Batteries
 

I wanting to switch over to NiMh batteries, In my TRX4, Mojave 4s, and Tekno DB48. I know the cars Will not go as fast as lipo but that doesn't bother me cause I could care less if they go 50+ mph. As long as they go pretty Fast and I get some long Run times that's all that matters to me. With that said What are some Strong Long Run Time NiMh batteries I could get?

Can I ask why you wish to make the change? Lipos are stronger and last longer than NiMh batteries.

Agree with OffRoadJunkie, LiPos should have higher capacity than NiMH.

A quick search online shows you can get some sub C NiMH batteries around 5000mAh. If memory serves me correctly, I think the last NiMH I actually used was an IP 4200mAh.

That said... Good lord, why? I most definitely agree OffRoadJunkie , you can get much longer runtimes and performance out of LiPo batteries. They also last longer and are much easier to take care of. Yes there are downsides that I will not go into.

Only thing I can think of why he wants to ditch Lipos is he watched some videos of Lipo fires!

Judging from the Mojave 4s name, your cars takes 4s lips. To have the equivalent voltage output as lipo, you need 14 nimh cells. Not really sure what size pack your chassis take, assuming they all use standard 2 2S battery packs, then you can probably only fit 2 6 cell nimh pack. Will be slightly slower but seems like you dont mind. Runtime and power wise will be significantly less tho.

Please don’t go to nimh. Lipos are higher capacity, give more runtime and power and are cheap. That’s like going from a lambo to a pinto lol.

Maybe a goot thing to say, when going for lipo, be sure your charger is able to charge LiPo, most RTR chargers for NiMh are not...

Umm yeah had one do it and I'm Done with lipos! I'm either going something safer or I'm selling everything I got

Damn sorry to hear that. Hopefully there wasn’t any damage other than the battery. You could switch over but your speed controller needs to be set up for NiMh batteries.

Converting to NiMh may not be straight forward. It will likely trip the ESC low voltage cut as the voltage will sag. Arrma Spectrum brushless ESCs are usually programmed for Lipo only. You may have to swap out the ESC for one with a programmable low voltage cut. You maybe able to buy a program card and flash the ESC firmware to make it work too. You may also need to fit new battery connectors.


NiMh cell performance car vary a lot. In my experience, the larger capacity cells, circa 5000mAh are not as good as the smaller cells circa 3000-3600mAh. If you want to do it you'll need 2x 7.2V 6 cell packs for the Arrma 4S. You could maybe use 1x 6 cell and 1x 7 cell (hump pack) for a bit more performance.


For what it would cost, you could look how to improve the safety of your LiPo setup. What do you have now?


Consider buying a a good quality charger, charger leads, new packs and one of those bat-safe charger boxes if you want. Inspect them from time to time. If the wiring is good, charger works properly and the batteries are properly secured in the vehicle they wont be a problem.

I can't find the right article which discusses the key differences but an equal capacity NiMh of 5000mAh compared to a LiPo of 5000mAh is staggering where the NiMh will be close to double the weight and nearly immediate loss of punch with high drain brushless systems.

You can't charge NiMh nearly as fast as LiPo either.

NiMh only makes sense for older brushed motors or very low drain 540 brushless motors.

https://hobbiesdirect.com.au/blog/ni...o-rc-batteries

Right now I have an Imars Charger, 4 Zeee 4s packs. I have a lipo Bag I always charge in (Outside). I don't run them a whole lot and I store them for quite sometime But I store them at 50% capacity. We do have some pretty Cold temps here in SC So they are stored in my bag in my building so the packs does get pretty cold at times.
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When he asked for NiMh equivalents, The first thing that I pictured was the old RC dragsters that had 20 batteries stacked on them.

I did a super, super, quick analysis, based on one hobby shop, so the results are not universal. I offer without opinion, a graph comparing mAh vs $ for NiMh and LiPo batteries they had in their catalog.
https://cimg8.ibsrv.net/gimg/www.rct...46a18255c3.png

Notes:

• It's one hobby shop in my region, not across the globe. Data will like change on local availability of products
• It only shows price and capacity; no other characteristics which have already been discussed in this thread
• You too can perform analysis like this! Modern tools make it so much easier.