kenstogie

Purchased a Duratrax Piranha and am quite impressed with it. But want to make sure i have the right settings...
just bought two 3300 Venom NiMH 7.2 batteries
what settings do I put my charger on? Heres what I have so far....
NIMH (of course I am not that dense )

Evader ---> MGT

Yup, should be
NiMh
3300mah capacity
Cut off at 12mv

And I think that's it...

PS, I hate the tone it plays at the end. TURN IT OFF!

kenstogie

CURRENT I have at 2.9 but am not sure what it should be at, usually I use AC Should I put it at full always? (3 for AC is max according to the directions and 5 for DC)
8.7mv/c I understand this means mila volt cut off but what does that mean to me and the battery??
Then there's a trickle charge thing too, arrrgh RC battery stuff is soooo darn confusing!

guver

My Feedback: (325)

The capacity should be something over 3300 , the mv should be about 5-8 (it is a per cell figure) and the manual is wrong.
The charge rate can be set to anything up to 5 amps and it will go to 5 on DC and it will stay at 3 on AC by itself.
Trickle can be 0 , 100, 200 and should be 200 ma for a new battery. Leave it on trickle for a number of hours. After the first charge it can be set at any value. It is a good charger.

kenstogie

So there are 4 normal settings,

Battery type (easy choice there ) NIMH
Capacity (again easy choice there too), 3300
Current (which is set at max or 3 amps for AC, 5 amps for DC) for me 3 amps as I am using AC
Delta Peak (which manufacturer recs at 8 for NiMH or 6 for NIcad, also I got that I think) 8 is my setting as per manual

There's also the trickle charge setting which I haven't touched.

Here's the issue is that I have these settings and I get about 1 min run time from the batteries and the charger takes maybe 15 mins before the finish song plays. ?????? That seems rather short. Do I have my settings messed or maybe my batteries messed up or what?

Muchos gracious my RC Friends for your past wisdom and any future light you can shed on this.

guver

My Feedback: (325)

15 minutes is adding about 687 mah to the battery and should really run longer than 1 minute.

If the battery was dead to begin with then either restart charge or set the mv at 12 like evader>mgt said.

It can definately be a battery problem. An idication of a full charged pack is that it's quite warm at the end and even temp. A bad/weak cell is indicated by a hot cell after charge or after use.

Is it possible to eliminate either the battery or charger by using a different batt or charger?

drevil

My Feedback: (5)

It sounds like the battery may be defective but just for the heck of it try cycling it a few times. Charge it at 3 amps, then run it until it feels like its starting to die (not until it's completely dead). Then do it all over again. Sometimes new nimh are flat and need cycling. Even then they usually give much better performance than what you're getting but with these things you never know. I'd try cycling it a few times and if the performance doesn't go up return it.

Also while charging it feel around the battery pack. If any one part of the pack is getting much hotter than the rest stop charging and return it.

kenstogie

I actually have 2 of the exact same battery

both don't even get warm and stay about room temperature,

Both packs have the same result give or take

I guess that means I have my settings right so that's cool. I think I remember reading that these packs were mediocre maybe I got 2 duds.

(not to be demanding but is sure would be nice to actually use the car I bought what a tease)

Evader ---> MGT

The packs should take over an hour to charge... hmmmmm

I think the charger's delta peak setting is too low. I have never had any problems with Venom Battery packs. The batts should get pretty warm when they're done charging...

kenstogie

I think it goes up to 12 should I try that? I know that NiMH's arn't supposed to have a memory but it it possible these do somhow?1

guver

My Feedback: (325)

No memory problems, try just restarting the charger if it isn't adding close to 3000 mah. OR leave it on the chargr with trickle set at 200 ma for 15-20 hrs. The battery will be full and balanced regardless of how the fast charge went.

Evader ---> MGT

The peak sensitivity goes up to 20mv. I normally set it at 12 (just used to it), but 15mv or so should stop the charger from having false readings causing it to stop charging, since the charge rate is so high.

BTW, I normally set trickle to 0mA. I've read that is isn't so great for Nimh batts, but I am not entirely sure...


Now, on the first cycle for a battery, it is ultra recommended that you fully charge and discharge the battery before discharging it again. Give it a full good cycle. Afterwards, you can charge or discharge as little as you want.

kenstogie

Put thePeak Sens up to 20 and tried it again same result
I bought my car (Rustler VXL) two batteries and the charger from the same dealer, and a ParkZOne t-28 Trojan RTF for that matter so I am pretty sure he'll make good on them. I am going to call later today, I do think it's strange that both batteries would do this but maybe it was a bad battery lot.

ALso the box for the batts says "DO NOT TRICKLE CHARGE BATTERIES" also charging instructions say "3 amps for extended life 4 amps for improved performance"

MANY THANKS for the help gentlemen I think after all the troubleshooting y'all have helped me with it is not me and that is a relief.

UPDATE:
Called the LHS where purchased they said to keep hitting charge a few times and it should go up I will give it a shot. He didn't seem surprised that it was finishing so quick (FWIW)

drevil

My Feedback: (5)

Did he say to run them (discharge) between charging them like that or did he just say to keep hitting charge over and over? Repeaking them over and over like that is really bad for the batteries and will eventually lead to them being overcharged.

guver

My Feedback: (325)

Start with dead battery, note capacity on screen and restart repeatedly until about 3000 is reached. Once it is over 2000 it may do it on it's own just like it is supposed to. No amount of cycling will balance the cells like leaving them on 200 ma for extended period of time.

The only way to balance a stick pack is to use slow current for long time.

kenstogie

Well got back from the RC store and here is what the deal is....
According to the [link=http://www.traxxas.com/products/electric/rustler3708/blueprints/manuals_instr/070912%20RustStmpBandVXL%20Owners%20KC1081.pdf]Manual[/link] page 19 is says "Traxxas
recommends leaving Low Voltage Detection on at all times. When Low
Voltage Detection interrupts driving, NiMH batteries will already be at
the end of their useful charge and voltage will be decreasing rapidly."

I can tell you this is totally incorrect if your using 3300 7.2v Venoms. According to the owner if the LVD is on it cuts out at 6v (or there abouts) and when your on the throttle it drops below this and caused the thing to go wacky, then it trips the shutoff for the motor. Which simulates a dead battery.

Turning off the LVD it was like Dr Jeckyl and Mr Hyde. Holy $H!g!!! WOW that thing goes like a bat outta he!!. It's got more balls than batting practice for a Major leage team.

Just to be on the safe side the owner gave me 2 new batteries and took back the old ones. Good job on service. I can pull wheelies now too. I also don't think I'll go lipo for a while it's pretty fast already.

guver

My Feedback: (325)

Thanks for the update, it is always nice to here the rest of the story.

So you were trying to charge a full battery, and the trouble was really in the truck in that it kept tripping lvc making the battery seem dead. Good lhs owner. You'll be back to that shop.

kenstogie

Silly me for following the Manual. How was I to know? Your right guver I will be back. When the LVD was on it acted like a dud, not much better than my 15 yo Bandit kinda dissapointed with it. Flick the switch and it's funtime got a big grin and can't wait to baja through some dirt.

Dudelive

Glad you got it all working correct, give the suggestion by guver a try when you get a chance. The charging at low millamp will give longer run times and it is better on the battery actually.

I did not catch which motor an esc you are using. Just curious

supamagician

funny. we use that same charger, and i have the same batt. for the longest, i was running a 1800 nicd batt. until my stepdad bought me that 3300 batt. we shared a the same charger between my 3300 and his 5000, then a few weeks laater, he went and bought me my own charger, and a 5000 batt.

kenstogie

It is a stock Traxxas Rustler VXL with a Velineon 3500 motor, and a Velineon VXL-3 speed controller.

I have read if I charge at a higher rate I will have I higher discharge rate which would mean faster truck, less run time and quicker charge time? Conversly if I charge at a slower amp rate, slower discharge, more run time and slower truck, is my concept of charging correct?? Not that I won't charge at a lower amp rating because I probably will just trying to understand how batteries/charging works.