TRAXXAS Battery Problems

[Sdhyde17]

Hi All, I purchased a TRAXXAS STAMPEDE 4x4 for my son for Christmas. It came with a car charger and (2) 7 cell 8.4V NIMH 3000MAH batteries.
I then in February purchased an SCX10 II and an 8 cell 9.6V 5000MAH battery to go with it and had the LHS guy put TRAXXAS ID connector ends on the SCX10 II. Well when I got home the SCX10 would only run like 3 feet and then the motor would cut out. Still had steering but no drive for more than 3 feet. I was frustrated until I tried the 9.6V battery and it worked fine so I just ran the 8 cell in it and the 2 7 cell batteries in the STAMPEDE. Well another month went by and I bought an SCX10 for my son to drive with me. Long story short I did the same thing and had the LHS guy put TRAXXAS ID ends on it and bought another 8 cell for it.

Now here is my problem...One of the 8 cells (the newest one) doesnt work in either SCX10 truck, but it does work in the STAMPEDE. The other 8 cell has always worked in all 3 trucks. The 2 7 cells will not work in the SCX10 II but up until his afternoon they worked in my SCX10.

Now neither of the 7 cells nor the newest 8 cell will work in the scx10 or scx10 II... When I install them the trucks just run about 3 feet and the motor cuts out. Steering always works but no forward or reverse unless I reset the trigger. This just started after a run yesterday and this morning in which I ran the 8 cell in the SCX10 II and both 7 cells in the SCX10 for about 2 hours. I ran all 3 batteries to dead and then charged all 3 on the car charger and tried to go for another run after lunch but the 2 7 cells will no longer run in the SCX10 or SCX10 II, they do the same thing when I plug them in either truck, they run about 3 feet and then dead stop until I release the trigger and try again??? They just worked this morning for 2 hours?

I charged all 4 battery packs with the car charger and put a meter on them each and noticed that both 7 cells read 9.6V but the packaging says they should be 8.4V??? Both 8 cells read 11.2V but the packaging says they should be 9.6V??
Sooo, I looked at the car charger and finally realized that it says 6/7 cell batteries and no LIPO. It doesnt say anything about 8 cell batteries.
I dont think I was supposed to charge the 8 cell packs with this charger, but I didn't realize that until today. I am kind of a newb. been lurking for about a year but just got my first truck at Christmas.

What has happened? The one 8 cell still works in any of the 3 trucks, but the 2 7 cells and the other 8 cell only work in the STAMPEDE.

Can this be fixed or do I need to just scrap all the traxxas batteries and go to something else? I really did not want to go to LIPO because my boys are only 7 & 5 and I dont trust them with LIPO packs, I dont even know that I like the idea of the volatility of LIPO even for myself. I typically keep all my RC trucks in a bin in the backseat of my truck and hit the trails 3-4 days a week on the way home from work. I dont want LIPO in my truck all day because of heat.

Thanks in advance!

[Sdhyde17]

That was long let me clarify and shorten
The (2) 7 cell packs worked this morning in the SCX10 just fine. I ran one yesterday and then again this morning until it died. I then ran the other one until it died.
At the same time I was running the SCX10 II with the older 8 cell pack and I ran it dead. We then took lunch and i let all 3 batteries charge on the car charger for about 2 hours total. After lunch I plugged them in and now neither 7 cell pack will work in the SCX10...

[EeePee]

Nimh batteries blow up too. Same as a lipo battery.

Maybe the lipo cut off built into the ESC is turned on? Which would mean if it reads a low voltage it will more or less stop. In other words, make sure the ESC is in Nimh mode.

[OSRC]

^^ this. Be sure your voltage cutoff is set correctly.

[Sdhyde17]

Thanks...but i didn't change anything from this morning to after lunch?
All I did was turn it off and recharge the battery packs?
Can an ESC change itself?

[Sdhyde17]

Originally Posted by EeePee

Nimh batteries blow up too. Same as a lipo battery.

Maybe the lipo cut off built into the ESC is turned on? Which would mean if it reads a low voltage it will more or less stop. In other words, make sure the ESC is in Nimh mode.

It is in NIMH mode. The HW Quicrun has a small pin bar that is set in the NIMH mode. Should I switch to LIPO, I am thinking it may solve all my issues, but i am not sure.
Recomend any brands and charger combo units or even an online retailer with good deals?