Be cautious ordering generic blue wrap LFP cells
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Alloy
Well-known member
Looks like there's an aquarium heater in the glycol tank
shade
Well-known member
I think something along those lines is the way to go, whether it be liquid based or heating pads.
Relatively low wattage in an insulated battery box, with a simple thermostat. Low power consumption would allow it to be left active continuously over long periods, which would keep all cells at approximately the same temperature. No need for more control than that, and no hot or cold spots in the battery. It may take some experimentation to find the right wattage to maintain the desired temperature, but once that's done, flip the On switch and leave it be.
hour
Observer
K so new router arrived. Hacked it open, installed antennas, found serial ports, went down that rabbit hole. So the particle photon is listening to MPPT and BMS, and listening+talking to the router. Can do band locking which wasn't even in the routers UI.. sending AT commands from particle. So, from a BMV to this I've gained... viewing amps in and out and displaying the net, instead of just displaying the net... viewing how long heat ran in 24 hours, how much power it used running heat alone to sustain whatever set temperature, network stats for photon, router signal stats, temp setting, blabla. Think I'm done with the app for now and the features. Install tomorrow.
high temps are for testing. I didn't want to make it free entry for a number of reasons in firmware and in app.
and this thing fitted a little better
high temps are for testing. I didn't want to make it free entry for a number of reasons in firmware and in app.
and this thing fitted a little better
luthj
Engineer In Residence
Tangentially related, a user over on sprinter-source is building a 180AH LFP pack using the chargery BMS and CALB prismatics.
sprinter-source.com
Building a LiFePO4 system
Looks like you hardly put a dent in your capacity. I suppose you could lower your cell voltage cutoff even a bit further - but don't know what kind of real battery life gains that would result in.
luthj
Engineer In Residence
A little. The builder (retired engineer) is a summer camper, so I don't think there will be any heating included in that build.
This setup is ridiculously expensive, but the heater and wiring layouts are interesting.
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dreadlocks
Well-known member
I put a couple layers of reflectex on the bottom of my battery box this time around, I realized this aluminum frame is a great heatsink after this last time I went out and my 7g water jug nearly froze overnight sitting on the tongue.. so figured a lil bit more isolation between the floor and the battery might help.. I dont have the lid on the battery box right now and I've got my electric space heater set at 40F and so far thats been keeping my battery from dropping below freezing through several snow storms and stuff.. and the space heater is not even circulating air through the battery compartment like my propane furnace would.. battery is disconnected at 20%, just keeping an eye on it from the comfort of my warm bedroom when trailer is covered in ice/snow.
shade
Well-known member
That's some serious money. Too bad the roof is too crowded for more panels.A little. The builder (retired engineer) is a summer camper, so I don't think there will be any heating included in that build.
This setup is ridiculously expensive, but the heater and wiring layouts are interesting.
In-Depth RV Lithium Install & Wiring Film - Mike Mas
In-Depth RV Lithium Install & Wiring Film - Mike Mas Hello Sprinter Owners, With all the excitement and activity regarding the integration of Lithium Batteries to RV’s, Linda and I decided document our own independent installation and share it with other RV owners who might be considering a...
I'm sure that's all working well for them, but some of their judgements don't ring true for me, like the 2-3 hour a day energy budget for cooking. I'd also give serious thought to adding a second alternator before giving up the money & space for a generator.
shade
Well-known member
That little heater is a good idea, as long as no vermin take up residence. I'd like to arrange things so I can leave my battery in my truck year-round, with charging shut down most of the time. It's my daily driver, so it'll be easy to add some charge to keep the battery happy.
I should have a few uninterrupted days to start figuring out how I'm going to mount my battery, and temperature control will be a factor. I'm going to see if I can find a plastic toolbox to use as an outer case, since that will help with insulating and anchoring it. In warm months, I could leave the top off and maybe remove some insulation.
dreadlocks
Well-known member
if its in daily driver mode can you just disconnect the battery? do you have any actual loads that need to run off it daily?
I was surprised how well a lil bit of insulation worked, before the battery would not be within 10 degrees of ambient when it was that cold out.. tho I should known with how frigging cold the trailer floor gets at night, for the love of god dont step on the metal floor anchors with a bare foot.
In a truck def isolate it from the metal body, the worst part about my Westfallia is how cold that german steel can get.. its not all covered by plastic on the inside like modern cars.
I was surprised how well a lil bit of insulation worked, before the battery would not be within 10 degrees of ambient when it was that cold out.. tho I should known with how frigging cold the trailer floor gets at night, for the love of god dont step on the metal floor anchors with a bare foot.
In a truck def isolate it from the metal body, the worst part about my Westfallia is how cold that german steel can get.. its not all covered by plastic on the inside like modern cars.
shade
Well-known member
I'll have manual, mechanical disconnects in addition to Victron BatteryProtects so I can be absolutely sure it's fully isolated when not in use. With no daily loads and no camping use over a long period, there's no reason for me to leave the system energized. I can monitor SOC directly from the battery, so I haven't decided if I want to leave the BMV connected full-time.
dreadlocks
Well-known member
it works wonders for my canvas popouts, so your 99.9% useless claim seems dubious its the difference of the heaters doing practically nothing to furnaces cooking us out.. yeah it would probably be as effective as putting spacers under the battery so it didnt sit flat on the floor and had some air under it.. but I had a bunch extra bits so I cut out a couple the shape of the bottom and slapped em in there.. wouldent do the sides or top or nothing with the risk of shorting out the mylar.. If I had some foam board insulation I'd of used that instead, but idea is just to separate the battery from the outside with a bit more air, instead of surface to surface to surface to outside w/no insulation whatsoever.
Before this I'd seen the battery under 40F with the inside heated to >60F.. now its staying within 10 degrees of inside ambient, so its effective at least for me w/my testing.. a little bit of insulation in the right spots can go along ways.
Before this I'd seen the battery under 40F with the inside heated to >60F.. now its staying within 10 degrees of inside ambient, so its effective at least for me w/my testing.. a little bit of insulation in the right spots can go along ways.
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