Sprinter-Forum    
 

Go Back   Sprinter-Forum > Sprinter-Based RV's & Conversions > Sprinter-Based RV Brands > Leisure Travel Vans > Unity


 
Thread Tools Display Modes
Old 02-17-2017, 04:34 AM   #1
Incredulocious
2016 LTV Unity TB
 
Join Date: Aug 2016
Location: Santa Cruz, CA
Posts: 193
Thanks: 19
Thanked 115 Times in 65 Posts
Default Investigating drop-in replacement Lithium batteries

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've read that some (many?) lithium batteries can be damaged if charged at below freezing temperatures. When converting to lithium-based batteries, I see that some folks move their battery bank into the heated interior or add some mechanism to warm the batteries and I see that AM Solar adds a "cold charge disconnect" to their systems. Part of my concern is that even if moved inside, an unattended, cold-soaked battery would still potentially receive a charge via the solar system. Also, it would be simpler to replace the provided house batteries in their existing battery compartment.

So I asked these two manufacturers if this was an issue with their batteries and, if so, do their battery management systems (BMS) protect against charging at temperatures that are too low?

----- SmartBattery (Operating Range: 4F To 158F):

So far, I've only received a brief reply from SmartBattery that didn't exactly answer my question:
Quote:
The main effect low temperatures will have on our batteries is reduced capacity. [chart showing usable capacity from 103% at 140˚F down to 60% at -22˚F]
I've tried a couple more times to get a definite answer on charging at below freezing temperatures and I'll update this thread with any reply I receive.

------ StarkPower (Operating Range: -22˚F to 140˚F):

With StarkPower, it took several back and forth emails to get a more definitive answer:
Quote:
You are correct. You should take caution when charging below freezing temperatures. However, we do recommend operational temperatures for the unit between -22-140F. Again, you are correct that the BMS will protect the cells and battery from temperatures out of the recommended operating range. The unit will turn itself back on once in safe operating temperatures.
Note that this is not strictly true keep reading to their final answer.

Here's my follow-up: "Thats nice to hear. However, Im still concerned because on your web site your specifications include specific over- and under-voltage cutoffs and limits on charge and discharge current but no mention is made of any temperature safety cut-offs. Can you reference written documentation or warranty information on this temperature protection? I would not want to have to rely on just this email if it turns out there was a misunderstanding and that installing these as house batteries for my Sprinter-based RV and allowing them to charge via the alternator or my solar charge controller (even when parked and unoccupied) might damage them when the temperature drops well below 32 F. (I see that some installers like AM Solar actually add expensive cold charge disconnect systems.)"

Quote:
Yes. You can view specifications under the description tab at the bottom of the product page:

StarkPower Deep Cycle 12V9-EP has 12 volts and a 9Ah capacity and is perfect for powering your deep cycle systems. StarkPower Deep Cycle has an internal microprocessor controlled battery management system (BMS) that monitors the key operational parameters during charging and discharging, such as voltages, currents and internal temperatures. Easy drop-in replacement solution for antiquated lead-acid battery system with no modifications necessary.
I replied with: "That product description you referenced seems to only say that your BMS monitors these parameters. Its difficult to presume from this whether it disconnects the battery at high or low temperatures. If it does disconnect, you dont specify at what temperatures this occurs and whether these numbers are different for charging vs. discharging. May I suggest that you really need to describe these parameters as you do for the over- and under-voltage cut-offs and max currents in your specifications?"

This was eventually forwarded to their "head engineer" and CTO, Martin Koebler:

Quote:
Thank you for your feedback.
You are correct we should provide more data information on our website on temperature parameters along with max peak current. Usually our peak current allows for 3x of the continuous rating for 5 seconds. For our 12V 100Ah battery rated at 100A continuous our peak max current would be able to provide 300A for 5 seconds.

The BMS does turn off when the battery temperatures reaches 60C and typically needs a 10C temperature drop to automatically turn ON again. 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.

The exact values do have some variations with other variables involved such as part tolerances along with single cell voltage measurement vs entire battery pack voltage measurement.

I hope this helps some, we will continue improve information on our website to provide accurate information.
Incredulocious is offline   Reply With Quote
The Following 2 Users Say Thank You to Incredulocious For This Useful Post:
alichty (02-17-2017), DieselFumes (02-17-2017)
Old 02-17-2017, 05:34 AM   #2
DieselFumes
2015 4x4 2500 170 Crew
 
DieselFumes's Avatar
 
Join Date: Feb 2014
Location: WA
Posts: 854
Thanks: 99
Thanked 611 Times in 367 Posts
Default Re: Investigating drop-in replacement Lithium batteries

Wow. Good work being tenacious with these folks.

I was reading about charging lithiums below freezing on the battery university site.
Quote:
Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0C (32F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a sub-freezing charge. This is permanent and cannot be removed with cycling. Batteries with lithium plating are more vulnerable to failure if exposed to vibration or other stressful conditions. Advanced chargers (Cadex) prevent charging Li-ion below freezing.

Advancements are being made to charge Li-ion below freezing temperatures. Charging is indeed possible with most lithium-ion cells but only at very low currents. According to research papers, the allowable charge rate at –30C (–22F) is 0.02C. At this low current, the charge time would stretch to over 50 hours, a time that is deemed impractical. There are, however, specialty Li-ions that can charge down to –10C (14F) at a reduced rate.
What's interesting is that solar charging in the winter may not be more than 0.02C anyway. 200Ah batteries, 200W solar, you're probably not going to see more than 8A charge (although I wouldn't guarantee it).

I'm sure you're aware that it's possible to make a temperature-based disconnect for your charging sources. I agree it would be much better to see this done by the battery's BMS but if you're set on a drop-in system you could engineer something to make it work.

There are a couple of other vendors too - did you rule out Relion? Assuming you want standard size batteries then the Victron, Starlight and EVTV options wouldn't work for you.
__________________
2015 4x4 2500 170 adventure/camper conversion. See details, tips & tricks at sprintervanusa.com
DieselFumes is offline   Reply With Quote
The Following User Says Thank You to DieselFumes For This Useful Post:
charlievette (05-23-2017)
Old 02-17-2017, 03:40 PM   #3
Incredulocious
2016 LTV Unity TB
 
Join Date: Aug 2016
Location: Santa Cruz, CA
Posts: 193
Thanks: 19
Thanked 115 Times in 65 Posts
Default Re: Investigating drop-in replacement Lithium batteries

Quote:
Originally Posted by DieselFumes View Post
Wow. Good work being tenacious with these folks.

I was reading about charging lithiums below freezing on the battery university site.

I'm sure you're aware that it's possible to make a temperature-based disconnect for your charging sources. I agree it would be much better to see this done by the battery's BMS but if you're set on a drop-in system you could engineer something to make it work.

There are a couple of other vendors too - did you rule out Relion? Assuming you want standard size batteries then the Victron, Starlight and EVTV options wouldn't work for you.
Thanks. Not surprisingly, I've already seen both of those pages you linked to in my investigations. I also have a number of other lithium battery suppliers that I've found that weren't listed on sprintervanusa.com, but I've only followed up so far with SmartBattery and StarkPower due to their sizing and capacity.

StarkPower's claimed operating range is impressive if true. I mean to ask them how it's possible in order to both confirm their claims and to suggest that it's odd they aren't touting such a unique capability more loudly on their web site. I was tempted to link to batteryuniversity.com when emailing them earlier but decided not to.

SmartBattery is tempting because they have a single 300Ah self-contained battery that would appear to be narrow enough to fit in the Unity TB's compartment, providing even more amp hours than two Stark 125 Ah's batteries in parallel and leaving room to install this Victron BlueSolar MPPT controller I bought in the same compartment.

As for adding my own cold charge disconnect, I don't believe I have the expertise to do that, particularly after seeing the complexity of the package that AM Solar offers on their web site. I feel similarly about the more complex non-drop-in lithium battery kits. And of course there's a huge lead time with the well known installers and I haven't been impressed with the knowledge of my local RV shops.

Last edited by Incredulocious; 02-17-2017 at 03:42 PM.
Incredulocious is offline   Reply With Quote
Old 02-17-2017, 03:50 PM   #4
avanti
2014 GWV Legend 3500 I4
 
avanti's Avatar
 
Join Date: Sep 2006
Location: PA
Posts: 4,083
Thanks: 1,485
Thanked 2,547 Times in 1,564 Posts
Default Re: Investigating drop-in replacement Lithium batteries

Quote:
Originally Posted by Incredulocious View Post
As for adding my own cold charge disconnect, I don't believe I have the expertise to do that, particularly after seeing the complexity of the package that AM Solar offers on their web site.
I admit that I haven't been following the nuances of this issue too carefully, but wouldn't a generic home furnace thermostat suffice for rough-and-ready low temp charging protection? I guess you would have to find one with a set point low enough. Then again, there are off-the-shelf residential freeze-protection stat/relay devices available. People used to use them to turn on a red light in their window for their neighbors to see when they were out of town.
__________________
--Pete
Formerly: 2005 Airstream Interstate (2500 T1N)
Now: 2014 Great West Vans Legend SE (3500 NCV3 I4)
avanti is online now   Reply With Quote
Old 02-17-2017, 04:19 PM   #5
Peter Tourin
2012 LTV Unity MB
 
Peter Tourin's Avatar
 
Join Date: Oct 2013
Location: Jericho Center, VT
Posts: 1,981
Thanks: 824
Thanked 780 Times in 500 Posts
Default Re: Investigating drop-in replacement Lithium batteries

You can put a temperature controller in series with whatever you're using for charge control. Put the sensor in the battery compartment right on the batteries (the issue is battery temp going below freezing, not ambient temp). Set the controller to shut off at around 35 degrees and come back on after a time delay at some higher temp, maybe 40. There are dozens of these for sale on eBay very inexpensively, for example: http://www.ebay.com/itm/bayite-DC-12...IAAOSw-0xYiVft
I breadboarded one into my charge system circuitry and it worked quite well - you can test it with an ice cube <g>...

I had to press SmartBattery on this issue - lots of phone calls, as you're experiencing. This page http://www.lithiumion-batteries.com/...on-battery.php shows a chart with DISCHARGE capacity vs temperature, and the battery is quite useful over a wide range, up to 140F with slightly increased capacity and down -22 at 60% capacity - you won't be camping in the RV with battery compartment temps that low! But they finally told me that you couldn't charge them below freezing without damaging the chemistry. Thus the need for temperature sensing...

I don't know how these 2 companies are now, but when I was researching and calling them, getting real info was like pulling teeth. They're both battery sales companies, not manufacturers, and they seem to be much longer on sales talk than on solid technical information. Caveat Emptor!
__________________
Peter Tourin
2012 Leisure Travel Unity MB
Peter Tourin is offline   Reply With Quote
Old 02-17-2017, 04:34 PM   #6
ablock
 
Join Date: Aug 2016
Location: Marin County
Posts: 461
Thanks: 59
Thanked 176 Times in 114 Posts
Default Re: Investigating drop-in replacement Lithium batteries

That's interesting. Elite puts some of the GBS battery specs (we have 2 x 200 Ah packs) right on the web page. For operating (not charging) temperature limits they claim -20 to 65 C or -4 to 149 F, with 90% capacity at -20C. As for charging, the BMS will open the charging relay if any cell sensor reads lower than 0C.
ablock is offline   Reply With Quote
Old 02-17-2017, 04:47 PM   #7
DieselFumes
2015 4x4 2500 170 Crew
 
DieselFumes's Avatar
 
Join Date: Feb 2014
Location: WA
Posts: 854
Thanks: 99
Thanked 611 Times in 367 Posts
Default Re: Investigating drop-in replacement Lithium batteries

I appreciate that you don't want to do the wiring. The complexity isn't too high, but it involves learning about stuff you may not want to deal with. Of course, the alternative is to rely on the promises of somebody else and pay them for those promises. It's always a trade-off.

As Avanti and Peter say, it's not hard to build an in-line device that cuts the power. I'm using a small cheap thermostat and a larger capacity relay to control a heating element for my cold water tank (the relay on the thermostat isn't quite beefy enough for the current). You could use this same thermostat, with the probe taped to your batteries, to control a relay that can handle the power coming from your solar charger and/or shore power charger. Don't be scared by the fact that you can see the printed circuit board and the components. The thermostat just tells the relay when it's safe to open or close.

Alternatively you could wire up a heating pad under the batteries to keep them warm. If it works for my water tank, it should work for your batteries. Plus, if you run the heating pad from the batteries, the very act of using power from the batteries will warm them up - win/win!

By the way, I'd love to know what other battery companies you found so I can update the page I linked to.
__________________
2015 4x4 2500 170 adventure/camper conversion. See details, tips & tricks at sprintervanusa.com
DieselFumes is offline   Reply With Quote
Old 02-18-2017, 01:53 AM   #8
Steve Zoller
 
Join Date: Feb 2016
Location: Columbus, OH
Posts: 63
Thanks: 31
Thanked 22 Times in 19 Posts
Default Re: Investigating drop-in replacement Lithium batteries

Per Peter’s comment about these two companies being battery sales companies, try talking to Stephen Tartaglia, the Engineering Manager at Lithionics Battery. They make their batteries and I think he’ll tell you what they know or don’t know.
Steve Zoller is offline   Reply With Quote
The Following User Says Thank You to Steve Zoller For This Useful Post:
Peter Tourin (02-18-2017)
Old 02-18-2017, 12:08 PM   #9
Peter Tourin
2012 LTV Unity MB
 
Peter Tourin's Avatar
 
Join Date: Oct 2013
Location: Jericho Center, VT
Posts: 1,981
Thanks: 824
Thanked 780 Times in 500 Posts
Default Re: Investigating drop-in replacement Lithium batteries

Thanks Steve - I haven't looked at the Lithionic site in several years - their batteries are too tall to fit in my battery compartment. But their BMS and monitor system is nice at first glance. I can't even guess how many hours I spent trying to figure out how to monitor and do charge control for my SmartBattery installation - complete well-designed systems have a lot to be said for them!
__________________
Peter Tourin
2012 Leisure Travel Unity MB
Peter Tourin is offline   Reply With Quote
Old 02-18-2017, 12:39 PM   #10
Twinbridges
 
Join Date: May 2016
Location: Mt. and NC
Posts: 39
Thanks: 2
Thanked 16 Times in 10 Posts
Default Re: Investigating drop-in replacement Lithium batteries

I have 6 100 ah Relion batteries pared with Xantrex 2000watt charger inverter. It has a no charge setting that if I expect really cold temps I can just select do not charge. For temp monitor in insulated battery box I have Sensor Push remote which is about 1 inch cube that you control on your smart phone. You can set whatever limits you want and it alarms you as the temp passes that point. Very simple and user friendly. Also displays humidity and if temp is rising or falling.

Relion says the batteries will charge at less than 32 but with low charge rate but I just set the monitor and don't worry about it until the temp gets close to freezing and then just select no charging. With 600 ah I can really go a good while, several days, with no charge so not really a big deal. Maybe if I was in the artic or some other really cold place that might be an issue. I normally see the battery box is 8-10 degrees warmer than outside temp.
Twinbridges is offline   Reply With Quote
The Following 2 Users Say Thank You to Twinbridges For This Useful Post:
boogie944 (03-04-2017), TooMuchHair (02-20-2017)

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT. The time now is 11:38 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.