Electronics > Power/Renewable Energy/EV's

Lipo power to weight ratio.

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SMdude:
Hi Guys,

Just wondering if anyone has some general power to weight ratio for lipo packs?

For my 7.4v packs I get about 28ma/gram.

Reason I am asking is I have just taken delivery of some packs and they are smaller than my last packs and lighter.

And on a third note, does anyone have a battery manufacturer for custom lipo packs they have used and trust that they would like to share via pm?
I'm feeling like I might have been a little done over here...

Cheers

HackedFridgeMagnet:
 Specification
That sounds about right if this battery is anything to go by.



I assume you are talking about Energy/Mass or Wh/gram. Apparently it is called specific density, whereas Energy Density is measured as Wh/L

Because u say power/weight but measure in Current/Mass. So  careful with your units.

--- Quote ---    Votage: 3.7v
    Capacity?1000mA
    Continuous Discharge Rating: 1C
    Maximum Discharge Rating: 1C
    Connector: PH2.0 JST connector
    Cable Length: Approx. 70mm
    Size: 58x35x5mm
    Weight: 22g
--- End quote ---

(random internet battery.)
Energy/Mass = V * Ah/kg = 3.7 * 1/ 0.022 = 168 Wh/kg


(your battery.)
Energy/Mass = V * Ah/kg = 7.4 * 28 = 207 Wh/kg

Maybe the series cell arrangement is confusing you. This will give the same Wh/kg, a higher voltage but less Ah/kg

SMdude:
Thanks!

Yeah, my power to weight is really just a quick check of mAh/weight.
It seems there has been a booboo! I have run these new packs through several cycles and they are consistently 1Ah less capacity than my 40g heavier 3 years old(in storage) packs  :-//

So far no response from the seller/manufacturer, though only emailed a few hours ago as I had to do a lot of testing to make sure my battle was a worthy one!

Lol, and it was the one pack I could not compromise on  |O

Thankfully, I can make use of them.

Nusa:
In the end it's not whether they're better or worse than your previous packs.
It's whether they meet the specification the manufacturer promised to deliver.

SMdude:
And the answer to that is a big fat NO.
But being on an entirely different continent, I am not holding my breath that it will get sorted out.
All I can do is work out a way to use/unload them and get more from a different supplier that are built to spec.

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