Sidewinder Voltage Limitations
 

I have a Sidewinder that I've been forced to use my 6-cell NiCds on for a week or so now while I wait for my LiPo to come in the mail. I know that my 4600Kv motor is capable of 3s LiPo or 12-cell NiMh, but the sticker on the side of the ESC is what confuses me... It says 3s LiPo, 8 NiCell, 15 volt Max. I know that a 3s LiPo is well under 15V at 11.1V, but so is a 12-cell NiMh (14.4V, I believe). A 8-cell NiMh would only be 9.6V. Was it a mis-print, or what?? I am thoroughly confused...

Not sure why it was printed that way on the ESC.
According to the website....

4600:
Up to 3s LiPo
5-12 cell NiMH**

5700:
Up to 2s LiPo
5-8 cell NiMH**


**Will work on 4 cell NiMH with modification. See a diagram of 4 cell operation modification here.

I read that, too, which is what is confusing me. Also, just going by the ESC, if it can handle 15V, then it should be able to run a 4s LiPo. Then again maybe the don't say that because a fully charged battery may exceed its voltage requirements. Hmm. :weird:

Sidewinders have LVC support for 4s and will happily run it

Cheers

Think part of the confusion is over voltage - 4s lipo 'nominal' voltage is 14.8v, but charged, 4S is 16.8v (4.2v/cell is max voltage) and the esc rating is based on the charged voltage, not the 'nominal' voltage.

NiMh may be 1.2v nominal, but a decent cell fresh off charger is closer to 1.5v. But NiMh voltage falls so fast that an esc can get away with running something thats apparently higher voltage than what is allowed for lipo. Lipo voltage stays higher much longer than NiMh and thats part of the rating diff.

Really? Do you have experience doing this? I'd be hesitant because the manual says that use of a 4s pack is under warranty only on Monster Max ESCs.

Yeah, that's what I was thinking. But do you think that running 2 6-cell NiCds in series would be totally ok? They cold add up to as much as 18V together, which is obviously above the 15V rating. Then again, maybe I could run them individually down to 7.5V apiece, then hook 'em up and run them in series... I really don't want to blow anything.

You may have issues with the Internal BEC running those kind of voltages. Also you won't be covered under warranty. I'd play it safe and wait for the lipo.

The weak link in these the internal BEC in the esc - overheats and fails and then there's no power to the esc. You can run an external BEC and run higher than rated input pretty reliably. I ran 4S and 5S with my MM using an external BEC for a while and never had any probs doing it.

I don't see where 2 6 cell NiMh pacs in series should cause probs, as soon as you hit throttle, voltage will be under 15v and since you're running 4600, its within specs. There is no diff in two 6 cell pacs wired together in series and one 12 cell pac from a voltage standpoint.

Right, but it's the 8-cell limit on the ESC that concerns me. I still find it odd that the max is 15V, yet they say the max # of NiMh cells is 8. That's only 9.6V. Oh well, I guess I'll just wait for my LiPo to come in from HobbyKing. Too bad I picked standard registered shipping. I ordered it on the 12th and it has yet to leave Hong Kong :rolleyes:.

I'd go by what's posted on the website, not some confusing sticker that needs some interpretation on the esc. They plainly have two sets of specs depending on which motor you're running. How do you cover that situation with a small sticker anyway?


Better yet, call Castle and ask, I've always found them helpful -

http://www.castlecreations.com/support/contact.html



You might be looking at a long wait.......

Yeah. I called them during spring break to ask them another question about the sidewinder and they were really helpful. Only problem now is that 9am-5pm central time = 7am-3pm pacific... And I'm in school until 3:10 :rolleyes:. I would email, but I never get the auto-reply from them and my emails only sometimes get to them.

I'd be calling them during lunch break on my cell. :D

I've seen some complaints that HobbyCity is taking extra long on orders and offering no explanations. I hope when you ordered there was plenty of stock on hand of the lipos you ordered. That was why I said you may be in for a wait, hope not, but its possible.

Yeah, I probably will call them during lunch :p. And no problems with my order, luckily. It's already been shipped out from HobbyKing's facilities, and the tracking status from Hong Kong Post or whatever says it's being processed for departure to the USA. I am hopeful that it may come before next weekend, but it's unlikely...They only work 5 days a week there.

I misread the original post. 12 cell nimh should be fine on a 4600. It is withn spec and shouldn't cause bec issues unless you are running a power hungry servo or lots of auxillary stuff like lights.