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phemens

Montreal, Canada

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Posted: 12/22/20 08:19am Link  |  Quote  |  Print  |  Notify Moderator

dennych1 wrote:

My battery is 10.5x20 you think I can stick the pad right to the bottom and do you think I would have to enclose battery. It’s great to converse with someone that has done this


I think if you centered it you'd be fine. My footprint is considerably wider and it does fine with the aluminum sheet. As far as enclosing the battery, it depends on where it is located and to what temp you expect to use it. The heating mat can reliably keep the battery temp a minimum of 10C above ambient (at least from what I've observed in limited testing so far). I use foam insulation because they're located in the front storage compartment that has openings for the landing gear and gets quite cold. The batteries have considerable thermal mass, so it shouldn't take much to keep them in the acceptable temp zone with the heated pad. I'm probably veering on the other extreme of precautions, but I want to protect my investment.
I think a good temperature sensor on the batteries is a must for this.


2012 Dutchman Denali 324LBS behind a 2006 Ford F-250 V10 out of Montreal
1 DW, 1 DD, 1 DS, 2 HD (Hyper Dogs)
1200w solar, 600AH LIFePO4, Yamaha EF2000 gen, Samlex 3000w Inverter

dennych1

Long Island New York

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Posted: 12/24/20 09:36pm Link  |  Quote  |  Print  |  Notify Moderator

Thanks you have been very helpful

gatorcq

Arizona

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Posted: 12/26/20 05:49am Link  |  Quote  |  Print  |  Notify Moderator

I installed Universal Car Seat Heaters. There are 2 pairs, 1 for bottom, 1 for back.
Setup using a small T-stat controller (C degrees) less then $15 for 4 units.
Tied directly into the battery terminal (Fused).
Working very well in Toronto, On.
My LB are installed up front, next to the Generator. Used Foam board to insulate around the LB. Heaters underneath and behind.
T-stat turns on at 40 Degree F. Works very well right now. Batteries will stay up around 40 to 60 degrees.


Dale & Susan
DaGirls II Rv - Dakota & Tilly Traveling Companions.
2008 Alfa Gold, 2015 Ford F150 XLT
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800 Lithium Battery
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FWC

The Wilderness

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Posted: 12/29/20 09:00am Link  |  Quote  |  Print  |  Notify Moderator

A couple of things to think about before adding heaters to your LiFePO4 batteries:

1. Are you really 'protecting' them? Many (most?) LiFePO4 batteries have a low temperature charge cut off built in to the BMS, so they protect themselves and won't accept a charge below a certain temperature (I think it is about -3C for Battleborn). The downside of not having a heater is that you may miss out on some charge opportunities when it is very cold, not that you will damage the batteries.

2. How much energy will heating the batteries use? Several of the solutions presented here keep the batteries MUCH warmer than they need to be. There is no advantage in heating the batteries to 20C and it wastes energy. You also only need the batteries to be heated when charging, they can be cold while discharging. It is far more (electrical) power efficient to heat your batteries with what ever heater you use to heat your living space - which I assume you keep above -3C.

3. There are situations where you really do need to heat the batteries - but they are less common than most folks think. In the case you do need heat then external heat pads are the best option. While internally heated batteries seem like a good idea, if you us a battery monitor to track things (eg a Victron BMV) the internal heaters will throw everything off as the current for the heaters cannot be accounted for by the monitor.

dennych1

Long Island New York

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Posted: 01/06/21 08:37pm Link  |  Quote  |  Print  |  Notify Moderator

Using the tank heater pads can you actually feel the warmth when it’s on

phemens

Montreal, Canada

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Posted: 01/07/21 05:58am Link  |  Quote  |  Print  |  Notify Moderator

FWC wrote:

A couple of things to think about before adding heaters to your LiFePO4 batteries:

1. Are you really 'protecting' them? Many (most?) LiFePO4 batteries have a low temperature charge cut off built in to the BMS, so they protect themselves and won't accept a charge below a certain temperature (I think it is about -3C for Battleborn). The downside of not having a heater is that you may miss out on some charge opportunities when it is very cold, not that you will damage the batteries.

2. How much energy will heating the batteries use? Several of the solutions presented here keep the batteries MUCH warmer than they need to be. There is no advantage in heating the batteries to 20C and it wastes energy. You also only need the batteries to be heated when charging, they can be cold while discharging. It is far more (electrical) power efficient to heat your batteries with what ever heater you use to heat your living space - which I assume you keep above -3C.

3. There are situations where you really do need to heat the batteries - but they are less common than most folks think. In the case you do need heat then external heat pads are the best option. While internally heated batteries seem like a good idea, if you us a battery monitor to track things (eg a Victron BMV) the internal heaters will throw everything off as the current for the heaters cannot be accounted for by the monitor.


To your point 1) & 3), that's exactly why I have the heating pad, to permit charging in conditions where normally the BMS would prevent it. Admittedly for me this is in cases where it's marginal (i.e. the battery temp is already close to the cutoff @ 5-8 C according to my Victron battery temp sensor) but I never reached it. Better safe than sorry for me, having the capability to charge when I want was important to me - we leave our RV at a remote site off grid and keep the residential fridge running, so I need to ensure the batteries stay charged.

For point 2), the heating pad draws a steady 6 amps @ 12v. For me, since I have more than ample capacity, I don't worry about that too much, the solar tops batteries up usually before noon. Batteries are in the front compartment and it is not ducted for heat, and we rarely run the main heater, we prefer to use a Mr. Buddy to cut down on noise. (we only run it when we're up, not overnight).

gatorcq

Arizona

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Posted: 01/13/21 06:42pm Link  |  Quote  |  Print  |  Notify Moderator

Folks, my system works very well in 17 degrees F. The batteries are staying around 40. You be the judge, I can charge my batteries with no issues.
Oh I forgot to mention, my LB were $420 ea @100 Ahrs. Far cry from $1000 BB.

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