Aerohawk Battery
#26
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Join Date: Feb 2004
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Have now finished looking into whether the aerohawk as it is can use a 11.1V Li-ion battery, and the answer is... yes with the addition of a small heatsink on the linear reg.
Why? Well I have done some tests, the Aerohawk main board requires 200mA (load supply) with both servos moving at the same time. The peak current is about 400mA (both servo's at maximum limit), but this can be ignored. Now with the standard 8.4V battery and 200mA load supply the linear reg has to dissipate 0.68Watts into heat, with a 11.1V battery this would be 1.22W. Now assuming the Ambient temperture of the room is 25degC, with the standard 8.4V battery no extra heatsink is required, but if a 11.1V battery is used then an area of about 0.5insquared copper would be required! a tiny IC heatsink attached with special glue will do the job, but I would not recomend anyone using a 11.1V battery unless this was done, otherwise the regulator will burn-out and fail!! which could destroy your mixerboard!
Hope this is of help
Lee
Why? Well I have done some tests, the Aerohawk main board requires 200mA (load supply) with both servos moving at the same time. The peak current is about 400mA (both servo's at maximum limit), but this can be ignored. Now with the standard 8.4V battery and 200mA load supply the linear reg has to dissipate 0.68Watts into heat, with a 11.1V battery this would be 1.22W. Now assuming the Ambient temperture of the room is 25degC, with the standard 8.4V battery no extra heatsink is required, but if a 11.1V battery is used then an area of about 0.5insquared copper would be required! a tiny IC heatsink attached with special glue will do the job, but I would not recomend anyone using a 11.1V battery unless this was done, otherwise the regulator will burn-out and fail!! which could destroy your mixerboard!
Hope this is of help
Lee
#28
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Join Date: Jan 2004
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Hi all. I think you are being far too technical with the battery voltage, there is always tolerance bult into electronics.
My aerohawk is using 11.1 volt lipo and a 310 tuning motor without any problems, my tail motor is out of a hummingbird ll. All I did was put heatsinks on the fet`s which greatly improved their capacity, after all that is what makes electronics fail is heat.
Maybe Ive just been lucky but Ive had my bird now for about 4 months and the only thing thats gone wrong is the tail motor which was a lesser quality than the HB ll. The new tail motor is about 3 1/2 months old.
Im gonna push my luck now and Im going to go for the HB 370 motor and see how things go.![Big Grin](images/smilies/biggrin.gif)
My aerohawk is using 11.1 volt lipo and a 310 tuning motor without any problems, my tail motor is out of a hummingbird ll. All I did was put heatsinks on the fet`s which greatly improved their capacity, after all that is what makes electronics fail is heat.
Maybe Ive just been lucky but Ive had my bird now for about 4 months and the only thing thats gone wrong is the tail motor which was a lesser quality than the HB ll. The new tail motor is about 3 1/2 months old.
Im gonna push my luck now and Im going to go for the HB 370 motor and see how things go.
![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)