Which batteries for HK 500.

T-rex 500 manual shows configurations for 4S 5S and 6S. Doesn't have any 3S configuration. You can find a .pdf version by googling it.

you should definitely download the Align Trex 500 pdf manual - there's a lot of very specific information in the last few pages on different pinions, battery packs and headspeeds.

My preference would be to use 2 x 450 size batteries in series to make a 6s pack, since I already have a few good 3s packs, and two Nano-Tech packs on the way if Swiss Post ever deliver them!

Remember that for any given power, you will draw double the amps using 3s than using 6s, so you'll need a bigger ESC. 6s seems about optimum for the 500, and of course there is a very slight gain in overall electrical efficiency the higher the voltage you use.

Most 500 motors seem to be pitched at 6s use, and for starting out with moderate power the HK 500H 1600Kv looks perfect, with either a 12t pinion, or, my preference, a 13t or even 14t pinion when using governor mode. I really like the governor mode on the Superbrain ESC's, and like the way that the heli feels exactly the same at the end of the battery as at the beginning.

Your flight times will depend mainly on the HS. Full-on stick banging 3D flyers will want the maximum HS, and most of the battery energy will go on parasite drag in the main rotor! Not to mention everything will wear out quicker and your servos need to be stronger. I prefer to strike a balance between duration and power, and prefer smooth, quiet flying at lower HS - I reckon using governor mode and a 13t pinion on 6s with a 1600Kv motor, you'd get good results with HS 2100 to 2400 and that should be good for up to 7 minutes or so, maybe more at the lower HS.

In fact the Align manual shows approx 11A at hover on 6s at HS 2150 with a 12t pinion - which would give you over 9 minutes hovering with a 2200 pack, using 80% of the pack capacity. That might suggest 15A hovering at HS 2400 giving 7 minutes.

It's also worth looking at what batteries are available, and at what prices.  You have to make sure the batteries fit too, and that they're not too heavy - so forget any posts that go on about using much bigger batteries! With current battery technology, 6s 2200 seems to be about the sweet spot, with the single 6s packs costing and weighing a bit less than 2 x 3s packs of the same capacity. The Align manual recommends 6s 2100 - 2500. Anything outside of that might not fit under the canopy, and might result in your tail servo being half way down the tail boom! I'm not keen on that look.

Update: I think the Nano-Tech batteries are a bit lighter than the equivalent regular ones, so 6s 2650 might be a great size for the 500.


Edited by 2Doggs - 16/Feb/2011 at 1:18am

Originally posted by Sooty There is a summary of all the collective wisdom from the HK 500 posts here in MSWord.doc: Topic: HK-500GT Build Thread Summary     Posted: 04 Feb 2010 at 8:47am The attached MS Word document is an 11 page summary of the collective wisdom contained in the first 1000 posts (67 pages) of the RC Groups build thread.   Obviously the contents are biased to what I thought was important and contributors with proven knowledge and experience. uploads/25254/HK-500GT_Helicopter.doc The general consensus is that 2 x 2200 3s 30c in series is a good option. Better to cook a cheap 3s battery than an expensive 6s. Besides these batteries can be used for lots of applications beside helos.

There is a summary of all the collective wisdom from the HK 500 posts here in MSWord.doc:

Topic: HK-500GT Build Thread Summary
    Posted: 04 Feb 2010 at 8:47am


Edited by Sooty - 04/Dec/2010 at 3:18pm

Originally posted by boxo53 I see lots of advice but no direct answers.   I use these for aggressive flying ; http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10276   And these for milder flights ; http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9945   Both work well and give me 5-6 minutes depending on flight conditions. Both can be mounted to get a good CG.   Hope this helps.