Lithium Confusion

"(From what I have read so far, it looks like RVs and Lis don't mix very well in most RVing scenarios)"

This opinion is considered invalid by some here who have been using Li batts in their RVs with success in their particular scenarios.

They have not shown that their particular scenarios are like "most RV scenarios", so it is up to them to show how their experiences are in fact typical, and thus why most RV scenarios would work well with Li batts.

The confusion the OP has asked about is over
1.floating vs not floating, and we can add
2. whether to fill to 100% SOC or not.

BB has a list of chargers they consider suitable and some IMO confusing answers to questions on that topic in their website. If it were not confusing, people should be able to just read that and ask no more about it.

It would be of help to hear from those here who have been using Li drop-ins in their RVs what they do wrt those things. Not much has been heard in detail how they actually operate their drop-ins.

pianotuna wrote:

MDKMDK wrote:
Don: The Relion RB100-LT specifically designed to charge normally at lower ambient temperaures (-4F / -20C) - they use some of the charging power to self-heat, so that they can accept charge at a normal rate below 32F/0C. There's no chemistry involved, it's just a LiFePO4 battery that heats itself. I have 2 of them, bought last year, and they function as designed. They weren't cheap (C$1800/each) but they are worth every cent.

Hi MDKMDK,

Unfortunately I need -40. There is at least one LI chemistry that can do that--but nothing in a large format jar. Lithium titanate

Hi Don. -40? I can't imagine camping in anything at that temperature, but apparently you do. In that case, I guess your options are limited. I guess you'd better stick with lead/acid, in some form or another, until they develop miniature nuclear reactors for RVs. :B

BFL13 wrote:
"(From what I have read so far, it looks like RVs and Lis don't mix very well in most RVing scenarios)"

This opinion is considered invalid by some here who have been using Li batts in their RVs with success in their particular scenarios.

They have not shown that their particular scenarios are like "most RV scenarios", so it is up to them to show how their experiences are in fact typical, and thus why most RV scenarios would work well with Li batts.

The confusion the OP has asked about is over
1.floating vs not floating, and we can add
2. whether to fill to 100% SOC or not.

BB has a list of chargers they consider suitable and some IMO confusing answers to questions on that topic in their website. If it were not confusing, people should be able to just read that and ask no more about it.

It would be of help to hear from those here who have been using Li drop-ins in their RVs what they do wrt those things. Not much has been heard in detail how they actually operate their drop-ins.

Did you read my posts? I said, I've been using 2 X 100Ah Relion drop ins for almost 7 months now, and I have been charging them with a PD 9245/shore power, my MB 220A alternator, and my Zamp solar and ZS-30A CC w/AGM/Lithium settings to top them off. What part don't you understand? Perhaps I can help ?

The OP has made up his mind, see post #12 - no confusion there...
"Posted: 04/16/20 10:23am Link | Quote | Print | Notify Moderator
I have decided to go with the pendant mode. The switch to lithium is to gain OCCC and reduce maintenance of the lead acid batteries. Since I leave my coach plugged into a 30 amp outlet, any suggestions on a timer that would work would be appreciated. The idea of using a float charge with the pendant and a timer seems like a perfect solution.

Thanks for your ideas."
I see no confusion or anything about floating or charging to 100% mentioned. Where did you come up with those "resolutions"? Some FLA users have parroted some myths about lithium. Maybe that's where it came from?

As for Battle Borns "confusing answers" - perhaps you're applying FLA knowledge to lithium technology when you read it, and of course, it doesn't make sense to you? Either way, it makes perfect sense to those of us who have bothered to research and ask questions of the various technical support resources at BB or Relion or wherever.

Dude, give it up. You've waded into a pool of 'gators, and you're covered in bacon grease.

Yea I don't see the confusion either. Like any battery just follow the charging and operating specs for best results. Just do what it says, don't read into it. Not rocket science.

MDKMDK wrote:


Hi Don. -40? I can't imagine camping in anything at that temperature, but apparently you do. In that case, I guess your options are limited. I guess you'd better stick with lead/acid, in some form or another, until they develop miniature nuclear reactors for RVs. :B

Hi Mike,

I've used my RV at -37 C. Moving Sue and Photo Mike both have me beat--they have used their units at -40.

The lowest storage temperature for me is about -42 C.

My RV is modified to be able to survive these low temperatures. I don't have slides thank goodness.

I find this amusing:

“ They have not shown that their particular scenarios are like "most RV scenarios", so it is up to them to show how their experiences are in fact typical, and thus why most RV scenarios would work well with Li batts. ”

“Most RV scenarios” ??....I wish you good luck Sir on defining that one - lol !!

BFL13 wrote:

BB has a list of chargers they consider suitable and some IMO confusing answers to questions on that topic in their website. If it were not confusing, people should be able to just read that and ask no more about it.

It's been awhile since visiting Battleborn`s site and figured maybe they changed something that is confusing and doesn't appear to be. Here are some pretty straightforward questions and answers.

FAQ...
Q. Do I have to buy a special charger for LiFePO4 batteries?
A. You do not need a special charger to charge your LFP deep cycle battery. As I mentioned above the battery prefers to bulk charge at 14.4 volts and float at 13.6 volts. Most standard chargers can handle these settings. There are some made for lithium chargers available on our store page and they will charge faster than a regular charger in most cases.

Q. How long will it take to charge a LiFePO4 battery?
A. The length of time it takes to charge a li-ion deep cycle battery depends on the type and size of your charging source. Typically, you can only charge lead acid batteries below 20% of their actual capacity, this is not true with li-ion. You can charge a Battle Born battery up to 5 times faster, although we only recommend that you charge at 50% of the capacity to extend the life of your battery. Keep in mind that you can charge a 100% the capacity of the battery, this will shorten the cycle life (our measurements indicate this would result in 2000 cycles with 80% capacity remaining) but the battery and the BMS can handle it.

Q. Rate of Discharge and How does it Effect Capacity of a Battery?
A. The rate of discharge is how fast you are pulling power from a battery. It’s important to take this into account because most lead acid batteries are rated at a 20-hour rate – meaning the advertised capacity in amp hours is based on the fact that you will pull the power out slowly over 20 hours. If you discharge the battery in 5 hours you will get less energy out of the battery, then you would at 20 hours.
Our LFP (Lithium Iron Phosphate) batteries will deliver their advertised power even if you discharge them in an hour. Even at a 1C rate the batteries will give you close to 100% of their power. And they will do it thousands of times. A sealed lead acid battery discharged in an hour will give you about 40 amp hours. LFP is a better battery than an AGM battery when it comes to actual battery capacity.

Q. What is Depth of Discharge (DOD) and how does it affect a battery?
A. When a battery is discharged, the amount of energy taken out will determine the depth at which it was discharged. For example if you have a 100 amp hour battery and use 50 amp hours you have discharged the battery 50% which means the depth of discharge is 50%. If you took the same battery and discharged it only 20 amp hours or 20% of the battery, your depth of discharge will be 20%. This is an important number to keep in mind, because depending on which type of battery you are using, the number of cycles will be vary based on your depth of discharge.
Most lead acid batteries experience significantly reduced cycle life if they are discharged more than 50%, which can result in less than 300 total cycles. Conversely LIFEPO4 (lithium iron phosphate) batteries can be continually discharged to 100% DOD and there is no long term effect. You can expect to get 3000 cycles or more at this depth of discharge.

Q. What are the charging parameters and what chargers do you recommend?
A. Video will walk you through the required battery charging parameters and a couple chargers that we recommend. From video, 14.4v Bulk or Absorbtion, 13.6v or lower Float, Equalization off or @ 14.4v.

Q. What is a battery cycle?
A. A cycle is the process of fully charging and discharging a battery. Typically lead acid batteries cannot be cycled below 50% depth of discharge. If you go lower than 50% you will significantly shorten the lifespan of the battery. Our LFP batteries can be discharged nearly 100% for thousands of cycles without shortening their lifespan.

Q. How can I charge a Battle Born Battery?
A. You can use any standard charger, solar or wind charge controller to charge our LIFEPO4 deep cycle battery. There are some chargers and controllers that are programmable to get full usage out of your battery, but most will have an AGM setting which normally bulk charges about 14.4 volts and floats at 13.6 volts. These levels are great for your Battle Born battery.

Q. What is a BMS?
A. BMS stands for battery management system, this is the brain of our deep cycle lithium battery. The BMS protects the lithium cells from getting damaged in several scenarios. From low or high voltage, low or high temperatures, or if there is a short in the system. The BMS will shut off the battery to protect the li-ion cells and the user of the battery from unsafe operating conditions.
The BMS also regulates the amount of power you can take out of the battery. The BMS on our 100 amp-hour battery is rated to 100 amps continuous, 200 amps for 30 seconds and any higher loads for ½ second.
Our BMS also keeps all of the cells in balance. At the top of each charge cycle, the BMS reduces the charging rate in cells that have been topped off first, letting the rest of the cells catch up. This ensures that the cells are always in balance, and maintains the quality and efficiency of the pack.

Q. What are the current limits of your BMS?
A. Our BMS is rated to 3 different levels.
1. 100 amps continuous (1200 watts at 12 volts) – this means you can pull 100 amps out of the battery when you need it until the capacity is all used up. This would be a 1C discharge rate.
2. 200 amps for 30 seconds (2400 watts at 12 volts) – if your device has a surge an individual battery can deliver 2400 watts for 30 seconds.
3. ½ second surge up to the max capacity of the battery. If you have a high momentary over 200 amps the battery will handle this for ½ second.

*Keep in mind that when you have to 2 batteries in parallel you will double these surge numbers, with 4 batteries in parallel you will quadruple these figures.

https://battlebornbatteries.com/faq/

time2roll wrote:

BFL13 wrote:
If you have an inverter/charger, you must have the battery connected to it or you get nothing (unlike with a converter). How do you still get 12v to the rig and not float the battery?

Float is fine at a reasonable voltage. It is the PD converter designed for Li battery that will actually kill the Li battery. Insane.

Perhaps that PD profile is to avoid dropping to 13.x before the Li batt is to 100% SOC, per this from a link provided by Itinerant1 in the BB thread. (ISTR a BB comment on that too--will edit it in if found)

"A LiFePO4 battery can be safely overcharged to 4.2 voltsper cell, but higher voltages will start to break down the organicelectrolytes. Nevertheless, it is common to charge a 12 volt a 4-cell seriespack with a lead acid battery charger. The maximum voltage of these chargers,whether AC powered, or using a car's alternator, is 14.4 volts. This worksfine, but lead acid chargers will lower their voltage to 13.8 volts for thefloat charge, and so will usually terminate before the LiFe pack is at 100%.For this reason a special LiFe charger is required to reliably get to 100%capacity."

https://www.powerstream.com/LLLF.htm

It seems you then turn it off at 100% or now drop to 13.x for floating. That you do not leave it to float at 14.x is clear. There is some advice not to leave it floating at 13.x for a long time either, which the OP has seen, and wants a timer to limit his float time. AFAIK there is no automatic charger that will hold to 100% in the CV stage and then drop to Float.

The PD with CW has the auto drop to Float and then Storage but no timer for floating and it drops to Float before the battery is to 100%.

That should not matter if the Li does not need to get to 100%, which is often seen, but then why the emphasis on getting to 100% as in the above quote?

Since I am not allowed to speculate on that :) those who do have Li batts in their RVs can explain it better if they wish. ---I see Iteinerant1 has posted so will check that out.

"Q. How long will it take to charge a LiFePO4 battery?
A. The length of time it takes to charge a li-ion deep cycle battery depends on the type and size of your charging source. Typically, you can only charge lead acid batteries below 20% of their actual capacity, this is not true with li-ion. You can charge a Battle Born battery up to 5 times faster, although we only recommend that you charge at 50% of the capacity to extend the life of your battery. Keep in mind that you can charge a 100% the capacity of the battery, this will shorten the cycle life (our measurements indicate this would result in 2000 cycles with 80% capacity remaining) but the battery and the BMS can handle it."

It seems the author meant to say "DIScharge--below 20%".

Also charging up to "5 times faster" turns out to mean (I think) at a higher charging rate, and not to mean you can do a 50-90 in 1/5th the time it takes to do a 50-90 with a lead acid battery of the same capacity.

BFL13,

No, they mean for best lifespan, lead acid should not be charged faster than c/5.

Of course the charging rate for lead acid is a "moveable feast". If you want the least amount of shaling on the plates--keep the charge rate at 20 amps per 100 amp-hours of capacity.

Then at 85% state of charge, for lead acid, the "acceptance" rate is only 12.5 amps. As I'm sure you are aware, that drops more and more as the jar get closer to 100% SOC.

If my batteries are hungry I see 20 amps per 100 amp-hours (111 amps to the bank).