Planning Stage Switching to Lithium Battery

[Steven@147]

Well I too am in the planning stage of switching from a single LA Battery to Lithium. This is prompted by our 5 year old LA battery getting tired and we will be installing the JC Refrigeration dual compressor mod to our Dometic fridge and doing away with the 120VAC / propane system.

My first step is to figure out how the 12VDC battery and charging system in the RV is setup and wired now. Size of wires, length of wires, also the converter capability and our truck charging circuit to pin 4 of the 7 way plug. Then how I have to modify what is there for the two 100AH LifePro batteries I plan on installing. Please excuse my crude hand drawn schematic diagram.

What I have now and you can see on my diagram,
Converter 9855-AD 55 amp - I don't know if it will auto detect the Lithium battery or not. I know not the best, but for now ok.
Backup power = 3500 Generator - No Solar wire disconnected from battery.
Truck charging power = 220 amp alternator constant hot through pin 4 of the 7 way through a 30 amp reset breaker to the OEM 12VDC bus bar in front storage compartment.
Have some idea of the wire run lengths of 6 awg that the OEM used.
The OEM battery cut off switch is rated to 300 amps

I Plan on using a new 12VDC bus bar to connect the two new Lithium batteries to the OEM 12VDC bus bar.
I want to get two 100AH BMS Group 31 Lithium batts with Bluetooth and Low temp cutoff. Bluetooth so I can monitor the batts without a shunt. I am looking at these or something similar
https://www.amazon.com/dp/B0CNVBL5T...M9&ref_=aip_sf_list_spv_ofs_mixed_d_asin&th=1

My concern is the 6 awg wire run from the RV power distribution center all the way to the battery is too long for 6 awg wire and the amps that might be running through it.
You add the 6 foot piece of 6 awg wire from the converter charger to the distribution center and then 15 feet or so from the distribution center to the new Lithium batteries and I am looking at something like 21 feet of 6 awg wire. From the converter charger through the distribution center to the new batteries up front.
From the RVs power distribution center, there is a Red 6 awg wire running @ 15 feet or more all the way up front to the Battery disconnect switch in the front storage compartment and then to an OEM 12VDC bus bar, and then to the LA battery. It's a long ways from the RV's power distribution center to the current LA battery in the front storage compartment.

The converter is directly connected to the RVs power distribution center through a 6 foot piece of each Red & Black 6 awg wire. The converter is within 6 foot of the RVs power distribution center.

The LA battery is connected to the OEM 12VDC bus bar through a positive Red 2 foot piece of 6 awg wire. The Black battery negative 6 awg wire is tied to the RVs chassis frame ground right by the battery.

I still have to figure out some things and try to figure out how many amps I might be pulling across those 6 awg wires. How much power the new JC refridgeration dual compressor mod will take to run. (11.6 amps 12V 140 watts)
We don't plan on boon docking but maybe just over night it at all and if needs be I can use our generator to keep the new Lithium batteries charged. Eventually I will get a new Lithium capable converter and get away from the WFCO. I think our truck will handle keeping the new Lithium batteries at least charged while driving.

Ideally the power distribution center, converter and batteries should be in close proximity to each other to keep the wire runs short and the same distance. Right now the converter is in the mid storage compartment behind the rear wall.

any comment suggestions welcome, I'm sure you guys can help me spend some more money!

Tami says she didn't know it was going to take this much planning just to replace a battery!

 

[triplethreat]

Here is a convenient place to mount the converter or even if you end up buying a new converter that is LFP specific. This picture shows where I mounted my Meanwell NPB-750-12 converter. It is mounted to the "ceiling" of the baggage storage compartment, which places it closer to the battery in the front compartment hydraulic/generator bay. It also actually moves it a bit closer to the 12VDC fuse distribution that is part of the breaker panel. Notice there are two sets of wires there, coming off of the converter. The heavier ga. wires (#2ga) are headed over to the new battery disconnect switch I installed, then on over to the 12V Pos. and Neg buss bars I put in the front compartment. The other set of wires (6ga.) are the original OEM wires that went from the original converter to the 12VDC fuse distribution area in the breaker panel. I ended up cutting about 1 1/2' off of them because it wasn't needed any longer.....Oh, and BTW....I've got the JC mod on my Norcold 2118 and it's the twin compressor version. If both compressors are running at the same time it's pulling about 12.6 amps. A normal day (24 hour time period), will draw approx. 145 AH off of my 302AH battery. The Meanwell charger/converter that I'm using has an ON/OFF switch on the back of it, which makes it easy to shut off if I'm not using it.....like during the winter when I've got it winterized. If I need to get in the camper and need some lights or ???, I can just open the baggage storage door, reach up there and turn it on.....then turn it back off when I'm done. The LFP batteries go into winter storage with about 50% State of Charge and I don't keep them on even a trickle charge. I've also got a 300A battery disconnect that I added coming off of the Pos battery cable and before it gets to the Pos. buss bar. There is a very slight draw on the battery though, and that is from the BMS that I put on the battery when I built it.

 

[Steven@147]

Here is a convenient place to mount the converter or even if you end up buying a new converter that is LFP specific. This picture shows where I mounted my Meanwell NPB-750-12 converter. It is mounted to the "ceiling" of the baggage storage compartment, which places it closer to the battery in the front compartment hydraulic/generator bay. It also actually moves it a bit closer to the 12VDC fuse distribution that is part of the breaker panel. Notice there are two sets of wires there, coming off of the converter. The heavier ga. wires (#2ga) are headed over to the new battery disconnect switch I installed, then on over to the 12V Pos. and Neg buss bars I put in the front compartment. The other set of wires (6ga.) are the original OEM wires that went from the original converter to the 12VDC fuse distribution area in the breaker panel. I ended up cutting about 1 1/2' off of them because it wasn't needed any longer.....Oh, and BTW....I've got the JC mod on my Norcold 2118 and it's the twin compressor version. If both compressors are running at the same time it's pulling about 12.6 amps. A normal day (24 hour time period), will draw approx. 145 AH off of my 302AH battery.

So you are essentially using the terminals off the converter as another buss bar? One set goes to the distribution center the other set to your batteries.
2ga holy crap batman!
I don't think I can stuff that kind of wire + the 6 awg wire into the WFCO terminals and screw down the allen lugs.

 

[triplethreat]

So you are essentially using the terminals off the converter as another buss bar? One set goes to the distribution center the other set to your batteries.
2ga holy crap batman!
I don't think I can stuff that kind of wire + the 6 awg wire into the WFCO terminals and screw down the allen lugs.

Yep, I went with 2ga and also put a new battery disconnect where the OEM was at, cleaned up all connection points including the new buss bars I put in, plus the 300A Total battery disconnect, plus the battery terminal itself. I was getting a .6 to .7 volt drop from the converter to the battery. After I did all that, I get about .1 volt drop from the converter to the battery. Voltage drops will slow the charging way down, depending on how bad the drop is.....and .6 to .7 was significant. One I got it all cleaned up I tested the charging current flow. The Meanwell is capable of putting out 43.xx amps and mine will show that I'm getting 42.5....maybe right at 43 amps to the battery. That's only possible if you don't have a lot of voltage drop in the path from the charger to the battery. And of course, the bigger the wire, the less resistance the actual wire has........thus the 2ga from the charger to the battery.

 

[Steven@147]

I'm still in the discovery planning phase of my switch to Lithium batteries. I'm starting to gather a list of parts and components I am going to need. I've been watching a lot of Utubes, manufacturers and owners, reading manuf web sites and reading this forum. Taking good ideas from all sources. I plan on getting Lithium batts that are bluetooth so I don't need shunts. two 100ah parallel configured.

I've got a diagram laid out before conversion (left side) and after (right side), helps me keep my mind straight and so I don't forget anything. I think this is the most current one. On the right of the diagram is what I'm planning. Installing the new Lithium batteries in the right side center storage compartment, next to the back wall for better climate control and also to keep the batteries and new buss bars as close to the new converter as possible. Shorter wire runs.

Oh that's another thing, I'm planning on installing a new converter. From the old WFCO 9855 AD 55 amp to a Progressive Dynamics 9360 60 amp. The new PD 9360 has two + power cable connections 2-10 awg wire and two - cable connections. Installed in the same place as the old converter. Hook up the batteries to the new buss bars and new converter using 4 awg cables. Also including cables from the battery - terminal to RV frame. In videos some do and some don't add battery - frame ground cables.

Got to do some reconfiguration and construction of the center storage compartment back wall adding some 2x2 and 2x4 supports and a door leading to the rear interior of storage compartment.

I need to keep in mind the charging wire through pin 4 of the 7 way. From the 7 way, across the OEM buss bar, across the OEM cutoff switch, through 15 feet of 6 awg to the distribution panel, then across another 6 foot of 6 awg wire to the new converter, then 4 awg wire across another cutoff switch, then through the new 12VDC buss bar, and finally to the new Lithium batteries. There wont be much if any charge voltage/amp left to do any good for the batteries.
Keeping in mind when we upgrade our fridge to the 12VDC JC dual compressor. Will need to pull a new 10 gage wire for the fridge conversion. In the diagram I've got it fused and connected to the new 12VDC buss bar right at the batteries. Traveling we will most likely be pulling out more amps from the batteries than putting back in from the truck charging system. So we will probably have to add a DC to DC Charger, got to read up on those and how and where to install.

Also have to keep in mind the trailer emerg brake switch volts/amps. From the new configuration it's a long way from the batteries in center storage to front storage compartment then to the switch and then back out to the RV brakes. Currently the emerg brake switch is tied into the pin 4 charge wire that also gets power from the OEM 12DC buss bar and LA battery in the front storage compartment.

Switching to Lithium batteries isn't just swapping the batteries. I could save myself a whole lot of planning, costs and frustration just upgrading to two gel cells in the front storage compartment and forget the Lithium. But for longer term it would be better to do the lithium switch now.

All responses, critiques, popo's, ideas welcome

No solar yet!!??

 

[SolarPoweredRV]

Good Luck !!

 

[Butcher]

I have a '20 29RS and I installed my original set of LifePo4 batteries next to the steps [in the storage compartment]. I removed the side panel and there was the stock converter and enough space to put two batteries in. Under the stairs I put the inverter. All the components are within a couple feet of each other. That allowed me much less wiring if I installed the batteries where they come stock.

I ran 1/0 wire from the batteries to a buss bar which is inches away from the 3k inverter. I used 4/0 wire from the buss bar to the inverter. I ran 2ga wire from the converter to the buss bars.

I swapped out the converter to something that would compliment the capabilities of the batteries. I settled for a 100A converter.

If you start peeking behind some of the side storage compartments, you might just find plenty of space to put all the components you are thinking of purchasing. That way, you'll gain space [since your stock battery will be gone]. Putting all the components close to each other allows you shorter wire runs.

If you do elect to start looking behind panels, beware, there is a huge rabbit hole behind them. The area is a mess. You will probably want to 'clean up' the stock wiring, plumbing, ducting, and the saw dust that they leave behind. I spent a day changing out the plumbing, changing out the plastic fittings, finding better routing, etc. I gained so much space on that side of the 5th wheel, I was able to put two more LifePo4 batteries there.

I have not done, but I plan on doing some type of vehicle charging system on my Ford. Dual alternators is the goal. I do not know, but with location of the alternator and the LifePo4 batteries, I will be needing much more than a 6ga wire. I suspect a separate Anderson connector is what I will be using. Again, I do not know the size wire, but I can't see myself using anything less than a 2ga and will probably go 1/0. Yeah, a huge cost but I suspect with a good connection to the steel frame of my truck, will keep the ground side a bit cheaper than the power side.

One thing to thing about is to see if an old school Ford fender mount solenoid is a good thing to put in line. That way, the truck would be disconnected when the vehicle is turned off.

 

[SolarPoweredRV]

I have a '20 29RS and I installed my original set of LifePo4 batteries next to the steps [in the storage compartment]. I removed the side panel and there was the stock converter and enough space to put two batteries in. Under the stairs I put the inverter. All the components are within a couple feet of each other. That allowed me much less wiring if I installed the batteries where they come stock.

I ran 1/0 wire from the batteries to a buss bar which is inches away from the 3k inverter. I used 4/0 wire from the buss bar to the inverter. I ran 2ga wire from the converter to the buss bars.

I swapped out the converter to something that would compliment the capabilities of the batteries. I settled for a 100A converter.

If you start peeking behind some of the side storage compartments, you might just find plenty of space to put all the components you are thinking of purchasing. That way, you'll gain space [since your stock battery will be gone]. Putting all the components close to each other allows you shorter wire runs.

If you do elect to start looking behind panels, beware, there is a huge rabbit hole behind them. The area is a mess. You will probably want to 'clean up' the stock wiring, plumbing, ducting, and the saw dust that they leave behind. I spent a day changing out the plumbing, changing out the plastic fittings, finding better routing, etc. I gained so much space on that side of the 5th wheel, I was able to put two more LifePo4 batteries there.

I have not done, but I plan on doing some type of vehicle charging system on my Ford. Dual alternators is the goal. I do not know, but with location of the alternator and the LifePo4 batteries, I will be needing much more than a 6ga wire. I suspect a separate Anderson connector is what I will be using. Again, I do not know the size wire, but I can't see myself using anything less than a 2ga and will probably go 1/0. Yeah, a huge cost but I suspect with a good connection to the steel frame of my truck, will keep the ground side a bit cheaper than the power side.

One thing to thing about is to see if an old school Ford fender mount solenoid is a good thing to put in line. That way, the truck would be disconnected when the vehicle is turned off.

In regard to your charging of your Lithium batteries from the Tow Vehicle, I started a new thread addressing that topic.

Here is the title: Charging Lithium Batteries From Your Tow Vehicle, it is located in the "Electrical Systems and Wiring" forum.

 

[Scott'n'Wendy]

One thing to thing about is to see if an old school Ford fender mount solenoid is a good thing to put in line. That way, the truck would be disconnected when the vehicle is turned off.

That would be a very good plan imo. Having a truck length constant hot wire is asking for a problem.

 

[Butcher]

I would agree but there are plenty of high end German cars that have the battery in the trunk and they have no problems. The newest cars the cable is part of the SRS system so when the car is in an accident, the cable circuit blows.

It's all about planning and executing that plan. I tend to think about everything in life that could go wrong. That way you can plan for it. Sadly, my wife thinks I'm full of negativity. We've never been stuck on the road, never needed a tow truck, and 20 years of hang gliding, I survived.

 

[kb0zke]

Plan for the worst, live for the best. We can't control a lot of things, but there are things we can control. Thinking about "what if..." means that you are at least a little bit prepared.

We are often in Tornado Alley in the spring, so we pay attention to the weather. It usually isn't feasible to try going somewhere else, though, so we just plan on where to go with the two of us and our cat. The truck and trailer will just have to fend for themselves. That's what insurance is for. Planning for a way to disconnect the battery is something good to think about.

 

[Butcher]

Plan for the worst, live for the best. We can't control a lot of things, but there are things we can control. Thinking about "what if..." means that you are at least a little bit prepared.

Two words 'Hog Wash' At least that is what my wife would say. Well, not exactly. I can't write what she would say on this forum.

 

[Steven@147]

I might as well finish the thread I started and tell you what I (we) ended up doing, though Nothing i had initially planned !

Thanks to all who post and contribute to power threads on the forum. I have read through a lot of them, invaluable information.

Tami and I sat down and did a cost justification Vs needed function analysis. We don't boondock but maybe an overnight at a harvest host. We may even drop that since we really don't use it enough to justify the $75 annual renewal. We don't plan on using it at all this year.
We have the appointment with JC Refrigeration in July to convert our Dometic gas/electric fridge to 12VDC dual compressor. Calculations say a 100AH LifePO4 battery will hold the load fine if we do boondock overnight. We have a generator in case we need or lose power that we have had to rely on a few times.

No solar. Tami and I did discuss the need for a suitcase solar panel in case we can't use our generator or can't get gas for the generator.

So what we did - I purchased a single Mehrpow 12V100AH LifePO4 battery $190. Installed it yesterday and it initially had a 50% charge. It has bluetooth and I installed the app on my iphone and watched it. The WFCO 9855 AD converter didn't recognize it as expected but it did charge the new LifePO4 battery up to 98% in about 7 hours. Now if or when the WFCO bites the dust I'll then decide which new converter to replace it with.

I also purchased a LifePO4 standalone charger for $94 and will mount it in the front cargo hold to bring the new batt all the way up to 105% and not rely solely on the WFCO converter charger. https://www.amazon.com/gp/product/B082LZNDRH/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

So basically we switched to a Lithium battery by purchasing and installing what we think we need (and not to excess) for the way we use our rig and camp - Total Cost $284

As far as our truck supplying enough power to maintain or charge the Lithium battery (without a DC-Dc charger)while the new fridge conversion is pulling on the battery during travel days, that remains to be seen. Our maximum travel days are @ 5 hours.
As long as we start out on travel days with a 98-100% charge on the LifePO4 battery, I think our truck with its 220amp battery charger will just keep up. As soon as we get to a camping site and plug back into AC power, that will bring the batt back up to 100%.
Owners experience varies on Ram truck charge power output through the 7 way but somewhere between 5-9 amps is what I am expecting. The truck charging system should not be damaged as it is supposed to have a smart charging system to prevent that. I think the battery bluetooth app will come in handy to tell us what's actually going on when traveling down the road.

We will see how our decision works out later this year when we compete the fridge upgrade in July. JC says the fridge mod doesn't take that much more power to run on 12VDC.

 

[huntindog]

Be aware that a charging "test" when you are not using the unit will always give much better results than when you are using the RV....Reason being that you will be consuming power that would have been used to charge the battery.
This difference can be quite large

 

[Butcher]

The WFCO 9855 AD converter didn't recognize it as expected but it did charge the new LifePO4 battery up to 98% in about 7 hours.

Good to know that someone else had the same results that I did with the stock converter.

 

[Butcher]

Be aware that a charging "test" when you are not using the unit will always give much better results than when you are using the RV..

Yes, that is true, but if you are plugged in over night, most 12v consumers would be off. I do not know, but I suspect if you drive during the day, plug in at night, the stock converter would keep the 100ah battery fairly well charged.

 

[triplethreat]

I might as well finish the thread I started and tell you what I (we) ended up doing, though Nothing i had initially planned !

Thanks to all who post and contribute to power threads on the forum. I have read through a lot of them, invaluable information.

Tami and I sat down and did a cost justification Vs needed function analysis. We don't boondock but maybe an overnight at a harvest host. We may even drop that since we really don't use it enough to justify the $75 annual renewal. We don't plan on using it at all this year.
We have the appointment with JC Refrigeration in July to convert our Dometic gas/electric fridge to 12VDC dual compressor. Calculations say a 100AH LifePO4 battery will hold the load fine if we do boondock overnight. We have a generator in case we need or lose power that we have had to rely on a few times.

No solar. Tami and I did discuss the need for a suitcase solar panel in case we can't use our generator or can't get gas for the generator.

So what we did - I purchased a single Mehrpow 12V100AH LifePO4 battery $190. Installed it yesterday and it initially had a 50% charge. It has bluetooth and I installed the app on my iphone and watched it. The WFCO 9855 AD converter didn't recognize it as expected but it did charge the new LifePO4 battery up to 98% in about 7 hours. Now if or when the WFCO bites the dust I'll then decide which new converter to replace it with.

I also purchased a LifePO4 standalone charger for $94 and will mount it in the front cargo hold to bring the new batt all the way up to 105% and not rely solely on the WFCO converter charger. https://www.amazon.com/gp/product/B082LZNDRH/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

So basically we switched to a Lithium battery by purchasing and installing what we think we need (and not to excess) for the way we use our rig and camp - Total Cost $284

As far as our truck supplying enough power to maintain or charge the Lithium battery (without a DC-Dc charger)while the new fridge conversion is pulling on the battery during travel days, that remains to be seen. Our maximum travel days are @ 5 hours.
As long as we start out on travel days with a 98-100% charge on the LifePO4 battery, I think our truck with its 220amp battery charger will just keep up. As soon as we get to a camping site and plug back into AC power, that will bring the batt back up to 100%.
Owners experience varies on Ram truck charge power output through the 7 way but somewhere between 5-9 amps is what I am expecting. The truck charging system should not be damaged as it is supposed to have a smart charging system to prevent that. I think the battery bluetooth app will come in handy to tell us what's actually going on when traveling down the road.

We will see how our decision works out later this year when we compete the fridge upgrade in July. JC says the fridge mod doesn't take that much more power to run on 12VDC.

I'd be concerned about the length of time that the WFCO took to charge the 100AH battery from 50% SOC to almost full. If those numbers are true....it actually being at 50% SOC, you are only talking about putting an additional 50AH into the battery and for it to take 7 hours to do that, something is not correct. I'll give you and example: My 302AH battery at 50% SOC should have approx. 150AHs in it, and need another 150AH to be full. When my charger starts charging in the bulk/Constant Current mode, it is putting out 42/43 amps....and the Converter Charger is only capable of 43.xx amps. Of course after the Constant Current mode is done, it switches to Constant Voltage mode to finish it off, then float. So assuming that most of the charging is done in the bulk mode (42/43 amps going in), it should take less than four hours to go that additional 50%.....or 150AHs. In your case, with a 100AH, it only needs another 50AH.....and for it to take 7 hours to do that, averages out to a charging rate of 7 amps. Like I said, something is amiss there.

 

[mwdilday]

Converters with the suffix "AD" are auto-detect and will detect Lithium batteries.

#6 wire can carry 35-50 amps at 19-22 feet in length so your power center to battery should be fine.

I would not be concerned about the wire size from the truck being sufficient since it is going to be protected by a fuse in the fuse box probably under the hood. My 2023 Chevrolet Silverado has a 30 amp fuse for the trailer battery charging circuit. Most people will tell you that trucks only trickle charge the trailer battery but I question that. My truck charges the trailer battery at about 25 amps. Keep in mind that the truck is not going to charge the LI batteries to 100% because of the voltage differential. If you have not had any issues with the LA batteries you will not have any with the LI batteries.

Since you don't have solar that is not a concern.

I installed 2-100AH BattleBorn LI batteries in my Solitude with the Furrion 12 volt fridge. I found that 2-100 amps are not enough to boondock with the solar charging to 100% each day. I had to add a 3rd battery. This test was done with the RV in the driveway not plugged into the 50 amp just running on solar each day. The batteries would discharge 176 amps of the 200 available leaving no capacity for any other loads like lights or television or charging devices. Good luck on your install.

 

[huntindog]

See my post #14 .
Every test I have seen in real life camping situations has had remarkably similar results.
Right at 62% charge.
If that is good enough for you, carry on.
When it comes to charging capabilities, there is no free lunch. If one doesn't test under real use conditions, it will come up short.

Kind of like these people I see on TV all the time stating "I told my truth".
I know right then that whatever they said was not the truth.
There can only be one truth...It doesn't change regardless of who is doing the talking.

 

[mwdilday]

Quote <So what we did - I purchased a single Mehrpow 12V100AH LifePO4 battery $190. Installed it yesterday and it initially had a 50% charge. It has bluetooth and I installed the app on my iphone and watched it. The WFCO 9855 AD converter didn't recognize it as expected but it did charge the new LifePO4 battery up to 98% in about 7 hours. Now if or when the WFCO bites the dust I'll then decide which new converter to replace it with.>

Your WFCO 9855 AD converter will recognize the LI battery but it may take a while. It recognizes the charge/discharge cycles to determine that battery type. I would take the battery through a few complete charge/discharge cycles using the converter to charge and it will probably recognize it properly.