Replacing OEM batteries with LiFePO4's

Frazier_Far_Out

2015 170" WB - 4 cyl
What is everyone using for a LiFePo4 BMS and Solar Charge controller? Anyone seen/heard of this guys (http://electrodacus.com/) project that marries the two specifically for LiFePo4 use? For $300 it seems like it might be worth a try.

Also, where is everyone sourcing batteries from? I am thinking to go with the CALB Prismatics or New Energy versions from the ElectricCarPartsCompany out of Salt Lake.

Lastly, anyone have experience with this AIMS inverter from Amazon. From the reviews it seems like a good product at a good price. The biggest downside that is holding me up is the $140 remote that gets terrible reviews. Anyone know if you could use a different remote?

Thanks!
 
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wade5979

New member
that's an interesting little piece of electronics. I used the same GBS batteries they use in their setup. got them from ev propulsion Advanced RV also uses GBS. If you get that BMS let the group know how it works out.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
Good to post that link! Chris and Cherie have been working with LiFePO4 technology for a long time now - they were the ones who got me interested. This particular link is a very good summary - they're quite clear about the pros and cons, the issues around the newness of the technology, etc. They've touched on the areas of debate in the community - mainly temperature issues, charging voltage and profiles, and float vs. no float. Good guys to read multiple times and carefully.
 

Eugene Rider

2016 Unity TB
I haven't called amsolar yet to see if they even have these but was looking starting with 2 - 200 amp and their system - 5 year warranty , then add to it

best warranty I have seen and seems to be priced right

https://www.victronenergy.com/

http://www.amsolarrv.com/lithium

Anybody check Victron out ?
I live in Eugene, called AM Solar, booked until July. The guy who started it has retired, sold it to his very competent staff. I'm going to install all the batteries myself with all kinds of goodies, will have some guidance from them and have all kinds of fresh ideas on the subject. AM Solar will consult with me, wonderful to have someone to bounce ideas off of.
Will keep everyone up-dated as this project goes along. Want to build a climate controlled area for these batteries, will see how that pans out. I didn't get the generator with the Unity.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
That'll be a cool project to watch! I'll bet your thread on it will get as big as this one is <g>...
 
I haven't called amsolar yet to see if they even have these but was looking starting with 2 - 200 amp and their system - 5 year warranty , then add to it

best warranty I have seen and seems to be priced right

https://www.victronenergy.com/

http://www.amsolarrv.com/lithium

Anybody check Victron out ?
Victron is high quality marine grade equipment so it should perform well in an RV. You will be paying extra for that level of equipment and it is likely not overpriced for the quality. Many will find that they are looking for something that still provides good value at a lower price point and that is rugged enough for an normal RV. The high end expedition vehicles typically use marine grade systems since the reliability and ruggedness is a key factor for overland travel and getting repairs is possible where they travel.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
Victron stuff is expensive, though not waaaayyyy more. Victron BMV 702 battery monitor is ~ $200, Tri-Metric 2030 ~$170. So in the ballpark.
 
True, some of the Victron components are not much more expensive but take a look at the complete Victron lithium battery systems that AM Solar is going to be selling. They look to be around twice the price of the ones sold by Starlight Solar that I linked to above that uses the same Elite Power System components used by Advanced RV in their high end Class B vans. I am sure the Victron stuff is more rugged and ultra reliable so likely the price is justified but maybe overkill for a typical RV.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
The thing I'd want to know is how much in depth knowledge each of the companies have. I know that AM Solar tests their systems pretty thoroughly before marketing them. I'd expect the same of Victron systems (though I don't know for sure), since they've been supplying marine systems for some time - my strong impression is that the marine world is further along with lith battery use and understanding than the RV world. On the other hand, I'm not sure about the drop in companies like SmartBattery and StarkPower. They seem more like sales outfits, and I've certainly had a hard time getting any detailed information at all from SmartBattery. Do you pay more for a system that's solidly designed and tested, or less for a system that may or may not be? It's a hard choice just now, since the field is relatively new and there's no consensus on some rather basic issues like how you should charge a battery bank.
 
Take a look at Elite Power lithium systems which seem to be pretty good from all reports. They are sold by Starlight Solar at the link above. They are used in the Advanced RV Class B which is known for selecting high quality components. This is also the lithium battery system used in the Wheeling It upgrade I linked to above. This is a step above the Smart Battery and Stark Power systems but surely not at the same level at a complete Victron system. No question that you need to do your homework and look at all the options...

http://www.elitepowersolutions.com/
 

lrcasella

Member
A larger converter won't help a lot to reduce charging time. Why? Main reason is cable size. At 14.4 volts and 70 amps, the cable voltage drop (if #6) will be about .3 to .4 volts. I suspect that you since you have a 55 amp converter, the cable is a #6. The maximum safe current for a #6 cable is 60 amps, so any converter larger than that is not per code and can cause damage. I'm not familiar with the Unity wiring but if it's done legally, the cable from the converter to the batteries will pass through a DC breaker or Fuse that is probably 55 amps, so even if you squeeze 70 amps out of the converter for a while, it probably won't last before you blow a fuse or pop a breaker. Of course, you could go to higher amp breaker and let the wiring overheat which, overtime, further reduces the current capability. Main issue with overcurrent, besides voltage drop, is the cable insulation starts to break down and eventually fail causing direct short.
 

wade5979

New member
Victron Support called Victron Engineering and got a detailed answer about Parameter 11, the relay mode parameter. Apparently it was an interesting conversation since the engineers are Dutch <g>...

The logic is the same for DFLT and CHRG: The control relay closes when ANY condition is met, but it only opens when ALL conditions are met. The difference is that in GHRG mode the relay responds only to the SOC and voltage parameters 16-21; in the DFLT mode the relay responds to parameters 16-31, so it will respond to temperature as well as SOC and voltage. They said that BMV-700 users set param 11 to CHRG but BMV-702 can set it to DFLT if they want it to respond to the temp sensor. There are also a few time delay params you can set (14 and 15) so that the relay doesn't keep popping closed and open with only small changes.
Peter, I know you have had other conversations with tech support since this post does the above logic still hold true any parameter activates relay but all parameters have to be made to deactivate relay?
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
It's true that for both DFLT and CHRG, any of the specified params activate the relay but all must be met to deactivate (assuming the relay operation is set to normal). But they haven't yet told me whether this includes the temperature parameters if you have a 702 with the temp sensor hooked up. I asked them to check with Engineering on this, but they didn't get back to me - this reminds me that I should call and push a bit for an answer.

I'm hoping that there's some unexplained logic for the temp parameters - if they work like the other params (which is what is implied in the Victron manual), they can't be used to block charging around freezing and allow it with temps higher than mid-30's.
 
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