Replacing OEM batteries with LiFePO4's

Eugene Rider

2016 Unity TB
You can buy batteries or buy systems. I'm going to get a time tested system from AM solar. The old owner is out testing the systems now in real life.
Two thoughts that are clear in my mind today. I knew more yesterday then today but know more today than tomorrow. But, I know people who know.
 
No question that if you purchase one of the Victron lithium battery systems shown on the AM Solar site you will have a high quality, rugged, reliable, well integrated system. It is a complete off the shelf system from one of the best marine suppliers.
 

wade5979

New member
I guess it would hold true if the relay was inverted (function #12) to open (activate) and close (deactivate) then all the upper limits have to be met to close (deactivate).
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
Eugene, I'm glad you feel that you can be absolutely clear about... about... about that <rofl>...

I know that AM Solar has been updating the website but hadn't noticed that they've gone to Victron systems. Expensive, but I also would think it would be a very solid way to go. Eugene sure said it: "You can buy batteries or buy systems" - I did the former and I'm still working to get my charging system set up. Half the price of a Victron system, 10 times the work <g>...

Wade, I don't think switching Param 12 is of any help. You'll still use 16/17 the same way for SOC, 18/19 the same way for voltage and 26/29 the same way for temp. If you set 16 for low SOC and 18 for low battery voltage, going down past the setpoint of either one will change the relay state. Same logic no matter how you set Param 12. But if you invert it, the relay is normally held shut instead of sitting open - and going below any setpoint will open it instead of shutting it. That's a convenience for using the relay to drive different systems but it doesn't change the logic.

You'll notice that in the Param 12 section they say that the monitor will use more juice in the normal state if you invert - that's because it's added the current to hold the relay shut.
 

pattonsr

New member
Eugene Rider,

Have you thought about where the Victron system will be located? I know you deleted the generator. Are you thinking of an outside compartment or inside under one of the twin beds? Then you have to run a 3/0 or 4/0 wire to that location from the Balmar regulator controlling the second Nations alternator. Add a compressor fridge and you are all set.
 

Eugene Rider

2016 Unity TB
Eugene Rider,

Have you thought about where the Victron system will be located? I know you deleted the generator. Are you thinking of an outside compartment or inside under one of the twin beds? Then you have to run a 3/0 or 4/0 wire to that location from the Balmar regulator controlling the second Nations alternator. Add a compressor fridge and you are all set.
I don't know yet but would like it in between the wheels. I have not gotten the Unity yes, pick it up this Friday so will be looking more at the set up.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
The word is in from Victron support - you can't use either the low temperature/clear or the high temperature/clear parameters to control battery charging in conjunction with the SOC or voltage parameters - the logic isn't correct. Too bad! - it would have been very slick. Eugene, I like the direction you're going - way easier on the brain cells!
 

Eugene Rider

2016 Unity TB
The word is in from Victron support - you can't use either the low temperature/clear or the high temperature/clear parameters to control battery charging in conjunction with the SOC or voltage parameters - the logic isn't correct. Too bad! - it would have been very slick. Eugene, I like the direction you're going - way easier on the brain cells!
I will keep the Unity board informed.
I'm picking it up at Johnson RV tomorrow, have my 2016 Subaru Crosstrek ready to be towed back behind the Unity. Did all the tow stuff myself, Road Master all the way. Nice stuff.
Have new fans, rear shocks, rear sway bar, Rear view mirror with Homelink,... to do.
 

wade5979

New member
Has anyone come up with a satisfactory solution for the below freezing charging condition. Any battery heating pad solutions?

Thanks
 

israndy

2007 LTV Serenity
Roadtrek's website seems to say they have a complete solution. I don't know what it looks like to copy their solution, if they are buying from a 3rd party or if it's all custom. Their manual seems to indicate their BMS will not allow charging when it's full or frozen, nor draining when it's below 20% or frozen. The heating pads come on when the engine comes on if needed. The engine can come on automatically if the batteries need a charge or if the AC needs to run. I think the Advanced RV guys probably have an equal system. Still looking for an aftermarket setup.

-Randy
 
If you are interested in the Stark drop in lithium batteries, here is an installation in a Travato...

http://www.classbforum.com/forums/f23/stark-batteries-finally-in-my-travato-5430.html#post43921
Here's the direct link to their Stark batteries installation where they dismiss their previous Smart Battery lithium setup for not having a "true" BMS like the Stark battery:
http://wincrasher.blogspot.com/2016/04/stark-power-lithium-battery-upgrade-for.html

However, they've since switched to a single, large Lithionics battery, now calling the Stark BMS rudimentary:
http://wincrasher.blogspot.com/2017/01/lithionics-600ah-lifepo4-battery.html

They've also been cycling through chargers and solar controllers...
 

ablock

Member
However, they've since switched to a single, large Lithionics battery, now calling the Stark BMS rudimentary:
Weird. He writes:

...the NeverDie BMS has a low end cut-off. It's set at 10% SOC. The thinking is, that it will shut itself off before it can be completely discharged and leave you stranded.
Is he suggesting the Stark didn't have a low-voltage disconnect? That seems very odd as 100% discharge can mean permanent death for a lithium pack.
 
I've written to StarkPower and SmartBattery to ask each about what sort of protection they offer for below freezing temperatures for their "drop-in replacement" lithium battery systems. I'm still waiting for a satisfactory answer from SmartBattery (beyond "the main effect low temperatures will have on our batteries is reduced capacity") but after several back and forth emails with StarkPower, I got this reply from their CTO, Martin Koebler:

We do not have low temperature charge control since 99% of the time the battery can take a charge even at lower temperatures. Our batteries are used outside in the field in extreme conditions such as in Alaska where customers do insulate the batteries with extra insulations.
They rate their batteries for use from -22˚F to +140˚F.

I'll post a more complete summary of my email exchange in a separate thread, for those that are interested.
 

boogie944

New member
I've written to StarkPower and SmartBattery to ask each about what sort of protection they offer for below freezing temperatures for their "drop-in replacement" lithium battery systems. I'm still waiting for a satisfactory answer from SmartBattery (beyond "the main effect low temperatures will have on our batteries is reduced capacity") but after several back and forth emails with StarkPower, I got this reply from their CTO, Martin Koebler:



They rate their batteries for use from -22˚F to +140˚F.

I'll post a more complete summary of my email exchange in a separate thread, for those that are interested.
I asked someone from Victron Energy who mentioned the temperature limits are for the cells, not the ambient temperature. He mentioned it is very unlikely that cell temperature of an active battery drops below freezing. He mentioned only need to worry about first time charging when the battery is not in use.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
Funny - I just read that StarkPower thread and started wondering about low temp charging again - I just emailed Victor at SmartBattery and asked a few questions, including low temp charging. When I bought my batteries, they told me that charging when the cell temp was below freezing would damage the cells. I wrote and asked whether this is still how they feel or whether anything has changed with their experiences over the last few years - I'll let you know if I get an answer.

It is correct that the charging issue relates to the cell temp and not the ambient temp. So I suppose you could argue that if you store your RV at home in the winter and get a sudden yen to travel, it's safe to apply a 12V load, and the load will warm the battery chemistry so that they'll be fine by the time you need to start charging them. But I'd still want to understand the issue of below-freezing charge issues before I took that route!

I'm still not sure that I understand that StarkBattery comment about "use from -22" - I don't know whether he's referring to charging (that'd be a better spec than SmartBattery) or just discharging (SmartBattery says 60% rated capacity available at -22; their discharge vs temp chart basically says the same thing as StarkPower, that is, -22 to 140 F).

I'm trying to be sure I always know what I'm asking and what they're answering, because I can picture wanting to take winter trips now and then.
 

casmith32

Member
Peter -

Everything I've come across says that it's safe to DISCHARGE LifePo4 batts when below freezing (per manufacturer spec of course), however your capacity diminishes as temps drop I believe.

However ideally you do not want to charge them at or below freezing.

So in general you wanna have your charge sources off when battery temps or battery compartment temps approach freezing; unless you pull a draw from the batteries, which would likely keep the batteries at a safe temp for charging.

Funny - I just read that StarkPower thread and started wondering about low temp charging again - I just emailed Victor at SmartBattery and asked a few questions, including low temp charging. When I bought my batteries, they told me that charging when the cell temp was below freezing would damage the cells. I wrote and asked whether this is still how they feel or whether anything has changed with their experiences over the last few years - I'll let you know if I get an answer.

It is correct that the charging issue relates to the cell temp and not the ambient temp. So I suppose you could argue that if you store your RV at home in the winter and get a sudden yen to travel, it's safe to apply a 12V load, and the load will warm the battery chemistry so that they'll be fine by the time you need to start charging them. But I'd still want to understand the issue of below-freezing charge issues before I took that route!

I'm still not sure that I understand that StarkBattery comment about "use from -22" - I don't know whether he's referring to charging (that'd be a better spec than SmartBattery) or just discharging (SmartBattery says 60% rated capacity available at -22; their discharge vs temp chart basically says the same thing as StarkPower, that is, -22 to 140 F).

I'm trying to be sure I always know what I'm asking and what they're answering, because I can picture wanting to take winter trips now and then.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
Yes, that's exactly my understanding too. It's why I'd like to get a clarification of the StarkPower quote - I'm betting that quote is about temp range for USING the batteries, not CHARGING them. I also haven't been following the lith forums as much as I used to, and I'm curious whether a few years of in-the-field experience is causing the battery suppliers to relax that minimum charging temp or not. But I doubt that anything has changed.
 

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