Losi 2.0 Night Crawler Loses Power

[ultimatum]

Gents,

I have a used Losi Night Crawler 2.0. It loses power after about 5-10 minutes of operation. I have tried two different batteries with the same results.
Venom 5000 NIMH 9.65 starting voltage/ 9.22 after the power loss. I have a 3000 NIMH that has similar characteristics after 5-10 minutes of operating time. 7.84 start 7.65 after 5-10 minutes.
Temps taken after it loses power. Motor=149 degrees F / Rear diff = 125 degrees F /Front diff =78 degrees F / Battery = 85 degrees F / ESC 75 degrees F. The ambient temp was about 45 degrees F.
After it loses power , I immediately installed the other battery. Same results after 5-10 minutes of normal operation. The drive axles seem to turn easily by hand. I did install a new brushless motor before this test with no improvement. Same problems I had with old motor.
My total rookie thoughts:
ESC or/and worm gear friction. The rear diff, although hot seemed to turn ok.

Your comments are much appreciated

 

[magic_yeti]

Sounds like the lipo cutoff jumps in. Cause you are using nimh batteries, did you disable the lipo cutoff in the esc settings?

 

[rob5059]

You need to grease the worm gears

 

[ultimatum]

Gents,

I suspected the diff grease as well but tentatively ruled it out due to the performance returning to full output with a battery change. The motor and diffs barely had a chance to cool in the time it took too change the battery. It seems as though something resets with the battery change as the performance returns to normal for 5-10 minutes. Then it's down to 5%.


How do I go about checking the setting on the ESC for lipo or nmhi ?

Thanks for your patience. I recently retired after fifty years. Thought this would be a fun hobby with the grandkids.

 

[dacaur]

If it were something to do with the ESC, you wouldnt have to change batteries, you could just unplug your battery and plug it back in and be good for another 5-10 min...

Looking at your voltages, I would say the issue is your battery(s). A fully charged 7 cell pack fresh off the charger should be very close to or over 10 volts. Likewise a 6 cell pack fresh off the charger should be over 8 volts. For your 6 cell pack, 7.65 is pretty close to dead, but should have some power left. Same with the 7 cell pack, at 9.22 volts, it should have a bit remaining....

So there are two possibilities. Either both packs have a cell going bad, or your power draw is higher than it should be... How long has it been since you greased your diffs? Worm gears require constant maintenance, its not like a normal gear diff that you grease once and forget it. You need to verify the housing is packed full of grease. If its getting warm, its probably low on grease, and is therefor increasing amp draw.

 

[dacaur]

Gents,


How do I go about checking the setting on the ESC for lipo or nmhi ?

looking at the esc from the top, with the bank of pins/jumpers at the bottom left, there is a jumper on the bottom row, thats what determines nimh/lipo. For nimh it should be on the two rightmost pins.

 

[jgrim]

Like others have said, grease the worms! I struggled with what I thought to be bad motors and ESC's only to discover it was lack of grease in the worms.

 

[CM9000]

run a lipo if you can. if you have only ran it a few times, the grease is a non issue. ive been running losi axles since 2009.

a 13.5 sensored system on 3s lipo is the best electronics setup in these rigs. now, if you are looking into trailing this rig, you would need to mod the axle for a grease port so you can constantly apply grease without having to take the rig apart so many times.

check out the losi comp crawler section just down the page for more answers and help with mods.