NiMH Battery Health

[Mtbmatty]

We got a 2wd rustler for my my son this past Christmas. it came with a 3000 mah battery and i also got a 5000mah battery as well. Both batteries are 8,4 volts.

I had been using the basic traxxas charger that came with the kit, but i charged them both this past weekend with my new Ultra Power charger.

When done the 3000 mah battery reading was 10.29v and 2759mah
The 5000 mah battery reading was
10.31v and 3874mah

Why are the volts higher? Is it possible that the 5000 lost or possibly never had the claimed capacity??
We’ve been happy with the run times, so more curious than anything

Thanks

 

[WickedFog]

8.4v is nominal capacity for your packs, or 1.2v per cell. The charged capacity will vary between 1.4v-1.5v per cell.

The 5000mAh battery likely never had that capacity to begin with.

Some NiMH batteries don't perform to their full capacity until fully charged and fully drained a few times. You could try that and see if it helps. But if the pack is a cheap China no-name pack, it is likely never going to get there.

 

[Mtbmatty]

Both packs have been run through the car several times, and are both Traxxas branded. After a a few cycles there was a definite increase in run time. Which was awesome!!

The stock charger was charging at 4amps, I charged them both at 3amps this time. Would it make any difference charging the larger battery at higher amps??

 

[tntpoof]

You got a better charger now than the oem.so your capacities are more and you fully charged voltage is more.. enjoy some factory stuff is really not that good wait till you go 2 cell lipo .. do you know how to adjust delta peak on your charger and can you?of the joys and sudden deaths of nimh..

 

[WickedFog]

If you charge the 5000mAh battery at 5A, it will charge faster. Just watch for excessive heat while charging.

 

[Mtbmatty]

You got a better charger now than the oem.so your capacities are more and you fully charged voltage is more.. enjoy some factory stuff is really not that good wait till you go 2 cell lipo .. do you know how to adjust delta peak on your charger and can you?of the joys and sudden deaths of nimh..

Yes, if delta peak is the max capacity cutoff. Have a couple shorty 2s lipo batts that so far I’ve only used the charger as a meter to check the storage charge. Hopefully will be charging the this weekend and running the car.

If you charge the 5000mAh battery at 5A, it will charge faster. Just watch for excessive heat while charging.

They got pretty warm using the factory charger so I opted to do both at 3 amps and see how it went. They both got warm, but only at the end of the charge cycle. Will turn it up for the 5000mah on the next charge.


Happy with the charger so far, relatively user friendly….

 

[Sebkauff]

Just my 2 cents but one thing I would recommend is either only running NiMhs in a car or only running LiPos in a car. It's easy to forget to switch your car from LiPo mode to NiMh mode and running it in the wrong mode is a really easy way to ruin your day lol. So if you forget things as easily as I do I would recommend sticking with one type of battery. But if you think you can remember it then go for it, I don't want to keep you from running your car more just because of my personal preference Have fun driving with your son!

 

[Mtbmatty]

Just my 2 cents but one thing I would recommend is either only running NiMhs in a car or only running LiPos in a car. It's easy to forget to switch your car from LiPo mode to NiMh mode and running it in the wrong mode is a really easy way to ruin your day lol. So if you forget things as easily as I do I would recommend sticking with one type of battery. But if you think you can remember it then go for it, I don't want to keep you from running your car more just because of my personal preference Have fun driving with your son!

Great advice, thank you!

the lipo batteries are for a separate vehicle, not for the rustler.

 

[Mtbmatty]

You got a better charger now than the oem.so your capacities are more and you fully charged voltage is more.. enjoy some factory stuff is really not that good wait till you go 2 cell lipo .. do you know how to adjust delta peak on your charger and can you?of the joys and sudden deaths of nimh..

So I started setting up Memory settings on my new charger, and it then asked specifically for the delta peak sensitivity. It had a default value of 4m v/c. It is not what I originally thought it was, and I have no clue as to where it should be set.

advice…..

If you charge the 5000mAh battery at 5A, it will charge faster. Just watch for excessive heat while charging.

I did charge it at 5amps after we ran the pack down today. Again heated up towards the end of the charge cycle, but not to an uncomfortable level. The charge was greater compared to last time, it finished at 10.49v and 4573mah compared to 10.31v and 3874mah last time around.

 

[WickedFog]

Good. You got em broke in

 

[Mtbmatty]

Good. You got em broke in

Forgot to mention, the 3000mah battery seems to have taken a dump. Started out fine, but barely 5 minutes later it was creeping along. Gonna contact traxxas and see what they say. It has only been in service since Xmas

 

[Sebkauff]

I've had problems with Traxxas NiMh batteries before, I had one that smoked and melted some of the battery cause of a bad cell, and I had another one (same type of baterry, 3000mah 7 cell hump pack) that also had a bad cell. The second one didn't smoke though so that was good. Traxxas replaced them both at no cost but I don't have complete trust in them anymore. But I mostly use LiPo's now so

 

[Mtbmatty]

I've had problems with Traxxas NiMh batteries before, I had one that smoked and melted some of the battery cause of a bad cell, and I had another one (same type of baterry, 3000mah 7 cell hump pack) that also had a bad cell. The second one didn't smoke though so that was good. Traxxas replaced them both at no cost but I don't have complete trust in them anymore. But I mostly use LiPo's now so

Good to hear they replaced them for you. I plan to reach out to them this week. I’ll let you know what they do, hoping for a new battery and a new MAXX for the pain and suffering

 

[Chubaka]

Good to hear they replaced them for you. I plan to reach out to them this week. I’ll let you know what they do, hoping for a new battery and a new MAXX for the pain and suffering

Its been a while, but traxxas was kind to me also. The first vxl escs, I must have sent 10 or 15 atleast.

If they do charge you, its usually less then off the shelf. Just dont wait 3 or 4 weeks until payday as they will toss your stuff. Dont ask me how I know.

 

[Mtbmatty]

I did end up having 2 batteries warrantied, Traxxas was great about it. Unfortunately both batteries crapped out shortly after we got them back.
I ended up getting a pair of 2 cell lipos and enabled the low detection mode on the esc. Wish I had done it sooner!! Converted all connections to IC-5, so the batteries will fit an ARRMA as well. My son has been saving for a Big Rock and he’s almost got the cabbage to go get it