Most cost effective way to power Heli's / Planes

[chrisleematt21]

I am looking into purchasing new packs as most of mine are on the way out. Previously I have bought cheap packs and lots of them, mainly because I didn't have a field charging option.

Now circumstances have changed and I have a container at the field, and 90% of the time I am there on my own.

I now have a generator which is 2.1kv, it is a conventional generator so a little noisey, but I can station it far enough from where I fly that its not an issue.

I think it has a 2.5L tank, its petrol and will charge 6 x 6s 5000 lipos 5 times on one take (JUST!!) that's about 2.5 hours run time. I am using a PL6 with a 1150W power supply.

Currently I have about 16 packs which means I can charge 6 at a time and then fly back to back all day. Its takes about 30 mins to charge the six packs at once at 6.66 amps.

Now I am trying to work out if it would be cheaper to buy fewer packs and charge more often at a higher rate say 2-3c or to buy more packs and charge less.

I would like to fly my Trex 700 back to back for approx 25 flights on a Saturday & Sunday (I am usually there from 10-8 / 10 pm), the weeknights 10 flights, depending on weather and light of course. I do fly a lot currently usually 5-7 times a week.

I was looking at replacing my packs with the Optipower Ultra 50c 5000 as my flying is progressing nicely and I am harder on the packs, also I thought if I purchased a better quality pack it should stand up to the abuse a bit better.

So is it cheaper in the long run to buy more packs and charge less or fewer packs and charge continuously?

Is charging 2 x 6s at 15 amps more cost effective than 6 x 6s and 6.66amps?

I was thinking of getting another PL6 and then I wouldn't have to wait for one charge to finish before starting to charge another pack.

I was also looking at more fuel efficient generators as well. Obviously buying a different generator would be costly upfront but would probably pay for itself over a year or two.

What are others doing in the same situation?

[trillian]

Hmmmm, that's an interesting situation. At the places I fly I just never have the chance to fly back to back that way for that long. So I'll bring maybe 6 flights worth (12 packs) for a 700 and a few for the 450 and over the span of 3 or 4 hours I'll barely fly them all twice due to the wait between flights while the flightlines are busy.

My initial thought would be that in such a case having fewer packs that can handle higher charge rates and will last for more cycles is ultimately the answer, but... it depends on how much difference we're talking about in the cost of the LiPos and will it really be significantly offset by the cost of petrol in the generator.

[chrisleematt21]

Exactly.

The fuel costs do get quite expensive if you start adding it up. I was going to experiment at the weekend, take 6s packs (3 12s) and just use them to charge fly charge fly and see how much fuel I use, then i'll have a better idea of the fuel costs with my current geny. Another option could be a lot of solar panels and an inverter...

[trillian]

Exactly.

The fuel costs do get quite expensive if you start adding it up. I was going to experiment at the weekend, take 6s packs (3 12s) and just use them to charge fly charge fly and see how much fuel I use, then i'll have a better idea of the fuel costs with my current geny. Another option could be a lot of solar panels and an inverter...

Solar power would be amazing if it was possible to have enough panels and enough sunlight, and I suppose the really slick thing would be having them charge some big storage batteries the rest of the time. It's a great concept anyway.

The only way I could do 25 flights in a day is to just fly the gasser, maybe split some of those with a 450.

[Grumpy]

Solar power would be amazing if it was possible to have enough panels and enough sunlight, and I suppose the really slick thing would be having them charge some big storage batteries the rest of the time. It's a great concept anyway.

And that's the cruncher.. For solar panels to have enough power in all seasons you would need a vast expanse of panels, far bigger than would be transportable. It might be feasible if a club invested in a large fixed solar array and big battery storage facility, but it would take many years to pay for itself and what club would have the funds?

[chrisleematt21]

OR I may be lucky as the farm I fly from does have a decent solar power system and i * might * (Fingers crossed) be able to run a long cable from them to the airstrip which would then solve a few issues for the price of a couple of hundred meters of cable , which is far less than the cost of running the generator for X hours per day.

But if that option doesn't pan out then I still have the generator.

So far I am thinking a good starting place is to buy another PL6 that way i don't have to wait for one charge to finish before I start another. I am currently thinking that 6 x 6s packs (3 x 12s ) would be enough to keep me flying and charging. I am making the assumption that charging at 15amps it will take 15mins ish to charge my packs. So with 2 PL6's I can charge my 4 packs at 15amps (60amps total) in fifteen mins whilst flying one pack, that should then make the geny more fuel efficient and give me back to back flying ish.

[JoeBailey]

the biggest difference you'll notice in the packs is weight, the 50c opti packs are now very light and produce superb power. I have a 3 sets of opti 6s 500s that are now 3 years old with 100s of cycles on them, yes they are tired but with a little pitch management they can still produce the flights, so don't worry about pack longevity.