Battery Question

kenkorona wrote:
OP here. Thank you all for some great insights. I read all your posts and did other research and now I understand the pros and cons of the battery types. Now with that information other questions are raised and again I look forward to any insights you can offer.

I am planning on buying a new TC and it will not come with a generator nor with a generator hookup. I am also planning a pretty long trip for next year. Right now it looks like it will be a total of 4 months with at least 2 of them in Alaska. We enjoy boondocking; usually no shore power, so having adequate battery power is important.

To that end, I'm sold on the benefit of the lithium batteries and plan to put at least 2 in the TC. The reasons I'm sold on them are 1) lighter weight, 2) OK to discharge further without degrading its capacity, 3) accepts a charge faster.

So my next question is... is there anything special I need to know or do if I decide to put Lithium batteries in a TC when the manufacturer was planning on it using FLA batteries? The camper will be equipped with solar panels, either 2 or 3 100w panels. But my question is not about whether those panels would be enough to recharge that much battery capacity, rather the question is about the equipment's compatibility.

Thanks

I'd question "no generator hookup." You mean it's a 12V only unit with no provisions for shore power?

The bigger question is, your first post says you're currently camping with 2 plain ole batteries and no power supply issues to speak of and virtually no requirement for shore power (presume that's what you meant by "only used the generator once for 15min" since you also said you boondock.

What is it about your new camper and trip that makes you think you need to bomb proof the electrical system for an apocalypse?
Wouldn't 2 normal batteries and some solar maybe work just fine, like it is now?

I think many of these projects are more "hobby" than necessity.
IE, a person who plumbs in on board air all over the truck, DC-DC charger, big solar array, LiFe battery(s), super charge controller, best converter on the market, etc.....and then doesn't use the built in generator for anything.

Personally I'd analyze your needs before getting serious about big time upgrades.
JMO

Kayteg1 wrote:


All prime locations in Alaska will force you to stay at campgrounds.
When you really go into wild, you better have good supply of bear spray.

This has to be the most inaccurate city-slicker post of the month!

Thanks for the entertainment!

pianotuna wrote:
adamis,

Starting with the RV at -30 in storage, how do you plan on heating the batteries up? You can't draw much current from them, so you can't run the furnace. It is a fail. You could run a generator, but DAMHIK that may not work too well. Shore power would work running an electric heater.

There is a good solution which doesn't involve Li, which is cheaper unless you wish to "roll your own" Li.

Or more accurately, even though "you" personally want your rig "camp-able" at -30 deg and colder, LiFe's still have issues below freezing and you can't just "turn on he furnace" as one person suggested, although they will still "work" to discharge, IE provide power down to well below freezing (Not -30, someone can look it up though ). It's charging when the batteries themselves are around or below freezing.

Bottom line, they are a great option for lightweight, and duty cycle for warm weather campers. Not worth fiddling with if one is winter camping.
Although it appears some folks (on rvnet here anyway) really enjoy engineering and maintaining "off grid" solutions. I wonder if the "maintenance free" aspect of LiFe's is lost on the added $ and effort to make them work though.

for the original poster, they are buying 4 batterys because for the longest time all comercial builders offered was 100AH batteries. which for the average person with a older camper is enough. but new camper have slides, power awnings microwaves, ac, tv sterio and on and on where 100ah can be used up pretty quick, and you can usaly fit 4 in some of the larger battery compartments or genny compartments. the other way you could do it is to build your own and for a few inches bigger in a two of the three dimentions you can get up to 300ah in one battery.

pianotuna wrote:
adamis,


SiO2 share many of the attributes of LiFePo4. The difference is weight--where Li are lighter, and cold weather, where SiO2 can be charged and drawn from at -40. SiO2 do not need a a bms. They can be continuous discharged at more than double the rate recommended for Li, which makes SiO2 wonderful for large inverter use.

your forgetting a few things again also your previous post using the term cool weather realy. haha

so yes weight is a huge dufference, 1/3 to 1/4 the weight, cold weather meh for the 0.01% of people on here that extream camping might be a concern, and can easily be mitagated. even for you if you would move your house batteries inside the heated space.

I dont know why people are hung up on a BMS, it isn't something you need to buy extra, it is part of the battery.

dischage rate is good on SIO2 but you cant do it for very long. people tend to get hung up on this also, but it is a floating target. generaly the discharge rate is 1C, or a arbatrary number a manufactur sets because they want to save money and use a smaller BMS in there build. so at 1C on a 100AH battery the rate is 100amps for one hour where a 100AH SIO2 can only do it for 30 min if you want to get the most life out of them. also the thing I dont like about using the discharge rate is , who is going to put one 100 AH battery in a unit when they are planing on usung draws over 100 amps? as the original poster stated people are putting 4 batteries in so four 100 amp Li will give you a 400amp draw ability. or if battle born would get with it and start making things afordable and building what some other companies are you can get a 300AH 12v battery that isnt much bigger than the present 100AH offerings and they are 300amp discharge out of the box.

Li prices have droped to the point where SIO2 are actualy more expensive now also. and the other disadvantage to SIO2 which is also the reason people use them at -30 they only have 60% of the original capacity, which is way better than agm or LA ... so if you have a 100AH SIO2 qt -30 it only has a capacity of 60AH of which only 30AH are usable if you want the long life out of them. yes they can handle some totaly discharges but it still isnt recomended to go past 50% for max life on them. with Li , camping at that tempature takes some tempature managment planing so the battery will have 100% of the capacity availble.

there is downsides and upsides to both and I think SIO2 are one of the only two real choices and I think they are more for a specialized situation where you can't move your batteries and you don't care about weight. seeing this is in the truck camper forum I would say there is a good chance everyone who has a truck camper has weight of things on there mind as most of the campers now days are already over the capacity of most trucks before you even start. take mine for example, it is old and light, but after I squeezed two GC2 batteries into it to get a whopping 210AH capacity which I can only use 105AH out of. My weight when up by 132Lbs and I lost a outside storage compartment, yes I have a older unit that only had a space for a single battery and was to small to do anything with. when My LiFePo4 cells arive (sorry I can't aford to buy battle born and it dosent make sence when I can already put six 6V batteries togeather to have a 12V output. ) so I am building my own. there is a small useless storage area inside that amazingly is just large enough to get two home made batteries in,so I can expand if I put a microwave in later or what ever... right now I will just be putting a singel 300AH battery in which will give me 3X the capacity of what I have now, free up that whole outside storage again and reduce my camper weight by 90Lbs. its even a more dramatic change in the 5th wheel, Ill free up 200lbs of direct hitch weight, free up 8 cubic feet of storage in the front hatch and take the capacity from 230 usable AH to 900 usable AH.

Steve

kenkorona wrote:
OP here. Thank you all for some great insights. I read all your posts and did other research and now I understand the pros and cons of the battery types. Now with that information other questions are raised and again I look forward to any insights you can offer.

I am planning on buying a new TC and it will not come with a generator nor with a generator hookup. I am also planning a pretty long trip for next year. Right now it looks like it will be a total of 4 months with at least 2 of them in Alaska. We enjoy boondocking; usually no shore power, so having adequate battery power is important.

To that end, I'm sold on the benefit of the lithium batteries and plan to put at least 2 in the TC. The reasons I'm sold on them are 1) lighter weight, 2) OK to discharge further without degrading its capacity, 3) accepts a charge faster.

So my next question is... is there anything special I need to know or do if I decide to put Lithium batteries in a TC when the manufacturer was planning on it using FLA batteries? The camper will be equipped with solar panels, either 2 or 3 100w panels. But my question is not about whether those panels would be enough to recharge that much battery capacity, rather the question is about the equipment's compatibility.

Thanks

As several folks have already mentioned, you may want to consider building a DIY Lifepo4 pack. We purchased 4, 200ah prismatic cells and a 200a BMS from two different US distributors. Total cost was ~$800 for the cells, BMS, and hardware. We ended up with 200ah of capacity in 1/2 the space that two BB or Lifeblue 100ah batteries would have taken---at 1/2 the cost. The 4 prismatic 200ah 3.2v cells and BMS all easily fit inside one Group 24 battery box.

We often use our Lifepo4 to power our 11k a/c in our truck camper when we take short breaks on the road. When we get back on the road we use our 40a dc to dc charger to charge the Lifepo4 to 100% to prep for our next break. Already taken 3, 10-14 day, cross-country trips this summer powering the a/c on a regular basis with zero issues. Have given some thought to building another 200ah DIY pack to bump our capacity up to 400ah. We have enough room in our truck camper for two group 27 size batteries.

As for equipment compatibility, we passed on purchasing a lithium converter. Our OEM 45a 3-stage 14.4v lead-acid converter in our TC charges our Lifepo4 just fine.

adamis wrote:

pianotuna wrote:
adamis,

Starting with the RV at -30 in storage, how do you plan on heating the batteries up? You can't draw much current from them, so you can't run the furnace. It is a fail. You could run a generator, but DAMHIK that may not work too well. Shore power would work running an electric heater.

There is a good solution which doesn't involve Li, which is cheaper unless you wish to "roll your own" Li.

I am curious, is this your personal situation or a realistic hypothetical based on where you live.

Hi adamis,

I live where it gets to -40. I have boondocked at -37c (-34f).

I've had a generator fail to start at -29.

So it is my personal situation, before I was full time (5 years), and now afterwards when I'm back to trips starting with a cold soaked class C.

There are no storage facilities with shore power available in my town.

I believe LI batteries are excellent, but it is best to have an superior battery management system. Many folks are having good results using them.

For my personal situation and for anyone who has to deal with extreme low temperatures SiO2 share many of the attributes of LiFePo4. The difference is weight--where Li are lighter, and cold weather, where SiO2 can be charged and drawn from at -40. SiO2 do not need a a bms. They can be continuous discharged at more than double the rate recommended for Li, which makes SiO2 wonderful for large inverter use.

pianotuna wrote:
adamis,

Starting with the RV at -30 in storage, how do you plan on heating the batteries up? You can't draw much current from them, so you can't run the furnace. It is a fail. You could run a generator, but DAMHIK that may not work too well. Shore power would work running an electric heater.

There is a good solution which doesn't involve Li, which is cheaper unless you wish to "roll your own" Li.

I am curious, is this your personal situation or a realistic hypothetical based on where you live. Being from California, I'm a fair weather guy so your needs and view point are clearly going to be different. If the camper is in storage, is it stored in a location where you have no power at all?

Our cold weather is probably laughable by your standards. The one time we did camp in some colder weather it was probably in the high 20s. Now ordinarily the wife and I would just put some extra blankets on the bed and turn off the heater for the night. However on this trip, we had our seven month old twin girls along so it was necessary to keep the camper warm for their sake because we couldn't put blankets on them.

This was about the 4th night of camping for us where we were running the furnace to keep things warm for the girls. The previous three nights was lower altitude so we still had some juice in the battery as it didn't cycle as much. We were also running two bottle warmers that pull about 600w for ~5 minutes several times a day. If I had thought about it I would have run the generator for the bottle warmers so we didn't tax our battery so much.

The 4th night was the coldest by far and the furnace ran off and on all night. Thankfully it made it to right about 6am in the morning before the battery died completely. At this point it was getting really cold in the camper, too cold for the girls. It being early I was hesitant to start the truck and disturb others.

My truck does have a DC to DC charger to pull power from the truck when it is running but because it pulls directly from the battery via a larger cable (not the accessory line on the truck), I have a switch inside the camper that disables all of this unless I absolutely need it and know I will be running the truck. I was able to flip the switch and pull power from the truck batteries long enough to run the furnace for about 30 minutes to warm the camper back up. At this point I was worried the truck might not start but thankfully, she started right up. I then ran the truck a while so I could continue to run the furnace and keep the camper warm.

So a couple things I learned from this. First, I didn't realize the battery wouldn't charge when cold (BMS) so even while running the truck, the DC to DC wasn't putting anything but a trickle into the battery. I realized this much later when it dawned on me the cold weather limits for charging. The second thing I learned is that if I did this type of camping more often, I would get at least one more 100AH battery along with another 200w of solar (for 400w total) to make sure those batteries stayed topped up. Finally, the fact that I had a LiFePo4 battery allowed me to run it down to zero without fear of damage to it. With AGMs, I could have also run them down to zero but there would have been lasting impacts.

kenkorona wrote:
Right now it looks like it will be a total of 4 months with at least 2 of them in Alaska. We enjoy boondocking; usually no shore power, so having adequate battery power is important.

All prime locations in Alaska will force you to stay at campgrounds.
When you really go into wild, you better have good supply of bear spray.
Good side is that you don't need generator and AC for the trip.
We have been there in 2019, what was summer of century and we did get 72F heat wave. All Alaskans were sweating, when for us, coming from triple digits in Vegas, that was jacket weather.
With 2-3 solar panels, any pair of cheap batteries will power micro oven, coffeemaker and will still leave some power for morning furnace run if you extend the season.

pianotuna wrote:
adamis,

Starting with the RV at -30 in storage, how do you plan on heating the batteries up? You can't draw much current from them, so you can't run the furnace. It is a fail.

There is a good solution which doesn't involve Li.

You would start your furnace to warm the batteries, or if you have a battery heater yo would switch it on.

However, it is only a tiny percentage of folks who live anywhere where it regularly gets to -30, and of that percentage it is a vanishingly small number of folks who go camping in those conditions. You maybe one, but that does not imply that your limitations apply to others.

The lithium temperature issue is majorly overblown.

Most LiFePO4 batteries are rated to discharge down to -20F/-30C and will likely work lower than that, they are just not tested that cold. There is no BMS limit on low temperature discharge. The charge cutoff is programmed into the BMS and varies by manufacturer, but for Battleborn is is 24F/-5C.

A simple rule is that if you camp where your are using your RV water system, then you don't need to worry about lithium batteries.

It is fine to install LiFePO4 batteries inside the living space of the camper, in which case there is no temperature issue, as most of us don't keep our RVs below freezing when we are using them. If you cannot install the batteries inside the living space AND you plan on using your RV where the AVERAGE (not the minimum) temperature is significantly below freezing, then a battery heater and a blanket around the batteries may be necessary. You can buy batteries with a built in heater, or you can add an inexpensive tank heater under the battery bank.