barefooterjr

I have a custom fiberglass nitro boat with a KB 7.5 cc outboard engine on it. I have been playing with different props and adjusting the trim but it still cavitates and doesn't really run like a nitro should. The exhaust was underwater but I custom made an exhaust pipe so it is now above the water. I think this is what was holding it back. What are your thoughts?

Also, can I hook a 6 cell, 7.2 volt battery up to my reciever? The way I have my electronics set up it is a pain in the rear to change the batteries when I have to. This way i could mount the battery outside the water tight box. The guy at the hobby shop said this would destroy my receiver box but the little i had played with it I noticed no problems. The servos are very responsive. Please let me know what you think about doing this.

Thanks.

DRAGONFIRE81M

i havent had a problem with my rx but it did kill my servos . the will get very glitchy just be for they go . i did this on my nitro vee where they have the rts system tied in to the rx i wonted a little beter speed coming back so i poped a 2s lipo on there i ended up replaceing the two servos and splitting the rx from the rts

TedMo

RX's and servos are meant to be operated on 4.8 to 6.V. Pretty sure you manual will tell you that. Amazing what can be learned by reading.

Got RPM

Some receivers are just fine up to 10 volts, but most servos should not be operated above 6 volts/5-cells. Why not just get a 5-cell 1400 mAh pack? Then you'd be golden...


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GRANT ED

Your RX will probably be ok but your putting your servo's at risk. If you really must use that pack then I suggest you add a voltage regulator.

mfr02

When reading spec sheets for servo chips, I never found one that was rated above 7.5 volts max. Maximum is just that. Any more and the chip will respond by frying itself to death. A 6 cell nominal 7.2 volt battery will, when fully charged, give about 8.5 volts, more than enough to cook the innards of the chips.

LtDoc

Can higher than rated voltages destroy a receiver or servo? Sure. Will it? That depends, on the particular receiver and servo, some are just more 'sensitive' to abuse than others. A 7.2 volt battery is a fairly common size, find them in lots of things. And while it's always good to either over estimate, or under estimate 'things' to be on the safe side, it's also fairly common to use this voltage for powering R/C electronics. I've used a 7.2 volt battery for models with no problems. Not having had any problems using them, I also haven't done much checking of spec sheets, so my 'good luck' is more of a 'dumb luck' thingy than anything else, I wouldn't particularly recommend it. I can only say I haven't had any problems -yet- (and with my luck, the next time I connect one, all the smoke will come out of the electric stuff).
There is almost always some 'fudge factor' built into things. Depending on that 'fudge factor' isn't the smartest thing in the world to do. 'Over-volting' is not good practice as far as most things are concerned.
- 'Doc

(What was the purpose/reason for all that? I read the thread and got to thinking that the subject is another one of those 'dumb' things I've never thought about. Or put a little better, I've/you've caught me doing something else that's kind of dumb. Typical, but still dumb. (I do 'dumb' very well!))