Lithium battery too much for 30 y/o Dometic fridge?

[EllPea in CA]

My RV guy worries about adding a lithium battery to a 30 y/o trailer... mainly the refrigerator. He says the battery output is different to what the refrigerator normally gets?

I have no converter or other legacy stuff in there, so if I do lithium I'm kind of starting from scratch anyway, but I don't want to push the refer over the edge.

Any discussion on this issue appreciated, TIA!

[Raspy]

That concern doesn't sound valid to me. Maybe he can be more specific.

The Expion lithium iron phosphate batteries have a recommended charging voltage of 14.2 to 14.6. The recommended float charge for these is 13.6 volts, or no float charge. These values are pretty much the same as for lead acid batteries, and the voltage is much more constant than with lead acid batteries, where the voltage continues to drop under load. Battle Born too, designs their batteries to be direct replacements for lead acid batteries. The only significant difference is the charging profile. You should get a lithium specific charger if you switch. But there is no adjustment to the equipment being powered.

[EllPea in CA]

Originally Posted by Raspy

That concern doesn't sound valid to me. Maybe he can be more specific.

The Expion lithium iron phosphate batteries have a recommended charging voltage of 14.2 to 14.6. The recommended float charge for these is 13.6 volts, or no float charge. These values are pretty much the same as for lead acid batteries, and the voltage is much more constant than with lead acid batteries, where the voltage continues to drop under load. Battle Born too, designs their batteries to be direct replacements for lead acid batteries. The only significant difference is the charging profile. You should get a lithium specific charger if you switch. But there is no adjustment to the equipment being powered.

Would you mind telling me more about "lithium specific charger"? Thanks!

[Raspy]

Lithium batteries need a slightly different charging program than lead acid. Their max charging voltage is 14.6, their absorption phase is very short compared to lead acid batteries, and they need no float charge if not under load. In addition to the external charger, lithiums have an internal battery management system that assures all cells get charged evenly, cuts off charging voltage if it is too high, and shuts off charging below about 30-40 degrees F, or turns on an internal heater to keep the battery in it's proper working temperature range. Partly because of this BMS, a conventional lead acid charger can be used if necessary. In the case of Battle Born batteries, they can be used with the standard charger in older trailers designed for lead acid batteries, if needed. But if so, the lithium solar charge controller will help make up the difference.

I'm sure others here can add to this and know more about it than I do. I did a lithium conversion in an Oliver a few years ago where we kept the Progressive Dynamics charger, designed for lead acid batteries. Battle Born was very helpful at the time with answering all the questions. And the system has worked very well. I don't remember all the details at the moment.

When monitoring lead acid vs Lithium, voltage can be used to find the state of charge on lead acid, but not really on Lithium. This is because the voltage stays the same during discharge on lithiums until the battery is nearly dead. Lithium monitors count how much power goes out under load and how much charging current comes in. They know what the full capacity of the battery is and can calculate the state of charge from that information.

[CarlD]

Originally Posted by EllPea in CA

My RV guy worries about adding a lithium battery to a 30 y/o trailer... mainly the refrigerator. He says the battery output is different to what the refrigerator normally gets?

I have no converter or other legacy stuff in there, so if I do lithium I'm kind of starting from scratch anyway, but I don't want to push the refer over the edge.

Any discussion on this issue appreciated, TIA!

I am not familiar with your trailer or the fridge, but if this is truly an issue, you can install a DC-DC converter to provide a constant desired voltage to your fridge. You will suffer some efficiency losses. I have such a device that isolates and conditions the voltage from my truck to be appropriate for a LFP battery system. It is a Victron 9 amp DC-DC isolator, which works great. I have had problems with my maxxair fan tripping out due to voltage issues, so I disconnected the OEM control and installed a DC motor control and a couple switches, no more problem.

[parmm]

EllPea, can you tell us a a bit more about you Bigfoot trailer? It should have a converter/charger I would think. The attached link shows that the Lil Bigfoot came with a 12 vdc, 20 amp converter/battery charger and 110vac outlet: https://www.rvroundtable.com/wp-cont...otBrochure.pdf This converts shore power from 110 vac to 12 vdc and charges your batteries when connected to shore power. It also provides 110 vac to any 110 vac appliances or outlets you may have. Most for travel trailers are 30 amp. The lithium batteries require a higher charge voltage that lead acid batteries. I had to replace the converter/charger on muy 2006 Scamp when I changed over to lithium batteries.

[sokhapkin]

Originally Posted by EllPea in CA

My RV guy worries about adding a lithium battery to a 30 y/o trailer...

Sounds like a BS to my ear.

[EllPea in CA]

Originally Posted by parmm

EllPea, can you tell us a a bit more about you Bigfoot trailer? It should have a converter/charger I would think. The attached link shows that the Lil Bigfoot came with a 12 vdc, 20 amp converter/battery charger and 110vac outlet: https://www.rvroundtable.com/wp-cont...otBrochure.pdf This converts shore power from 110 vac to 12 vdc and charges your batteries when connected to shore power. It also provides 110 vac to any 110 vac appliances or outlets you may have. Most for travel trailers are 30 amp. The lithium batteries require a higher charge voltage that lead acid batteries. I had to replace the converter/charger on muy 2006 Scamp when I changed over to lithium batteries.

As far as I know, there is no converter/charger. The PO had done a lot of restoration work, and when I looked for stuff a few years ago (the trailer has been parked for a while), I found no converter.

My favorite RV guy is really a gem, he knows I need to replace the old lead acid and am looking at lithium... so we're not charging in willy nilly... he's not as pro lithium as I am mainly because other customers have tried to move to lithium without making other necessary changes to converter/chargers, etc. (to their detriment), so I think that's his hesitation. Maybe it was changes like that caused problems for propane refrigerators?

But since I'm essentially starting from scratch here, this shouldn't be too terrifying, I would think!

[Jane P.]

Originally Posted by EllPea in CA

My RV guy worries about adding a lithium battery to a 30 y/o trailer... mainly the refrigerator. He says the battery output is different to what the refrigerator normally gets?

I have no converter or other legacy stuff in there, so if I do lithium I'm kind of starting from scratch anyway, but I don't want to push the refer over the edge.

Any discussion on this issue appreciated, TIA!

Won’t your refrigerator be powered by propane when not hooked up?

Did you mean to say that you have a newer converter in your trailer? As opposed to not having anything? You’d probably need to upgrade the lower section of your converter.

You should contact the manufacturer of your refrigerator. Talk with the technical support. Contact Battle Born in Nevada. They have a great customer service staff who can discuss this issue with you. They do not pressure you to purchase their battery.

Check out Will Prouse videos on you tube. His older videos discuss basic electrical concepts for RVs & trailers. You should research other you tube & internet sites as well.

In another thread, you mentioned that you prefer hooking up to electricity. I am a big proponent for lithium. But, if you do not anticipate dry camping very much, you may want to rethink why you want a lithium battery. Understand that in addition to the battery, you will have to purchase and install a lower section to your converter, and a BVM - $300-$400 plus the cost of the battery. This is a lot of money for technology you do will not be using when hooked-up to a tower or under tow.

Better to research the smallest wattage (lightest) inverter generator that will support your electronics and recharge your battery, and where/if you can safely mount it on your trailer for those trips you do plan to dry camp. Unless you utilize medical equipment like a CPAP machine, a single lead acid battery & a backup generator will meet your basic needs.

[kip22]

I'd go with the lithium battery. They are far superior to lead acid for RV's. See how it goes with the fridge. My guess is you won't have any issues and like CarlD said if you do just install a voltage regulator.

[EllPea in CA]

Originally Posted by parmm

EllPea, can you tell us a a bit more about you Bigfoot trailer? It should have a converter/charger I would think. The attached link shows that the Lil Bigfoot came with a 12 vdc, 20 amp converter/battery charger and 110vac outlet: https://www.rvroundtable.com/wp-cont...otBrochure.pdf This converts shore power from 110 vac to 12 vdc and charges your batteries when connected to shore power. It also provides 110 vac to any 110 vac appliances or outlets you may have. Most for travel trailers are 30 amp. The lithium batteries require a higher charge voltage that lead acid batteries. I had to replace the converter/charger on muy 2006 Scamp when I changed over to lithium batteries.

Pat, I believe what you are looking at is a list of potential features for all Bigfoot trailers. The Lil Bigfoot did not offer the converter/battery even as an option. Here is a list from the original brochure which came with my trailer:

[EllPea in CA]

Originally Posted by Jane P.

Won’t your refrigerator be powered by propane when not hooked up?

Did you mean to say that you have a newer converter in your trailer? As opposed to not having anything? You’d probably need to upgrade the lower section of your converter.

No, I actually DID SAY there is no converter. It is a three-way fridge and there are times it would be running on battery.

In another thread, you mentioned that you prefer hooking up to electricity. I am a big proponent for lithium. But, if you do not anticipate dry camping very much, you may want to rethink why you want a lithium battery. Understand that in addition to the battery, you will have to purchase and install a lower section to your converter, and a BVM - $300-$400 plus the cost of the battery. This is a lot of money for technology you do will not be using when hooked-up to a tower or under tow.

Seriously, there is NO converter. In replacing the battery, I am starting from scratch anyway. I would say we do 50% with shore power (which is always nice but not necessarily preferred) and 50% without. In the occasions where we are without, we have often been OVER WARM. I need to power the fan during hot days, and the lead acid battery did not cut the mustard over a weekend, even with some solar charging. I also prefer to keep the cell phone charged.

Better to research the smallest wattage (lightest) inverter generator that will support your electronics and recharge your battery, and where/if you can safely mount it on your trailer for those trips you do plan to dry camp. Unless you utilize medical equipment like a CPAP machine, a single lead acid battery & a backup generator will meet your basic needs.

Well, the research end of it is what we are doing in this discussion (obviously) and on a few other threads, in addition to outside of these forums. I have no interest in using a generator.

[Joe MacDonald]

I installed a new 3 way fridge, on Battery, it will suck the battery dry in minutes, on propane it can run for days with my two 100 watt panels hooked up and charging.
12v power only for a fridge is always dicey unless you have a compressor fridge, which would not be a three way fridge.
120v or propane are really the only long term solution for a three way fridge, even when towing the draw from the fridge, if placed on DC, is pretty high, and often will draw the battery below useable amounts.
some older three ways do not require 12vdc for controls, my 81 did not. my new one does

joe

[parmm]

Originally Posted by EllPea in CA

No, I actually DID SAY there is no converter. It is a three-way fridge and there are times it would be running on battery. .......................................



Seriously, there is NO converter. In replacing the battery, I am starting from scratch anyway. ...........................

But, if you expect your battery (either lead acid or lithium or what ever) you need to keep a proper charge on it at all times!!! The longer they go without a charge, the quicker they die. Take a listen to the following video to give you a understanding:

https://www.youtube.com/watch?v=ZJD19RogRtg

My trailer stays plugged in while sitting in the back yard. And when I converted to Lithium LiFePO4 batteries, I had to replace the Scamp's converter charger because it did not offer the proper charge cycle and voltage for the Lithium LiFePO4 batteries. I can go off grid for several days without hurting my two Lithium LiFePO4 12 vdc 100 ah batteries.

[EllPea in CA]

Originally Posted by Joe MacDonald

…
120v or propane are really the only long term solution for a three way fridge, even when towing the draw from the fridge…
joe

I agree. Have never proposed running the refrigerator long-term on a lithium battery.

The most I would expect to use the battery for on the refrigerator, is when stopping the tow vehicle for lunch or some other brief period. At which time —until I get some kind of shut off switch— it is necessary to unplug the trailer from the tow vehicle, so the refrigerator does not draw down the battery of the tow vehicle.

During these times, I expect the refrigerator to run on the trailer’s lithium battery. I am not one of those who believes it is OK to run the refrigerator on propane as I’m driving down the road, and I’m not about to attempt to start the propane system while I’m stopping for lunch.

So, for approximately 30 to 45 minutes, I am expecting my trailers battery system to support the refrigerator. I do not believe that is out of line.

[EllPea in CA]

Originally Posted by parmm

My trailer stays plugged in while sitting in the back yard. And when I converted to Lithium LiFePO4 batteries, I had to replace the Scamp's converter charger because it did not offer the proper charge cycle and voltage for the Lithium LiFePO4 batteries. I can go off grid for several days without hurting my two Lithium LiFePO4 12 vdc 100 ah batteries.

I realize that a lithium battery requires a different kind of converter. I believe this is why my RV technician is worried about me converting to lithium… too many of his clients have switched to a lithium battery without changing out the converter.

As I’ve said several times, I do not have a converter, so *that* is not my problem.

I’m not suggesting I would continue without a converter. I am reassuring those concerned that if I went to a lithium battery, which I am Pretty certain I will do, that it is therefore quite simple for me to get the rest of the materials needed to make sure the battery functions properly and is recharged properly, since I’m essentially starting from scratch anyway.

[Glenn Baglo]

Originally Posted by EllPea in CA

So, for approximately 30 to 45 minutes, I am expecting my trailers battery system to support the refrigerator. I do not believe that is out of line.

A lot cheaper to just get your 7-pin wired properly, so that it doesn't draw power from the vehicle when the engine is off.
The fridge will stay cold for 35 minutes if you don't open it.

[EllPea in CA]

Originally Posted by Glenn Baglo

A lot cheaper to just get your 7-pin wired properly, so that it doesn't draw power from the vehicle when the engine is off.
The fridge will stay cold for 35 minutes if you don't open it.

Glenn, I’m not messing with my 7 pin wiring… hooked into newly installed software in the Volvo. But isn’t there a switch between the trailer and the 7 pin… somewhere… which shuts off access TV battery when it is not running. I swear I just read about that somewhere.

Possibly this software does that anyway… haven’t had the opportunity to test this out yet. But of course, the refrigerator will stay cold for 35 minutes. This just points up one of the times when the refrigerator will be using a battery draw when it is not hooked up into shore power or accessing propane.

[Joe MacDonald]

That might work, just do the battery drain calculation and see where it puts you.
I don't drive with propane on either,
Currently the fridge automatically switches to propane when the engine shuts off
I actually am in the process of installing a separate feed directly to the fridge from the tow vehicle alternator, with wiring suitable for the drain-#8awg wire and 40 amp connectors, my fridge is factory wired for that option

[John in Santa Cruz]

Many but not all 7 blade connectors have a relay on the vehicle side that only switches on the power to the trailer when the vehicle engine and alternator are running

My Tacoma and two Ford trucks all with factory tow came this way.

If you use a lithium battery with a lead acid charging system it will take quite a bit longer to fully charge, and might not get the last 2-3% big whoop.

Someone above said batteries should always be stored fully charged, while that is very true for Lead Acid, it is NOT true for Lithium, they can be left at almost any charge state except completely flat for weeks, even months.