. So it was not long and the solar charge controller was re-programmed too.

Now the only thing left for me to do is to deal with the alternator charging the lithium issue. I do have some questions regarding that.

1. Can I assume that if my lithium batteries are charged up, driving the motorhome will not harm the alternator because it only has to keep them topped off?

2. I am considering putting an on/off switch in the wire labeled "solenoid" on the BIRD unit. I would turn it off when driving and the solenoid would not connect the two battery banks. When not driving, I turn it back on and the solenoid could connect the battery banks to keep the chassis batteries charged. Is this idea valid, or am I missing something?
If anyone could answer those questions, it would be really helpful. I am hoping my adventure here will be helpful to someone trying this project. The days that were hard were a bit physically taxing but not really a big deal. People can do this on their own.
Thanks,
Pete

You shouldn't depend on tour lifepo4 batteries being full to limit the current, since you don't want to burn up your alternator when you end up with low batteries.

Instead what you can do is run your batteries to almost empty and measure how much current is going out with your maximum load you expect. Then start your motor and measure the current into the batteries. If the sum of those 2 numbers is greater then about1/3 of your alternator capacity then an LBIM, or a DC to DC charger is strongly recommended as well as disabling your merge relay.

It may be too late but having your batteries in the same bay as your inverter isn't ideal, since lifepo4 batteries don't like running too hot, and your inverter can heat up an electric bay. Since you already installed them it's unlikely you want to move them
Maybe monitor the temperature and if they tend to run too hot then consider adding some kind of ventilation, or move the batteries.
.

[nvs4602]

When I moved my lifepo4 under the dinette. I used buss bars mounted in the original battery box in the steps. Connected all the wires that were on the batteries to the bus bars then just ran wires from the battery to the bus bars.

I added a 40amp DC-DC charger for my alternator. I think it is better than the BIM.