cnchelicopter xme-100ad esc q's

[jayjay283]

I bought the cheap esc off ebay to play with. ( The MMM debacle has caused me to buy dumb things for summer fun) It arrived with 1 motor wire off, no biggie get what you pay for. It arms and the programming card works but as long as im getting to soldering on it ~ My q's

can I mix the caps ? the esc has 2 small 35v 220uf caps and I have some big old 25v 2700uf caps. If I can, will 25v ones melt or something if I use 6s. Or should I just leave it and try and run 6s until it smokes, or put the 25v caps on too and run 4s & 5s ? Id like to run 6s because I have a an older pair of maxamps 3s that wont cause me to violently smash things if they get messed up.

http://global.ebay.com/gbh/viItem?ItemId=370041594514



dont know why but pic of the cap lol



*Note my user title, input where applicable, and I appreciate any help !

[lincpimp]

That 25v cap is going to be too close to a peaked 6s lipo for my tastes. I would see if you can find a decent sized 35v cap. Those tiny caps on the esc look to be about useless. They definately need some help! You can run a large cap across the main leads close to the board. It does not matter if the cap is larger than the ones on the esc.

[BrianG]

But any cap you use needs to be low-ESR type. Look for 105*C rating on the cap. If it's just 85*C, it will overheat and eventually blow...

[jayjay283]

Thanks guys appreciate the help. Thats what I needed. Ill go check out what radio shack has, if not ill find an old electronics store, the kind you need to wear an asbestos/dust mask in. They always have good stuff

[BrianG]

RadioShack won't have low-ESR caps. Chances are you'll get the deer-in-the-headlights look when you mention that to them.

And stay away from old electronics, especially caps. The electrolyte breaks down over time.

[jayjay283]

lol ok plan B, I better refine my search.

[jayjay283]

well I didnt find anything locally, I guess a couple hours away is the Illinois Capacitor Company though lol ah well ..I know they're huge but so is this esc ! Its going in a emaxx anyway do you think a couple/few of these will work ?

CAPACITOR 35V 1200UF LOW ESR HITEMP,HIFRE.RAD 12.5DX35.5LMM

http://www.mcmelectronics.com/product/31-5730

[BrianG]

You can find sources online - even shipping from across the world would be cheaper than the gas that a 2 hour trip will require; $40-60 in gas for $10 in parts.

Anyway, 25v caps are not good enough for 6s - peaked, 6s lipo is at 25.2v and you always want a little headroom. Besides, the back-EMF pulses may well exceed 25v when braking. 35v caps minimum for up to 6s. Don't know what that ESC is rated for, but the next step up for typical cap voltages will be 50v, which is good for 10s (although it won't hurt anything to use 50v caps even running only 4-6s - it just means physically larger caps).

As far as capacitance value goes, if the selection allows, it's better to go with a few smaller caps than one large one of the same total value (meaning 4x330uF = 1x1320uF). The extra surface area helps them shed heat better, and you also get better transient response. Of course, you pay for it in physical space needed and wiring hassles.

[jayjay283]

Thanks for your help Brian, I ordered a few up. I refuse to drive anywhere more than 30 minutes away lol Ive had the same tank of gas since the middle of May. Love the VW. My wife has a company car with a gas card but you cant do long(ish) trips they calculate the milage relatively accurately. Local runs are free though ! ID rather spend my money on RC than donate it to oil companies and government taxes. If anyone has some good pics of configurations to soldering up 4 caps link away, ive seen some nice ones here ill start digging, Thanks again.
Jay

[BrianG]

Don't know about 4, but adding two is easy enough. Some pics of added caps to my Quark 125: