Battle Born battery at zero state of charge

[Air Doug]

I ran my Battle Born LiFePO4 100Ah battery to zero state of charge and I wanted to report here my experience. Through two errors on my part, a design shortcoming in the Truck Fridge installation by Lil Snoozy, and a weather event, a light was left on for an unknown amount of time in our Lil Snoozy and the battery went dead. All four problems had to happen together to drain the battery, which is another story. I will start another thread on that when I have some more information for a full report.

I had been checking the battery state of charge every few weeks during the first fall storage of the trailer after my Battle Born battery installation. See http://www.fiberglassrv.com/forums/f...ozy-85205.html
for information on the install. During one check, the master 12V power switch LED did not illuminate when I turned it on. I then checked the Victron BMV-700 and the light didn't even come on, much less provide any voltage information. I started to worry. I checked the voltage on the Battle Born battery with my multimeter and got a reading of 1.9V. I figured I had a $950 door stop at that point.

So I switched on the charger and the battery immediately started to charge. I have a 60 amp charger (also explained in the above install post), so I cycled it on for a minute or two only, then waited an hour or so and repeated. It continued to charge. So I stopped charging and ordered a 3 amp charger from Dakota Battery
https://www.dakotalithiumbattery.com...ithium-charger
and waited for it to arrive to continue charging. After it arrived I plugged it in and slow-charged the battery up to a 70% state of charge, which is where it is now.

The bottom line is that the Battle Born battery's battery management system shut off discharge before the battery could be irreversibly damaged. Battle Born has claimed in other forum posts that the battery has reserve capacity to protect the battery in addition to the advertised 100Ah . I don't have any specific performance data to confirm this, only what I reported above. I also don't know if repeated discharges to zero state of charge would reduce the battery's capacity or maximum number of charge/discharge cycles, but I don't care. The battery did what I hoped that it would do under extreme conditions and I couldn't be happier.

[David B.]

Doug, I am so glad your battery came back to life. Does the battery have to be slowly charged? I thought these batteries charged up faster than lead-acid batteries. Keep us up-dated on your progress and how the Truckfridge was wired incorrectly.
Thanks
Dave & Paula

[Air Doug]

Dave and Paula,

The battery doesn't have to be charged slowly and I specifically got a big converter/charger so I could charge quickly when on generator. But lower charge rates are supposed to preserve capacity and increase longevity. The altEstore says this on their website about BB batteries: "Lower C rates will extend the battery life. Mfr suggests a C/2 charge as optimal. After 3000 cycles, there will be approximately 75% battery capacity remaining if charging/discharging at C/1 rate." I've seen that multiple other places about LiFePO4 batteries. My 60 amp charger is is a little higher than C/2 and the 3 amp charger is way lower. I had the time so I used a lower rate.

The Truck Fridge issue is the lack of a cutoff switch. Lil Snoozy hard-wired it so it is always on. The main trailer DC cut-off switch doesn't shut off the fridge so the light comes on if the door is open. I will report back after I pull the fridge to install a switch like MCDenny did.

[Gompka]

Good to hear you had a positive experience. I know LiFePO4 are a different chemical composition than standard LiIon found in your phone or laptop, the LiFePO4 are more stable. They should work very similarly to your phone and laptop though, those devices get routinely discharged to the point the devices shut down in my case and they have lasted for 3+ years with little effect on battery capacity. Obviously, nothing is free and the more you charge and discharge a battery the more it gets used up, but the premium you are paying for these batteries is supposed to be justified by being able to discharge them all the way without damage.

[Tom 72]

Very good to hear. Many products from Teslas to flashlights use the 18650 lithium cell in banks. So do many ebikes.

Teslas have battery management systems, flashlights do not. If discharged fully by leaving a flashlight on, I have noticed several sets of 18650's will not accept a charge. I am still learning.

Yes, about a 2/3rds charge, I hear is good for storage.

PS, Gompka, I appreciate your reply below. I did not realize that at least some form of battery management system/protection is available at the individual cell level. More to learn.

[Gompka]

Originally Posted by Tom 72

Very good to hear. Many products from Teslas to flashlights use the 18650 lithium cell in banks. So do many ebikes.

Teslas have battery management systems, flashlights do not. If discharged fully by leaving a flashlight on, I have noticed several sets of 18650's will not accept a charge. I am still learning.

Yes, about a 2/3rds charge, I hear is good for storage.

Tom the 18650 example depends on if you are using protected or unprotected cells. Higher quality cells have a bms built into the top of the cell and it helps prevent overdischarge of the battery. The unprotected sells are mostly sold for people to make packs with and provide their own bms, although the wholesale market has found that consumers want these for their lower cost and people don't realize that with an unprotected cell over discharging can permanently damage the cell. I would think that at the price point Battle Born has a built in bms.

[CarlD]

Gompa,


The Battleborn LFP battery has a BMS that monitors temperature, overvoltage, undervoltage, etc. You can even charge them with a stupid lead acid charger if you want and it will shut itself off when fully charged, although it will charge slower. I use mine with my trolling motor and will also use it in my Lil Hauley when I get it.

[Air Doug]

Originally Posted by CarlD

Gompa,


The Battleborn LFP battery has a BMS that monitors temperature, overvoltage, undervoltage, etc. You can even charge them with a stupid lead acid charger if you want and it will shut itself off when fully charged, although it will charge slower. I use mine with my trolling motor and will also use it in my Lil Hauley when I get it.

Hey Carl,

Adding to your first sentence, the protection happens at the individual cell level, which is fantastic.

My experience with the WFCO charger supplied by Lil Snoozy is that the float voltage was too low to fully charge the BB battery. The battery had to drop below 12.2 volts (I think, if memory serves me) before it would kick into a higher charge voltage. That is almost fully discharged for a lead acid battery but more than 60% charged for a lead acid battery. Your charger must behave better than that. I believe that, in general, lead acid chargers don't have high enough voltage to fully charge LFP batteries. But the LFP batteries have such great capacity because of being able to fully discharge them that it probably doesn't matter for your trolling battery. Another reason to use LFP.

I look forward to seeing your Lil Hauly build out!

Doug

[CarlD]

Doug,


The other really really nice thing about the LFP for my trolling motor is the 27 pound weight!! I only put it in the boat when I am going fishing, so I haul it around a lot.

[Uplander]

Batteries are the penance one must endure if one must RV.

You might spend the time to read “the 12 volt side of life” available on the net...
Just google it !

Knowledge is power !
Battery technology seems to be in a state of flux and many of the batteries coming out of China are substandard junk. It is hard to find quality.

[Glenn Baglo]

Here: https://www.reuters.com/article/us-b...-idUSKBN1JZ11Y

[Civilguy]

Around 240 million euros ($280 million) will be invested in the first phase of the project, Wolfgang Tiefensee, Thuringia’s minister of economic affairs, told journalists.

BMW plans to source 4 billion euros ($4.7 billion) of battery cells from CATL over the next few years, with 1.5 billion euros coming from the new site in Erfurt in eastern Germany, the carmaker’s purchasing head, Markus Duesmann, said.

$4.7 billion return on just $280 million investment?!? That's over 16:1!

Out'a my way, count me in!

[David_I]

Originally Posted by Uplander

Knowledge is power !

Actually Power P = V × I = R × I2 = V2 / R, knowledge is something totally different.

[Air Doug]

Update:

I had some concerns in the back of my mind, wondering if you really could run the battery down to "zero" and not damage it. The three-year warranty from Battle Born is to retain 75% capacity.

A couple of months ago we were camped in the woods with cloudy days and I forgot to gas up the generator. By the time we drove to civilization for gas the battery was down 92 amp hours. So the battery retained at least 92% capacity after I ran it down.

I'm totally satisfied with that.

[CarlD]

We just returned from our 80 day Alaska adventure. We have the BB 100 Ah battery configured to charge from the truck and from 2 100 watt solar panels. The lowest charge state our battery got to was 35% and we never plugged into shore power. The most challenging camp site was in the redwood trees in Crescent City, Ca. Not a lot of light gets thru and we were losing about 20% per day. We only stayed 2 night so it wasn't an issue. We are really happy with our configuration.

[Rzrbrn]

Really appreciate your posting this Douglas. I am about ready to have solar installed on my Big Foot 25RQ and am considering using the Batterborn lithium batteries. I don't mean to hijack your thread, but why select a BB 100ah 12v over a BB 50ah 24v battery?

[Jon Vermilye]

Battleborn wants you to charge for at least 20 minutes per battery at 14.4 volts. This is the voltage when the cell balancing takes place. While you don't need to do it every day, charging to less than that constantly does not balance the cells, which can result in a shorter overall battery life.

As Doug noted, some standard converters & solar controllers will never get that high, staying in float at 13.6V or less unless the battery goes below 12.2V - 12.3V. Since a lithium battery will still be providing over 12.3V at 10%, the controller/converter thinks it is still over 70% full. The WFCO is one of the converters that seems to have his problem.

[Jon Vermilye]

Originally Posted by Rzrbrn

Really appreciate your posting this Douglas. I am about ready to have solar installed on my Big Foot 25RQ and am considering using the Batterborn lithium batteries. I don't mean to hijack your thread, but why select a BB 100ah 12v over a BB 50ah 24v battery?

You would need to add a DC to DC converter to power your 12V stuff if you went to a 24V system. The 24V system would allow for smaller gauge wiring, but unless you are looking at a large system (many KW of storage & an inverter) I don't see any advantage.

[Rzrbrn]

Thanks Jon

[Air Doug]

Jon said it just right.