Anyone tried using NiMH in their ES600?

[nasukaren]

Well, my maiden ES600 flight ended really quickly when my tail briefly touched some debris in my back yard and a little white tail rotor went flying across the grass. Phoeey.

ES600 meets FOD. FOD wins.

Anywaayyss, while I'm waiting for spare parts, I was thinking about my battery situation. I'm currently using 4 of my Belt CP LiPOs chained together into one large 2S2P 4400 mAh pack. Unfortunately, I only have 5 Belt CP lipos and with 4 of them used in my ES600, it puts a crimp on my crashing style.

Looking around my house, I spotted some of 3800 mAh 8 cell NiMH packs from my very short EV experimentation (long story). I'm thinking...... a 2S1P NiMH pack would give me 19.2 volts @ 3800 mAh. A short visit to my handy digital scale gives me the following weights:

4 x 3S 2200 mAh LiPo (2S2P; 22 v @ 4400 maH) == 27 oz / 765g (w/ serial-parallel wires)
2 x 8S 3800 mAh NiMH (2S1P; 19.2v @ 3800 mAh) == 31 oz / 878g (w/ serial wires)


What do you'all think? I guess one big Q would be if the NiMH could give the current draw that the ES600 would want.

[damyxz]

I used to have a logo 20 which used 20 nimh 3800mAh cells powering a plattenberg motor. It's got power and decent 3D potential. very heavy though. I remember mikado making a logo 24 bionic too.

[nasukaren]

Well, I tried it out with the NiMH batteries. I only got a few minutes of hopping before the motor started powering down and then cutting out.

Charging it, I could only put 1300 mAh back in. I think I have to play with my Turnigy Plush ESC cut off -- I do have it at NiMH and at 'low' -- but maybe I'm forgetting something.

Karen

[Locitur]

Why don't you give a try to A123? I began with Lipos, but now I only use A123.
There are many threads where you can get a lot of info about them!

[nasukaren]

Originally Posted by Locitur

Why don't you give a try to A123? I began with Lipos, but now I only use A123.
There are many threads where you can get a lot of info about them!

I thought of making an A123 pack, but it didn't seem like the economics were good:

1 x A123 (2Ah) cell from a Dewalt battery pack == roughly $10 each?

I would need 6S2P configuration or around 12 cells == $120 per pack.

At that rate, LiPos at $100 a pack (at HobbyKing) would be nominally cheaper. Although A123 have many more advantages -- much tougher, don't catch fire, etc.

I'm really hoping we can buy individual A123 cells soon -- and for much cheaper. If they sold them at $5 a cell, I think no one would be using LiPo anymore.

Karen

[Locitur]

mmmmmmm.....

I am just sport flying with 7S only and can achieve around 6-7 minutes. 7 X let's say $12? = $84 Of course you'll have to do some soldering to custom build the packs. In my case I have a 4S + 3S in series. This way if I wanted to use the 3S pack for the CopterX450 I could do so too. I actually have a 3S pack in the 450 kinda permanent. I just charge the 7s pack in the ESmart without even taking them from the heli! The same for the 450 pack.

[nasukaren]

Originally Posted by Locitur

mmmmmmm.....

I am just sport flying with 7S only and can achieve around 6-7 minutes. 7 X let's say $12? = $84 Of course you'll have to do some soldering to custom build the packs. In my case I have a 4S + 3S in series. This way if I wanted to use the 3S pack for the CopterX450 I could do so too. I actually have a 3S pack in the 450 kinda permanent. I just charge the 7s pack in the ESmart without even taking them from the heli! The same for the 450 pack.

I thought the DeWalt A123s were only 2000 mAh each? Are you getting more?

Your flight times are actually not too bad, and definitely changes the financial equation for me. I'll have to explore more.

Karen

[Locitur]

A123 (26650 cell) has 2300mAh capacity. This is a good link for you to start exploring:
http://www.rcgroups.com/forums/showthread.php?t=599316