Lithium rv trailer battery

[crispyboy]

Wanted to ask an electrical rv/truck question. I am considering replacing the worn out lead acid battery in my travel trailer with a lithium battery. The lithium batteries are getting to a price low enough to consider one.
My new converter (Progressive Dynamics 9345) in the trailer has a mode to charge a lithium battery. This charge voltage is between 14.2 v and 14.6 v. Charging on shore power won't be an issue.
When traveling down the highway I assume the output of these batteries will be much higher than the trucks voltage. My assumption the truck will likely be 13.2 to 13.6 v output by the alternator.
Do you think this higher voltage coming into the trucks electrical system will cause issue? I really didn't want to fiddle with a dc/dc charger in the trailer. The trailer doesn't have heavy 12v electrical loads when being towed. It has a regular gas absorption refrigerator. I have no interest in going to a new 12v refrigerator. No solar.

 

[Jim W]

Why do you assume that the lithium batteries will have a higher voltage output than the normal lead acid batteries due. These are still 12V batteries are they not?

I use lithium batteries in all of my normal lead acid batteries devices such as flashlights, battery operated toys for the grand kids and so forth. To me they are interchangeable as long as the device is design to use lead acid batteries.

I don't use lithium batteries in my truck, car or RV trailer, as I just can't justify the cost difference between a lead acid batteries and lithium batteries. As they both do the job and last anywhere between four and 6 years depending on the battery life targets at time of sale.

Another thing I do not like about lithium batteries for vehicles and trailers are if there ever a fire, you cannot put the fire out with standard fire extinguisher or water. They just burn.

Just my $0.02

 

[Tuesdak]

Quick answer is the "useless" pickup charging doesn't matter for either battery type. The small charge wire on your pickup isn't big enough to do enough charging to matter. By the time any current is put on the wire the voltage drops to where it isn't charging. Look at the fuse size for the truck's wire: there isn't that many amps available in the first place for charging. Topping off or trickle charging maybe.

I suggest adding 100W+ of solar. For either battery type.

If you do go that way: Make sure it's a Li IRON battery chemistry as they are way less likely to catch fire.

Make sure you know the disadvantages of Li:
On board battery controller, one more thing to go wrong, that kicks the battery out for hot/cold temps. That's right it won't charge if it's too cold. Now you may have to look at heated batteries.

I use drop-in lead acid replacement Li batteries for one of the parent's mobility scooter. It likes to kick one or the other Li battery out, without warning, requiring a push. Then it won't charge with the standard charger requiring me to use a high amp charger for a moment to kick the battery controller back on. If it wasn't for the lighter weight when tossing the scooter the back of the pickup when their LEMON GMC mobility van is in the shop I would have returned them. It appears to have an issues in series where one doesn't charge as much as the other even though they are OEM approved for series 24V use.

Li isn't murdered by leaving it at half charge for a week like lead acid and/or AGM. However if it does reach zero charge it's DONE and can't be charged again. This would be say discharging till the controller kicks it out then self discharge and controller current killing it. For example look at what they do to charge a Tesla when it's at say an airport parking lot and the car "phones home" an emergency low state of charge.

How many lead acid batteries have died in the RV? Switching to a good Li (not a cheap no-name what brand label is on the container only for today) may save you $$$$ in the long run over easy to murder via sulfation lead acid if you keep some charge in it and overcome it's disadvantages.

For reference this is my RV setup on expensive AGM's including adding a battery fuel gauge. The batteries are 6+ years old now and still work even with the repair shop having overdischarged them once.

https://www.turbodieselregister.com/threads/rv-house-batteries-for-dry-camping.259757/

 

[BigPapa]

The only advantage I see to lithium batteries is weight. Are you concerned about the weight of this battery?

 

[Road Dog]

Why do you assume that the lithium batteries will have a higher voltage output than the normal lead acid batteries due. These are still 12V batteries are they not?

They are similar but different. A fully charged 12V lead-acid battery (at rest) is 12.6V and a fully charged LiFePO4 battery (at rest) is 13.6V. To add to the confusion, some lithium batteries have a battery management system (BMS) so they charge and discharge like a lead-acid battery.

A 12V RV battery is made up of 6x2.1V cells. A 12V LiFePO4 battery is made up of 4x3.4V cells. There are different lithium battery chemistries and the battery in your phone is different than your cordless tools is different than you RV.

To get back to the OP, that long thin +12V wire from the trailer battery to the vehicle battery adds enough resistance that the voltage difference doesn't matter.

 

[Ozymandias]

I'd never buy a LiFepo4 battery without a BMS, integrated or separate as an add on.
All standard LiFepo4 that you can buy today have an integrated BMS, most of the time with Bluetooth capabilities.
Charge voltage is important but in a different way, using only the Alternator the LiFepo4 won't be fully charged, which isn't a problem most of the time as you reach 90% any time and the battery likes that and lasts longer then when charged to 100% every time.
What should be installed is a battery monitor (Victron for example) with a shunt to keep track of the SOC as the Voltage gives not a real information.

Any more questions?

Post scriptum: Lead acid is outdated for RV use.

 

[GAmes]

I switched over to Lithium batteries in my bass boat for the trolling motor and the graphs which required buying a new on board charger. However, Mercury Marine will void my outboard engine warranty if I use one as a starting battery, so lead/acid it is. My new charger will work with both. How that compares to the charging system of your tow vehicle I can't tell you, just wanted to throw it out there.

 

[Learjet]

I see we still have some cave dwellers stuck in the lead age not talking about starting batteries.

 

[Tuesdak]

I see we still have some cave dwellers stuck in the lead age not talking about starting batteries.

Well let's take a closer look. But first there is an option to get more out of the truck's charging circuit as a DC to DC converter although the OP declined. It's a cost involved to solve the problem. Likely better, and maybe more Frugal, DC to DC converters out there as the documentation on how to do it exactly is lacking. (Happen to have this and was checking Li compatibility when I noticed this. )

https://www.bogartengineering.com/products/solar-charger-controller.html

Although Battle Born offers a drop in product.


My example would need a new converter rated for Li (Amazon $286 Inteli-Power PD9360V 9300 Series Converter - 60 Amp), reprogram solar charge controller... and +$200 heated battery option as I have camped in temps of 20F-120F. 220Ah is from all the room I have in the RV's battery box for AGM Lead.

The OP is correct as top of the line AGM lead is nearly as expensive as a top of the line Li for Ah capacity. (Figuring long life of only 50% DOD for lead and 100% DOD for Li.) If the need arises I can trade AGM battery life and use 100% DOD where same cost Li "Shuts off" at half the Ah of lead because it's 100% DOD. So my AGM lead acid has an emergency reserve for the same money as Li.

By the voltages IMO I could get by with the existing power converter, but, I would follow up with Battle Born first.

100AH Battle Born brand Li heated $949 on sale. 10 year warranty

110Ah at 50% Depth Of Discharge: 220Ah quantity two 6V Lifeline AGM GPL-4CT ~$4-500 each depending on where purchased. 5 year warranty.

After all that I am out over "Starting batteries". When I hit the Onan generator starter button... The manual calls for 450 CCA. BB10012H allows for 100 Amps continuous, 200 Amp surge for 30 seconds, and 1/2 second surge for loads over 200 Amps. Two ~$2,000.00 of batteries just for starting the generator? No not enough CCA. It would take three of them. Better off getting the heated GC3 for $2449.00 (600A continuously and 1,000A for 30 seconds) and working the battery box over or a new battery location. I do not appear to need more than 110Ah from my historical use.

It may be Frugal to stay in this 13,000Lb cave as the weight of the lead isn't even a scale rounding error. As I like my generator it's not Frugal to go Li at this time.

 

[GAmes]

I see we still have some cave dwellers stuck in the lead age not talking about starting batteries.

The point was the electronics of the engine that are connected to the battery, not the starter. Although the amperage going to the trailer batteries is lower the same dynamics apply.

 

[Learjet]

The point was the electronics of the engine that are connected to the battery, not the starter. Although the amperage going to the trailer batteries is lower the same dynamics apply.

My comment was mocking the anti LiFePO4 comments from un-informed crowd.

 

[crispyboy]

Thanks for all the insight.
Many of the deep cycle lithium ion 100 ah batteries are nearing $200. They also make single 200 ah and 300 ah batteries for more money. Many of these are claiming 10 years of use. My current lead acid batteries are 4 years old and here at the end of camping season they are starting to have troubles. My plan is to get them load tested this week.
Either way I am planning on installing a Victron shunt over the winter for monitoring.
My truck must be pushing a decent enough charge to the trailer batteries because the electric tongue jack really screams when unhooking at the destination. I have read about the pros and cons. A few years ago I never would have considered lithium ion but the technology and price seemed to have improved quite a bit. My main concern was the truck’s electrical system. It’s working good and I don’t want to mess it up.

 

[GAmes]

You could give a lithium company a call and ask their take on the subject. Customer assistance at Dakota Lithium is excellent.

 

[Ozymandias]

Decent wiring is a must for charging any battery in the trailer, chemistry of the battery doesn't matter for that.
All trucks factory installed wiring that ive seen so far for that topic is inferior, not even close to being good.
A decent charge wire would be 2AWG for the given distance, connected with an Anderson plug at the hitch.

So, if your charge wire is already screaming it will do so even more with a LiFePO4 battery.

 

[Grumpy8811]

you can assume if the DC converter in the RV is capable of charging a Lipo battery when connected to shore power any issue with the truck charging system while on the road is not going to be a concern.. the trucks charging system is designed to power the truck's electrical system and charge the truck battery and nothing else...

Do you keep the RV plugged into shore power when parked at home?

 

[Learjet]

Thanks for all the insight.
Many of the deep cycle lithium ion 100 ah batteries are nearing $200. They also make single 200 ah and 300 ah batteries for more money. Many of these are claiming 10 years of use. My current lead acid batteries are 4 years old and here at the end of camping season they are starting to have troubles. My plan is to get them load tested this week.
Either way I am planning on installing a Victron shunt over the winter for monitoring.
My truck must be pushing a decent enough charge to the trailer batteries because the electric tongue jack really screams when unhooking at the destination. I have read about the pros and cons. A few years ago I never would have considered lithium ion but the technology and price seemed to have improved quite a bit. My main concern was the truck’s electrical system. It’s working good and I don’t want to mess it up.

As others have said the wire on the truck will act like a resistor and limit the amps going to the battery with the natural voltage drop over the length of the wire, you know you'll have a problem if you blow the 30 amp charge circuit fuse on the truck. Also my trailer has 30 amp truck charge breaker. I have two 300 AH Vatrer, self heating and Bluetooth batteries on the way. I have been looking at going this route for a while myself. This will give me 600AH of useable vs ~230AH useable from my 4 x 6 volt at half the weight. I have 600 watts of solar and onboard generator, so I'm not interested in upgrading the charge circuit on the truck at this time. Also, I already have the Victron Smart Shunt to monitor the batteries. Good luck and let me know if you have any issues.

 

[AH64ID]

To get any effective charging from the TV with any battery you need a DC-DC charger installed as close to the trailer batteries as possible.

My lifeline AGM’s are starting to show their age after 11 seasons, but still doing quite well. When they get replaced I’ll go with lithium. I currently have a 300AH bank and haven’t decided if I’ll drop to 200AH or stick with 300AH. Either way I’ll have more usable AH.

The only advantage I see to lithium batteries is weight. Are you concerned about the weight of this battery?

Lithium batteries last longer than lead acid batteries, and have more useable amp hours. For example Dakota Digital batteries come with an 11 year warranty.

A standard RV battery shouldn’t be drained more than 50%, so a 100AH battery has 50AH useable. On a lithium battery they can be discharged 100%, so the same size battery has twice the usable amp hours.

 

[Grumpy8811]

one thing I know for sure is crispyboy can use the Lio battery in his RV because the converter is capable of charging that style of battery.
The question of whether the truck will charge it is irrelevant as almost assuredly won't.. so as long as crispyboy connects to shore power where ever he is staying
he should be good to go.

any other modifications after that will just revolve around jumping down the rabbit hole and spending way more money than he needs too.

I do know one guy who basically lost sight of the forest because of the trees,,, he started out wanting to do a Lio system with solar charging where the original intent of it being able to run the AC in the trailer for an hour before he got where he was going, so it would be cool inside... and he jumped down a rabbit hole of monumental depth. he now has a full solar array on the roof, a quad Lio battery setup, it took a special charging system, wiring, as well as tieing the system thru an inverter to power the whole 110 side of the RV..

 

[Grumpy8811]

Lithium batteries last longer than lead acid batteries, and have more useable amp hours. For example Dakota Digital batteries come with an 11 year warranty.

.

the question crispyboy needs to ask is how much current does he need and will one LiO battery do the job or should he just stick with a standard battery? It sounds like one Lio battery will do it..

on my RV I went with 2 golf cart batteries instead of one 12v battery... simple, last a while and relatively cheap with no other changes being necessary.. but that isn't crispyboys question.

 

[Learjet]

I went with two batteries instead of one incase one battery has a BMS failure I'm still good. Also, I'm adding a 40 amp charger at the batteries to supplement the onboard converter when necessary....ie quick charge.