Endless Sphere

If power density is all you care about, then W/L is the only unit of measurement that's easy to compare like for like in theoretical situations, but again, in practical situations, can be somewhat cumbersome. People want to maximise their use of space, so a really nice battery that is 1cm too big f...

I know it is like aasking "How fast do you go from 10-35mph"... when you got the data on the time i t takes to go 40mph and that is all you have for empirical data. Hope this is starting to make sense to you. It has made sense for much longer thanyou give me credit for, friend. W/L is all I care abo...

Breakin 8,000w any day now. 21s. Max is now 44mph on the flat. Kelly shuts down @ 85.8V.


10.64 Horsepower. On an 85 lb bike. 7.98lbs/Hp.

So a 1000Wh pack, if 10C is the max sustained rate - direct function of that chemistry's DCIR So the Crate stays the same with a 2p vs 1p because capacity. Is this right? Both batteries ( the 1p vs the 2p) would BOTH be a 10C, regardless. Is this right? I am NOT right when I would assume the 2p batt...

Both are 1000Wh, both allow sustained 10kW output from the same 2kg weight, also same volume.

Where does this 10Kw sustainde come from? One drops alot more thn the other.

The 2p can sustain more POWER? No?

"How many V do you drop per A" isnt telling me anything when it comes to power . "How many V do you drop per W" does tell me a thing or two about the power. IF ( ony if) our packs are all sharing some similitude, such as weight, and size. Most ebike packs look similar to me. Maybe you can see the di...

"Can you see why expressing voltage sag as volts per 1000w is misleading" In you r example It tells me both batteries are very similar ( and are, identival in weight, cell capacity, and volume,)...And your example tells me perfectly... Absolutly, in using the weight, IR, output, and droop, Which pa...

Thats my option two I thnk. I have beenon the lookout for big (plasma cutter) IGBTs and drivers.

Picture of parts coming together....

Do you guys think I can throttle the load with a Curtis motor controller for a load regulator? The Curtis 1207B programmable motor speed controller provides efficient, cost-effective, and simple-to-install control for a variety of small electric ve-hicles. Typical applications include walkie fork/pa...

I mean, yall know me by now, Imma OCD stickler... But.. I do make dam sure every place human hand touched on a cell is washed with soap, water, and the alcohol to remove ANy contaminant before final assy and wrap. Penetrox and seal with Kapton ( so you can see through it). I even pickel every c-tap ...

Well, I have my opiinions about building homemade lipos, and my tests. I do want to critique this build. Firstly, one thing sticks out to me. 6) There are ZERO external forces acting on clam-clips that would pull or bend clips away from tabs. You have no consideration for heat ( thermal expansion an...

Good sag then, for 15 ah or so. I figured they were a quality cell with low IR, but I had no idea if they were 10 ah, or 50ah. Everybody else reading knew, but I didn't . No prob I know Im a hack and get rammy, sorry I dint mention it. I am about to go 21s and see if there is much differences. So.....

I mean, am I getting it wrong, but isn't it just about 1-2mph differences across the acceleration/speed range? The Tq is almost the same?

Grin Calculator will tell you exactly how fast in Mph/sec. and the tq. with any throttle application between the two.

How do you like those cells they sound interesting. Good price. BAH no, Friend... . Lol. Ive tested a few and watched reviews. Mutiple low Ah reports ( even on Facebook as we speak) and polarized pouches ( some into the 3.3V+ region).. Not good!) 7Ah and more like 125 Peak, not 200A, Higher than ad...

DogDipkid? what Volt cells do you use in your pack? there are first and second GEN cells used in Volt. I ride on 11S2P secondGen cells. I have seen ( dissembled myself) Gen 1 cells. I have found, LGXP1. P1.5, and P1.7 cells in these. The P1 datalogged at 13Ah repeatable ( old? Idk.) 2012-13 car. Th...

My entire front wheel is 19x2.5 1.4 SurRon rim/hub,tire, 9.9lbs. Lightest tire rim combo could find. The shinko inthis size is 8 lbs. I got a Duro HF319 for the tire.
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I agree about the pics. On occasion I have linked to a pic to save time, but when a picture is important to the post and the treasure of info here, I save the pic to my laptop and then upload it. I'm afraid I don't have the power to change that here on ES. So many great pics have been lost in the o...

Dogdipstick, what's with all the missing images above? SM, if people have the privilege of sharing pics on the forum, then they should have to be actually shared by uploading. Disappearing images or being forced to join photobucket etc is an irritating disservice to all. I am sorry, I will be certa...

Today I did a voltage sag test on 2 different Chevy Volt module packs...a 21s 2015 from a low mileage car that I've had in service for about a year with no notable signs of diminished capacity. At 210A the voltage sagged from 80.2V to 75.2V. The other pack is a 16s module from a 2017 Volt version2 ...

Anybody know how the CA3 calculates IR from its inputs? I mean exactly? I got more to input based on your guys thoughts.. but I'll get back to that. Ive really been wondering how the CA3 does its extrapolation.

You know, I know it is not a constant ratio... But I think it is a good comparison. Without knowing what the impedance, size, or voltage of the pack. I d know if it is anything rational... I bet out packs all kinda weigh the same too.... 10-15 lbs.? I know it is not linear, looking at it. I think th...

It must be horrible if your pack drops 8 volts per 1000w ( as stated above for a 18650 pack).... I guess you hit LVC everytime when you try a "high power" pull. Lol "Shark"... Like I said, I had a nanotec/multistar lip0 guy tell me his 64Ah 72v pack sags 7v with a 60A hit.. or 1.75v/1000w... Very le...

You voltage drop is proportional to your power out. With no regard to the actual number of volts, or regard to energy transferred, in Wh... or regard to "crates".... or capacity.... Your voltage drop will ALWAYS be proportional to your power out. No matter what, period. On any battery, any size, any...