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#1
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NiMH question
I've recently built a team c Jekyll with my son and installed a simple brushed motor and ESC from Absima. When I have test run it with LRP 4400mAh 7.2 stick pack the car is totally dying after a relatively short run. When I plug batteries in the charge they are showing 7.6-7.7 volts and when I charge at 1A they are going to approx 8.5v, but then only powering the car til they drop to 7.6ish. The steering is still working, but just no power for motor.
Is this normal? How long should a Nimh last on a full charge? Any help gratefully received
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I've got Araldite and a Swiss Army Knife - what more do I need? Yokomo YZ-2 No 4WD because nothing lives up to my original Optima. Until now maybe?... |
#2
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Depends on the wind of the motor and what surface you've been running on, but a 4400 should generally last 10 minutes even on grass with a hot motor. When you say its dying does it noticably get slower or just suddenly cut off?
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#3
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Is it possible that your esc has a lipo cut off?
If so, your cells might be dropping below this on load, even though they are above voltage off load. 4400 mAh cells should last 10-15 minutes maybe more depending on the motor used
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Team C TC02c - My son breaks it, I fix it. |
#4
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Quote:
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#5
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Hmm. Good suggestions.
ESC is an Absima ecu-1 which apparently can take lipos so I will look into whether it has a cut off. I will also try charging at higher amperage see if it gives a little more punch. I will time a full run to see length of run before power drops
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I've got Araldite and a Swiss Army Knife - what more do I need? Yokomo YZ-2 No 4WD because nothing lives up to my original Optima. Until now maybe?... |
#6
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Well, I tried again today with full charge batteries and they lasted approx 3mins. I had a spare 3300mah battery so tried that and it gave almost 15 mins so must be a battery issue. Will try discharge/ charge cycle and if that doesn't help it can go back to shop!!
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I've got Araldite and a Swiss Army Knife - what more do I need? Yokomo YZ-2 No 4WD because nothing lives up to my original Optima. Until now maybe?... |
#7
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Sounds like there is a faulty cell
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#8
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you are charging using a NiMH setting? If you had the charger on a Lithium setting then the voltage would be limited to 8.40V which is not suitable for NiMH which require charging at constant current.
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