I need to setup a Hot Spot outside, Work arounds on Charging Lithium batteries In sub-Freezing?

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Photowhit
Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
edited November 2019 in Off Grid Solar & Battery Systems #1
So I lost my sweet deal with my one neighbor who has moved in with her daughter.  
I've got a MiFi by Verizon, I'm on it now, I haven't  found consistent 4g service and will likely put it up 30 feet or so and would like to rig up a battery charger. Should I dump the lithium entirely and use NiCad or lead acid? My choice would be nimh not sure how they handle cold, but can be run with out a charge controller dissipating extra energy as heat. (discovered this long ago, think I posted a link here at some point.)
Any ideas? I have many small 6 volt nominal 4-5 watt solar panels or could run electric up to it from home.
Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
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    You're putting the hotspot up 30'?  Does it have an antenna port?  If so, I'd put an external antenna up higher.  If not, maybe a vehicle type booster.

    AFAIK, lithium has to be heated to > ~0°C to charge.  My hotspot knows the internal battery temp and won't charge cold.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #3
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    Estragon said:
    AFAIK, lithium has to be heated to > ~0°C to charge.  My hotspot knows the internal battery temp and won't charge cold.
    Nice to know, perhaps that is what I was running into yesterday. I set in car with a power bank attached. it appeared to charge during the day but quit charging after sunset, only got down to 33-34 when I brought it in and charged.
    No antenna port, it's a 'Jetpack' my brother had bought for my mom's trip years ago.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • wellbuilt
    wellbuilt Solar Expert Posts: 763 ✭✭✭✭
    #4
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    I’ve been using this for a year  and it takes me from lol most no G to 4 Gs for 89 bucks off eBay . 
     This one is for att service but the sell different units , my buddy has one that will do version att  
      Last week I ran the wire up 22’ and mounted it on the house then dropped down the wall into the kitchen . 
       In a moment of excitement I drop the little block box and broke the antenna 🤯. 
      The unit in the pic is a replacement . 
       Disregard the poor reviews on Amazon this thing works great . 
      I would bet the people making the poor reviews are not snugging the antenna connections with a wrench . 
      I used this unit sitting on a 5 gallon bucket for a few weeks before I hung it up . 
      It uses a few watts of power . 
      The only down fall is the connections are a little Fragile
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #5
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    Just sayin, FWIW...
    https://www.wired.com/story/unlicensed-signal-boosters-amazon/


    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #6
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    I'm not sure if mine does it or not, but the hotspot may throttle charge rate down as temp approaches 32F.  I know mine stop lower than that, but can't tell if it starts throttling the rate at (say) 45F.  Some power packs need a minimum draw to wake and/or power the output, so it's possible the hotspot throttled to below the min pack amp draw in the cool/cold?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
    · Share on Twitter

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