Running 4 flight batts

Discussion in 'ALTA 8' started by Ben Platts, Jun 28, 2016.

  1. Ben Platts

    Ben Platts Active Member

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    I have a 2 week natural history job in Africa coming up next week. The company we were hiring batteries off in Africa have just informed me they can't get hold of the 10000mah Tattu batts we were supposed to be using. They have 8500mah, which wouldn't quite give us the flight time we need, or they suggested running 4 x 5500mah batts in parallel. Just wanted to double check with all you knowledgeables that I wouldn't run into any issues running 2 batteries down one Alta battery cable? I assume it will all be the same currents drawn etc but wanted to check! Thanks
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    In theory it should be fine IMHO, but it does introduce quite a few additional potential failure points with all the splitter cables you'll need. Be very careful sourcing them (or making them) and make sure they are up to the task. It's also important to burn in the batteries by running them through several charge/discharge cycles (under load) and make sure they're up to snuff, quality wise. One bad LiPo in parallel with 3 good ones can cause a disastrous current loss.
     
  3. Ben Platts

    Ben Platts Active Member

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    Thanks Steve. Apriciate the input
     
  4. Sam_Girardi

    Sam_Girardi New Member

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    How about using 6-8 batts, 99.9wh 6s 4500? TSA friendly :)
     
  5. Ben Platts

    Ben Platts Active Member

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    Good idea. Don't know if six would fit though. That's a lot of charging too!
     
  6. Steve Maller

    Steve Maller UAV Grief Counselor

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  7. James Adkins

    James Adkins Member

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    We have been running 4 batteries since day one with no issues. My question for Freefly is can I run 3 batteries without causing a current inbalance?

    Progressive makes great stuff for sure.
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    How do you plan to configure the three batteries, James? Two on one ALTA connector and one the other?

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  9. James Adkins

    James Adkins Member

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    That was my thought but without knowing power distribution
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I think there may be an issue with that configuration: the problem being one of imbalance -- the pair of LiPo's on one connector will lose voltage more slowly than the connector with just one. My reasoning being that there is twice the milliamp/hour capacity on the "dual" connector than the single.

    And what happens then (if I'm right) is that the single battery will attempt to "charge" the dual battery combination so there will be a cross-flow current.

    Out of curiosity have you consider and abandoned the idea of running with four batteries? That way you could minimize the cross-flow current.

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  11. James Adkins

    James Adkins Member

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    Thanks Andy. That's what I figured. 90% of the time 2 or 4 is fine. Occasionally 3 is the perfect capacity for the payload/flight time needed. I noticed other HL copters running 3 which is why I asked.
     
  12. Steve Maller

    Steve Maller UAV Grief Counselor

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    Personally, given the attendant risks, I'd recommend purchasing LiPos with different capacities and still running only 2 batteries.
    I suspect there'll be weight savings, as well.
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    And just clarify Steve's comments, whatever pair of Lipos you end up choosing should be the same capacity -- so Steve means "purchase a pair of Lipos of different capacity from the pair you're using now." I'm sure that's what he meant to say. Really. Honest. :)

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  14. Steve Maller

    Steve Maller UAV Grief Counselor

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    Once again, @Andy Johnson-Laird is flaunting his ancestors' invention of the English language. Damn you, AJL! :rolleyes:
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    We didn't invent the English Language. We "borrowed" pats of it from West Germanic tribes. Going from memory it was called an Anglo-Frisian dialect. We then bolted on (aka stole) parts from French, Norman (yeah, good old Norman), a soupcon of Greek, Latin, the Gaelic, the Celts, the Scots, and anything else we Brits could lay our hands on, both linguistically and physically (e.g. The Elgin Marbles).

    That said, Mr. Maller, I feel appropriately damned. :)

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
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  16. Guillaume MARION

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    Travelling a lot with my A6, from my first session.

    Using 4x4500 tattu, getting 4stormcase 2075 to fit 8 in each. And Never Bean stopped in planes!

    Working great, only bad point Is that quite more heavy then, then on A6 have to take care of the combo. Should be ont à problem on A8!
     
  17. Ben Platts

    Ben Platts Active Member

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    I was getting good flight time in Africa running 4x5500mah. About 14 mins with Red weapon set up on the ALTA 8. Would still be a good 8-9 mins with commercial flight friendly 4500mah I would think. Just a lot to take on a plane. 8 in a case sounds good though.
     

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