Adding Lithium to a NiMh RTF
01-28-2004 | 12:12 PM
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From: Superior, CO
Adding Lithium to a NiMh RTF
I am interested in flying my Aerobird challenger with a 1500 or 2000 mAh, 2-cell LiPoly battery. There are two key issues I have to address.
(1) Does the voltage cutoff matter? I haven't been able to find out from HobbyZone what the cutoff is, and/or if it is different for the 6 vs. 7 cell NiMhs.
(2) Figuring the aerodynamics. Since I want to fly with both, I don't want to hack up the plane just for the new battery. I am imagining that I could strap it to the side of the fuselage, far enough forward to keep the CG ok.
(1) Does the voltage cutoff matter? I haven't been able to find out from HobbyZone what the cutoff is, and/or if it is different for the 6 vs. 7 cell NiMhs.
(2) Figuring the aerodynamics. Since I want to fly with both, I don't want to hack up the plane just for the new battery. I am imagining that I could strap it to the side of the fuselage, far enough forward to keep the CG ok.
01-28-2004 | 01:46 PM
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From: Venice, FL
RE: Adding Lithium to a NiMh RTF
Hopefully the voltage cut would not be a probem.... The AB 6 cell is 7.2v nominal, The LiPo should be 7.4 v nominal.
I would try to fit the battery inside, and just ad some balast in the far nose to put the balance where it belongs.
Let us know how it works out!
I would try to fit the battery inside, and just ad some balast in the far nose to put the balance where it belongs.
Let us know how it works out!
01-28-2004 | 03:05 PM
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From: Spencerport, NY
RE: Adding Lithium to a NiMh RTF
The voltage cutoff, if there is one, will probably be down around 5 Volts, which is the minimum necessary to power the receiver and servo(s). All this means is that you will have to be careful. Fly for a few minutes, land, measure the voltage. Keep track of how long you fly. Do this until the voltage is down near 6V at rest. Add up total flying time to get a good idea of how long you can fly.
01-29-2004 | 12:33 PM
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RE: Adding Lithium to a NiMh RTF
Voltage cut off on the AB is a smidge less than 5v which is too low for LiPo packs. But, a lot of people fly LiPos on ESCs that have very low cut offs - its pretty noticeable once the power has dropped that its time to land.
The problem with most 1500-2000 mAh packs is that they arent the right shape and size to fit the AB. You could remove some of the foam in the battery compartment, but then you lose any protection you had before and with LiPos, any extra you can get is helpful. Dont put the pack outside the plane - LiPos are far more fragile than NiCad/NiMh packs.
To help with the space/CG/flight time requirements on the AB, Thunder Power will be selling a 2700 mAh 2 cell pack thats nearly the same size and weight as the stock 6-7 cell 900 mAh packs. Give them a call to find out more on that:
(702) 228-8883
Flight times would easily be 3-4 times longer than what you get now with no need for any mods or changes to the plane and battery compartment!
The problem with most 1500-2000 mAh packs is that they arent the right shape and size to fit the AB. You could remove some of the foam in the battery compartment, but then you lose any protection you had before and with LiPos, any extra you can get is helpful. Dont put the pack outside the plane - LiPos are far more fragile than NiCad/NiMh packs.
To help with the space/CG/flight time requirements on the AB, Thunder Power will be selling a 2700 mAh 2 cell pack thats nearly the same size and weight as the stock 6-7 cell 900 mAh packs. Give them a call to find out more on that:
(702) 228-8883
Flight times would easily be 3-4 times longer than what you get now with no need for any mods or changes to the plane and battery compartment!
