Hi, I recently got a stampede and after burning out my Titan TWICE I decided to go brushless. This thread is not just about lipos, but it is the next best forum to post it in. I'm getting the Velineon 3500kv system. I'm wondering a few things:
1. With the stock Titan and stock gearing, the speed was perfect. Almost a little too fast, actually, so what kind of speed would I see with the Velineon with NiMh's? With Lipos?
2. Can I/should I use the Velineon with NiMh's? I would prefer to, but I've heard mixed stories on whether it is fine to use them or not, and it gets confusing.
3. If I do decide to go with lipos, what equipment should I get to safely charge them?
4. Again about lipos, I'm honestly a little scared that Im going to cause a fire or damage them or something. I usually run my battery temp up pretty high, to the point where you can't touch it for more than a few seconds, and I don't knwo whether lipos are right for me considering the abuse I put my vehicle through.
5. What gearing should I use, with NiMh's and the Velineon system? With lipos?
1) NiMh is usually a little faster for the first few moments of the run... 2S LiPo vs 6C NiMh... but the LiPo is going to get you up to speed faster and be more consistent with its speed throughout the run.
2) Yes you can, but the NiMh will suffer and live a short life... they just cannot keep up with brushless amperage demand very well.
3) EZPeak Plus is a decent entry level charger. I personally decided to go all out and get the last charger I would ever need right off the bat and have not regretted it once; my choice was an iCharger 206B.
4) LiPo's are actually less dangerous than NiMh as long as a few basic guidelines are followed. The heat you are experiencing with NiMh is due to the inefficiency of the battery and you will probably not have any heat with the LiPo in the exact same situations. It takes a VERY good (read: expensive) NiMh to compete even with the cheapest of LiPo's when it comes to amperage delivery.
5) Gearing always depends on temperatures and never on anything else... I suggest investing in an inexpensive ($10-15) temp gun in order to find out what gearing works best for you. What works best for one is not always going to work best for another.
I thought I should add I have seen more NiMh unexpectedly pop and cause damage than I have ever saw a LiPo vent. Every single LiPo "explosion" on YouTube I have ever saw was caused intentionally by severely abusing the pack.
Also... this might be neat for you to read:
If you took two identical RC's and two identical RC drivers, with the only difference being the batteries... in the beginning of the race the NiMh will probably be faster. But, by the end of the first few laps (and sometimes not even that long) they will be neck and neck because the NiMh's voltage has dropped to match the LiPo's voltage. As they continue to race, LiPo's consistent voltage and amperage availability will allow the LiPo powered RC to pull ahead and win, meaning at this time LiPo has the higher voltage and the higher amperage availability. If the track is really twisty and forces the driver to slow down and power out of corners, the superior amperage availability of the LiPo will actually beat out the higher voltage of the NiMh and the LiPo would not fall behind, even in the beginning.
Also, if you want to take into account weight and dimensions; the same capacity LiPo is probably going to be about half the weight. If you match the weight, the LiPo will be about twice the capacity... meaning that while the NiMh is being charged (and NiMh can only be safely charged one at a time vs LiPo's capability to be safely charged in multiples) the LiPo still has enough capacity to race another heat... or two.
Last edited by JimmyNeutron; 09-01-2013 at 07:26 PM.
Whatever it is I just typed... could be wrong.
bump bump bump
That is very good info Jimmie. Thank you.
I also have a VXL slash/raptor. I recently acquired two 3s 4000 mah LiPos. Both the Slash and Grinder are significantly faster on the 3S Lipo versus the 7 cell NiMH, to the point where the 3s is too fast. You need a large area to use the VXL on a 3s as you will quickly run out of runway, unless you're using the 3S in training mode. A 2s LiPo is more comparable to the seven cell NiMH.
I use the Traxxas ez Peak for my NiMH. I recently purchased the ez peak plus when I purchased the LiPos.
My recommendation to you would be to install the VXL and see how you like it with your existing batteries. From there, you can assess whether or not it makes sense for you to upgrade to either a 2s or 3s LiPo and a new charger.
Stampede 4x4 VXL; Slash 2wd VXL; MJ Grinder VXL
From the RC helicopter world I learned a saying
If you haven't made the jump you are missin out.