A theory on hill-climbing: MASSIVE 12s LIPO's, FOC, dual 6374, and the c-word

In it’s current state of evolution, my build is fairly intense. It’s built for hard, wide-open-throttle uphill acceleration, and aggressive downhill braking. Do I ride it that way? Yes, sometimes. Mostly, however , I use it mostly for running my big handsome dog Louie:

Specs: Dual 6374mm motors on 15mm belts Dual FOCBOX controllers Abec 11 97s Dual Gens Tattu 4s 22Ah25c lipos in 8s (651.2Wh) Dual TB reverse mounts with added idler pulleys. TB 218mm hangers on caliber ii 50 deg. baseplates

So what’s the deal with the massive batteries? Just think about that 25c rating on a 22Ah pack. Can I pull 550 Amps continuous? Of course not. That would vaporize everything. What I CAN do, is pull pretty heavy current with almost negligible voltage sag. Pretty intense range too. No matter how hard and far I’ve ridden, I can’t even put a dent in them.

That being said, the obvious theme of this build is overkill. I wanted to create a vehicle more than capable of anything I put it through, and so far, SOOO good.

The best performance enhancing addition I’ve made is the addition of an Idler-pulley to my @torqueboards reverse mounts ($5total cost), which I documented here: http://www.electric-skateboard.builders/t/my-obsession-with-idler-pulleys/30191

The next step in refinement of this project is going to be the addition of a BMS with communication, so I can measure the actual power related metrics. Maybe even add another battery for 12s…


Hey Pat, your build is looking better all the time. I can surely vouch for this beastly setup. I have seen it fly up some really steep hills. Adding another one of those batteries for 12s would make it insane but I’m not sure the Focbox would handle 12s in FOC mode. You might have to switch to BLDC. How’s your plans for an enclosure going?


I’m curious as to how many more amps the FOC box will handle in FOC at 12S as well. I can vouch for it up to 40A and 149KV. I’ve been running 12 FOC with sensors in the FOC box for about 4 months now.

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Beast build, I like it! Once you go 12S with high amps I bet you wont go back though :wink:

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Where abouts did you get those batteries? What was the price?

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Slowly, because there’s always something that I am tweaking, or improving. I definitely plan on using part of the enclosure you gave me! The batteries wont fit though

If you want to make an enclosure of fiberglass, I think I have some cloth left over from when I used to do my own surfboard repairs, you would just need to get some resin and catalyst. Epoxy resin would be best because it is more flexible than Polyester resin and less prone to cracking. I prefer the molded abs enclosures myself. Psychotiller could prob set you up with something that would fit. Runplayback used to make some really nice heavy duty abs enclosures. Don’t know if he’s still into that or not.

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Here’s a question Ive been confused about for a while: Does C rating effect torque? Will a higher C rating give me that little boost I need when goin uphills? I’m using 25c lipos and was looking at going to 40-45c

Fiberglass is a good idea, I may be interested

What’s your capacity? And what is the make

I believe they are turnigy 4000mah 3s in series for a 6s.

A higher C rating will decrease voltage sag during heavy loading like going up hills. Higher voltage seems to increase torque. Higher motor max setting in bldc tool will increase torque. Running large motors like 6374s increases torque over smaller motors like 6355s


25Cx4Ah= 100A continuous. Those are gonna sag hard on big hills. Also, what @Namasaki said

unrelated, pics of your dog aside from the avatar picture, please.

i run my two dogs on my board too, it’s where it gets the most miles. overbuilt board (dual 6374, 12s4p), average speed = trotting speed of two small dogs.

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Lol, the same!! Avg. Speed =trotting - pauses for sniffing

and going pee and :poop:, of course

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In my experience, polyester resins are more flexible than epoxy which is much harder. If you look at epoxy surfboards they are known for their stiffness. Either would be good for an enclosure though. If you want any pointers when you make one, drop me a line and I will try to help out.


I appreciate it!! And I will. If I were to do one, it would be hinged so that it could be easily moved out of the way, and strong enough to protect the batteries from assault. Tough concept.

Thats some slick looking stuff @bigben

Hinged? That sounds unhinged…

What I did is mix some polyester resin in a cup and some epoxy resin in a cup. After they cured, I removed the resin samples and tested them. The polyester resin sample was hard and brittle and would not bend but just broke. The epoxy resin sample did not feel as hard as the poly and I was able to bend it some before breaking it. I owned many surfboards over the years, polyester and epoxy and what I have noticed is that the polyester boards get cracks and dings much easier than the epoxy boards. Fact is that epoxy resin is 35% stronger than polyester resin. The difference in stiffness of epoxy surfboards and fiberglass surfboards is due to the different core used. An epoxy surfboard uses a polystyrene core which is stiff A Fiberglass surfboard uses a polyurethane core which is more flexible.

So if you want your enclosure to be 35% stronger, use epoxy resin. Besides epoxy resin doesn’t set as fast or get hot like polyester resin so it is much easier to work with. I know that you can mix polyester resin to cook slower but knowing how much catalyst to add can be tricky. With epoxy resin you simply follow the recipe on the bottle 2:1 for the resins I have used and it cooks perfectly every time.