Car not running correctly

[Simon Hester]

Hi

 

I have an older car that I have not driven that much.  I took it out and dusted it off charged the 2 NiMH 6 cell batteries but getting very mixed results. 

 

My Voltz 5300 mAh seems to charge and a multimeter shows it has a voltage of 8.2 from a search on the internet I believe it supposed to get closer to 8.7. When I use it in the car it will not drive on the road. If I lift it up the wheels will spin quite fast but then it will not move on the road it almost rocks back and forth in one place. Is this just the Battery that has gone and is not giving the car enough power to drive.  

My stock battery SC 3800 mAh that came with the car works a little better. I tested with a multi meter and after charging this is around 8.4v. The car will run but if you pull the trigger hard to full throttle it will not do and tends to stop start. If you gradually pull the trigger it will get up a little speed and run smoothly but you can't do any sudden acceleration or it goes back to the stop start. 

My Car is a BSD Flux Assault version 1
Ezrun ESC 
Motor is a KV3570

I think i know the answer but want to check as I'm novice at this. I assume the issue with the stopping and starting is caused by the low voltage on the battery pack is that right?

 

Is there anyway to re-condition the batteries? Whilst they are maybe 4-5 years old they have only been charged maybe 20-30 times. Although they were left in the box for maybe 12 months unused. I'm current have quite a basic charger Vector AC/DC NX85 which can only charge it can't discharge the batteries.

If i have to replace the batteries i was considering moving to LiPo good or bad idea? 

 

[Tug]

Definitely sounds like the cells at fault, cycling may help a little, but as you can't discharge them in the car, maybe try a car bulb?

 

Moving to lipo is probably best and not that expensive these days.

[Simon Hester]

Thanks Tug

Could I discharge them by running the car off the ground as it does run then? But I guess that would put  wear on motor as no idea how long it would take to discharge them. I could try and find a car bulb does it need to be a specific voltage bulb?

 

Thanks

 

Simon

[Tug]

Just a standard 12V lamp, somewhere around 50 Watts. 

 

If you go lipo, you'll need a new ESC with LVC (low Volt cut-off).

[Simon Hester]

I've checked and my current ESC has LVC or so the manual says I was wondering if this is what was causing the stop start so to speak. 

I can only run 2 cell batteries unless I want to update the fan on the ESC something to do with the voltage it needs is smaller than what a LiPo will deliver. 

I doubt i would use my car lots maybe 1 a week and  in the winter i could see it being left for good few months would LiPo still be goof for this type of use?

 

Thanks for the comments. 

 

 

[Tug]

It might be the LVC, can you check if it's switched on? It shouldn't be of you've never used it. 

 

Fans are cheap enough, but unless you're gearing up, you probably won't need one. 

[Simon Hester]

Not sure I can check there is a basic why to make program settings on the esc using a pin button  I have the instructions I guess I could set it and see how it goes.

 

How long should run the battery on a light I found a 12v 35w bulb. It been running for say 10 minutes now.

[Tug]

On nimh you can run it until it's virtually gone out. Expect about an hour on your stock nimh. 

[Simon Hester]

Possibly not done it for long enough ran my stock battery down to 6.4v well that was the reading on a multimeter. I have that on charge today doing a slower charge should i not bother and run it down further?

 

So many questions thanks for the help

 

 

[Tug]

6.4 on a 7 cell nimh should be low enough. May need a few cycles, but it's probably past its best. 

[Simon Hester]

I'm beginning to think so.

 

In my stock battery took down to 6.2v had it in charge for 8 hours on 0.5 amps toom it of charge and it only reading 7.2v tried to discharge it again and it went down to 5.3v in like 2 minutes.