JMYBFFT

I am currently running 3 vehicles with EZrun 60amp ESCs and 13.5 and 8.5 motors. In the last couple of weeks I have had the same issue with each vehicle at one time or another. What is happening is I can fire everything up and hit the throttle and the tires will spin, but as soon as I set it down it will not move as it doesn't generate enough torque under load. It has happened with each of my vehicles at one time or another over the last few weeks. I am now suspecting I may have a battery that is going bad, but only intermittently. Is it possible for a battery to be able to deliver enough current at times and not at other times? The suspect battery has gotten out of balance (.08 volts difference was the largest difference I have noticed) a few times in this same time period. Any ideas what can be causing this?

hbc865

Are you using 2s or 3s ? 5000mah 4 ,2.5 ? what type of charger , did you check voltage using a volt meter?

Duster_360

iTrader: (21)

Doesn't sound like it's the lipo, but one of the lipo's connections. Connections can and do fail intermittenly and can be frustrating to diagnose. When it does this, wiggle the connections and see if it will 'come back', both the ones for main power leads and the wires where they come out of the lipo. If it comes back in response to wiggling/moving/pulling on either, you know what it is.


.08v diff in cells is within most balancers tolerance (<10mv) so all that may be saying is the lipo has some age on it.

JMYBFFT

I am currently running 4000mah 2s 25C batteries. I have three identical batteries, although I numbered them so I can tell them apart. I think it may be something internal in the hard case as the problem has struck each of my vehicles at one point or another and then seemed to 'resolve' itself. It happened once in the middle of a race as I approached a jump and my truck kind of died an started rolling back down until the marshall gave it a shove back up the incline and the motor kicked back in and gave me no issues for the rest of the race.

I am basing the voltages off of what my chargers read when connected.

I have a Thunder AC6 and Accucel 6.

dynodan22

iTrader: (9)

You might want to check your esc settings , this sounds more like a stutter problem. My castle was doing this to 3 of my motors . Once I change the auto lipo feature to a setting and also changed the low punch setting to a medium the problem stopped for us. If your lipo connection fails it would happen more frequently or total complete

Dynodan22

JMYBFFT

Dynodan,

What are the chances that all three of my ESCs would start having this problem in the last month after running without issue for the previous 9+ months for two of them and 2 months for the third? It has only happened once where it came back immediately after happening, otherwise it was not until I did a bunch of other things and in retrospect I think put a new battery in. Up until Saturday I did not suspect the battery until the end of the night. I had the exact same 'failure' on two ESCs in two seperate vehicles on Saturday. I will do some testing tonight and see if I have the issue with my other 2 batteries and see if I can 'recreate' the issue with the battery I suspect.

These batteries have 4mm female bullet plugs built into the case. How would you go about checking for a loose connection inside the case or should I just retire that battery if I confirm my theory?

JMYBFFT

I confirmed last night that my one battery is not working properly. It seems to have gotten to the point now that it doesn't provide enough power under any circumstance now but it still shows a full 8.4V balanced charge.

Is this likely a problem with a connection within the battery that allows it to still take a charge but not allow it to discharge at a high enough level to supply adequate power to the motor?

Is there anything I can do to save this battery or is it time for a salt water bath?

Kylar

iTrader: (187)

Sorry to hear, considering their price it might just be time to buy a new one. How old are they? How many charges on them?

JMYBFFT

The battery is only about a year old with 3+ cycles per week. I don't think I did them any good as I used to store them with a full charge up until about two months ago. I also used to run the end with the plugs to the front of the car so I may have damaged the connectors internally then with one of my lawn dart landings at some point. These were my first lipos and I now know better (at least I hope I do).

rangerjkb

iTrader: (45)

I had same issue with one of my 1yr old batteries this season, ended up being the battery, even though it would register a charge and good voltage #'s. Changed battery and all was great. Hope you're able to figure it out and are back to racing fully equiped soon.