Lithium vs AGM

[brianconn]

I have pondered the Lithium vs. AGM topic for some time. Being an electronics engineer, I know about semiconductor failures. The BMS contained in the Lithium battery is an electronic control system using semiconductors. I can just imagine a failed semiconductor turning a very expensive Lithium battery into a heavy door stop.

I've not seen any evidence whereby the BMS can be repaired or replaced for a given battery. Given the infant mortality of electronics, I believe it safer and more economical to go the AGM route.

Agreed there are MANY benefits to using Lithium batteries. Rapid charge, deeper discharge without damage, current limiting, etc.

Bob

Thanks Bob! I think I'll take your advice.
Brian

 

[brianconn]

I‘ve used lithiums in my Polaris Ranger EV and an RV solar installation that would run an air conditioner for 8 hours after dark. But always with automotive lithium battery cells/modules (Nissan Leaf modules) using external charge and control electronics. I agree with Bob - I wouldn’t want to invest in lithium batteries that rely on internal electronics.

That said, if I did own a lithium battery bank with internal electronics that “went bad” outside of warranty, I’d take the thing apart and try to salvage the cells. From what I’ve seen, they are all 2.2 volts and just arranged in different configurations for varying applications.

Looking at the Ecotrek manual, my guess would be that while the BMS may have failed, it also might have protected your lithium cells/modules.

https://www.roadtrek.com/wp-content/uploads/2017/04/HOWTO-EcoTrek-Battery-Guide-April-24-2017.pdf

Lithium batteries have a very long service life when cared for properly and “electronics in the batteries have failed” is to vague to use as a basis for the decision to downgrade the system to AGM batteries. I would recommended more diagnostics and research before condemning the battery bank. You may already have this info, but if not, start with this:

http://home.roadtreking.ca/Manuals/FBgroup/Ecotrek%20Lithium%20Battery%20Reset.pdf

Thanks for the links Rich. I'll check them out

 

[Beemingbill]

Brian,
I bought a new Roadtrek Zion in Feb. and it now has 7500 miles on it. On our last trip one of the lithium batteries went bad and at the same time the shorepower converter quit working. That left us without AC and we had to spend the last two nights of our trip in motels because of the heat. I have a friend that bought a new Roadtrek Play and the lithium batteries went bad, burned up the alternator and nearly started a fire. It took his dealer 6 months to get the batteries replaced as no one had any of his type and style in stock and they were on back order. I would never buy an RV with Lithium batteries again. I have had 10 previous campers and one previous class B with Lead acid batteries and never had a minutes trouble with them. You can buy replacement AGM batteries at any auto parts store at 20% of the cost of lithium. I have had so much trouble with both the Roadtrek and the Dodge Promaster. It has been back to the Dodge dealer 5 times for two problems that they can't fix and back to the Roadtrek dealer 3 times for 6 different problems.
We are very disappointed after spending $125,000 and not being able to take one trip without several problems.
My dream of owning a new class B has turned into a nightmare. Just my 2 cents worth that I had to get off my chest.

Finely got the service dept. to work on my 21 Zion after over 30 days setting there. It seems that the number 1 battery went dead and would not turn back on even though the number 2 battery was still working. How does that happen? They are always both turned on at the same time but one goes dead and the other works normally! Some how they got it working again ( I need to find out how to do this myself), but the converter part of the inverter needs replaced and it has taken a week for the supplier to find and ship a new part. This is the 6th problem I have had to take it back to the dealer to get fixed. Along with the problems I have had with the Promaster itself. Needless to say I am not a fan of Roadtrek

 

[siggy]

I have pondered the Lithium vs. AGM topic for some time. Being an electronics engineer, I know about semiconductor failures. The BMS contained in the Lithium battery is an electronic control system using semiconductors. I can just imagine a failed semiconductor turning a very expensive Lithium battery into a heavy door stop.

I've not seen any evidence whereby the BMS can be repaired or replaced for a given battery. Given the infant mortality of electronics, I believe it safer and more economical to go the AGM route.

Agreed there are MANY benefits to using Lithium batteries. Rapid charge, deeper discharge without damage, current limiting, etc.

Bob

Hi Im not an engineer by any means, but I did run into a lithium battery that I was contemplating buying its made by AOLithium. Its been said that this battery is repairable. They actually show the insides on U tube. Interested in your opinion.

 

[Bob K4TAX]

Simple ---- more parts = higher percentage of failure. Of course, many pieces of medical equipment use Lithium batteries. They are operated by non-technical people and are expected to work when needed and not fail when pushed to the limits. Most medical applications have routine maintenance and inspections of equipment by qualified personnel or companies. I find this to be not necessarily so of RVs, etc. Many cell phones use Lithium technology but those go obsolete, usually before one can get them out of the box and home. I refer to the "cell phone model of the day".

Since we rarely boondock but do carry a suitable generator, I've found no reason to invest in Lithium technology for camping. A good quality AGM does the job for us, and the heavier weight of AGM vs. Lithium is not an issue. As to the longevity of AGM vs. Lithium, I seem to think both are about the same. Thus it comes down to $$/year of cost. Others of course may and will disagree.

I can always tell "mama" that I'm going to buy a new $150 battery for the trailer and she says "OK". If I said I'm going to buy a $750 battery I would get lots of ............. well you know. Not going there.

Bob

 

[Advanturous]

Interesting problem here and one of the problems immediately inherent is no system specs have been published so it is hard to know exactly what is being discussed. After spending some time researching Ecotek it seems the Ecotek is likely a 12 volt system but again I don't know as it has not been published. 2 Modules ( aka a battery which has a rebranded "marketing" name I also suspect ) equals how many amp hours or watt hours? Maybe 400 Amp hours? Maybe 800 Amp hours? Not sure. The batteries or modules should be clearly designated if you inspect them. We really need system electrical specs ( not some companies rebranded for profit jargon) to have a meaningful discussion. Having said that there are a few things I do have an opinion on from looking at other bits of information gleaned from a some amount of research. I believe your Roadtrek likely has a second alternator for recharge purposes and I believe that alternator is a 12 V alternator so lets start there. This assumption indicates you need 12 V batteries so that you don't have to replace other bits and bobs of equipment making it more expensive. Next thing, I read a 2018 document that said there is a 6 year warranty on Ecotek. Could you still have warranty perhaps? Then I wonder about temperature shut off. Lithium batteries ( the good ones.... not all of them ) have high and low temp cut offs in the BMS. Perhaps your batteries reached a high temp alert given the time of year you are posting? Maybe the BMS have just not reset? Could be as simple as that. I don't know how serviceable these Ecotek "modules" are I have never seen one. Are they a metal case or plastic glued I am not sure. So if I was you I would walk away from your RV tech. Number one, he has failed to learn all of the information developed in the last 10 to 15 years and wants to drag you down a road back to the 90s at his profit and your expense. I would not want the extra space and weight of a battery bank I can only use 50% of the amp hours of good for several hundred cycles. Not when I can use 80 to 90 % percent of a lithium bank good for 4000 cycles and STILL have 80 percent capacity. Much cheaper long term. And charge much quicker and more efficiently. Oh, and to change to AGM you will have to change the charging profiles of your chargers lest you burn out the AGMs did your tech tell you that? Hope that he did and knows how to make those electrical adjustments. This is pretty basic stuff to understand so anyone who doesn't get that probably I would walk/run away from. Next I would find a battery shop that sells nothing but batteries and knows lithium and take the van over there and have your batteries ( modules? why do we need to complicate things) removed from the van and tested by a professional and if they come up bad ask why and about how much to install a new BMS. You need to determine if it is the cells or the BMS that is bad or maybe an internal connection. Proceed from there depending if your batteries are serviceable or not. If not I feel for you. You should not have to use the same BMS as what is OEM but if you do change you change them in each battery. You determine the BMS by what cells you have and what features you want. A good battery shop/distributor will know this.

This fellow on Youtube is the real deal and he doesn't sugar coat things I like him. Spend some time on his channel and educate yourself a bit. He has been extremely successful telling the truth and how refreshing is that these days!
I think the SOK is a very good serviceable battery so I chose this particular video and it has a link to a distributor and price should you choose to use it. You could go with Battleborns at twice the money but it is not necessary. In this video he also talks about cell quality and the differences. I don't know what "Ecotek" uses. Who owns Ecotek anyway? Anyone know? And now you have a price point in your back pocket before you enter the battery shop and an idea of how to proceed. Will also has a forum for Lithium/Solar with lots of good resources so that is where i would go ask for a battery shop. Empower yourself and have the correct specifications at the ready. I am in no way affiliated or associated with this video channel. This is simply a resource for everyone here to use and educate themselves with.

 

[Advanturous]

I am also assuming you have checked your charging wire from your charging alternator and made the modifications to the wiring known for your vintage Roadtrek. There have been cases of it just being a loose wire in the charging circuit.