Are lithium batteries worth the cost?

[Avid_Fox]

I can carry two group 29s in my AF1150.

Are they worth it?

[time2roll]

BMS does not throttle power. On or Off with a MOSFET or Relay. BMS is really the last resort to save the battery. You should have a voltage alarm to reduce power or keep track of the state of charge and temperature with the BMS APP. There is no load shed like there is for 120 volt systems that I know of.

Similar can happen to lead-acid but there is no limit to discharge and possibly freezing up and killing the battery. So it is the same type of monitoring if you are in extreme conditions. Possibly need a generator auto start in either case.

[otrfun]

time2roll wrote:
Generally the BMS will halt charging at about 0c and halt discharge about -10c.
Of course no reason to get below 5c as you would want to add a heater if going that cold. However your battery would be protected if an unexpected cold snap was to slam down suddenly.

According to BattleBorn you can safely charge LifePo4 cells below 32f (0c), but you must reduce the charge current accordingly. I would prefer the option to reduce/limit charge current when temps get down to say, -3 or -5c, rather than rule out all charging below 32f (0c). That's one of the reasons I'm hoping to find a LifePo4 charge current/rate vs. temperature chart. Of course, to pull this off you need a programmable BMS. A nice advantage of a DIY LifePo4 cell pack.

[time2roll]

Generally the BMS will halt charging at about 0c and halt discharge about -10c.
Of course no reason to get below 5c as you would want to add a heater if going that cold. However your battery would be protected if an unexpected cold snap was to slam down suddenly.

[otrfun]

FWC wrote:

Grit dog wrote:
Keeping on topic and out of Kayteg land....
Anyone have practical experience using them at low temps?
I only know what I’ve read and what I’ve experienced with my Snowbike lifepo4 battery.
Seems this is the one practical Achilles heel of them.

Yes, I have used my lithium pack in low temperatures discharge down to about -15C and charging at ~ -10C. The voltage was definitely lower at low temperatures, and I assume they loose some capacity (I have plenty to spare, so I have not tested this). The loss of capacity with temperature is true of all batteries, and is actually less severe with LiFePO4 vs AGM/FLA:

My concern with LifePo4's would not be so much reduced discharge current capacity at lower temps, but the chance of permanently damaging the cells with *excessive* charge (and discharge) current at or below a given temp. I've always heard you should dramatically reduce charge current (or not even charge at all) below 0c (32f) with LifePo4 cells. I've heard -18c (0f) is a very similar type of cut-off for discharge current.

Did a cursory look for a graph that shows the maximum charge (and discharge) current and temperature relationship for LifePo4, but couldn't find one. Have you seen one?

[Grit_dog]

Interesting. I thought the loss of capacity was similar to the charging loss and not better than lead acid. That’s encouraging

[FWC]

Grit dog wrote:
Keeping on topic and out of Kayteg land....
Anyone have practical experience using them at low temps?
I only know what I’ve read and what I’ve experienced with my Snowbike lifepo4 battery.
Seems this is the one practical Achilles heel of them.

Yes, I have used my lithium pack in low temperatures discharge down to about -15C and charging at ~ -10C. The voltage was definitely lower at low temperatures, and I assume they loose some capacity (I have plenty to spare, so I have not tested this). The loss of capacity with temperature is true of all batteries, and is actually less severe with LiFePO4 vs AGM/FLA:

[jaycocreek]

Have you used it in cool/cold weather yet?

Just our local weather with highs in the 40-50's when I ran my fridge for 11 days off it..I charged it up to 70% when I was done playing with the Engel fridge and haven't used it since because plans keep getting changed for my fishing trip..LOL..

But I must ad,I keep it inside my TC,not in the battery compartment provided so weather is not a concern to me..While using or discharging them in cooler weather is not a problem,it is the charging that is the problem below 32ish..

My last two batteries I bought off line came with several foam exterior protectors for the battery that would make a great insulator for colder weather and making an opening to the battery compartment for inside heat circulation...

For every issue there is a fix...LOL

[jimh406]

jaycocreek wrote:
Just for kix I went to Amazon this morning and typed in 100ah lithium battery and just in the first two pages there was 10 Lifepo4 100ah batteries for under $500...That makes them not overly expensive anymore imho and a good reason to make the change if someone has been on the fence on going lithium..

After being on the fence myself for sometime and finally buying one and using it,I could not be more impressed..

Have you used it in cool/cold weather yet?

[3_tons]

Is a camper better than a tent??...For some folks a tent can make more sense...

3 tons

[SV_K]

Is a Prevost worth the cost?
Well…if all you can focus on is the price per square foot, probably not.

Is a heated bathroom floor in an RV worth the cost?
Not if you base it against a pair of Walmart slippers?

Is a diesel pusher worth the cost?
Not if you base it on miles per gallon only.

Are new tires worth the cost?
Not if you think all is great because your old tires are still round.

Is an RV worth the cost?
Not to someone who is content car camping. They have heat, light, add a bucket and they
have a home built way stronger than your average RV.

Are lithiums worth the cost?
Apparently not. At least that’s what the guys who don’t have them say, and they should know.

[Grit_dog]

Keeping on topic and out of Kayteg land....
Anyone have practical experience using them at low temps?
I only know what I’ve read and what I’ve experienced with my Snowbike lifepo4 battery.
Seems this is the one practical Achilles heel of them.

[jaycocreek]

LFP batteries can also last a very long time. Our Battle Born LFP batteries are rated at 3000 cycles, at a full 100% charge/discharge cycle. If you did that every day it makes for over 8 years of cycling! They last even longer when used in less-than-100% cycles, in fact for simplicity you can use a linear relationship: 50% discharge cycles means twice the cycles, 33% discharge cycles and you can reasonably expect three times the cycles.

[jaycocreek]

Just for kix I went to Amazon this morning and typed in 100ah lithium battery and just in the first two pages there was 10 Lifepo4 100ah batteries for under $500...That makes them not overly expensive anymore imho and a good reason to make the change if someone has been on the fence on going lithium..

After being on the fence myself for sometime and finally buying one and using it,I could not be more impressed..

[specta]

Avid Fox wrote:

Double that capacity would be awesome. LI batteries weight half as much as regular deep cycle also.

Looks like you answered your own question.

They wouldn't be worth it $$ to me but we camp differently.

[otrfun]

Avid Fox wrote:

otrfun wrote:

Avid Fox wrote:
I can carry two group 29s in my AF1150.

Are they worth it?

We just built a 200ah LifePo4 battery pack that fits inside a group 24 battery box for approx. $750 purchasing cells and BMS from US distributors (~$550 purchasing from China). I've easily gotten ~160ah out of this battery pack under high loads (>100a) discharging from 100 to ~20% SOC.

You could easily fit two of these in your truck camper. This could provide you with 320-360ah of unrestricted, usable power without stressing the battery. LifePo4's can be discharged down to almost 10% SOC under extremely high loads with only a .2v to .3v voltage drop (lead cells drop 2-3 times as much). With proper cabling you'll have zero worries about low voltage inverter alarms.

With 320-360ah you could power a typical 10k-11k truck camper a/c (120vac, 10-11a) for at least 3 hours (100 to 20% SOC) with the compressor running 100%. With the compressor cycling you could probably get 4-5 hours. Amazing performance from just two, small group 24 sized LifePo4 DIY battery packs!

And what do you use for charging them? Are they in a truck or RV which use DC charging sources?

We have one DIY 200ah LifePo4 battery pack (group 24 size) mounted in our truck camper. We have enough room for two group 29's just like you. However, 200ah is plenty of power for us.

Some feel lithium specific chargers are necessary to safely and fully charge LifePo4's. I respectfully disagree. Any converter/charger that can produce 14.4v to 14.6v will charge LifePo4 batteries to 100% with zero issues. We use the standard OEM Progressive Dynamic 45a converter that came with our truck camper new. We manually select the 14.4v bulk mode with the Charge Wizard and let it do its thing. It produces a full 45a of charge current for nearly 90-95% of the charge cycle. It tapers down for the last 5-10%. A lithium specific charger isn't going to do any better. Although it's not really necessary, we manually select a 13.6v float charge when the charge cycle is complete.

We also have the ability to charge our LifePo4 battery pack with a Renogy 40a dc to dc charger we installed in our truck camper (it's powered by the alternator in our truck). It produces 39-40a of charge current. We can use both the OEM converter and dc to dc charger at the same time to charge our battery pack at 85-90a. This allows us to charge a nearly depleted 200ah LifePo4 battery (10-15% SOC) to 100% in approx. 2 hours.