Battery Comparisons


#1

There are a lot of battery ideas being thrown around and I wanted to consolidate them into a form that’s easy to compare and add to. Here is the spreadsheet of all of the batteries we’re considering for the OpenPPG. This will be updated as more batteries are proposed by this community.

If you want to add a battery to this list, reply in this thread with a link and tag me so I’m notified. If you want to add to or edit this list Send me a PM on here with your email and I would be happy to grant edit access to anyone who wants to add batteries to the list. I won’t respond to edit requests in Google Docs because I don’t want to grant access beyond this community.

Notes:

  • I’m only adding batteries that have already reached the consumer market.
  • I’m only considering packs complete with housing and wiring. This forum is not a suitable place for designing custom battery packs; we already have too many risks to consider as it is. Of course you’re welcome to do so on your own, but we should be mindful that some in this community have very little experience with LiPos.
  • The flight time of course will be different for every person and every flight, but the figures right now seem to match up with every video Paul and the core team have released.

My takeaway so far: Paul’s done his homework on batteries, as of this posting the Bonkas remain the king. Here’s a sample of the comparisons so far.


13S15P Battery Pack Build
System Requirements
#2

Good idea.

A number of expensive 6S 22,000mAh packs out there (>$400).

I found this on ebay as a slightly better deal.

Approximately 187Wh/kg at $300 per pack.

It seems the Multistar packs are the best deal by a wide margin, but maybe hard to secure if out of stock. Maybe some deals on aliexpress… But i do worry about quality from many of these sources.


#3

Yeah those are nice! Only a touch heavier than the Bonkas. I added them to the list.


#4

I’ve reached out to Bonka for pricing on the 16 and 22 Amp 6S packs and received the following reply

[6/4/18, 15:43:42] Rebecca Wen: There is no MOQ limited for ur first order.
[6/4/18, 15:47:00] Rebecca Wen: BK-16000/25-6S 6375180mm 1900g $150.79/pack
[6/4/18, 15:47:35] Rebecca Wen: BK-22000/25-6S 6691195mm 2520g $232.35/pack

I’m also working on an 18650 pack capable of 160 amp draw on a 6s pack in 16000mAh and 24000mAh if anyone is interested in the details.


#5

@DanielArnett Thanks for putting this together!

Tattu offers a wide range of batteries—here’s a 28,000 mAh option: Tattu 28000mAh 22.2V 25C 6S1P Lipo Battery Pack

MaxAmps also has a wide range—here’s a 23,000 mAh option: LiPo 23,000 6S 22.2v Battery Pack. Note: “Custom configurations available upon request.”


#6

All added! Thanks for getting a quote!


#7

Maybe this was discussed in another thread, so my apologies, but how are you calculating flight time for this sheet? What is your assumed power consumption? I think Paul had thrown out some current he was seeing at steady state conditions…?

How did 200A come about as the nominal current?

As a side note, I have seen some numbers from Paracell E-PPG that indicated he could cruise at 3 to 3.5kW. That is with a single conventional prop. I am hoping that Open PPG would be capable of around 4kW average draw.

Sheet looks good!


#8

Good question: like I said in the original post that’s an estimate; it’s where I’m doing guesswork. See the “nominal power draw” variable in the top left of the sheet? Change that and you’ll change the “power on duration”, or how long the batteries will last. I guessed the nominal power on duration based on Paul saying something like 8 multistar batteries will give you 40 minutes of flight time. That’s all, and it needs backed up by data. Intuitively the flight times look reasonable, and no matter how much data we collect it ultimately depends on variables out of our control; wind speed, wing size, pilot weight, pilot flying behavior, and more.


13S15P Battery Pack Build
#9

I see. I think 100 amps (~4.4kW) is a better estimate, at least I hope. 200 amps would be super high. This is based on data from paracell with a factor (guess) for the inefficiency of having 4 props vs 1.

A suggestion: any flight time calculation should only assume only going to 80% depth of discharge. Exhausting packs to 3.0V per cell on a flight will quickly degrade them.

If I use the above values, 4 Bonka’s will give >20 minutes power on flight time at ~2kWh of total capacity.

One more suggestion: We should calculate flight time and capacity based on energy/power in kW and kWh rather than amps and amp hours. Since the voltage is not constant through the discharge, neither will current.

Doing the calculations in power compensates for that. An aircraft will require a specific power to fly steady state.


#10

@DanielArnett That google sheets you set up is awesome man! It really lets you easily evaluate the different options and changed my mind about the first batteries I was thinking of buying. Thanks for doing that!


#11

Thanks for putting that together. Could 38120 batteries be an option to compare?
Scratch that…they are not looking like a viable option.


#12

A factor that isn’t included in the comparison, which peeps should bear in mind when looking at the $ spent is the charge cycles you get in the life of a battery. Obviously there are many factors that can affect the cycles that you could get. I don’t have any references to back this up, but from what I’ve picked up whilst doing research is that Lipo’s generally get around 250 to 300, Graphene Lipos 600 and 18650’s 1000+.


#13

Battery cycles is certainly a consideration but to put things into perspective.

300 Cycles * 20 mins flight time is 6000 mins of flight (100 hours)

If you fly once a week for 20 mins you are looking at 5 years to reach the 300 cycles .
After each flight you have an extended period of time to recharge that set of batteries (think between 5 and 24 hours depending on your charger setup) so if you want to fly again on the same day or even the next day you will be purchasing multiple sets of batteries potentially pushing that time period out to 7-8 years.

In that time period we can expect battery technology to improve resulting in lighter more powerful packs meaning you will probably want to upgrade your batteries before they have reached their useful lifespan.


#14

Just to chime in: I have a large charger charging at 1C and am safely able to charge up my 20min pack in roughly an hour. Multiple flights on one pack in an afternoon is definitely doable.


#15

@zjwhitehead, Would you please tell us more details about what power supply, charger, and batteries you are using as well as how many batteries? To charge at 1C we need a charger capable of 250 to 550 watts per battery depending on the mAh. Most chargers capable of that don’t have a built in power supply.


#16

Respectfully, that is all and fine for yourself. But for me if I have a good weather window, I know I am not sitting around while my bat charges for the next round in one hr - I would have multiple packs to land and change right away or take off with enough to get my rocks off for that window. Could be a week before the next opportunity in this sport.

Cheers, Patrick


#17

@DanielArnett - On the MultiStar 12AH, I am curious why you have a minimum of 6 there, when other 10C rated batteries have a minimum of 4?


#18

Same as @Pdwhite - https://www.aliexpress.com/item/HTRC-HT700-DUO-AC-DC-1-8s-Lion-LiPo-Battery-Charger-350W-2-20A-2-Dual/32833042846.html
It can do two of the bonka batteries at a time


#19

Totally, it’s a no brainer if you want to be able to fly as much as you can in a small window. I was just commenting to say that with the right charger you don’t need to have a ton of batteries to fly multiple times in a day.
Being in Ohio I definitely understand wanting to fly whenever the weather decides to cooperate.


#20

Because that is their 12000mAh version. 12Ah * 10C = 120A of continuous output current. In other words, the C rating is proportional to the capacity of the battery.

Big batteries can output more current than little batteries with the same C rating. Since they can’t provide as much current you need more of them.

@zjwhitehead on this note, do you know why Paul’s comfortable flying with only two Bonkas (in series)? If the adapter he’s using is only rated for 150A isn’t there the risk of melting the XT-150 connectors if he exceeds 150A for too long? More importantly what happens when someone who doesn’t know OpenPPG inside and out decides to max throttle it at 300A until the batteries die? Has this come up?