JimBobtx

I’ve got a 1/18 scale ECX Torment running a Hobbywing 2435 brushless motor and their 16BL30 ESC, a 12T pinion, a 58 tooth spur with factory height tires that are much wider and more aggressive. With the factory tires and motor our Venom (15022) 1900mah NiHM battery would go 30-45 minutes of hard use but now it’s down to 5-10 minutes. I’m guess the bigger tires and brushless motor are wearing it down or is something else going on I should be looking for? What kind of life should I expect out of a NiMH battery that’s getting used hard and how will it last long term? I don’t mind spending money to upgrade to a LiPo but I don’t want to do that over another issue, thanks.

As should be obvious by the truck I’m new a this; I’m a car guy that got into this with my young son so he could start learning so take it easy on me! If my combo is junk or any of my parts are junk let me know because it’ll be news to me, thanks!

Davidka

iTrader: (86)

Adding power will hurt run time. A lipo upgrade will improve run time and power. Small nigh batteries aren’t very good for high current loads. If you have taller tires, lowering your gearing will also help (like a 10T pinion or 62T spur, if either is available) to restore run time.

killer rock

yes, bigger tires, hotter motor, less turns, higer voltages, larger pinions, larger motors. all increase amp draw and decrease run time. in nimh battery this is seen faster because of it higher internal resistance over lipos.

but before you make the upgrade/switch to lipos. id check to see if the new esc is in lipo mode. All lipo mode does is put in a low voltage cut off. this cut off is to high for nimh as it easily sags blow it. dramatically shortening run time.

Andy Koback

iTrader: (280)

1900 mah is way to small of battery to be running with an 1/8th scale Need to go higher in that department.

killer rock

1/18 scale not 1/8 scale

Andy Koback

iTrader: (280)

Sorry, misread that.

Milkdudd

iTrader: (13)

This thread has got me thinking about battery life and maybe a couple of you might be able to answer a question. Between running let's say a 17.5 motor in a buggy or an 8.5 motor with 2s lipo just as an example. What would likely be the extra run time with the 17.5 motor. I know there's a lot of variables but are we talkin 20% longer run time? 100% longer run time? My guess is it would be somewhere in between these numbers. Apologies in advance for going a little bit off topic

waitwhat

iTrader: (4)

You could calculate it using motor kv, but how you drive has a huge influence on how quickly you drain the battery. I have a 4wd SCT and I can drain the battery in 7 minutes if I drive it really hard. I can also drive really gently and get 20+ minutes out of it. Typically, a 17.5 is set up to run on the "turned up" side of things to get everything from them, while a mod motor is typically turned down to give you the most power you can handle without being too much. Timing, gearing, and ESC settings also impact run time.

JimBobtx

I’m not sure if this ESC has a LiPo mode, there wasn’t anything mentioned about it in the setup paperwork. I’ll take a look again, thanks!

the rc guy

if esc dont have a lvc for lipo get a battery buzzer plugs into balance wire ...good cheap and works...around $4 usd

JimBobtx

The tires aren’t any taller but they’re wider and much more aggressive; my guess would be the motor is seeing less RPM but higher loads. I went from the factory 14T to a 12T to compensate but I believe I can go one size up on the spur still and may do that, thanks.

JimBobtx

I’ll talk to my local shop, thanks!

Davidka

iTrader: (86)

It will be more run time but it’s not a linear relationship, mostly because 17.5 motors are run ar much more aggressive timing and gearing settings to extract as much power as possible from the limitations of the motor. An 8.5 has such an abundance of power that even run conservatively there’s plenty of power available for most drivers. Very skilled modified class racers would consider an 8.5 to be “mild” power but it’s downright nuclear if you’re not already used to that kind of power.