Lipo Prices

[Varelco]

I had one, but even a 120Ah battery would only give me 2 cycles or so. Given it's 12V, and not the 25V needed for the PL8, it draws 10Ah per 5000mAH pack. I'm no sparky so I'm making gross generalisations here, but to put the same kWh in to the pack at half the voltage, I'd draw double amperage surely?

So a 120AH leisure pack is going to have to give 20Ah (granted, a full charge is 80%, not 100%) for every 12S charge. Given that the Pb batteries don't like to be discharged far I'm only going to get 2, maybe 3, full charges.

Yeah you are right mate, I've not personally done it so wouldn't know what it would take to have one last for a day. I suppose you could put 2 deep cycle batteries in series for 24v but no one is going to want to lug 40-50kg of batteries around!

Couldn't tell you about the Jive setup as I haven't done 1 in years! Mr Mels headspeed calculator is a great tool, punch in the details there and it will give you a very good indication of what headspeeds to expect at each throttle %

[Planehazza]

Yeah you are right mate, I've not personally done it so wouldn't know what it would take to have one last for a day. I suppose you could put 2 deep cycle batteries in series for 24v but no one is going to want to lug 40-50kg of batteries around!

Couldn't tell you about the Jive setup as I haven't done 1 in years! Mr Mels headspeed calculator is a great tool, punch in the details there and it will give you a very good indication of what headspeeds to expect at each throttle %

If only I could hook it into my Model 3

Yeah MrMel's is mint, but it's down :/

I've sorted it out, and given my 60% throttle curve to achieve 80% PWM from ESC to motor, I'm running at something like 2200 RPM. Looking at the manual, my 530kV motor is a little out of range and a 450kV would be better. I might try dropping to an 11T pinion, though they don't exist in ALeeS world. Apparently an ALIGN one is compatible. Or I could just get an 800MX 440kV and get more power

[Planehazza]

If only I could hook it into my Model 3

Actually, going back to this... don't panic, I'm just mulling stuff over. It might take a long while, but what would be stopping me connecting a PL8 to the 12v socket, and limiting the current? As above, 12v input to charge a 24v 5000mAH pack, is going to require 10'000mAh from the source at 1C. So this is two hours per 12S setup. Not quick, but doable? I believe the model 3 12v has a 15A fuse, but obviously the heat from the current load is another thing to think about.

[trillian]

I have the Android version of Mr Mels calculator. With a 12 tooth pinion you'll have 2094 rpm at 60% and 2159 at 65% on the Jive. If you could get an 11 tooth pinion you would be at 1919 at 60% and 1978 at 65%

A 440Kv motor with a 12 tooth pinion would get you 1738 at 60% and 1792 at 65% (and up to 2000 at highest throttle)

[Planehazza]

I have the Android version of Mr Mels calculator. With a 12 tooth pinion you'll have 2094 rpm at 60% and 2159 at 65% on the Jive. If you could get an 11 tooth pinion you would be at 1919 at 60% and 1978 at 65%

A 440Kv motor with a 12 tooth pinion would get you 1738 at 60% and 1792 at 65% (and up to 2000 at highest throttle)

Thanks, those are the numbers I was very close to in doing in manually:

ratio x motor kV x V x 80% <-- 80% being the target ESC->Motor PWM value.
(12/122) x 530 x 12(4.2) x 0.8 = 2101

To get 80% PWM from ESC to motor, my TC would need to be at flat 60%: 80% PWM = 50%+(Throttle Curve/2).

Reading up on it, the PWM needs to be at 80-85% or so to both be efficient and give the gov a 15-20% overhead for the governor to do its job.

So plugging those nunbers in, my calculated HS is ~2150 as my IU thr. % is 64. Can't remember why it was set like that. I probably did it through some OCD to get it near 2150 instead of some random odd number

I think my best option is to find a suitable 11T pinion, or get a lower ~480kV motor which I'm not doing as it's too expensive. I'll try a new 11T when time allows.

[Varelco]

Harry I have a custom rewound Scorpion 4035 which would be perfect for your Alees… its wound to 441kv. Done by Bert Dekker, would be a nice power house yet run nice and cool. Its completely unused and sadly I have nothing to put it in.

[trillian]

You're welcome Yeah, just bumping down to an 11 tooth pinion makes a pretty big difference. If it's the same slant angle as the Align gear it won't be too hard to find. I'll mention also, The Next-D rave ENV / ballistic pinions are also compatible with Align, just in case you see one of those around. Compass 7HV pinions won't work as the angle is different.

I think my best option is to find a suitable 11T pinion, or get a lower ~480kV motor which I'm not doing as it's too expensive. I'll try a new 11T when time allows.

[Planehazza]

Harry I have a custom rewound Scorpion 4035 which would be perfect for your Alees… its wound to 441kv. Done by Bert Dekker, would be a nice power house yet run nice and cool. Its completely unused and sadly I have nothing to put it in.

I'll drop you PM 440kV might be a little too low. I remember the Rush likes a high HS, but I'm now more interested in getting it down to ~1900-2000 and having longer flight times and healthier packs. I never really needed 2200 given my ability.

[trillian]

I'll drop you PM 440kV might be a little too low. I remember the Rush likes a high HS, but I'm now more interested in getting it down to ~1900-2000 and having longer flight times and healthier packs. I never really needed 2200 given my ability.

I think you'd be pleasantly surprised at even 1750 headspeed - just up your collective range a bit. Or, with a 440Kv motor, you'd have the option to use a 13 tooth pinion if you feel you really need more headspeed but I suspect you'll find you don't need more than that.

[Planehazza]

So I've just discovered these. I can't imagine the claimed 60C (burst 120C) are accurate, but I just cannot bring my self to paying £200+ for a single 12S pair.

https://hobbyking.com/en_us/turnigy-...en_us_products

[trillian]

There was a good post some time ago where they did actual C rating tests of a bunch of different LiPo brands. It was quite interesting. I'll see if I can find it again (think it was in RC groups).

I found the thread about LiPo tests. I saw it in 2018 and it has evolved a bit now and there are newer tests, so I'll have to give it a read when I get a moment: https://www.rcgroups.com/forums/show...st-Comparisons

[Grumpy]

So I've just discovered these. I can't imagine the claimed 60C (burst 120C) are accurate, but I just cannot bring my self to paying £200+ for a single 12S pair.

https://hobbyking.com/en_us/turnigy-...en_us_products

They are actually really good performing packs, lower IR than many of the ‘designer label‘ brands costing twice as much. They are quite big and heavy But you can’t have it all.

[Planehazza]

They are actually really good performing packs, lower IR than many of the ‘designer label‘ brands costing twice as much. They are quite big and heavy But you can’t have it all.

I'm faaar from good enough to notice the 1% or so increase in AUW.

Edit, just checked. Turnigys are 20g heavier than the Haiyins I'm currently using so a total weight increase of 40g on paper.

[barryorbik]

Be careful with that weight increase - it's nearly a quarter the weight of a shrinkflation packet of Tangfastics !! lol

I'm no 3D er but have been successfully using the Blue Turnigy packs for ages now without any problems, and I have found they have lower ESR's and the cells are better balanced these days compared to the ones from around three years ago - before the Nano's came out.

Barry

[Planehazza]

Just ordered 4x Turnigy HD 60C 4000mAhs. Keen to see how they perform on an 11T pinion.