Battery fan won't run on battery bank USB, but will on 'puter USB... Any Ideas for lite bike elec?

Photowhit
Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
edited January 2018 in Off Grid Solar & Battery Systems #1
I've been contemplating setting up a bicycle travel, small solar system, using a lithium battery bank as the battery bank.



I've picked up a few odds and ends to this end, and last night I wired a small 5" battery fan with a USB cords and plugged it into my computer and it worked fine. Later I tried my battery bank and it won't run...

I had used red and the bare ground wire. 

After checking a color wiring pinout I went ahead and attached the black to the bare ground and it worked.


Curios why this happened? I guess the outside metal is wired on the computer, but not the battery bank? Just seems odd.

Can I leave it this way, or should I disconnect the bare ground?

Guess I should say, Mine was a thrift store find and didn't come with the usb cord, I just hard wired to the 4 - AA battery slot.

Open to other interesting electronic devices to add to the bicycle dashboard. maybe a small TV, I'll use a Sandisk sport for radio and mp3 player and a raspberry Pi zero for a computer. Looking for a small computer screen or a hack for a small high res picture display or some other monitor. Glad to hear ideas.

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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Comments

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
    Maybe it's just me, but I find the labelling on the pic a bit confusing. It seems to me a serial (uSb) cable minimally has receive-rx, transmit-tx, and signal ground. The signal ground is the reference for high/low signal voltage.

    It can/should be at about the same potential as the DC negative, but as it's important as the signal reference, generally a separate wire AFAIK. The bare ground is apparently the DC negative?

    There are small screens available for rPi, but I'm not sure about the zero. Maybe use a phone ssh app for kb/display?
    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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  • just starting
    just starting Registered Users Posts: 235 ✭✭✭
    edited March 2018 #3
    One of these
    200ah LiFePO4 24v Electrodacus Sbms40 quad breaker chest freezer to fridge- Samlex PST 1524 - Samlex pst3024  - 1hp shallow well pump-Marey 4.3 GPM on demand waterheater - mama bear Fisher wood burning stove, 30" fridgarair oven ,fridegaire dishwasher  Unique 290l stainless D.C. Fridge-unique 120l portable fridge/freezer 
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  • just starting
    just starting Registered Users Posts: 235 ✭✭✭
    #4
    And they make touch screens for the raspberry pi depending on how much you want to spend a cool case with a 3.5 screen is about 35$
    200ah LiFePO4 24v Electrodacus Sbms40 quad breaker chest freezer to fridge- Samlex PST 1524 - Samlex pst3024  - 1hp shallow well pump-Marey 4.3 GPM on demand waterheater - mama bear Fisher wood burning stove, 30" fridgarair oven ,fridegaire dishwasher  Unique 290l stainless D.C. Fridge-unique 120l portable fridge/freezer 
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