What batteries am I supposed to get to and what happens if I don't sign up for batch 2?

Disclaimer: I’m human, I make mistakes. Make sure you fact check with others before making purchases based on this post. Anyone reading this who already knows all of this: please consider reading through this post to fact check me. We really should have a go-to guide for this.

You can buy the Multistar online from other vendors, but it looks like we’re quickly buying up the available online stock, so here’s an example of how to look up alternatives.

First I go to HobbyKing, because it’s a good site for this kind of thing. Then I search for Lithium Batteries because they’re light, cheap, and energy dense. I filter my search by selecting 6 Cells. Finally I filter for only batteries above a 10 ampere-hour capacity, with a discharge rate of at least 10C. Here’s one of the batteries that I like:

Turnigy Graphene Professional 12000mAh 6S15C LiPo Pack w/ XT90

How do I know that it will work?

  1. It uses the XT-90 connector, which is what OpenPPG uses.
  2. It can output enough current for our needs. 12 ampere-hour capacity multiplied by the 15 “C” rating equals a maximum output current of 180 amperes. So with two of these batteries you should have enough output current (360 amperes) to run OpenPPG at max throttle (300 amperes).
  3. It’s also a “6s LiPo” battery. That means that it has 6 cells. Since LiPo batteries normally give out around 3.7 volts, that means a 6 cell battery provides around 22.2 volts normally. That’s what OpenPPG takes in, so that’s what will work.

Pros: They’re more energy dense. They provide 8.333Ah/kg, better than the 7.453Ah/kg density of the Multistar. They also claim to be able to handle more cycles than the Multistar as well.
Cons: They are lighter and have only 75% of the capacity of the Multistar. So you’ll either have a shorter flight time, or would need to put on more batteries. They’re also more expensive.

Here’s a good battery charger that will charge LiPos with any number of cells.

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