3 tons
NV.
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Grit dog said, “Although I’m beginning to understand that this whole battery thing is like a new hobby for senior citizens. And we all know hobbies cost money so have at ‘er!”
Ha! Well if one considers that the ‘early tech adopters’ of some cutting edge innovations, including the introduction of the automatic transmission, dishwashers, no-defrost refers, air conditioning, microwave ovens, sprinkler systems, garage door openers (etc, ad nauseam….), and what’s now become an unprecedented quality of life (living BETTER than 18th century KINGS - widely assumed as some kind of ‘normal’ - lol!!), then I’d say our ‘seniors’ are deserving of some very HIGH Praise indeed!! ![[emoticon]](https://forums.motorhome.com/sharedcontent/cfb/images/smile.gif "smile")
3 tons
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Itinerant1
Itinerant
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profdant139 wrote:Great info -- very thought-provoking. Someone mentioned a generator. I have a Honda 2000 and almost never use it -- I run it at home to keep it tuned up. We camp in search of silence (since we live in the city). So the generator is more for emergencies than for convenience.
I will look into the BB self-heated unit. But I do have a question -- if I insulate the battery box, and we are camping in 25 degree weather (not that cold), I assume that the internal heater will cycle on and off, keeping the battery at 35 degrees, right?
If that is true, then the 1.8 amp draw from the heater will be fairly minimal, since it is not continual.
otrfun, if you have the time, could you tell us more about the DIY heater you made? You mentioned that it has a "Switchable control (thermostat or BMS)." Please forgive my ignorance -- what is a BMS?
Do you have a post or a youtube video describing your setup?
I like the idea of a separate heater that is not built in to the battery. I find that when features are bundled within a high-dollar purchase, one point of failure can trash the whole assembly.
BMS= battery management system.
Basically it's the protection for the battery cells. It could be...
HVD= high voltage disconnect
LVD= low voltage disconnect
High temp disconnect
Low temp disconnect
and possibly other things depending on which hasbeen used.
If 25f is the low and during the day maybe higher you should be able to easily come up with a solution to keep the battery warm. Theft might have to be thought about tho.
12v 500ah, 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts)2s4p,Panels mounted flat. Magnum PT100 SCC, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365, daily 35-45% DOD 2,500+ partial cycles.
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otrfun
On The Road
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profdant139 wrote: . . . if I insulate the battery box, and we are camping in 25 degree weather (not that cold), I assume that the internal heater will cycle on and off, keeping the battery at 35 degrees, right?
If that is true, then the 1.8 amp draw from the heater will be fairly minimal, since it is not continual Correct. True. The BB heating element appears to be very efficient. Not sure insulation is necessary camping at 25f. The ah savings would be minimal. At 0f, the heating element only uses 13.2ah in 24 hours. At 25f, I'd guess-estimate 5-6ah. To give you idea how insignificant that is, your RV, with *everything* turned off, would probably still use 24-36ah (of parasitic current) in 24 hours.
profdant139 wrote:, if you have the time, could you tell us more about the DIY heater you made? You mentioned that it has a "Switchable control (thermostat or BMS)." Please forgive my ignorance -- what is a BMS?
Do you have a post or a youtube video describing your setup? No worries. 18 months ago I didn't know what a BMS was either. To answer your question, the BMS (Battery Management System) continually monitors voltage/current/temp of the cells. If it monitors anything that goes below or above preset values, the BMS will immediately turn off charge or discharge current as appropriate---protecting the cells from any potential damage.
As for the "DIY heater", this was not something we installed on an existing OEM lifepo4 battery. It was something we attached to the individual lifepo4 cells as part of a 200ah lifepo4 battery pack we assembled from scratch. If you think you may be interested in building your lifepo4 cell pack, I'd be happy to provide further details.
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profdant139
Southern California
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No thanks -- I'm not going to build my own battery. My previous attempts at soldering have all ended up looking like abstract sculpture, and not in a good way. ![[emoticon]](https://forums.motorhome.com/sharedcontent/cfb/images/wink.gif "wink")
I might give it a try if I could assemble a battery using duct tape!
It sounds like I'd be better off with a built-in heater. I understand that it would not be strictly necessary to build an insulated battery box, since it's usually in the 25 degree range at night when we camp in the Sierra.
But why not build a cozy box and conserve energy? Is there a downside that I am missing?
2012 Fun Finder X-139 "Boondock Style" (axle-flipped and extra insulation)
2013 Toyota Tacoma Off-Road (semi-beefy tires and components)
Our trips -- pix and text
About our trailer
"A journey of a thousand miles begins with a single list."
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profdant139
Southern California
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By the way, if anyone is feeling entrepeneurial (I think that is how it is spelled), there is a need for a sturdy insulated Lithium-compatible battery box that can be mounted on the tongue of a trailer. I have done a fairly good Google search (more than ten minutes!) and have come up empty.
Most of the commercially available boxes are vented, which is not needed for lithium and which defeats the built-in heater that would be needed for cold weather operation.
And in addition to designing and marketing the box, why not come up with an external add-on heater that would go into the box? I think Ultraheat has something that would do the job, with a little modification. If that works, you would not need a high end battery with a built-in heater -- just the box and the external heater.
Almost every problem is a business opportunity! (But not for me -- I'm retired.)
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otrfun
On The Road
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profdant139 wrote:No thanks -- I'm not going to build my own battery. My previous attempts at soldering have all ended up looking like abstract sculpture, and not in a good way.
I might give it a try if I could assemble a battery using duct tape!
It sounds like I'd be better off with a built-in heater. I understand that it would not be strictly necessary to build an insulated battery box, since it's usually in the 25 degree range at night when we camp in the Sierra.
But why not build a cozy box and conserve energy? Is there a downside that I am missing? Hey, I'm not gonna rain on your parade. Your call. If it feels good do it--lol! Good luck with everything.
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pianotuna
Regina, SK, Canada
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Joined: 12/18/2004
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Hi all,
Does anyone know if LiFePo4 are endothermic or exothermic on discharge?
With 25 f being the target, life gets a lot easier.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.
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pianotuna
Regina, SK, Canada
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profdant139,
I think there are more than a few Li battery companies with heaters. Dakota being one of them iirc.
* This post was
edited 12/10/22 06:47am by pianotuna *
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Bobbo
Wherever I park
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otrfun wrote:Grit dog wrote:^Another PT Barnum quote hidden in the above reply. Insteading of being vague, why don't you specifically address the Barnum quote to help out the OP?
I think he is referring specifically to BB's high price. Consider it a Convenience Tax.
Bobbo and Lin
2017 F-150 XLT 4x4 SuperCab w/Max Tow Package 3.5l EcoBoost V6
2017 Airstream Flying Cloud 23FB
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StirCrazy
Kamloops, BC, Canada
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Joined: 07/16/2003
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pianotuna wrote:Hi all,
Does anyone know if LiFePo4 are endothermic or exothermic on discharge?
With 25 f being the target, life gets a lot easier.
Exothermic, if it was endothermic they would make your campsite colder as they warmed up....
2014 F350 6.7 Platinum
2016 Cougar 330RBK
1991 Slumberqueen WS100
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