Lipo VS NiMH - A quick run time comparison

[KC5H]

Alright. No apples to apples here. Just something I thought some of the newbies (like me) would be interested in knowing.
I just steeped up to LiPO's and in my case it's in the form of a Thunder Power 1350 mAh 2s 25c. I have been running a Onyx NiMH 1800 mAh and the 1800 mAh NiMH that came stock with my Red Cat Racing RS10 XT.



Total of 3 runs at my rock pile on the Arkansas river.



Onyx 1800 mAh 7.2V NiCd = a noticeable lose in power 18 min.'s and at 28 min.'s it Would not crawl up a 5" ledge. The wheels just would not turn.

Stock 1800 mAh 7.2V NiMH = a noticeable lose in power 18 min.'s and at 31 min.'s it would not crawl up the same 5" ledge. The wheels would not turn.

TP 1350 2s 25c 7.4V Lipo = a slight lose of power at 26 min.'s and at 31 min.'s the alarm sounded at 3.2V. per cell. Easily crawled the same 5" ledge.

The TP 1350 is only about 1/4 the size and weight of the other batteries in this little comparison (less weight = less work) and I can tell a slight difference in wheel / ground speed."thumbsup""thumbsup"

***Note*** Please see the-- Yes you need a BEC Theard in the Electronics section.

 

[xCoolHandLukex]

So if I switch to Lipos do I need to run a BEC ?

 

[TacoCrawler]

So if I switch to Lipos do I need to run a BEC ?

no

but if yer going to run a high power(demand) steering servo
or other high power accessories... probably wouldn't hurt.

 

[h2recovery]

Yeah in my opinion there is no other way to go. Lipo ftw!

 

[Gravebane525]

I ran a 5000 mah nihm in my ridgecrest... worked fine. got about an hours runtime out of it before I really noticed it slowing. maybe another 15-20 mins before it was at the point it wouldn't be able to go.

got a 4000 mah 20c lipo, I think 1/4 of the weight is understating it. get about 1.5+ hours out of it most times. slightly more power to it.

got a 2200 mah 25c lipo, half the weight of the 4000 mah exactly. get pretty close to an hour play out of it. I think this one has slightly more speed to it then the other lipo but it could be in my mind.

I don;t notice an alarm on mine. but while I can see the nihm battery running down for the last 15-20 mins the lipos go from workin pretty good to not powering the motor well enough to get the front wheels over a 2" high ledge.

part I don't really understand... all 3 take roughly an hour to charge (from 50 mins to 1:15 or so). I tend to let the kids bash with the 4000 mah lipo and use the nihm as a backup for that. I tend to use the 2200 mah for crawling though I do use the 4000 when its charged and the 2200 is dead.

 

[KC5H]

I ran a 5000 mah nihm in my ridgecrest... worked fine. got about an hours runtime out of it before I really noticed it slowing. maybe another 15-20 mins before it was at the point it wouldn't be able to go.

got a 4000 mah 20c lipo, I think 1/4 of the weight is understating it. get about 1.5+ hours out of it most times. slightly more power to it.

got a 2200 mah 25c lipo, half the weight of the 4000 mah exactly. get pretty close to an hour play out of it. I think this one has slightly more speed to it then the other lipo but it could be in my mind.

I don;t notice an alarm on mine. but while I can see the nihm battery running down for the last 15-20 mins the lipos go from workin pretty good to not powering the motor well enough to get the front wheels over a 2" high ledge.

part I don't really understand... all 3 take roughly an hour to charge (from 50 mins to 1:15 or so). I tend to let the kids bash with the 4000 mah lipo and use the nihm as a backup for that. I tend to use the 2200 mah for crawling though I do use the 4000 when its charged and the 2200 is dead.

I'm sorry I OVER stated it just a little. My Lipos are actually LESS then 1/4 the weight of my lightest NiCD baterry."thumbsup""thumbsup"

My Thunder Power 2s 25c 1350 mAh = 66g
74mm long, 34mm wide, and 13mm thick.
My Onyx 6cell 1800 mAh NiCD 7.2 v = 313g
131mm long, 46mm wide, and 24mm thick.

My LVA is set at 3.2 volts per cell. That's 6.4 volts at alarm for my 2s lipos. And that is plenty power for even a 5" ledge. I'll post a short video for ya as soon as I get around to it.

If you are running your LiPo batteries without an LVA and also running them to the point that they, " go from workin pretty good to not powering the motor well enough to get the front wheels over a 2" high ledge." Then Dude maybe you should just stick to NiMH and NiCD batteris. That way you will be less likely to burn something a whole lot more important then your crawler to the ground.
Man, read up on LiPo batteries.
I ain't flaming,,,,I'm just saying.

 

[wings_of_fire]

If rc crawlers could run on diesel.....

 

[KC5H]

If rc crawlers could run on diesel.....

8)Wish I could afford that"thumbsup"

 

[wings_of_fire]

8)Wish I could afford that"thumbsup"

You made me think that they are already built by someone and are available for sale :roll:

 

[OH91awd]

I may just have to make the switch to lipos..

 

[DBoger82]

The most important thing to remember about lipos is to make sure your ESC has a lipo cut off on it. That way when the voltage gets too low, you wont toast your batteries, and most important your rig.

 

[Olle P]

... make sure your ESC has a lipo cut off...

I'd rephrase this to: Make sure you have some low voltage warning.
Usually it's built into the ESC, but you can also have a separate warning signal.

 

[jeepnvinny]

Even with the safety factor, Lipo is the only way to go!