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Has anyone tried a lithium battery yet? They are big, big bucks. Hell even Trojan and Interstate batteries are way up there. I use 2 6v deep cycles and have kicked around the lithium idea. Do they take a different charging system than my Iota on board charger?
Today I cheaped out and got Costco Interstate batteries. They last set went about 3 years. I talked to an Interstate Battery distributor and he said 3 years was about it, and after 2 years they are on borrowed time. With all the manufacturers going with a 1 year battery warranty I went as cheap as I could. $100 each at Costco.

I’ve had pretty good luck with Costco batteries. Ran them in my boat. Last set was maybe 5 or 6 years old and working well when I sold it.

Lithium batteries sound nice, but I’m too cheap to drop $500 bucks on a battery. They’d have to go about 20 years to pay for the increased cost. By then they’ll probably be cheaper.

I have been using two 6V T125's

I do year around maintenance.

I know a small amount about Li's but I'm sure no expert. They'll give you more juice than lead-acid or AGM. AGMs are a type of lead-acid and all of the following applies to both.
A lead battery can't be pulled down below 50% of it's capacity without damaging it. A Li can be pulled all the way to the bottom without damage. So, a 100AH lead battery gives you 50 usable AH while a Li gives you 100AH. However, since you pull more juice out of a Li, it takes that much longer to recharge.

There are 2 general types of Li's - lithium ion and lithium ferrophosphate, commonly called Lifepo4. The battery fires you hear about are almost all Li-ions. Lifepo4's are MUCH safer and fires are very rare. Almost all RV batteries are now Lifepo4's. The rolling inferno EVs are all using Li-ions.

Li's need to be charged at about 14.4 volts. Most on-board charges are more in the 13.6 range and can't give Li's a full charge. You recharge the Li to about 14.4v. After a short time it settles down to about 13.4. That's considered a full charge. If you can DIY it, a good Li charger costs under $100. You can just leave the old on-board charger in place and wire around it. In the power box, I disconnected the OEM charger and left it in place in case I ever want to switch back to leads. The Li charger had a 110v plug and battery clamps. I cut off the plug and hard wired it to the breaker in place of the OEM charger. I cut off the battery clamps and wired them to the leads to the batteries. It sits behind the OEM power box and can be seen when opening the power cord door on the outside. You need to read the instructions on any volt meter your have in the RV. It might not work right with Li's unless it's reset. An 80% charge in Li's isn't the same thing as 80% in leads and the meter might not show it correctly.
Also, newer on-board chargers might have a setting to properly charge Li's so making the switch might be much easier.

I also have a 200A solar panel that easily maintains the Li's. The controller has a Li setting that produces the 14.4v so it gives the Li's a full charge.

Li's are much lighter weight than leads. A 100AH Li weighs about 25lb.

One of the biggest problems with LI's is that they can't be charged below the freezing point. Trying it will permanently damage it. Most of the better ones have a 'battery maintenance system' (BMS) built it that will prevent it from charging when it's cold. For cold weather storage, you're better off to pull the batteries out and store them someplace above freezing. They'll hold the charge much better than leads, though, and likely won't need topping up more than once or twice during the winter.
They can be safely used in colder weather, just not recharged. Like any battery, they'll have a reduced capacity in the cold. There are some with built in heaters that allow charging in the cold. Now you're talking serious money.

Modern RV's have lots of small things that use power all the time whether it's in use or not. CO monitors are an example. If it sits without a trickle charger, after a month you'll find the batteries are way down. This is the RVs fault, not the batteries and it applies to both types of batteries. I wired a main switch in mine that shuts off everything except 1 light and the volt meter.

Thanks for the info RC!

Any Lifepo4 recommendations?

Twin Interstate 6V deep cells......

100 watt solar panel helps

I have 2 camp trailers. One is an old beater that I use for hunting. The newer one has Lifepo4s and the beater has 2 Interstate golf cart 6vs. I leave the 6v's in there because I use it in some real cold weather and need to charge them while hunting. Unless we have a lot of bad weather, my 200w solar panels will keep the 6v's charged easily to run the furnace.

I have 2 100AH from Ampere Time. I don't know how they compare to other brands. The reviews on them were good and they've been good at answering my questions. You can save a little by getting a single 200AH battery. That wouldn't fit in my space, though. They're an odd size. A 200AH weighs the same as a single 100AH lead acid so it cuts the weight by half. I think they're all Chinese regardless of brand. China has the world Li supply pretty well tied up.

Wow Rock, outstanding info. Did I miss it? Where did you get your solar charging system?
This was different, The local Interstate distributor wanted $179 each for the GC2 batts, Costco were $100 each. Interstate licensed to Costco to go find someone else to mfg the batteries? I couldn't get the distributor to say they were the same but he did say that the 3 years was a good run on 6v batts.

Awesome info. Thanks RC! You have put a lot of effort in your research and testing and sharing it is greatly appreciated.

Costco's GC2 are Interstate but they aren't the same as the big green ones that Interstate sells at their stores. Those cost more but have more than double the capacity. For the money, the store brand is less expensive for the capacity. For comparison, look at the RC shown on them. RC is the number of minutes it can crank out a set number of amps before it drops below a certain level. Costco's are something like 110 while the store brand is over 400.

My solar 'system' is 2 100w panels and a controller. I made a stand. They're Grape Solar brand and I got them from Home Depot. The panels come separate. I hinged them together and added a handle to carry them. They can be mounted on a roof but then you have to always park in the sun. I prefer shade when available. My stand is just some aluminum angle bolted together, nothing fancy. It's not fancy enough as it's a pain to break down. I need to redesign it. The panels themselves work great.
There are 2 types of controllers - PMW and MPPT. This unit has the PMW. MPPT's are said to be 30% more efficient but they cost a LOT more. I have 2 100w panels but the controller will handle up to 4 so it can make a lot of juice.
With a free standing stand, you can use 10ga extension cord and rig it to move them away from an RV to get the sun.

Just ordered the Ampere Time 100AH with heater. I want to be able to charge it with Zamp solar/Honda gen in cold temps.
Results to follow.

When I got mine, they seemed like plastic toys because of the light weight. At first, it's hard to believe they're real batteries.

I'm going to go with a Lipo set up next time. Those heavy bastards did a job on my neck and shoulders. I will have to mounnt my batteries outside, do you kow if there is a battery box available?

I put a 100 AH Lifepo4 in a size 29-31 box. Those are readily available. The 200AH Li's are an odd size so they need a special box. A little searching will find them. Many people get good metal locking boxes for security. Those can get pricey.

Be careful reading the measurements. I found that all of the box measurements are given at the top. They always taper to the bottom so the actual measurements are smaller.

All of those boxes seem to be black. Painting it white will reduce heat.

Thanks for all your input Rock.

I have an Oliver Legacy II that comes with 3 -130 AH US made Lithionics Lithium batteries (390 AH total) which can be charged through two 170w roof mounted solar panels or shore power if you wish. Amazing batteries which charge very quickly and can be discharged repeated down to 15% without any issues. Downside includes cost (bring lots of money) and the fact that you cannot charge your battery from your tow vehicle due to a typically lower charge voltage. You can bump the voltage with an inline DC-DC charger and an upgrade to the tow vehicle and (typically) trailer wiring ... need to upsize to handle the heavier loads. For that reason we carry a small Honda generator in case of extended cloud or tree cover which would lessen the effectiveness of the solar panels. After 1-1/2 years and 23,000 miles of four-season Northwest travel , we have yet to need the generator. A typical spring/summer/fall days usage will drop the bank by 7 - 10% and with any sun at all, we are back to 100% after 2- 4 hours. Fridge is the real power hog in our trailer and we switch to propane if not plugged into 110v.

There is a learning curve to Lithiums but I feel it has been well worth it. Lithiums are impressive batteries and I intend to put them in our sailboat when the 4 year old AGM's give up the ghost a few years from now.

Best bang for the buck, I believe, is still lead-acid flooded batteries.

Thanks for the input RC. I bought a new TT this and looking at battery and solar options.

The biggest issue I've found with Li's is cold weather. They can't be charged below 32F or they'll be damaged. Most have a built-in BMS (battery maintenance system) that prevents charging when it's too cold. If you use your RV for hunting in the cold, you'll soon run out of battery power since you can't recharge them. For cold weather storage, they'll hold a charge much longer than acids, but they still need to be topped up occasionally. For that, you have to keep them inside where it's above freezing.

By contrast, my old beater hunting camp trailer has 6V golf cart batteries. I can recharge them in the hills using my solar panels or generator when it's way below freezing. It got down to 12F on my last hunt this season and they charged up fine. The RV furnace pulls them down overnight so they need to be charged daily. Li's simply won't work for that kind of use.