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podolefsky
19 February 2011, 2000
Thinking WAYYY out to a future project and doing some calculatin'

Right now I have a 72V, 60 Ah GBS battery system (actually more like 80V in practice). I was checking out Headways and thinking about total kWh, volts, and amps. Here's my theoretical comparison chart - my question is whether this looks about right:

.........Standard Brick (TS, GBS)............Headway
Cells.......24s1p................................. ......32s3p
Ah...........60................................... ........48 (3x16)
Volts.......~80................................... ......~100
kWh........4800................................... .....4800
C rating...3 cont, 10 peak.........................10 cont, 15 peak
Current...180 cont, 600 peak.....................480 cont, 720 peak
Cost........~2100 (w/o BMS)......................~3000

So as I see it, Headways should give about the same capacity in kWh, but will have higher voltage and current, and they take up less space. They cost more and are trickier to set up (more individual cells).

I could actually fit 128 Headways in the same space as the 24 GBS, I was just shooting for similar energy capacity for comparison.

Anything I'm missing?

DaveAK
19 February 2011, 2006
Nope, I think you have it just about covered.

(Although I'm sure someone will say that they're no trickier to setup, but I get what you're saying. More connections, more work, more to consider for mounting, etc.)

ZoomSmith
19 February 2011, 2013
Don't forget to look at weight in your comparison.
Cylindrical cells are a little more work to design & fabricate battery frames, but something tells me you can handle that. ;-)

cycleguy
19 February 2011, 2018
I like Headways, 32 cells in series would be 102.4 Volts, kind of an odd voltage and hard to find off the shelf chargers and DCDC converters in that range.
A 30s4p pack would give you 96V/64Ah or 6.14 Kwh with 120 cells. Should make a very nice pack.
Although Headways are more difficult to bus the advantage is that you have more freedom to shape the pack to fit the frame more efficiently.

Skeezmour
19 February 2011, 2347
Hey our chargers are off the shelf :)

I know they don't fit on the bike but I'm working on that.

chef
20 February 2011, 0015
I'm a LiPo convert. Their continuous discharge rates are terrific, energy density high, and stacking pouch cells makes for very efficient use of space and easier mounting. Not trying to TC, just mentioning it as part of "vs the rest".

Nuts & Volts
20 February 2011, 0048
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16207
for reference :)
24s10p
50Ah
88.8-100.8V
5000Wh
20C, 30C peak (10 sec)
1000A continuous, 1500A peak
$2000 w/out BMS
70lbs
0.55 ft^3

Oh and and the price drops to $1707 if you use the swarm sale (http://endless-sphere.com/forums/viewtopic.php?f=3&t=25037 )
oh and shipping is 1cent in the US (limited time i think)

Not the easiest to work with, but the Wh/kg, Wh/L, W/kg, and W/L per $dollar can not be beaten :) please prove me wrong

foot for thought, and keep careful
Kyle

teddillard
20 February 2011, 0341
I put this together last snowstorm: http://www.elmoto.net/showthread.php?834-Turnigy-vs.-Headway.&highlight=headway+turnigy

Coninsan
20 February 2011, 0342
If we are looking way into the future, then consider 18650 cells. Several companies are working on LiPo cells with a Silicon grid anode which match or overperform 4000mAh per cell at 10C continuous and 15C pulse. Aaaand only 18mm x 65mm compared to a headway; 38mm x 122mm - Wh/kg, Wh/L, W/kg and W/L which matches or beats prismatic LiPo. :)
But alot of work unfortunetly.

Or consider these: http://www.saftbatteries.com/doc/Documents/defence/Cube769/VL6A_data_sheet.9ea09188-84ad-4c54-989b-a2206dc28da2.pdf
Those will get your C pumping.

teddillard
20 February 2011, 0411
Wow, what a profoundly bad website. But here's more info on Saft: http://saftbatteries.com/Technologies_Lithium_Liion_301/Language/en-US/Default.aspx

Here's some stuff their batts are powering, and yes, they look like an actual, real company:
(They had me at "Launchers".)

* underwater vehicles
* military electric and hybrid vehicles
* distributed power sources for new battleships
* directed energy devices
* UGV (Unmanned Ground Vehicle)
* launchers and other space vehicles
* high power UPS
* decentralised energy networks
* PV (photovoltaic) and other RES (Renewable Energy Systems)

jpanichella
20 February 2011, 0745
Wow, what a profoundly bad website. But here's more info on Saft: http://saftbatteries.com/Technologies_Lithium_Liion_301/Language/en-US/Default.aspx

Here's some stuff their batts are powering, and yes, they look like an actual, real company:
(They had me at "Launchers".)

* underwater vehicles
* military electric and hybrid vehicles
* distributed power sources for new battleships
* directed energy devices
* UGV (Unmanned Ground Vehicle)
* launchers and other space vehicles
* high power UPS
* decentralised energy networks
* PV (photovoltaic) and other RES (Renewable Energy Systems)

I read that saft used to make high performance flooded NiCad batteries for boats and such. They're definitely an actual, real company.

Coninsan
20 February 2011, 0811
Wow, what a profoundly bad website. But here's more info on Saft: http://saftbatteries.com/Technologies_Lithium_Liion_301/Language/en-US/Default.aspx

Here's some stuff their batts are powering, and yes, they look like an actual, real company:
(They had me at "Launchers".)

* underwater vehicles
* military electric and hybrid vehicles
* distributed power sources for new battleships
* directed energy devices
* UGV (Unmanned Ground Vehicle)
* launchers and other space vehicles
* high power UPS
* decentralised energy networks
* PV (photovoltaic) and other RES (Renewable Energy Systems)

Yea, pretty sweet cells they've got going, with C rates up to 175C continuous for their LiFe 10 - 25Ah cells, they would be killer in racing.
Unfortunetly their main focus is on military and space applications, so their probably not easy to get hold of.. I wonder if they perform what they promis?

teddillard
20 February 2011, 0825
We'll see. They have two local distributors, and claim that they do sell to private individuals, so I put in a query. I'll report back. :cool:

Coninsan
20 February 2011, 1055
We'll see. They have two local distributors, and claim that they do sell to private individuals, so I put in a query. I'll report back. :cool:

Awesome :cool:

I wouldn't mind a 22s3p pack of VL34P's
Voltage: 80 Volts nominal
Capacity Ah: (3x33Ah) 99Ah effective.
Capacity Kwh: 7.950kWh
Discharge: 15C continuous
Life: 5000+ @ 100% DOD

If only I had room for that in my bike! *drool*

BaldBruce
20 February 2011, 1502
SAFT is a European manufacturer of batteries that has been around for years. Some of the best batterries in each chemistry you can find anywhere. They do sell to anyone. The big negative is price. I asked for a quote 2 years ago on one of their cylindrical Li cells and was shocked at the price. Worth asking again in case they have improved their price points, but i wouldn't get your hopes up based on who they normally sell to......

Coninsan
21 February 2011, 0308
What prices did you encounter back then?
I would be very surpirised if the prices havn't dropped significantly since then..

teddillard
21 February 2011, 0440
Just started a SAFT thread here: http://www.elmoto.net/showthread.php?965-SAFT-battery-geekout-thread&p=8765#post8765

billmi
21 February 2011, 0801
Anything I'm missing?

Expected lifespan in number of charge/discharge cycles.

It's widely accepted online that real-world life for TS is shorter than their stated numbers, and I would expect a similar optimistic inflation from other manufacturers as well.

chef
21 February 2011, 0938
A guy around here has larger TS prismatics in his car and has over 1500 cycles. The cells are in good shape, >90% of original capacity. It all depends on the SoC and DoD levels and how they're charged. I think it's better not to use TS's advertised settings as their #s tend to be hard on the cells.

billmi
21 February 2011, 1027
If memory serves, Thundersky says they're good for 3,000 cycles to 80% or 5,000 to 70%. Headway, if I remember right is significantly lower like 1,000 or 1,800.

podolefsky
21 February 2011, 1233
If memory serves, Thundersky says they're good for 3,000 cycles to 80% or 5,000 to 70%. Headway, if I remember right is significantly lower like 1,000 or 1,800.

Thanks for that info. That's unfortunate - makes them not that much better than lead (well treated). Seems like that alone could make the difference for anyone not using them for racing (and has a pretty rich sponsor).

DaveAK
21 February 2011, 1234
Lithium has other advantages over lead than longevity though.

billmi
21 February 2011, 1237
And don't take my memory for gospel truth. I remember those figures from specsheets that EV Components had, and those are no longer online (their web site has finally vanished) - they should be available with a little digging.

chef
21 February 2011, 1303
Thanks for that info. That's unfortunate - makes them not that much better than lead (well treated). Seems like that alone could make the difference for anyone not using them for racing (and has a pretty rich sponsor).
Maybe I'm missing something here, but which leads have you been able to get more than ~500 cycles out of at 80% DoD?

frodus
22 February 2011, 0940
I like Headways, 32 cells in series would be 102.4 Volts, kind of an odd voltage and hard to find off the shelf chargers and DCDC converters in that range.
A 30s4p pack would give you 96V/64Ah or 6.14 Kwh with 120 cells. Should make a very nice pack.
Although Headways are more difficult to bus the advantage is that you have more freedom to shape the pack to fit the frame more efficiently.

102.4V is what I'm doing. I'm using a DeltaQ and it'l work just fine for up to 32 cells in series.

Vicor makes DC-DC's in that range.

frodus
22 February 2011, 0956
And FYI, the specs for the headways need a little of clarification....

they'll do 10C, but the voltage drop is quite a bit. They're fine at 5C, but once you go over that, voltage starts dropping. I really need to get a 16Ah cell to do some testing.

Can it fo 10C continuous? Yes. Should you? not if you want to drain your pack fast. At 10C, you'll get less energy out and the voltage drop will be significant. Another problem is the IR will cause some of that power to be lost as heat, which at 10C can heat up quite quickly (on just about any cell I've tested). The problem with that, is that you need to stay below ~140F.

So, for the way you're calculating, use 5C cont (240A continuous with 3p) and 15C as absolute peak. They're good batteries, but you need to really understand the discharge curve. See my 400W battery testing thread.

podolefsky
22 February 2011, 1215
Maybe I'm missing something here, but which leads have you been able to get more than ~500 cycles out of at 80% DoD?

None - need to clarify. 1000 cycles is definitely better than lead. Just that one of the selling points of lithium in general is that cost/cycle is similar to or better than lead in the long run.

Please check my math - but let's compare 72V, 60Ah packs. If I truly get 3000 cycles our of my GBS cells, that's about $1/cycle (including BMS cost). Similar lead setup ends up being about $2/cycle if you figure 500 cycles, so lead is actually 2x the cost over the life of the pack

If Headway is really only 1000 cycles, then it's roughly $4/cycle (assuming $3000 for 72V, 64Ah, about $1000 for BMS). That's fine, just need to realize that puts Headway in the "expensive performance" class when it comes to decision making.

harlan
22 February 2011, 1222
None - need to clarify. 1000 cycles is definitely better than lead. Just that one of the selling points of lithium in general is that cost/cycle is similar to or better than lead in the long run.

Please check my math - but let's compare 72V, 60Ah packs. If I truly get 3000 cycles our of my GBS cells, that's about $1/cycle (including BMS cost). Similar lead setup ends up being about $2/cycle if you figure 500 cycles, so lead is actually 2x the cost over the life of the pack

If Headway is really only 1000 cycles, then it's roughly $4/cycle (assuming $3000 for 72V, 64Ah, about $1000 for BMS). That's fine, just need to realize that puts Headway in the "expensive performance" class when it comes to decision making.

I don't think that's a fair comparison because you're not going to get 500 cycles from lead at 80% DOD. Likewise, if you were only doing 50% DOD with lithium, (as you would with lead), you'd get a whole lot more cycles than spec.

DRZ400
22 February 2011, 1323
Hello Travis, hope all is well. With the 5C real world Headway in mind....how do you feel a 1S4P Headway 10ah cell would compare to a single 40AH Calb cell? I think the Calb is 4C? Would I get similar V sag at 4C? I've read but never confirmed that Calb's often perform better then spec? Any comments? I'm going to get something this March....leaning towards 24 40ah calbs right now.

Phil



And FYI, the specs for the headways need a little of clarification....

they'll do 10C, but the voltage drop is quite a bit. They're fine at 5C, but once you go over that, voltage starts dropping. I really need to get a 16Ah cell to do some testing.

Can it fo 10C continuous? Yes. Should you? not if you want to drain your pack fast. At 10C, you'll get less energy out and the voltage drop will be significant. Another problem is the IR will cause some of that power to be lost as heat, which at 10C can heat up quite quickly (on just about any cell I've tested). The problem with that, is that you need to stay below ~140F.

So, for the way you're calculating, use 5C cont (240A continuous with 3p) and 15C as absolute peak. They're good batteries, but you need to really understand the discharge curve. See my 400W battery testing thread.

frodus
22 February 2011, 1342
- but let's compare 72V, 60Ah packs. If I truly get 3000 cycles our of my GBS cells, that's about $1/cycle (including BMS cost). Similar lead setup ends up being about $2/cycle if you figure 500 cycles, so lead is actually 2x the cost over the life of the pack

If Headway is really only 1000 cycles, then it's roughly $4/cycle (assuming $3000 for 72V, 64Ah, about $1000 for BMS). That's fine, just need to realize that puts Headway in the "expensive performance" class when it comes to decision making.


Those GBS cells are likely rated at 3000 cycles at 1C. I don't think you're gonna be riding around at only 60A battery side. It goes down as current increases. If you normally use ~2C, then expect less cycles. Also, as they get older, expect capacity to shrink as well. http://www.rebirthauto.com/Manuals/GBS.pdf
Also, I see >1500 cycles at 80% DOD for GBS on the www.electricautosports.com website. Do you have a datasheet from the manufacturer?
I have a datasheet on the 38120S and its showing a similar >1500 cycles at 1C and about 10-20% less capacity. I see on another website (http://www.evassemble.com/index.php?main_page=product_info&products_id=151) that it shows 1000 cycles at 100% and 2000 cycles at 80% DOD.

From where I'm standing, the lifecycle's are very similar at 1C.

frodus
22 February 2011, 1426
Hello Travis, hope all is well. With the 5C real world Headway in mind....how do you feel a 1S4P Headway 10ah cell would compare to a single 40AH Calb cell? I think the Calb is 4C? Would I get similar V sag at 4C? I've read but never confirmed that Calb's often perform better then spec? Any comments? I'm going to get something this March....leaning towards 24 40ah calbs right now.

Phil

MOTHER****ER.... I just had this huge writeup written and the page didn't load.... something has been screwy on the elmoto server lately..... anyway, short version because I'm lazy.

Anyway....at 5C a headway drops to around 2.9 and remains fairly flat. I want to test 7.5C and 10C to get some idea how the voltage sags. I also want to do 1 and 2.5C. My lead pack dropped comparatively as much at 2C.

For Calb, they don't show any discharge curves above 1C, so I'd suspect they have a decent voltage drop at 4C. That 4C is only good for 30S on the datasheet, and 12C bursts are for 5ms.... which ain't much.

I'd get larget capacity CALB's if I were you.

DRZ400
22 February 2011, 1454
I was thinking my normal use would be in the 1.5 - 2c range. 4-5C would only be for a few seconds. My bike pulls about 200 amps BS during accel.

frodus
22 February 2011, 1526
thats not bad, you should be pretty good... if you're only planning on 60-80A. I wouldn't wanna go much above 4C though.

podolefsky
22 February 2011, 1934
Those GBS cells are likely rated at 3000 cycles at 1C. I don't think you're gonna be riding around at only 60A battery side. It goes down as current increases. If you normally use ~2C, then expect less cycles. Also, as they get older, expect capacity to shrink as well. http://www.rebirthauto.com/Manuals/GBS.pdf
Also, I see >1500 cycles at 80% DOD for GBS on the www.electricautosports.com website. Do you have a datasheet from the manufacturer?
I have a datasheet on the 38120S and its showing a similar >1500 cycles at 1C and about 10-20% less capacity. I see on another website (http://www.evassemble.com/index.php?main_page=product_info&products_id=151) that it shows 1000 cycles at 100% and 2000 cycles at 80% DOD.

From where I'm standing, the lifecycle's are very similar at 1C.

Actually, I can't find any good data on the GBS cells, except for the claim of >1500 at 80% and the pdf from rebirthauto that claims ~2000 cycles at 100%. I'll bet that's at 0.5C because that's how a TS data sheet I have does its cycle life rating. For TS 60Ah, they claim >3000 cycles to 80% at 0.5C. But since cycle life isn't a linear function of discharge rate, I don't know what a 0.5C rating tells me - other than the best case scenario.

Anyway, I'm sometimes at 0.5C, sometimes at 5C. It's not like I'm constantly driving along at exactly 30 mph, so how do we know what happens in the real world? I think it would be hard to calculate this theoretically - too many variables, and most estimates of that type only get you within an order of magnitude. 1000 and 2000 are only different by a factor of 2.

frodus
22 February 2011, 2013
use this:
http://sites.google.com/site/lennonrodgers2/vehicle_calculations.xls
from here:
http://www.electricmotion.org/

It was actually pretty accurate for the people I've seen use it. It was almost dead on for a brammo enertia. It was pretty accurate for V1.0. I need to throw in some numbers for my bike, but I think it'll take about 60-70A cruising, about 1C.

billmi
23 February 2011, 1021
I was thinking my normal use would be in the 1.5 - 2c range. 4-5C would only be for a few seconds. My bike pulls about 200 amps BS during accel.

Yep, your experiences pulling the same frame, motor and controller with lead at 60-80 amps cruising are what let me feel safe going with 40Ah CALBs. I've not settled on my final gear ratio yet. I know you posted about the various set-ups you'd tried and their top speeds when you were still running the ME0709, but that was in the ElMoto 1.0 days, I'd certainly appreciate a repost. I've calculated what I think I want, but nothing beats real world data for comparison.

podolefsky
25 February 2011, 1223
use this:
http://sites.google.com/site/lennonrodgers2/vehicle_calculations.xls
from here:
http://www.electricmotion.org/

It was actually pretty accurate for the people I've seen use it. It was almost dead on for a brammo enertia. It was pretty accurate for V1.0. I need to throw in some numbers for my bike, but I think it'll take about 60-70A cruising, about 1C.

Thanks - that's really helpful. I put in some rough numbers and came up with about the same, ~60A (1C) at 72V for 60 mph. Spreadsheet says about 6 HP.

If I bump up to 70 mph, then it needs about 9 HP or ~90A. I should be able to do that easily, it's only 1.5C.

I think this is where gearing gets tricky, and what I meant by hitting a HP peak, or better to say HP wall - let me know if this seems like the right reasoning to y'all.

As RPM's increase, HP decreases. If you gear a bit higher, then you get back down into a regime of higher HP, and should sustain more speed, but it doesn't quite work out that way.

The spreadsheet says that at 65 mph, I need about 7.3 HP. Data from D&D says the motor will hit ~7.3HP at 3750 RPM. On my bike, getting 65 mph at 3750 RPM means a gear ratio of 4.33:1 (65:15). If I went to 4:1, I could go 68 mph at 3750 RPM...but actually I can't because I don't have enough HP to go more than 65.

75 mph requires ~11 HP, which data sheet says I get around 3000 RPM. But at 4:1, I'm only going 55 mph at 3000 RPM. As I try to go faster, HP drops and I actually can't go much above 65 again.

Now if I had a 2nd gear, I could drop down to 2300 RPM at 90 mph and actually have enough HP and amps available to do it (for a short time). (I know...this has been discussed at length before).

Anywho - seems like I'm basically stuck in the 60-65 mph range regardless of gear ratio. Maybe 70 with a tail wind :D

Nuts & Volts
25 February 2011, 1342
your reasoning seems to make sense, but why cant you gear it to hit 75mph at 3000RPM where the power is available. This will lower acceleration, is that why you dont gear it there?

oh and i feel ya on the 2nd gear thing, but not going there today.

podolefsky
25 February 2011, 1401
This will lower acceleration, is that why you dont gear it there?

Exactly. If I can't destroy kids in WRXs at stoplights, what's the point?


oh and i feel ya on the 2nd gear thing, but not going there today.

Word.

DRZ400
25 February 2011, 1427
With the Mars 709 I ended up with 15/72 at 72 volts. This gave good accelleration and a top speed of ~52 mph. I'm running 12/72 with the Agni now at 55mph.

frodus
25 February 2011, 1458
As RPM's increase, HP decreases. If you gear a bit higher, then you get back down into a regime of higher HP, and should sustain more speed, but it doesn't quite work out that way.

In order for HP to increase, RPM has to increase. Its dependant on RPM and Torque. Unfortunately, as RPM's increase, generally the Torque drops off after a knee. So it kinda decreases, but you should gear it so your max HP is right where your max Speed is, so see how much max HP you need, and then gear for that to reach a speed that the motor can support, if that makes sense.

HP = Torque * RPM / 5252


The spreadsheet says that at 65 mph, I need about 7.3 HP. Data from D&D says the motor will hit ~7.3HP at 3750 RPM. On my bike, getting 65 mph at 3750 RPM means a gear ratio of 4.33:1 (65:15). If I went to 4:1, I could go 68 mph at 3750 RPM...but actually I can't because I don't have enough HP to go more than 65.
Your batteries can't supply more than that? Because that motor sure will.

Do you have a motor curve for that motor?

ZoomSmith
25 February 2011, 1504
I've asked D&D for a motor curve, but was told they don't publish it.

DaveAK
25 February 2011, 1512
I've asked D&D for a motor curve, but was told they don't publish it.
Well that's one better than me, because I didn't get a response. :)

Nuts & Volts
25 February 2011, 1515
Exactly. If I can't destroy kids in WRXs at stoplights, what's the point?

Word.

Haha very true. I'd increase my gear ratio, but i cant fit a bigger rear sprocket (maybe ill try a 10 or 11 on the front).
One option you have is increasing your voltage which should extend your torque "knee" as travis stated. I wanted to do this with my pack, but it seems either the BMS wont increase or my charger can not be increased. Make sure your controller can handle more volts.

Also I may have to PM you with my two speed thoughts ;)


Well that's one better than me, because I didn't get a response. :)

sounds like we need someoneon El moto to build a dyno, travis has the battery testing on lock down, we need some motors tested now :)

Richard230
25 February 2011, 1538
I've asked D&D for a motor curve, but was told they don't publish it.

I was able to find a motor/torque curve for a 48 volt D&D motor at Thunderstruck. I have it on my computer files as a PDF, but it is too big to attach here.

podolefsky
25 February 2011, 2143
In order for HP to increase, RPM has to increase. Its dependant on RPM and Torque. Unfortunately, as RPM's increase, generally the Torque drops off after a knee. So it kinda decreases, but you should gear it so your max HP is right where your max Speed is, so see how much max HP you need, and then gear for that to reach a speed that the motor can support, if that makes sense.

HP = Torque * RPM / 5252

I get how HP relates to torque and RPM, but not as clear about max speed and HP. This would all be so much easier if we were in the same room with a chalk board...

Here's a test sheet for the ES-15-6. I can't remember where I found it, but it is at 72V. Highest HP appears to be around 1700 RPM...seems less than ideal to gear it to hit max speed at that RPM.

871


Your batteries can't supply more than that? Because that motor sure will.

Batteries will definitely provide enough power, as will the motor. Actually, I hit about 300A during hard accelerations, so I think there's room for more. Question is whether I can keep this power up at higher RPMs.

Maybe this needs a new thread on reading and interpreting motor data sheets...

Nuts & Volts
25 February 2011, 2200
dang that motors not very efficient. yea motor can be tricky sometimes. The best thing to have is a torque curve over RPM and an efficiency histogram of sorts. A RPM/V or A/Nm constant would just about be perfect. i think ill start another thread soon

podolefsky
25 February 2011, 2307
dang that motors not very efficient. yea motor can be tricky sometimes. The best thing to have is a torque curve over RPM and an efficiency histogram of sorts. A RPM/V or A/Nm constant would just about be perfect. i think ill start another thread soon

Not super efficient, but I think that's the nature of series motors. It's at least above 80% through most of the useful range (ignore the 50%ish numbers, that's at over 5000RPM which is likely zero load).

I agree, torque & efficience over RPM are the easiest to read. But seems pretty rare that manufacturers do that...some plot torque on the horizontal...Agni plots amps on the horizontal (?!!?)

lugnut
26 February 2011, 0940
Here's a test sheet for the ES-15-6. I can't remember where I found it, but it is at 72V. Highest HP appears to be around 1700 RPM...seems less than ideal to gear it to hit max speed at that RPM.

871



Thanks for posting that motor performance info. Unfortunately it is too fuzzy for me to read all the values. Is it possible for you to post a clearer view? Or maybe to rewrite the values for Actual Torque, RPM, Varm, Iarm? I can calculate the rest of the columns. I was going to enter the values into Xcel and plot it out, but can't see the blurry #s. If I get a decent plot, I'll post it up.

podolefsky
26 February 2011, 1111
I actually have a spreadsheet with the values somewhere, just need to clean it up.

I'm actually going to start a new thread on reading/interpreting motor spec sheets. It's hard to know how to compare motors when they're not all rated in the same way.

lugnut
26 February 2011, 1231
I actually have a spreadsheet with the values somewhere, just need to clean it up.


Thanks, I see that new thread.