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sfaust -> Re: Wondering about going to a 6V system in my new plane. (12/17/2002 6:18:24 AM)
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[QUOTE]Originally posted by Frankenthumb
I ordered a NiMh 1500mA battery for my new project, and it turned out to be 6V when I was expecting 4.8V. Instead of returning it right away I thought I would look in to setting up this plane with a 6 volt system. I have a couple of questions to get started, and the answers will surely lead to more questions.
First off, it's a 120 size Sukhoi, and I'm putting HS5925MG's on the rudder and elevator halves. I'll put 625s on the ailerons.
1. Can I charge the 6V battery with the wall warts I use to charge my 4.8V packs? (OK, I know that wall warts will eventually get me into trouble, but I mitigate the risk by cycling the packs every few months.) If not, is there a cheap way to charge?
2. How important is a regulator, and if needed, how much are they?
3. How much flying time am I going to lose with 6V?
Thanks in advance,
Frank [/QUOTE]
1. Some do, but I wouldn't use it. It will take much longer to charge your packs for one. However, if you follow the right procedures, it's not going to hurt anything. Just adjust your procedures accordingly.
2. A regulator isn't required, but can be a nice addition. The servos are designed to run on 4.8 to 6.0v per the manufacturers, however, a fully charged 6v pack has a higher voltage. JR and Futaba have been quoted as saying they are fine on a freshly charged 6v pack. When fully charged, the servos may jitter for the first minute or so, but it hasn't appeared to be a problem for anyone I know over the years. And most of them are running unregulated packs. In fact, most of the TOC competitors run unregulated packs.
Running a 6v pack, and using a voltage higher then 4.8v either regulated or unregulated, will give you an increase in speed and torque. Basically, the servos will perform better on a 6v pack than a 4.8v pack. There is also a voltage loss when using long leads, so having a 6v pack can help keep the voltage higher to the servos out on the ends of long leads. Thus instead of starting with 4.8v and dropping at it reaches the servo, you start with a higher voltage, and will end up with a higher voltage at the servo. Less than 6v, but more than 4.8v.
Adding a regulator between the battery and receiver adds two more connections which add their own failure rates, and the electrical components themselves. Basically, the reliability of the battery to supply power to the receiver is reduced. Not by a lot, but certainly a little. This is a trade off between overall reliability of the power system, vs reliability of the servos themselves, which will take more wear and stress with a 6v system.
3. You will loose approximately 20% of your flight time for the same capacity pack.
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