Alternator to Lithium Battery Charging Question

I see the Battle Born LiFePO4s are 12V batteries.  Are 6V Battle Born batteries available?  I wonder if two 6V (if available) would have an advantage as is with wet acid and AGM technology.

Lead acid batteries are constructed of 2V nominal cells, 3 in a 6V, 6 in a 12V.   Any one of these cells go bad, its like a link in a chain goes bad. The whole chain is worthless.

Larger lithium batteries are different. Most that I have (VERY LIMITED!!) experience with are moving to use 16850 cells. These, with a central control unit, are packaged in a form that we are used to for car batteries. They have many that are in parallel, so failure of a single cell does not render the battery bad.



Here is a good video of a teardown of the Battleborn battery. https://www.youtube.com/watch?v=G5E30u-66VI  According to it, there are 120 3400mA 16850 batteries inside.

Hope that clears it up! 

Hello , I find it interesting that you are allowing wire gauge and a fuse to control the current flow for your lithium battery. Like you said lithium batteries have a lower internal resistance and will draw current almost like a short. Here is my understanding on the alternator current charging circuit for my house battery on my 2017 2552.  The relay under the hood below the coolant overflow container is what allows the house battery to be charged. The relay also is operated by the white switch on the dash so you can supplement the chassis battery with the house battery if the chassis battery needs a boost. My question to you is this an efficient/effective way of charging your new lithium ion batteries? No its not and here is why, you are relying on safeties for charging a fuse, wire diameter and BMS etc. Plus you are not controlling the current effectively to ensure your $$$$ batteries are being charge correctly. The original system was intended for like in kind batteries being charged from the alternator (lead acid).

Here is what my plans are, disable the relay when the engine is started to charge the house batteries but leave it so the white switch on the dash will still allow the relay to close if the chassis battery needs a boost. Then choose the DC to DC converter that best fits my needs 30amp, 40amp, 60amp etc. Wire it from the alternator to the DC to DC converter and then to the house battery using the proper AWG sized wire for the current flow. The DC to DC converters I believe use a trigger wire to start charging after the engine is started to prevent from draining down the chassis battery. Now I will be able to charge my battery faster, safer and with-in manufactures specs. Which should allow me to achieve maximum life cycles.

Solar charge controllers are a great way to charge lithium batteries as long as they have that charge profile for lithium batteries. If you are using a MPPT controller even better its almost 25% more efficient in lower light situations then PWM. This however is only one way to get your lithium batteries charged. Your converter is another, which you say is already capable of charging lithium batteries by the flipping of a switch to achieve the correct charging profile, why wouldn't you go the rest of the way and ensure that your alternator is doing the best for your lithium batteries? 

Everyone is talking about Battle Born batteries as being the best choice.  Don't get me wrong they are good batteries but I don't believe the best the market has to offer. I just had an opportunity to tour the Lithionics battery factory in Clearwater Fl, and I can say that they have surpassed build quality and BMS technology of the Battle Born batteries. Here is why, they are UL certified.... They are the first and only 12V lithium battery manufacturer to hold this certification. This means no matter what you do to there battery you will not have a runaway event (cascading cell failure). The batteries use prismatic cell design like a newer Tesla most auto manufacturers except Tesla... This means fewer connection points unlike the round cell technology of Battle Born which is like a bicycle battery using a bunch of spot welds... The battery housing is made of aluminum and the BMS is mounted to the inside of the cover, using it as a heat sink a very effective way to remove heat associated with all BMS's.   The battery comes with a heating blanket made into the case, so the battery will still operate at low temps. The battery is blue tooth capable, you can see every cells voltage, every charging event, discharge event, when the battery was born, serial number etc. Lithioncs has developed secondary alternator packages with Balmar and Waze specific for lithium batteries.  The Waze alternator actually communicates with the BMS to achieve optimal charging on Lithionics. There battery also has a switch that can be used to turn off the battery for storage, and if you want the switch can be remote located by adding another switch by simply plugging into a port.  These are just some of the basics I got from the tour. While I was there I found out that they just got a contract with Newmar to supply batteries, and they have had a contract with Winnebago and Coachman as well. This should give you some food for thought...  There is a youtube video that compares Battle Born to Lithionics check it out.  Here is the link  https://www.youtube.com/watch?v=Tt0joJc9HPo&t=6s


Very Respectfully
Lance

Hello , I find it interesting that you are allowing wire gauge and a fuse to control the current flow for your lithium battery....

I truly appreciate your input Lance!  I not only don't claim to be an expert, but I claim to be the opposite - which is why I've posted my questions here.  I've also called the PC factory, and Battle Born.  Both of those sources (in addition to others on this forum that have Battle Borns, solar, and a converter/charger with a lithium profile) said there is no need for a DC-DC converter for my coach.  I don't think of it as "allowing wire gauge and a fuse to control the current flow."  Those are just limiting factors for max current scenarios, which for reasons already discussed, should never happen - but the system is protected if it does.

I asked a couple of places that sell solar chargers, including Battle Born, if there would be a benefit to switching out my Samlex PWM solar charger (it has a lithium charge profile) to an MPPT charger.  They said the benefit of MPPT would be fairly insignificant given the size of my array - two panels, and the fact that I camp primarily out west, where it is typically sunny most of the day.  I would like to have a solar charge controller that provides stats and history, so I'm considering the Victron Smartsolar MPPT solar charger, even though I don't think it will make much difference in charging capability.  For now , I'm going to just try the "drop-in" method, monitor charge rates with the Victron Smartshunt, and see how it goes...

Those Lithionics look very cool, but boy are they expensive - almost 50% more per Ah than I paid for my Battle Borns, which were already expensive!

Prior to upgrading my solar panel capacity last summer  I utilized a Morningstar 15 amp MPPT solar controller  (relocated from a previous camper) with my original 320 watts of solar panels.  I also utilized the two golf cart batteries supplied by Phoenix and found this worked reasonably well given its capacity and the fact I got over 5 years service life. However I did find that during periods of compromised solar irradiance and higher power consumption the system capacity was lower than what I wanted.  I installed a 30 amp Victron MPPT solar controller to replace the lower capacity Morningstar unit and two 100 watt panels for a total of 520 watts of solar array capacity.  I have found this a very cost effective system when coupled with the reduced internal resistance of the Battleborn Lithium Batteries.  I particularly like the flexibility of adjusting the solar controller charge parameters via Bluetooth.  This Victron solar controller also networks easily with the Victron battery monitoring system allowing me to easily monitor system performance with my phone.


While I am an engineer I am not an electrical engineer and I know I have a lot to learn about battery and solar technology.  From my experience to date with the system described above as in most system designs I know there are cheaper systems as well as more expensive ones but I believe the Battleborn and Victron components to be a good balance between cost and performance.  I originally had considered another brand of Lithium battery but found their technical support lacking whereas Battleborn with their online resources and their prompt phone support and desire to fully answer my questions very reassuring.

Hello here is a good video for those of you who wonder about the DC to DC charger, he is using the 30amp Victron. Toward the end of the video at 11min, 15s you can see the results of the DC to DC charger by watching his battery monitor. This is RV with Tito, not sure if any of you follow this guy but he is pretty sharp and I like his basic approach and explanations....
https://www.youtube.com/watch?v=lvOYUfSBlmM&t=1s

Very Respectfully
Lance