Onxy 1800 mAh NiCd battery

[KC5H]

I have one of these packs and have charged it 10 to 15 times and always at 0.9 amps. I cycle all of my NiMH and NiCd batteries at about every fifth charge
(ch-dc-ch-dc-ch) and I never charge at more then 1c except with my LiPos and then only when they are rated for it.

I charged this pack and two others last night. Well this morning I went out for a little bashing and right from the start this battery acted like it was half drained so I put in a 1800 mAh NiMH and bashed the hell outta my RS10 XT.

When I got back to the bench I but my meter to the battery and it reads 7.7 volts so I put it back in the RS10 and the same thing happens. I took it back out and checked the voltage again and get 7.7v. Then I checked it with a second meter and it reads 7.5v. (Close enough for me)

I'm thinking maybe a bad connector. Any ideas before I dispose of the battery?

[Charlie-III]

If they use Tamiya connectors, that is your issue. They are common on some RTR's and lesser batteries regardless of chemistry (NiCD, NiMH, LiPO).

Use a Deans or similar.

[KC5H]

Originally Posted by Charlie-III

If they use Tamiya connectors, that is your issue. They are common on some RTR's and lesser batteries regardless of chemistry (NiCD, NiMH, LiPO).

Use a Deans or similar.

Charlie-III

Thanks for the response but at the moment all of my connectors are Deans Ultra Plug. I even replaced the Deans that was on the battery with a new Deans, and fully charged the battery at 0.9amps, which took less then 10 minuets. I barely had time to put on a pot of coffee.
Straight off the charger the battery shows 8.2v. Hook it up to my RS10 and it's the same crap all over again. Within seconds it's like the battery is done. I checked voltage again, 7.7v . Man I don't understand this. I have no idea whats going on with this battery. My RS10 works great with all of my other batteries.
3x 1300 mAh 2s LiPos
2x 1800 mAh NiMh.
I'm thinking I have a bad connection inside the pack somehow and as soon as I start crawling things go haywire. For now I'm just not going to use this pack.

[Trubble]

Originally Posted by KC5H

........ and fully charged the battery at 0.9amps, which took less then 10 minuets. ........ Within seconds it's like the battery is done.

Sounding an awful lot like one of your cells sulfated or shorted on ya.

[Charlie-III]

Originally Posted by Trubble

Sounding an awful lot like one of your cells sulfated or shorted on ya.

+1...when it dumps on you, can you measure each individual cell? Sounds like one has died.
Is this a 6 cell pack?

[KC5H]

Originally Posted by Trubble

Sounding an awful lot like one of your cells sulfated or shorted on ya.

Yea, that's kinda what I'm thinking too.

Originally Posted by Charlie-III

+1...when it dumps on you, can you measure each individual cell? Sounds like one has died.
Is this a 6 cell pack?

No Sir, I only have a simple volt meter and a cheap Radio Shack one at that. The second meter I mentioned in the first post belongs to my buddy from across the street and is the same RS meter that I have.

[wings_of_fire]

what is the C rating for the Onxy Nicd batteries? I checked it on tower and there is no mention of C rating about it.

When you discharge them more than their C rating, their capacity to store current reduces considerably and any way this is a NiCd. I am sure you passed the C rating of the battery which has affected its internal chemistry.

[Charlie-III]

Originally Posted by KC5H

No Sir, I only have a simple volt meter and a cheap Radio Shack one at that. The second meter I mentioned in the first post belongs to my buddy from across the street and is the same RS meter that I have.

Simple meter is all you need, just connect to the end of each cell and see if one is a lot lower than the others. You may need to poke a small hole in the shrink wrap to do this.

PS, NiMH & NiCD really don't have a "C" rating like LiPO. Other than a "dead short" for a period of time, it really does not hurt the discharge of these cells.

[KC5H]

Originally Posted by wings_of_fire

what is the C rating for the Onxy Nicd batteries? I checked it on tower and there is no mention of C rating about it.

When you discharge them more than their C rating, their capacity to store current reduces considerably and any way this is a NiCd. I am sure you passed the C rating of the battery which has affected its internal chemistry.

The stock ESC (pt.# E401) on the RedCat RS10 XT has a low voltage sensor that will only allow the motors to work intermittently when nearing the low voltage threshold, and after you have reached the low voltage limit the ESC will kill power to the motors but maintain power to the receiver and servo.

Originally Posted by Charlie-III

Simple meter is all you need, just connect to the end of each cell and see if one is a lot lower than the others. You may need to poke a small hole in the shrink wrap to do this.



PS, NiMH & NiCD really don't have a "C" rating like LiPO. Other than a "dead short" for a period of time, it really does not hurt the discharge of these cells.

Charlie-III
I understand the no discharge "c" rating on NiCD and NiMH batteries. Thanks though.


As for as poking holes in the shrink wrap on this, the last NiCD battery that I own.
Nah I ain't gonna waste my time. I've gone to LiPo and that's where I'm staying.

[Charlie-III]

Originally Posted by KC5H

Charlie-III
I understand the no discharge "c" rating on NiCD and NiMH batteries. Thanks though.

That was really directed at wings_of_fire, not you.

[wings_of_fire]

Originally Posted by Charlie-III

That was really directed at wings_of_fire, not you.

Thanks
I had no idea about it. But still is there not a chemical chemistry in the NiMh and NiCd which has limits to its current giving capacity. I feel if it is over discharged they become hot to the touch and that might also kill them.

[Charlie-III]

Originally Posted by wings_of_fire

Thanks
I had no idea about it. But still is there not a chemical chemistry in the NiMh and NiCd which has limits to its current giving capacity. I feel if it is over discharged they become hot to the touch and that might also kill them.

The only real way to "over discharge" NiCD/NiMH (in terms of discharge rate, not final voltage) is to do a dead short, or close to it.

Most batteries don't have issues with high rate discharges as long as you don't go too low in voltage. Batteries DO have issues with high rate charges, some of it depends on the battery & chemistry.
For NiCD/NiMH, you actually WANT them a bit warm just before use, they perform better when warm.

I tend to charge at "1C" for all my packs.

[alexchen86]

Originally Posted by Charlie-III

+1...when it dumps on you, can you measure each individual cell? Sounds like one has died.
Is this a 6 cell pack?

Yup NiCD, NiMH and even crappy Venom lipos have all taken a dump on me after say 15-20 complete runs. I tried cycling several times and on batteries that I know are iffy especially when you see 15C on a lipo and you're going to bash it on a short course rig pulling a bunch of amps that's a recipe for disaster.

One of the cells in your NiCD stick pack is probably not making a strong connection. My Venom 15C 4000mah 3s crapped out on me after 15 so runs on a VXL system and a Castle SV1 5600kv on my Sprint 2. It never swelled and never got above 100 degrees. After a volt meter check one of the cells just couldn't hold charge anymore and I am not going to disassemble a lipo just to resolder a little wire.

I ran Venom 8.4V NiMH stick packs left over when I owned a Summit before I knew any better in the past because that's what I could afford and after 12-15 packs the battery literally melted apart. My gearing was stock and there were no upgrades at the time nor any sort of binding on a new Slash 4x4 Platinum years back.

Lesson learned: Don't buy Venom when you can find better packs out there for cheaper whether you're racing or just crawling. My Gens Ace hard packs 2s-4s never had an issues pulling my heavy brushless EMaxx with so many upgrades it's not even worth selling anymore lol.. Sky Lipos I never had an issue with either from 1000mah to 5000mah 3s and 4s. All 8 Sky Lipos I have never given me issues at all. Gens Ace as well....chargers I use is my old trusty Hyperion EOS0606i and my spare portable charger (due to size) Hitec X1 AC/DC both 50W do what they need to do perfectly.

Check out HobbyPartz if you're on a budget like me. Or cheapbatterypacks (CBP) and go with a better ESC if your current one cannot handle lipos. Not sure what electronics you're running on your RS10.

Plus with their cheap prices buy at least 3-5 packs and switch them between courses. Even with a 35C or 40C lipo I always set my LVC at 3.3V/c on the safe side.

[theloudone]

the simple solution would be to switch to lipos only