Questions about lithium batteries for travel trailer

[Josh and Sonya W]

Hi All,

We have a 2003 Bigfoot 25RQ that we purchased used two years ago. The trailer came with a 2013 heavy duty, tractor/truck, lead acid battery (estimated by the manufacturer to be about 100Ah, though lead acids are not usually rated that way).

The Bigfoot is our move up from a 17ft Casita that we purchased new in 2017. The idea has always been that when I finally retired, we wanted to spend a lot more time on the road, and my wife wanted more space and a walk-around bed (but still had to be fgrv).

We just did our first big trip, total of almost five weeks in Grand Teton National Park, and Flaming Gorge, UT. In preparation for the trip, we purchased a ZAMP 160 Watt portable solar panel, and we did the whole trip boondocking.

It worked out great, but despite checking out as OK by NAPA before we left town, the old lead acid battery was clearly declining. At the start of the trip, the battery would charge up to over 14V with about four hours of sun. By the end, it would barely make 12.7, and would drop pretty quickly as soon as I disconnected the solar array.

Oops, sorry. Yes there is a question in here somewhere.

After a bunch of reading, I've pretty much decided to go with lithium-iron-phosphate; leaning towards Relion as the brand. I found a local dealer that specializes in solar installation, but only during the winter.

The dealer has a Relion 300AH lithium battery that has been his floor model for about nine months. He's willing to give me a good discount on it; very tempting. I had him pull out a volt meter to check the battery, and it read 13.3V, presumably after sitting around unused for nine months.

So actually a few questions:

1. Is there any disadvantage to an LFP battery that has been sitting around unused for a long time? I've read that shelf life is one of the good things about LFP batteries, but should I be wary (the guy is a very strong salesman).
2. I was thinking about 200-400 AH capacity, but was planning on going with two or three smaller batteries. The price of the 300 AH battery is a really good deal, and it can be installed under one of the dining room seats. It occurs to me that having more than one battery gives us a bit of safety in the terms of possible battery failure, i.e., not all eggs in one basket. But one battery sure is simpler. Does anyone have any experience, good or bad, with one vs several lithium batteries? I can't see a disadvantage of having extra battery capacity, even if we may not have enough solar capacity to fully charge it up on any given day (or days).
3. For now, I'm not yet ready to put solar on the roof, need to do caulk removal and new caulking, cleaning, waxing, etc. It's still too hot to do that, so we'll keep using the ZAMP unit for now. Besides, I feel more comfortable trying things out for a while before going all the way. The ZAMP comes with a controller that has a setting for lithium, and ZAMP assures me that our unit would work great with a 300 (or any) lithium battery. We'll just be using 12V stuff in the trailer, and maybe a small inverter to charge and use laptops, phones, etc. We don't really need or plan to heavily use 110V electricity, so I'm not planning to move to a big inverter right now.

Does anyone have any advice about whether what I've described above are good or bad ideas? I'd very much appreciate comments and warnings about things to look for or avoid.


One problem: I probably have to make a decision about the 300 AH Relion battery tomorrow. I'll be out of town after that for a couple of days, so I might lose it. However, the battery is a big chunk of money, and I don't want to make a bad decision in terms of being able to meld it into an eventual roof-mounted solar system (but still, probably not more than a couple of hundred watts above, and the portable as a supplement on the ground.


My apologies in advance, I know this is long.


Thanks,
Josh

[John in Michigan]

I suggest considering two alternatives to buying/using one Relion RB300 battery:

1. Buy one or two RB100 batteries (rated 100 amp hours each)

2. Just buy two lead acid batteries and use the $$$$$ savings to spend on other things

The logic behind alternative 1 is that lithium batteries provide TWICE the useful capacity of lead acid batteries so you only need to buy half the rated battery capacity to get the same amount of energy. Lead acid batteries should only be discharged 50%.

The logic behind alternative 2 is that lithium batteries are still 10 times as expensive as lead acid batteries, so if you have other stuff you want or need, buy that instead.

Lastly, I am not familiar with the Relion technology. From what I have read, when charging lithium cells, usually electronic circuits must be added to ensure all cells charge up to the same voltage. Does Relion address this effectively inside each battery and across multiple (up to 4) batteries?

[John in Michigan]

Shelf life: From what I have read, lithium batteries have very long shelf life, so this is probably not a concern in purchasing a display model battery.

Reliability and fire hazard: From what I have read, lithium batteries if and when they fail can produce a much more intense fire than lead acid batteries. While this may be a low probability, what about in 5 or 10 or 15 years? It seems to me that down the road there could be a cell failure or a circuit failure. In consideration of this unlikely event, I would probably install the battery on the tongue...

[Ken C]

Just passing some good info along here, as other get to your specific questions.
http://www.fiberglassrv.com/forums/f...tml#post652474


Lithium Ion Batteries for RV Motorhome House System - LFP / LiFePO4 | Technomadia

[SilverGhost]

Originally Posted by Ken C

Just passing some good info along here, as other get to your specific questions.
http://www.fiberglassrv.com/forums/f...tml#post652474


Lithium Ion Batteries for RV Motorhome House System - LFP / LiFePO4 | Technomadia

Interesting read - the article also touches on running AC on solar. SPOILER - not practical and/or only for a few hours at a time.

Jason

[Raspy]

If the battery in question is really a lithium iron battery, the safety issues may not be important. Standard lithium batteries will burn spontaneously with moisture, but not Lithium Iron.

They do have a long shelf life, but no matter how long, the one you are looking at will last three years less than a new one. And since you are being pressured, I'd skip it. I also like the idea of having more than one battery for a fail/safe response to a failure.

Be sure you understand the charging needs and hardware required to support the lithium batteries. A whole new charging system in addition to the batteries?

Your analysis about the charging of your lead acid batter doesn't make sense to me. It load tested OK? It used to be easier to charge up?

When lead acid batteries fail, it's often a slow process of getting sulfated. This reduces the capacity of the battery and makes it easier to charge, because it has less capacity. If yours is taking longer to charge it may mean you are drawing it down farther before charging and it is still good, or hasn't failed as much as you think. Does that make sense?

[Josh and Sonya W]

Hi John,

I'm going to try something I haven't seen done before in the fgrv forum; trying to answer in your text in red. Don't know if it will work here.

Josh

Originally Posted by Raspy

If the battery in question is really a lithium iron battery, the safety issues may not be important. Standard lithium batteries will burn spontaneously with moisture, but not Lithium Iron. Correct, this is a lithium/iron/phosphate battery, fire should be a non-issue (at least until it happens, but it's not supposed to. ;>)

They do have a long shelf life, but no matter how long, the one you are looking at will last three years less than a new one. Agreed, they are supposed to have a long shelf life, especially in terms of not loosing their charge when sitting out of use. In the case of this battery, I caught the seller by surprise, and have no reason to believe he charged this or any other of the batteries he had sitting out in his showroom. I asked him to put a volt meter on it and it read 13.4V, presumably after the nine months it had been sitting on the floor. I called and spoke to Relion about the battery, and when I got to the voltage reading, the rep I talked to said that 13.4V was almost a full charge. The rep was not concerned about the time sitting around. I'm wondering why you think the battery would have three years less of a lifetime than one that has been sitting around for nine months, can you explain? And since you are being pressured, I'd skip it. Yes, I agree about the pressure thing, that's a bit of a turnoff, and maybe a warning sign. However, I did as much checking as I could, including more than half an hour of grilling a knowledgeable person at Relion in SC, and came out feeling fairly confident (self-deluded?) that this battery was a pretty good deal (i.e. almost $900 below list price; yeah, I know, another "dangerous" indication. I also like the idea of having more than one battery for a fail/safe response to a failure. Yes, I agree. Full Disclosure: After making sure the person I trust to do the installation is willing to take the job on, I went ahead and bought the battery yesterday. I sincerely hope I don't live to regret it. I'll update this Email string as I gain more experience with the battery.

Be sure you understand the charging needs and hardware required to support the lithium batteries. A whole new charging system in addition to the batteries? I discussed this with both Relion and Zamp (we have a Zamp 160W portable solar array), and both say that the trailer charging systems should work fine with the Lithium battery (truck alternator or shore power). The Zamp system comes with a charger as pat of the package, and it has a specific setting for different types of batteries, including lithium. However, the Zamp charger is PWM, which will not be as efficient as the more sophisticated and expensive MPPT type of charger. I'm hopping that the lithium setting on the Zamp charger will adjust some of the settings so that it will be a bit closer to MPPT in terms of charging efficiency. Eventually (maybe November), we'll probably take the next step and put a 325 Watt Panasonic solar panel on the roof. At that time, I'll get a new charger, and maybe an inverter so we can run the microwave occasionally, as well as more easily run computers and other small loads.

Your analysis about the charging of your lead acid batter doesn't make sense to me. It load tested OK? It used to be easier to charge up? Yes, it load tested OK, and it did seem to charge up more easily.

When lead acid batteries fail, it's often a slow process of getting sulfated. This reduces the capacity of the battery and makes it easier to charge, because it has less capacity. If yours is taking longer to charge it may mean you are drawing it down farther before charging and it is still good, or hasn't failed as much as you think. Does that make sense? In our case, the battery seemed to take a good charge fairly easily at the beginning of the trip, getting to well over 13V with just a few good hours of sun. As the trip went on, I found that the battery seemed to respond very quickly to the solar array, jumping up to high 12's almost immediately, and if the sun was good, the battery reading on the Zamp controller would get over 13V. Checking with my voltmeter, the battery would read the same charge. However, as soon as I disconnected the solar array, or if the sun went behind a cloud, the battery voltage reading on the Zamp and at the battery would immediately drop down to about one volt less than when the sun was out. It soon became apparent that I couldn't get the battery above about 12.5-12.7 volts. Even with minimal demand at night - two LED's and occasional use of the water pump, the battery was often down below 12V in the morning. Another odd think: I have little faith in the battery indicator that came with the trailer. However, at the beginning of the trip, the indicator would would get up to a full four bars. By the end, it was getting to a blinking third bar, and very quickly dropped to two bars, which is already the undercharge zone, if I remember correctly.

So this kind of sounds to me like what you were describing about a dying battery. Indications were that it was charging quickly, but it was not taking a full charge, wasn't holding a charge very well, and we were probably progressively drawing it down further and further each day.

There's a lot to think about when dealing with batteries...

[Buggeee]

I read that your solar panel comes with a controller that can manage a lithium battery. When you do plug into shore power, if ever, your onboard converter will be managing the battery, unless you disconnect it from the 12v system and go for solar 100% on that charging circuit.

Even though the sales rep said that the lithium battery would be ok on a standard charger, that has me scratching my head. Because I've never heard anything like that before. I'm not on lithium in the egg yet, but have a lithium electric car and have read a bunch about it for a couple years. Which means I know nothing. But still, double and triple check that comment until you are confident that YOU are the expert before plugging lithium into a standard charger. The consequences can be, well, significant... And not just for your battery.

I was browsing Progressive Dynamics site, for other reasons, and noticed they have a new line of controllers rolling out specifically for lithium. I'll litter your thread with a link in the event you, or any onlooker, finds it useful. Here you go:

https://www.progressivedyn.com/lithi...tery-chargers/

In the meantime, maybe consider just leaving the lithium battery on the solar charger all the time and disconnecting the onboard converter leads from the 12v system for now.

I'm more than a bit jealous of this acquisition by the way. Excellent find.

[Buggeee]

...oh, and another thing. Lol.

Lithium Iron Phosphate may or may not spontaneously burn in the presence of water, but I'm pretty sure you can toast your battery, and surrounding areas, by charging them wrong. Again, I know just enough to be dangerous (think Cliff Claven) so become your own expert and then clue the rest of us in. Lithium is a new frontier.

By the way, I heard an interview on the radio with some 98 year old dude who supposedly invented lithium or something, one of the heads that got us here, and he has realized something new that is going to blow it all wide open again. So there you have it meaningless babble from me. Stop over the site tomorrow for a coffee and I'll spew some more. Enjoy your Saturday with your awesome battery!

[Bill Lindenfelser]

Buggeee (did I get the correct number of e's?),
Thanks for the leads through Progressive. I'm chasing down the battery manufacturers called out there, asking each for a proposal for a replacement for our 2015 Trillium's sad electrical system (100W PV panel + 80A-hr deep-cycle Pb-acid, which bit the dust after only a year of service--RIP. That on the heels of its predecessor, which died similarly.)
I'll let you and others know what I learn.
Regards,
Bill

[k corbin]

Perhaps the first question to ask is "is there anyone reading this question who has any actual, hands on, experience using lithium ion for the house battery bank in their travel trailer? If so how long have you been doing it for?".

[Josh and Sonya W]

Originally Posted by Buggeee

I read that your solar panel comes with a controller that can manage a lithium battery. When you do plug into shore power, if ever, your onboard converter will be managing the battery, unless you disconnect it from the 12v system and go for solar 100% on that charging circuit.

Even though the sales rep said that the lithium battery would be ok on a standard charger, that has me scratching my head. Because I've never heard anything like that before. I'm not on lithium in the egg yet, but have a lithium electric car and have read a bunch about it for a couple years. Which means I know nothing. But still, double and triple check that comment until you are confident that YOU are the expert before plugging lithium into a standard charger. The consequences can be, well, significant... And not just for your battery.

I was browsing Progressive Dynamics site, for other reasons, and noticed they have a new line of controllers rolling out specifically for lithium. I'll litter your thread with a link in the event you, or any onlooker, finds it useful. Here you go:

https://www.progressivedyn.com/lithi...tery-chargers/

In the meantime, maybe consider just leaving the lithium battery on the solar charger all the time and disconnecting the onboard converter leads from the 12v system for now.

I'm more than a bit jealous of this acquisition by the way. Excellent find.

Hi Buggee,

Thanks for the thoughts and the concern, I'm a bit worried as well; I'll read the link shortly.

I asked the specific question about essentially "dropping in" the Lithium battery in place of the old lead acid unit of both the retailer of the battery, and the seemingly pretty knowledgeable rep at Relion headquarters in SC . Both said the trailer charger/controller would be no problem, though the seller of the battery did tell me that until I switched to an MPPT charger, I would not get the full benefit of fast charging.

Can't remember which of them asked me an interesting question, the retailer or the Relion rep: Does the microwave work if I'm running on battery only. The answer is no, and for whatever reason, to that person, that meant there would be no problem with switching to the Lithium battery without having to worry about the current controller in the trailer.

Still makes me nervous; I'll try to contact Bigfoot by email, to see if they have any comment. I think it's OK, and you are correct, I'm certainly not an expert yet, and I'd hate to become an experienced expert the hard way.

[Josh and Sonya W]

Originally Posted by Buggeee

...oh, and another thing. Lol.

Lithium Iron Phosphate may or may not spontaneously burn in the presence of water, but I'm pretty sure you can toast your battery, and surrounding areas, by charging them wrong. Again, I know just enough to be dangerous (think Cliff Claven) so become your own expert and then clue the rest of us in. Lithium is a new frontier.

By the way, I heard an interview on the radio with some 98 year old dude who supposedly invented lithium or something, one of the heads that got us here, and he has realized something new that is going to blow it all wide open again. So there you have it meaningless babble from me. Stop over the site tomorrow for a coffee and I'll spew some more. Enjoy your Saturday with your awesome battery!

HaHa! Unfortunately, I'm out of town for a few days. I'm also waiting for a battery monitor I ordered, so I can get that installed the same time as the battery. So the battery install won't take place until late next week.

FYI, the monitor that was recommended to me by the Relion rep I spoke with is this one:

https://www.amazon.com/Victron-BMV-7.../dp/B00MJ9TAN8

Seems to have good reviews, but I don't know anything more about it.

The 98 year old dude and his comment "...something new that is going to blow it all wide open again." Is not exactly the terminology I'd like to hear right now.

[charlsara]

FYI, the monitor that was recommended to me by the Relion rep I spoke with is this one:

https://www.amazon.com/Victron-BMV-7.../dp/B00MJ9TAN8

Seems to have good reviews, but I don't know anything more about it.

Some of the folks over on the Snoozy forum are using them. They love them. I just ordered mine.

[Raspy]

Originally Posted by k corbin

Perhaps the first question to ask is "is there anyone reading this question who has any actual, hands on, experience using lithium ion for the house battery bank in their travel trailer? If so how long have you been doing it for?".

I've had some experience with Lithium Iron on my boat for main propulsion. I have a Morgan 33 sloop with an electric drive and Lithium Iron batteries.

It will go over 16 miles and run for over 4 hours and still be going. I don't know what the maximum range is.

It has a special charger and cell monitors to manage the charging process.

In my case, I wish it had a small diesel of about 27 hp as that would be more practical for me.

It would be fun to have a big bank of lithium power tool batteries. Those are very powerful and grouped together in a bank of about 10 or 20 would provide a lot of power to our trailers.

[Buggeee]

Originally Posted by charlsara

FYI, the monitor that was recommended to me by the Relion rep I spoke with is this one:

https://www.amazon.com/Victron-BMV-7.../dp/B00MJ9TAN8

Seems to have good reviews, but I don't know anything more about it.

Some of the folks over on the Snoozy forum are using them. They love them. I just ordered mine.

Sounds good to me, I've got one on the way now too. I'm in the midst of a fresh build of this egg and for some reason I placed a rule that there'll be no propane inside, basically cuz this is a really tiny one. So I'm looking to do stupid things with my batteries and this will help me a lot. Thanks for doing the leg work on that.

[Josh and Sonya W]

Originally Posted by charlsara

FYI, the monitor that was recommended to me by the Relion rep I spoke with is this one:

https://www.amazon.com/Victron-BMV-7.../dp/B00MJ9TAN8

Seems to have good reviews, but I don't know anything more about it.

Some of the folks over on the Snoozy forum are using them. They love them. I just ordered mine.

Good to know, thanks Charlie.
Josh

[Mike Magee]

Without knowing the price, the battery itself sounds sweet. Glad you could afford it and will be reaping the benefits. It's probably the last battery you'll ever need to buy for your trailer, unless you abuse it horribly (which I doubt).

I'd take a 300AH LiFePO4 battery in a heartbeat if someone offered it to me!

[Josh and Sonya W]

Originally Posted by Mike Magee

Without knowing the price, the battery itself sounds sweet. Glad you could afford it and will be reaping the benefits. It's probably the last battery you'll ever need to buy for your trailer, unless you abuse it horribly (which I doubt).

I'd take a 300AH LiFePO4 battery in a heartbeat if someone offered it to me!

Thanks Mike. I just hope the battery lives up to my rationalizations for taking the plunge.

I definitely plan to take care of the battery. That being the case, after reading the various comments in this string, I'm going to call both Relion and Zamp again when I get back home, to double check on the question of charger/controller.

If it turns out that I might shorten the life of the battery (in terms of cycles or longevity) by not using an MPPT charge controller, the next step will be to ask Relion for a charge controller recommendation to work with their battery. Then I'll talk to Zamp to figure out how to bypass the controller (PWM-type) that came with the 160 watt portable unit we have, and wire it into a new controller.

I'm hoping this will all turn out to be not as complicated or expensive to modify as my overthinking can lead to. And if Relion reassures me again that there is no problem or possible damage resulting from using the Zamp charge controller on its lithium setting for a few months, I'll stick with that for a while. I'd like to see how everything works, before making other modifications (like adding a solar panel on the roof).

Josh

[Defenestrator]

A non-MPPT charger is fine for LFP, although an MPPT controller might let you get slightly more out of your panel. Unlike lead-acid, it's perfectly fine to leave a LFP battery partially-charged for long periods.

The main things to worry about with LFP are:
1. Do not charge it when the battery is below freezing. It's OK to discharge down to around 0F, but trying to charge it below about 32 will damage it.
2. Do not use a desulfating charger or desulfation mode on it. The brief high-voltage spikes can resurrect a lead-acid battery, but will kill a LFP.

You also have to be more careful about excess charge or discharge levels, but the Relion has build-in high/low voltage cutoffs that will keep it from being totally ruined.