I have a 2013 travel trailer that needs a new battery so I want to switch to lithium for those overnight stops and occasional 2 night boondocking trips when traveling. Going to purchase a 200ah LifePo4 and a WF-8950L2-MBA to replace the current lead acid charger in the stock WFCO8955...I don't have or want solar and don't need to charge the battery while driving as I will always have a generator with me to plug into to charge up the battery as 80% of our camping is on hookups. I have a 18 F150 as a tow vehicle. Do I need to do anything to the 7 pin connecting the trailer to the truck for the new lithium battery? I don't care about the small charge it may get from it and I don't want to install a DC to DC charger either I just don't want to harm the truck or new battery is all. Thanks Much everyone.
Switchover to Lithium
- Thread starter EBKRV
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Yes, you can eliminate the charge from the tow vehicle. There are many different ways that trailers are wired, but for me I pulled the main distribution panel out and found the wire that was coming from the distribution panel at the front of the trailer (where the 7 pin is wired into). I pulled that wire from the connection, taped it off, coiled it up and tucked it back into the cabinet. That works fine.
However, if you use that method, you will have lost the ability to provide power to the breakaway brake system. I retained a small battery on the tongue for that.
However, if you use that method, you will have lost the ability to provide power to the breakaway brake system. I retained a small battery on the tongue for that.
HRTKD do I need to isolate the 7pin charge to the trailer? I still want to provide power to the breakaway system.
That's what I figured I just wanted to make sure thanks
The 7 pin provides the power to the brakes for regular breaking - when you press the brake pedal. The breakaway system gets power from the battery. If you can find the circuit that provides power to the breakaway system, you can disconnect it from there and make sure it is connected to your battery. However, understand that the breakaway system will pull 12 amps on a dual axle trailer until the brake system burns out or the batteries are dead. Accidentally pulling the pin to the breakaway system is not uncommon. A Victron Battery Protect would help here to prevent the breakaway system from draining the battery.
Here is a quick-n-dirty diagram of how your system probably looked before you did anything.
This is how you want it to look afterwards.
I'm trying to understand why it must be different just for using lithium and not lead acid...some folks say plug n play nothing different and others say you must separate them etc what harm is it to the truck or trailer to not change anything out but the battery type in this situation.
John Frum
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The problem is the charge wire.
Its not a good idea to have your LFP batteries full and floating at alternator voltage for longer than necessary to charge them.
Also the LFP batteries could back feed to the car possibly melting that little wire.
Another issue is the liability of touching anything to do with the running gear or breakaway system.
Its not a good idea to have your LFP batteries full and floating at alternator voltage for longer than necessary to charge them.
Also the LFP batteries could back feed to the car possibly melting that little wire.
Another issue is the liability of touching anything to do with the running gear or breakaway system.
I agree with what smoothJoey posted. In my opinion, the charge profile coming from the tow vehicle just isn't what I want my LiFePO4 batteries subjected to.
My LiFePO4 battery bank gets no charge from the tow vehicle. I didn't want the added cost and complication of a DC-DC charger. My trailer has enough PV that my LiFePO4 batteries don't need the tow vehicle charge at all.
My LiFePO4 battery bank gets no charge from the tow vehicle. I didn't want the added cost and complication of a DC-DC charger. My trailer has enough PV that my LiFePO4 batteries don't need the tow vehicle charge at all.
Ok so all the reading I've done so far 50% of people state its a bad thing and others say they have been doing it for years ugh this does not help me
Could I simply pull the charge fuse from the truck to kill the charge to the trailers battery then?
John Frum
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I gave an explanation that should help.
It's worth a try. It should work. Hopefully the tow vehicle doesn't complain.
I understand what you are saying believe me I do its just frustrating when you read here as well that others don't isolate it at all and haven't for years and have been fine...it just comes down to who do you believe then that is why I'm just frustrated over this sorry for the rants ha!
Some of those 50% are simply ignorant of the issue, some just don't care. My travel time is usually more than 5 hours, sometimes as much as 13 hours in one day. I don't want my expensive batteries getting hit with 14.6 volts (or more) for that period of time. Yes, the BMS is supposed to cutoff the charge. But we've seen BMS that don't do this when they should and the batteries see more than 14.6 volts.
Most tow vehicles will never produce more than 30 amps of charge through the 7 pin. That right there can minimize the consequences, but I'm not willing to take that chance.
John Frum
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I call it like I see it.
Yeah I understand that as my travel days can be anywhere from 1 hour to 12 all depends on the timing and situation. Thanks Again
My battery is lucky to see 14.0 volts. I suppose if the WFCO has the battery at 100% as you leave for a 6+ hour drive the voltage could spike a bit.
I would be more inclined to add a switch to stop the charging from the truck if an actual issue is determined to exist.
For part time use I doubt it will matter much.
I would be more inclined to add a switch to stop the charging from the truck if an actual issue is determined to exist.
For part time use I doubt it will matter much.
I've reached out to a few RV Solar Install companies over the last 24 hours now and they have all stated the same thing for my situation.
Leave everything as it is drop in the the new 200ah lithium battery and plug in the 7 pin from the truck just like I would with lead acid in the trailer. They did state it won't charge it much and if there is any issue witch they say they rarely ever see is to pull the charging fuse of the truck. 3 large install companies have told me that now.
Leave everything as it is drop in the the new 200ah lithium battery and plug in the 7 pin from the truck just like I would with lead acid in the trailer. They did state it won't charge it much and if there is any issue witch they say they rarely ever see is to pull the charging fuse of the truck. 3 large install companies have told me that now.
12VoltInstalls
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I disagree. That’s bad advice. Most RV service people have no clue about solar in general, never mind batteries that have specific science differences from lead acid. They also aren’t financially effected by your battery upgrade. If they plug something in and a light works they’re happy.
Jumping on smoothjoey’s good advice:
For $40 you can get a breakaway battery. Disconnect the 7-pin wire on the camper side, fuse it, and connect to breakaway battery. Make the remaining camper wire safe and store it.
All problems solved.
The companies I contacted are large companies that are victron and battleborn authorized installers that do $20k systems all day everyday...These are not avg joe rv dealers they are rv solar and lithuim install corporations that is all they do
John Frum
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Sounds like an appeal to authority.The companies I contacted are large companies that are victron and battleborn authorized installers that do $20k systems all day everyday...These are not avg joe rv dealers they are rv solar and lithuim install corporations that is all they do
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