Looking for very light batteries for my buggy.
 

I have buggy with NEU 1512 2.5D(2050kv) + MMM ESC geared for ~35mph.
I can loose some run time but I don’t want to risk my packs or ESC.
Which one you thing would be better? Both of them weight 400 grams.
- 4S 30C 3600mAh pack
- 4S 20C 4000mAh pack

Either of those could work providing you keep currents on the lower side. The 3600 pack is good for 108A, but runtime would be rather short. The 4000 pack is "only" good for 80A, but you'd get a tad more runtime. Of course, I am assuming both those C ratings are real-world values unlike some cells that tend to be overworked when pushed to their max spec.

As a comparison, I get around 15 minutes of runtime on my heavy-ish Hyper8 on 5000mAh with a Neu 2d (2050kv) geared for around 35mph. This equates to around 300 watts of average power. To keep the same power level, running a 3600mAh pack would result in runtime of around 11 minutes. You might do a little better since weight is less. And more gradual throttle control helps too.

Thanks for fast respond. The pack brand is ZIPPY, I have very good results with them so far.
So since its safe enough I will go to the 4000mAh route.

THIS is the pack for you. Its a Hyperion 4s 35c 4200mah. I just got one last week, and its great, when I recieved it the pack was in perfect balance and lets me do wheelies in my 15inch wheelbase maxx truggy with a center diff filled with 10,000wt oil. Doesn't get hot or any of that. I get about 17minutes on the race track.

I run a zippy 3000 mah 40c 4s pack in my 8ight. I only use it for indoor races using the Tekin 1900 kv motor and works great. It's about 3mm thicker, and no wider, nor longer than a ROAR legal 2s hard case pack and weighs 350g, takes 20 minutes to charge (at 10A), and costs $36.

You charge the zippy at 3c? how has it affected it or has it?
phil

They're 40c packs can be charged at up to 5c. It says so on the label. As a matter of fact I have never charged it at anything lower than 10A since the first few charges, w/ no issues since I bought it in November.