Battery question

[Dixon Walsh]

I have a battery Question. I have a 11.1 volt 800 mAh, li-po battery in my Cp Pro and a 8.4 volt 650 mAh Ni-Mh in my Honeybee, can I run the higher volt li-po in the Honeybee with a 4 in 1, the Cp Pro has a 3 in 1 but both tail and main rotor motors are ths same? Or maybe run the Honeybee on a 7.4 li-po? I have'nt seen an 8.4 li-po........ Thanks Dixon
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[chaos]

I don't know but the new version does use the 11.1v battery.

It appears that the 370 motor has a Kv rating of 1200. So for every volt different from the intended 8.4 volts you will get around 1200 rpm difference. You have to divide that down by the gear ratio to get the head speed.
(11.1 - 8.4) * 1200 = 3240 for the increase in motor speed

Of course, another consideration is whether the 4-in-1 will put up with a higher voltage. I don't know. I'm not versed on electrics. If the gear ratio is 10, then the rotor would spin somewhere around 324 rpm faster. I don't think that's a problem, just more touchy to fly it, but I don't know if that would smoke the RX and the rest of it.

Going to a lower voltage, a volt less would give a motor speed of 1200 less, and using 10 for the gear ratio, 120 rpm less on the head. I don't know, but it doesn't strike me that this would be a problem, and it wouldn't burn up the electronics. I don't know what the gear ratio actually is. Maybe the manual says.

Maybe somebody who knows the answer will show up, but my ignorant guess is that the lower voltage battery - one stinking volt less - would work... but I'd be nervous about the higher voltage.

I have'nt seen an 8.4 li-po

That's because the li-po is 3.7 volts per cell and ni-cd are 1.2 volts per cell.

[Dixon Walsh]

Thanks Chaos, nice facts to know: volts per cell, rpm's.......

[chaos]

Hey Dixon... You might want to check this page over. It's about electrics but a lot of it is general.

http://www.swashplate.co.uk/ehbg-v17/ehbg_index.html

You can download that file zipped in a pdf format here,
http://ehbg.rchomepage.com/
Go down to the file named, ehbg-17-pdf.zip
A couple other useful files are:
Bent_Shaft_Checking.pdf
Corona_Blade_Balancing.pdf

[Dixon Walsh]

Thanks again Chaos, I downloaded the 17 pdf, I want to take it to work tomarrow to print out for my 2 copilots, (hirobo XRB, and Venom Ocean Rescue). and I need the basics too. (E-flite Cp Pro, and E-sky Honey Bee)
Thanks again Dixon