Lithium battery replacement question

[heathman]

Hi all. First, I'm going to apologize now for posting this question. I know this has been asked countless times before and I've read tons of threads on this but can't seem to find the correct answer.

I have a 2020 North Poing 377RLBH with no solar and my tow vehicle is a 2021 Ford F-350 SD with tow package. My RV has a Progressive Dynamics PD4560K. My basic lead-acid batteries power my RV for *maybe* 30-45 minutes after disconnecting from my truck (unless I plug into shore power).

My goal is to just have enough power for lights and my residential fridge for a bit longer when I boondock without having to run a generator all the time. I purchased a 12V 200Ah LiFePO4 battery with BMS from Walmart which is being delivered in a day or two.

Swapping the battery and flipping the Lithium switch on my PD4650 is a piece of cake. Is there anything else I need to do? I read something about getting a DC-DC charger due to something about an impact on my truck's alternator when driving. Is that the case? I was hoping to just throw the battery in and flip the LI switch.

Thanks so much for the advice and again, I apologize for the duplicate question.

-Heath

[GHen]

I’ll let others discuss the dc to dc charger.

Add a solar panel, or 4. Best modification I’ve done. Will also help keep that refer running while driving down the road on long trips.

[Mopar_Earl]

No need for a DC-DC charger with the factory wiring. If you go to high amp charging, then yes.


Earl

[ARoamer]

Originally Posted by heathman

Hi all. First, I'm going to apologize now for posting this question. I know this has been asked countless times before and I've read tons of threads on this but can't seem to find the correct answer.

I have a 2020 North Poing 377RLBH with no solar and my tow vehicle is a 2021 Ford F-350 SD with tow package. My RV has a Progressive Dynamics PD4560K. My basic lead-acid batteries power my RV for *maybe* 30-45 minutes after disconnecting from my truck (unless I plug into shore power).

My goal is to just have enough power for lights and my residential fridge for a bit longer when I boondock without having to run a generator all the time. I purchased a 12V 200Ah LiFePO4 battery with BMS from Walmart which is being delivered in a day or two.

Swapping the battery and flipping the Lithium switch on my PD4650 is a piece of cake. Is there anything else I need to do? I read something about getting a DC-DC charger due to something about an impact on my truck's alternator when driving. Is that the case? I was hoping to just throw the battery in and flip the LI switch.

Thanks so much for the advice and again, I apologize for the duplicate question.

-Heath

Most tow vehicle's OEM wiring will only supply around 6-8 amps to charge when driving, so no problem overloading your alternator.

But-

"A 12v lithium LiFePO4 battery fully charged to 100% will hold voltage around 13.3-13.4v. Its lead acid cousin will be approx 12.6-12.7v. A lithium battery at 20% capacity will hold voltage around 13V, its lead acid cousin will be approx 11.8v at the same capacity."


Only issue is Lithium batteries having a higher voltage, may try to push that slightly higher voltage back to your tow vehicle battery when stopped. Not a deal breaker. If over nighting or longer, simply disconnect trailer 7 way plug. I installed a relay that is energized by the running lights, batteries only get TV charge when lights are on.

[RogerR]

X2 on adding a solar panel or panels to keep your lithium up. I switched from a group 27 lead battery to a 100 AH lithium and 2 100 watt panels, all from Renogy.

Camping at Great Sand Dunes NP there is no electric sites. Even with snow and 30s or lower at night and lots of furnace use my battery was topped up to 100% before mid-afternoon. Some mornings before noon!. No gas generator and nothing from Jeep. I don't have a lithium capable RV converter so my source is 100% solar and it is great to not worry about a dead battery!

[Stavman]

Ok

Why are u only getting 30-45 min on your batteries. That makes no sense at all
I'd say 1st off, test your batteries, because they are dead/bad or not getting charged from your truck

I use two portable solar panels, works fantastic in AZ since we hide from the sun. I can move them as needed and keeps my batter charged for fridge, lights, etc

[heathman]

First, I sincerely appreciate the awesome feedback and support! Thanks all!

I opened my PD4560 and realized I didn't have the LI/LA switch so I ordered a PD Lithium converter (PD4560CSV) from Battle Born.

@Stavman, I'm not sure why we only get 30 or so minutes of power from the two 75Ah batteries... I tested my current converter using instructions from PD and it tests out fine as far as providing the correct charge. I even checked the water levels of two batteries. I suppose I'm using this as an excuse to upgrade to Lithium, honestly. ha!

My North Point is wired for solar but I haven't broken down and ordered the 30amp charge controller (yet). You're all doing one heck of a job convincing me of getting that done and getting solar though!

Again - Many thanks to you all. This forum has been outstanding and I value the knowledge and experience of each of you.

[ARoamer]

Originally Posted by heathman

First, I sincerely appreciate the awesome feedback and support! Thanks all!

I opened my PD4560 and realized I didn't have the LI/LA switch so I ordered a PD Lithium converter (PD4560CSV) from Battle Born.

@Stavman, I'm not sure why we only get 30 or so minutes of power from the two 75Ah batteries... I tested my current converter using instructions from PD and it tests out fine as far as providing the correct charge. I even checked the water levels of two batteries. I suppose I'm using this as an excuse to upgrade to Lithium, honestly. ha!

My North Point is wired for solar but I haven't broken down and ordered the 30amp charge controller (yet). You're all doing one heck of a job convincing me of getting that done and getting solar though!

Again - Many thanks to you all. This forum has been outstanding and I value the knowledge and experience of each of you.

I leave my 120vac breaker off for my not lithium friendly PD converter and let the solar do it's thing.
If going down the solar route, do some research before buying. Go larger for a solar controller for possible future upgrades. Victron makes nice mmpt controllers but are a bit pricey. Bluetooth models are good, mount it close to batteries. Residential solar panels (larger panels) may give more power per dollar with less holes in the roof.

[craigav]

If you don't already own one of these then I would purchase one soon.

https://www.amazon.com/dp/B07Z398YWF...v_ov_lig_dp_it

Doesn't have to be this one, but should be able to measure DC current and preferably true RMS voltage (as this one does).

With that, you can determine the draw on your batteries and as an example, if you had 150a of battery capacity, that should provide close to 150a for one hour. If your batteries only last 45 minutes, then I suspect that the amp draw is higher than you expect and\or that the batteries have diminished capacity. Not an issue now, but something that would be very helpful to know (the meter will tell you) when you install the LifePo4 batteries.

On a side note, welcome to the Jayco Owner's Forums, I see you have been here since March but I didn't see when you joined to say welcome at that time. I lived in Monroe about 40 years ago and I still own some land west of West Monroe, in the upper NW portion of the Parish.

[craigav]

One other thought, if you plan to have the residential fridge running while traveling (as I suspect you would), and you want to have the batteries fully charged upon arriving at the campground, I would highly suggest you purchase a dc2dc charger and run larger wires to the trailer batteries (truck to trailer). A Renogy 40a dc2dc charger would be my choice. You could do this (run the fridge while traveling) without the need for any solar, and of course to get 40a of solar means you would need about 5~600 watts of solar on the roof which is certainly doable, but not every day that you travel and camp will provide for the full solar panel's output, not too mention if you are camping in an area shaded by trees. ~CA

[Yooper906]

Originally Posted by craigav

If you don't already own one of these then I would purchase one soon.

https://www.amazon.com/dp/B07Z398YWF...v_ov_lig_dp_it

This may or may not be like most of the cheaper ones. And it may not make a difference for what you are measuring. This meter probably can't go around the whole cord to check amperage, the cord insulation has to be split and the clamp around the hot wire. The pricier ones which you may not need anyway, can just wrap around the whole AC cord without splitting the hot wire out. Seems like a good unit, but most have limitations you may not be aware of.

[craigav]

Originally Posted by Yooper906

This may or may not be like most of the cheaper ones. And it may not make a difference for what you are measuring. This meter probably can't go around the whole cord to check amperage, the cord insulation has to be split and the clamp around the hot wire. The pricier ones which you may not need anyway, can just wrap around the whole AC cord without splitting the hot wire out. Seems like a good unit, but most have limitations you may not be aware of.

This would simply be a consumer grade, not the quality of my Fluke for example. I do have one like this though and it seems to be accurate and is highly rated on Amazon.

In any case, my point was not about this item in particular, but simply to obtain one that measures dc amperage and is true rms. Also, just fyi, you can't get an accurate measurement of the current in an AC power cable (unless it only has one conductor) without separating out the hot wire, this limitation is not particular to the meter and applies to my Fluke as well as all other clamp style amp meters. The reason is that as the AC current in one conductor flows one way, in the other conductor it flows the opposite way (60 times per second) cancelling out each other in regards to what the meter can measure. I have an adapter I use in such cases so as not to damage the AC cable I am measuring. ~CA

[NCRetired]

When you are pulling do you have your lights physically On (not Auto). Not sure but I do know that the backup and side cameras require the headlights to be physically On. It may be the same for the RV battery get a charge while you are driving down the road. That would explain only 30 mins or so of power left in the battery.

[heathman]

Thanks again all for the great information and support. I really appreciate you all taking the time to help.

I swapped out my PD4560 charge controller with a PD4560LICSV only to realize my original charge controller had a lithium jumper onboard. Doah! Wasted $250 on that... I picked up an Ampere Time 12V 200Ah Plus Lithium LiFePO4 w/Built-in 200A BMS from Walmart for around $750. Lastly, I installed a AiLi Voltmeter Ammeter from Amazon with a 350A shunt.

From what I can tell, everything seems to be working great. We had an RV park power outage yesterday for ~6 hours and the battery held everything up with no problem and only dropped to about 80%, according to the ammeter. I haven't burn down the RV yet so I consider this a success! haha!!

Next on the list will be to get another 200A battery and a Go Solar controller with a few panels!

Again - I appreciate the comments, suggestions, and support. Thank you all!

-Heath

[jetlag]

Originally Posted by GHen

I’ll let others discuss the dc to dc charger.

Add a solar panel, or 4. Best modification I’ve done. Will also help keep that refer running while driving down the road on long trips.

Amen to that

[Jeeper90]

There is some really bad advice on here! I would suggest you go to Battleborn batteries website and read about the battery isolation module or DC/DC charger requirements. Li batteries can damage your alternator if not correctly done.
Good luck.

[videoarizona]

Agreed on Li can be easily damaged.
If you are going to use your tow vehicle to charge, then a good DC/DC charger and associated gear is needed to safely charge from your truck.

Also, as others have said, you really need to do a real world test on your RV to see what is drawing current and how much. A good clamp on amp meter will do that.

Your 2 75 amp/hr batteries were good for only 75 amps before reaching the 50% point for low draw.
That's not much especially when running residential fridges, etc.. Even a small inverter sucks some residual current even at idle. So a real world test is necessary.

Do suggest you consider adding solar as well.

Running a traditional fridge.... I'd recommend at least 400 amps of batteries. 400 Watts of solar. And the associated gear to charge/isolate/shutoff and manage/read your current draw as well as battery bank state and state of charge.

Do the above and you will be pretty much energy independent.
I'm heading in that direction without the traditional fridge. I'll be going with a 12 volt compressor fridge once my oldstyle unit starts to give up the ghost!

[ARoamer]

Originally Posted by Jeeper90

There is some really bad advice on here! I would suggest you go to Battleborn batteries website and read about the battery isolation module or DC/DC charger requirements. Li batteries can damage your alternator if not correctly done.
Good luck.

OP has a trailer and was asking about a trailer.
IF it was a MH, it's alternator is connected to it's house batteries with much larger gauge wire which would likely overload your alternator as decent 100AH lithium batteries can easily accept 100 amps of charge each.

Please point out the "bad advice" given.

[Jeeper90]

Karen, not your post, I was simply eluding that the no action recommendation could be a problem. You sound like you know if you charge a 100 amp battery at a 100 amps on a long drive, say 8 hours, it will have averse effects on the alternator ie overheating and possibly destruction. It really does not matter if it's a motorhome or a trailer. A trailer you can simply pull the fuse on the 12vdc charing wire on the 7 way plug.

[ARoamer]

Originally Posted by Jeeper90

Karen, not your post, I was simply eluding that the no action recommendation could be a problem. You sound like you know if you charge a 100 amp battery at a 100 amps on a long drive, say 8 hours, it will have averse effects on the alternator ie overheating and possibly destruction. It really does not matter if it's a motorhome or a trailer. A trailer you can simply pull the fuse on the 12vdc charing wire on the 7 way plug.

Bad advice and attitude? You're in the lead.

Yes, it really does matter if it's a motor home or trailer. A tow vehicle can not supply enough current with stock wiring to fry it's alternator. I have 3-100 AH of lithiums in parallel for a total of 300 AH of in my 5er, towed many, many hours, everything is fine.