Nsd…Are you just here to rabble rouse? OpenPPG is an amazing design and a very viable, cutting edge flying machine. If it’s not for you then so be it. I think these guys have been far nicer to you than most. Do you actually think that you’ll ever fly anything? You gotta do you, brother. You may be better off posting on an internal combustion engine site…Cheers
Great info Voltair! Can I ask where your school is located? I’ve just ordered the X4 . Please can you help with my battery choice… Ideally I would prefer a very light weight setup even if the battery life & flight time is severely compromised.
Can I please ask your experience with 2 x 22000 6s bonkas?
Is this feasible or is it potentially dangerous with overheating?
Can it be quantified approximately how many battery cycles are expected with 2 batteries?
I will probably later get an additional 4 x 22000 for longer flights but I would like to start with the light weight option.
(I have 60 hours PG experience and a few flights on petrol PPG).
My school is located on Long Island, NY.
2 Bonka 6S: the flight was shorter of course - the machine lighter by12lbs which I liked a lot, but they were kind of warm/hot which made me go for a 4 Bonka 6S system. I hate the weight, especially where one flies on the beach - it is a pain to walk/run around with 60lbs on my back, or try to inflate a wing in soft sand.
I do not care about the split leg harnesses for PPG which is kind of ironic because it is the only type of harness I fly with while Paragliding, beach, mountain or towing.
A standard wooden seat plate full harness is the best option for PPG but the downside is that they weigh more. No so much an issue on firm grounds to walk/run takeoff.
Having 4 Bonka really made a difference and the batts are not heating as much. Never had a problem so far. I just wish my machine was 10 to 15lbs lighter😉
As he has a x4 do you think 2 7s in stead of 2 6s bonkas would stay cool enough?
You can use higher discharge lipos, the bonkas you are referring to are 20c you could get 40 or 60c ones so there is less heating if your just going to run 2 of them.
So this could be a cool light weight setup for the x4 voltaire could use that in 6s too with x3 but 6s is more expensive than 7s now and andyoptom and i have a x4 system
2 6s bonkas is 12 cells and they get too hot (over 60c).
4 6s bonkas is 24 cells and they reach the maximum recommended temperature (60c).
6 6s bonkas is 36 cells and they stay under the maximum recommended temperature (50-55c).
2 7s bonkas is only 14 cells and you can see where that fits in on the scale above. Therefore, I still recommend 4 packs.
Higher C ratings should help with heat but they cost a lot more and I would rather use the money to pay for the extra packs and carry the extra weight and get the longer flights.
Thank you for your datas - you really have a talent to explain things that i can understand them!
You are right 6 bonkas same price as 2 of the 40 c 's
But if lightweight is important 2 of the 40 c could be great as well.
Special voltair writes he would love to have a light solution becouse of his special situation.
Maybe 6 bonkas and 2 40c batteries are the ideal solution, the 2 of the 40 c 's would be loadet fast and if they dont suffer to be used it would be nearly 1 hour flighttime together… each use
In the magazinetest pdf the reporter wrote that he had a good flight and 3 starts and fooddrag all together about 20 minutes with 2 bonkas…
But i think thats not for all day use becouse the batteries would die to early.
40 c could be cool if they really stay cool enough.
These are pretty equivalent capacity and voltage to the 7s Bonkas. Nearly double the price and slightly heavier. The advantage of these packs will be the built in packaging (water proof), apparently high cycle life (lifetime warranty). Another caveat is the 12awg wire. Bonkas come with 8awg. 12 might be quite small for our usage.
You are right thank you for your comment.
Main advantage should be the 40 c compared to 25 c …
And the pricegap is 250 for 1 bonka to 800 for 1 of the 40 c as special offer price ( 1050 without offer! )
Great to hear there is a possibility of the lightweight configuration with the maxamps 2x 40C 22000. If anyone gets these pls post your experience! I might try but it could be a few months. Obviously much more cost & decreased flight time but might be worth it for the weight saving. Appreciate the valuable info thanks.
hello, regardless of what c rate the manufacturer writes to a battery … if the cables are only AWG 8 and the plug 150 … It is completely clear that the system is only suitable for soft cruises low above the ground. And even then the battery will be hot.
They are much smaller : only awg 12 ,
The bonkas have awg 8 which is much more in diameter…
So if we use the cells you recommend how many do you think we have to use at least to be able to fly up till the batteries are empty without being forced to stop the motors to let the batteries cooling down bevore the batteries are empty?
Do you think that the weight comparson is at least 4 bonkas or even the recommendet 6 ones?
Becouse if not than there would be no light solution possible at the time…
For some 8 years, some extremely light projects have been flying. nevertheless, each system has minimum 2 pieces awg 8 cables per pole. (4 cables to the ESC and 4 plugs / sockets 150)
So paul wrote he uses 1 8 awg per pole and the cables not even get hot or warm…
But he keeps them short as possible, but that is what you also do always, so i am surprised…
I could even use 75 or 90 mm2 cables but if that is not necessery than i wantet tu use 1 8 awg per pole like all the heavy users here…
to explain: if I speak of 2 awg 8 per pole is meant that 2 per pole go to the drive. that means at 2 bonkas this is 1 pcs. per pole, with 4 bonkas this is 2 pcs. per pole. at 6 bonkas it is 3 pcs. per pole.
I have a Theory: If 4 standard bonkas (25C x 4= 100C) do not have an over-heating problem: and 2 standard bonkas (25c x 2= 50C) do overheat… we therefore need around 100c.
2 of the 40c Lipos gives us 80c so that may just work. Then I saw a 120C! Lipo on maxamps!!! 2 of these in parallel should give us our lightweight option with just 12 lbs of battery weight and hopefully no chance at all of overheating?! Can anyone see a flaw in this theory?
Normally, the “C” rate means the maximum removal of electricity. this means: if 20 C are specified and the battery has 10 Ah multiplied by 20 C then a maximum of 200A are possible. The rates are only printed on all batteries. has nothing to do with reality. of course, peaks of a few seconds are possible, as is usual in model flight. but never a permanent load. if you test a bonka pack or every other brand in drone flight scenne and load it with 250A until it is empty, it will burn in front of you! The cell arresters are getting so hot that they ignite the electrolyte. I know many will not like the truth, then just delete my post if he bothers.
I agree that you can’t trust the manufacturer C rating. Also, the higher C packs use cells that have a lower internal resistance… aside from that there is no difference. The resistance of the cells will go up with use over time so keep that in mind as well.
Professional drone pilots use exclusively cell types with very low levels of mostly 10 C cells. because they are permanently loadable. Cells with a stated high c rate are not suitable for continuous operation. it sounds illogical but it is. developers of brands such as kokam, which also build industrial cells, confirm this. since 2014, the internal resistance of the cells from the data is also automatically calculated for each flight when evaluating the flight data. depending on the situation, eg dependent on the temperature and load behavior, the real value is output. sony vtc cells show virtually no change in internal resistance, as do the 21700 samsung cells. The loss of capacity is identifiable and is roughly estimated after 3 years about 5% and after 5 years about 10-15%. after 250 flights. (250 flights are very much!)