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Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 20 2021 12:04am
by Jonathan1981
Merlin wrote:
Sep 18 2021 4:42pm
sure...

380 x 148 x 158 gives you a tight 20s14p of 21700
for example p42 molicels = 4kwh capacity / 560A peak power/ 20kg weight in 1,5mm Aluminium case.

or 5kwh with 5Ah cells and ~ 280A peak power
Holy crap. Sure that's correct?? that seems REALLY small... just a tad bigger than the stock batt.... so does that include the BMS inside? and all the balancing wires etc. Is there any sort of insulation in the case? plastic sheet etc.?

so if my math is correct, then that's a 72V, 55ah batt vs. the 60V, 32ah stocker...

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 20 2021 3:58am
by Merlin
Yup should be correct. incl BMS and GFK plates as insulation.

i think 20kg is a "Good" Battery weight. "We" want a "bigger-surron" and not a full size MX Bike.

so Ending up with 75Kg should be the target.

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 20 2021 7:17am
by smdub
Jonathan1981 wrote:
Sep 19 2021 11:54pm
Haha, OMG, and that's exactly why they're out of business, that must have cost a fortune to do....
Likely not the reason. KTM/Honda/SurRon/etc all go full custom. That casting wouldn't have been too expensive. If you are going to hit those performance/weight targets there is no other choice.
Jonathan1981 wrote:
Sep 19 2021 11:54pm
CR85 forks, IFICR, are ~ 20lbs... they're not light, but not CR250 or KTM450 fork heavy. A pretty nice sweet spot. But they're also 11.8" travel :) that's the key. But I think an aftermarket company could make something 8-10" and that would be great also. Like a marzocchi trials bike fork. That'd work just fine also.
CR85 forks are 275mm/10.8" stroke unless you've modded them somehow to 300mm/11.8"?
20# doesn't seem right either? The 43mm 270mm stroke Tech forks are 10kg (22#) incl. the triples.
https://www.rideformula.com/products/mo ... o-o43-usd/
Their 39mm 270mm pitbike forks are 6.3kg(13.9#) but no triples incl.
https://www.rideformula.com/products/mo ... e-o39-usd/
FWIW, I didn't know Formula made the Tech forks until just now. I have the Techs w/ aluminum stanchions on my '19 Sherco 300ST Factory trials bike and knew they were pretty light and went searching for their weight. Browsing their website I found the above linked pitbike & enduro forks.

I will have to say the '21+ Freerides got larger Formula brakes than the older models. So far they feel awesome (better than the Brembos on my full sized KTMs.) I've always gotten the impression the Formula stuff was low end but their Tech forks are really nice and these brakes have changed my mind. They must just make a low end cheap line for the low budget mountain bikes.
Jonathan1981 wrote:
Sep 19 2021 11:54pm
Yeah so, like I mentioned, I've tried to play around with this before but the longer batt packs are a really issue. I'm not too keen on trading that length for width either...your idea about two seperate packs is interesting. That could definitely free up some design freedom.... I'm not an electrics guy so not sure how feasible that would be, I'm assuming you'd need fairly large cables between them....
Putting batteries in series or parallel isn't too big a deal. The cables aren't any bigger than those currently used if in series. They only have to be sized to carry a little more than the continuous current. They can be even smaller if running parallel packs. Imagine of you had a main 40Ah pack and an aux 20Ah pack. The aux pack it delivering 1/2 the current the main pack is and wires can be sized appropriately. Wire runs on a bike are fairly short too so they don't have to be so oversized to reduce voltage drop.

The other advantage to multiple packs is better cooling. In the RC world where we are discharging packs in 5min (20C avg rate) we are putting spacers between the packs to get more airflow. The center cells of the 6S packs are getting toasty! I know some folks have had thermal issues w/ the surron batts when pushing hard so the problem exists on the bikes too. KTM/Alta/Zero/Energica are using water cooled motors but still air cool the batteries AFAIK.

I've been playing w/ the idea if I raise the Surron seat, I can stuff a parallel 10+Ah under there. As far modded as mine is, I've still resisted raising the seat or rear linkage. W/ the moto tires its about the perfect height for my wife so anything I'd do to better fit my 6'2" frame, I'd have to undo for her. Now that I have the KTM I'm less tempted to make the Surron taller (but its not completely gone.)

Opps, I got sidetracked and forgot to measure the height of the Litespeed pack. Will try to remember tonight.

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 20 2021 7:42am
by smdub
Merlin wrote:
Sep 20 2021 3:58am
i think 20kg is a "Good" Battery weight. "We" want a "bigger-surron" and not a full size MX Bike.

so Ending up with 75Kg should be the target.
I don't think 75kg is achievable.
A stock SR is about 55kg?
fork: Fox40 2.8kg, CR85 10kg = +7kg
wheels/tires: 8.8kg oem (no sprockets/brake rotors), ~14kg moto 21/18 = +6kg
battery: oem 11kg vs your proposed 20kg = +9kg
motor: oem ?kg vs QS 4kW 13kg = +?
=77kg+motor and the frame isn't enlarged or beefed up yet. Need better brakes too. 90kg is prob a more realistic target. The KTM is 111kg.

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 20 2021 12:03pm
by Jonathan1981
haha, you're so picky. Yes, notice the ~ sign. 20lbs or 22lbs for the CR85 forks. Close enough. I was just guessing. Yes, you're right. they're 10.8", again was just going on memory.

and bike @ 65 vs. 77kgs. You're not going to be able to have an exact number here, it weighs what it weighs when it's done. Anything under 175lbs would be considered pretty light weight and I'd be happy with that.

Those Formula forks look pretty interesting, love the weights. What about pricing and they take a 21" front wheel? Would have to use the 865mm model. What about crowns?

Hmmm. I have the CR85 forks measuring 35.629", the 865mm formula models are a bit short, but the 895mm would be about right, but they're the larger style 43mm forks, says they're only 10kg tho... So I wonder if they're as burly as the CR250 or KTM450 forks (which I'd like to avoid). Or maybe they're somewhere in between. I wish I had funding for this project...I'd start ordering a few parts to experiment.

If the battery can be packed into the dims that Merlin is saying, then no need for two packs, I looked into last night and at that size it should just squeak by. Now I just need a model or dims of a direct drive motor and I can do some prelim stuff. BTW, BAC4000... good choice for controller?

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 20 2021 12:06pm
by Jonathan1981
Merlin wrote:
Sep 20 2021 3:58am
Yup should be correct. incl BMS and GFK plates as insulation.

i think 20kg is a "Good" Battery weight. "We" want a "bigger-surron" and not a full size MX Bike.

so Ending up with 75Kg should be the target.
Very cool. So can you take time to really double check those figures and make sure they're feasible. I'll be designing tight dims around those numbers so I just want to make sure they're G2g. Case is a rectangle box, no protrusions? how does the lid look/work.??

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 20 2021 1:11pm
by Merlin
bac4k too small for a "big bike"
its barely enough for a surron (phase amps)

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 20 2021 11:38pm
by Jonathan1981
Merlin wrote:
Sep 20 2021 1:11pm
bac4k too small for a "big bike"
its barely enough for a surron (phase amps)
Oh really? huh, from what I could gleem from forums, seems like it was enough and the 8000 was overkill. Remember, this isn't a "big bike", it would be more "mid sized"...

So a 72V 40ah'ish pack would need a BAC8K??

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 21 2021 4:22am
by Merlin
battery amps are fine with a bac4000 since the surron motor is a bitch.

but phase amps on a bac4000 is pretty "similar" to the stock controller only.

bac8000 is overkill simply because with 800+ phase amps your surron motor overheats in a minute.

theres nothing inbetween. But for a QS Mid your fun starts with 600+ phase amps.

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 21 2021 1:38pm
by john61ct
Besides cost/size/weight, overkill is no problem

so long as limiting logic prevents overwhelming the motor.


Merlin wrote:theres nothing inbetween. But for a QS Mid your fun starts with 600+ phase amps.
Sorry but could you be specific which motor, maybe a link? Their model naming leads to confusion.


Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Sep 21 2021 1:59pm
by smdub
Litespeed 72V 32Ah molicell 21700 batt is 373mm tall. The cables glands sticking out the top are taller.

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Oct 12 2021 8:46am
by thoroughbred
https://litespeedbikes.mybigcommerce.co ... n-battery/

This one is 450mm tall and is 20s10p molicells, looks like the cells are held by snap-together honeycomb

I have bigbirds waterlogged litespeed opened up. It was obviously not waterproof/rainproof! I would say avoid any water exposure but don't people ride in the rain or park these out in the elements? maybe i should start a separate thread...

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Oct 13 2021 12:15pm
by Hawaiiguy
I’d like to know more about what you find on the Litespeed batteries,I have tried to waterproof mine as best I can but the top of the battery acts as a funnel to catch water.

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Oct 13 2021 4:25pm
by QuietRush
Just popping in here as I've normally lurked over in the Stealth owners threads, but have been working with a local company as they build out their range of ebikes and emotos. We did a recent videoblog with Jeff Steber (founder of Intense Cycles) about the mods he'd been doing to his SurRon, which I think people here might find interesting. Article is at https://ebmx.odoo.com/blog/posts-1/jeff ... -special-4

Full interview is linked below:


Quick take:
KTM 65 forks
18"/21" wheel combination
KTM freeride plastics + seat

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Oct 13 2021 9:37pm
by liveforphysics
Merlin wrote:
Sep 21 2021 4:22am
battery amps are fine with a bac4000 since the surron motor is a bitch.

but phase amps on a bac4000 is pretty "similar" to the stock controller only.

bac8000 is overkill simply because with 800+ phase amps your surron motor overheats in a minute.

theres nothing inbetween. But for a QS Mid your fun starts with 600+ phase amps.

1min to overheat of harder acceleration seems like a nice place to be for most of my riding. The 8000 has its place if you enjoy silly fast 0-60mph times.

Re: SURRON LB: RESEARCH & DEVELOPEMENT

Posted: Oct 16 2021 3:49pm
by Merlin
sure, give her all she wants for a drag :lol: