DIY Battery Upgrades for Goped ESRs

Lightweight / Folding / Portable EVs - seats optional
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scoot   1 kW

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DIY Battery Upgrades for Goped ESRs

Post by scoot » Jul 25 2010 10:44am

As most everyone out here is probably already aware, Goped, or PMW (Patmont Motor Works) as they are often referred to, has for many years been one of the leaders in the standup scooter field. They are well known for their innovations and have routinely provided a high quality American made product that has withstood the test of time. 8)
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Their electric ESR scooters have demonstrated their viability as serious portable commuter vehicles and are gaining wider acceptance on public transportation modes including light and medium rail systems.
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Todays ESRs are a rugged dependable stand-up scooter platform; hence, it has attracted many enthusiasts for the purposes of modifying them for extraordinary performance. One highly notable after market upgrade that has just recently become available is the incredibly powerful and durable Torkinator drop in (plug and play) motor. Because of the advent of this remarkable motor, previously experienced limitations for steep hill grades and high speeds, I'm happy to say are now a thing of the past. While extended range has always been a high priority for ESR owners, this new ability to achieve these unprecedented speeds and climbing power has also served to further raise the demand for electrons. The subsequent pursuit for battery upgrades to satiate this demand has now achieved new heights.

PMW currently provides two battery options in their stand-up scooter line available from from the factory. They include the standard SLA (sealed Lead acid batteries - B&B HR9-12) in a 2s2p configuration (24 volts), and more recently their proprietary 7s 8ah Lipoly packs with built in BMSs in configurations of 2, 3, and 4 packs per scooter. Over the last couple of years, many ESR owners have successfully retrofitted the stock SLA powered ESRs with oversized SLAs and other assorted Lithium based batteries. Among the DIY Lithium retrofit projects are A123s, Lipo, and most recently Headway LiFePO4 cells. Another cell type that is yet to be attempted are the LiMn2O4 type cells (e.g., Konion).
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IMG_0460.JPG (74.06 KiB) Viewed 1996 times
DIY upgrading of the ESRs (or any other standup scooter for that matter) presents numerous unique challenges beyond the typical ones encountered with the some of the usual E-bike conversions, among which include:

1) A very rigidly defined battery compartment in regards to overall space and dimensions. This has been by far the most challenging limitation to address in my opinion, as it limits not only the cell type available for use, but also the battery management hardware options.

2) How to incorporate the onboard controller... this has probably been the least challenging aspect, since fortunately, it has been proven to be a very robust controller and its performance over time has established a quite reliable track record. It is capable of running up to 130 amps (factory programmed control limit) and will accept up to about 30 - 31 volts without modification or additional programming. Therefore, the ESRs need batteries capable of high C discharge rates.

3) How to effectively incorporate the stock on-board charger... The on-board charger was originally designed around the SLA battery configuration and is fully integrated with the controller to the extent that battery charging and discharging occur through the same high current connections and wires.

The purpose of this thread is to generate discussion, display and describe previously attempted upgrades, and serve as a support group for those who have already engaged in these various battery upgrades. Additionally, it is to facilitate the education of all who are interested in pursuing and improving upon the process. It is anticipated that many of us will not be particularly knowledgeable about battery, electrical, and electronic hardware principles; therefore, I suspect the level of discussion on these topics will most likely be quite often at the most basic level. Where and when higher levels of expertise are required, it is certainly hoped that all of the super smart folks lurking out here in the Sphere will chime in and assist us as needed... that's one of the primary reasons for initiating this thread out here, not to mention the recent interest expressed to me from several ESR owners.

Eventually, the intent is to soon develop some additional build threads (multiple participants) that provide instructional step by step guidance for specific battery upgrade installations. I for one, have committed to doing so for Headway conversions... well, at least to the extent that I am able, since things are constantly changing and new hardware options are constantly showing up.

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Re: DIY Battery Upgrades for Goped ESRs

Post by hmbab2000 » Jul 25 2010 11:20am

This is the thread I've been waiting for!

I have already performed several upgrades attempting to gain range on my ESR scooters.
I'm currently running the BB EVP1212's in my regular riders.
However, I live on a second floor and these things are pretty heavy now.

As for my scooters...

1 Pre-'08 ESR750 running BB 1212's geared at 15/76.
This is my girlfriend's ride, she has a seat w/basket, suspension front end, and a remote on/off.
She tops out at 23mph in Turbo.

1 Hoverboard, running 3 BB 1212's @ 36V, Kelly 36V controller, and Torkinator motor, geared at 15/72.
This is my machine!
Geared now it tops at 28mph, but flies to the top!
This one I'm hoping to add some capacity to, but would love to lighten it up as well.

1 Pre-'08 ESR750, almost stock.
I've got cheapo 7.2Ah alarm batteries in there.
They were cheap and get it moving...!

I look forward to learning more and possibly getting involved in some DIY battery work!

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Re: DIY Battery Upgrades for Goped ESRs

Post by swbluto » Jul 25 2010 2:51pm

hmbab2000 wrote:
1 Hoverboard, running 3 BB 1212's @ 36V, Kelly 36V controller, and Torkinator motor, geared at 15/72.
This is my machine!
Geared now it tops at 28mph, but flies to the top!
This one I'm hoping to add some capacity to, but would love to lighten it up as well.
I don't have a Goped but oddly enough, my RC scooter with gearing at 15/72 belt drive also tops at 28 mph (At 36 volt) and also flies to the top. The "Flying to the top" part is the trait I really like about it. :mrgreen:

My scooter weighs a total of ~29 pounds with its a123 batteries. It only gets 6-7 miles range though (Good for one-shop trips, but not for multiple stops, unless I charge in between.). I have an external battery port to extend the range if desired with my "backpack battery" - that extends the range by another 24 miles or so.

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Re: DIY Battery Upgrades for Goped ESRs

Post by mwkeefer » Jul 25 2010 4:04pm

My ESR runs 6S 20C 4P 20AH but I have them split into 3S portions and wired as 3S2P block (to replicate the stock setup, I have tons more space left over)... This allows the internal charge to be used (I upgraded by replacing it in the end, but it worked for months without issue) as it will just require a slight reduction in output voltage to keep it within a safe limit for 6S @ 24.96.

I had thought this solution (6S) was going to suck wind since nominal voltage is a tad lower than the SLAs (in theory) at 22.2 or 11.1v but in reality, since the Lipos hold (even a single 5AH pack) their voltage so well in 20C variety... My top speed actually increased by 2-3mph (depending on Depth of Discharge), my accelleration increased very notably... before I could pull a wheelie on a fresh charged (and brand new) SLA pack but at 160lbs (me) only if I pulled back a tad and leaned it back too.. now with the lipo I can thumb it up into a wheelie from nominal pack voltage and up (mostly 80% of the pack life)...

While my scooter is now infinately lighter and has about 3x the range with better accelleration and more top end (my batteries alone went from 28 lbs to 7.4 lbs) - I think the next upgrade will be ditching the brushed motor (it's great and has worked for years but it weighs about 8-10 lbs easy) and designing an adapter tube so I can mount an Inrunner in the same place - just need to find one with a low enough kV and proper diameter :)

-Mike
Regards,
Mike

{My Rides]
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w

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Sheriff Jon   100 W

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Re: DIY Battery Upgrades for Goped ESRs

Post by Sheriff Jon » Jul 25 2010 4:30pm

Image GREAT thread 8) I am looking forward to seeing what kind of alternative power configurations you Explorers can come up with :!:
"HOW we ride today, may determine IF we can ride tomorrow"

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Re: DIY Battery Upgrades for Goped ESRs

Post by swbluto » Jul 25 2010 4:42pm

mwkeefer wrote:I think the next upgrade will be ditching the brushed motor (it's great and has worked for years but it weighs about 8-10 lbs easy) and designing an adapter tube so I can mount an Inrunner in the same place - just need to find one with a low enough kV and proper diameter :)
I don't know what the proper diameter is, but my 230 kV outrunner works fine with a 72/15 gear ratio with 30 vots. That implies a pretty good kV compatibilty range assuming one of the inrunners, like an astro, has the "proper diameter" (Unknown to me what the "proper diameter" is.).

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Re: DIY Battery Upgrades for Goped ESRs

Post by scoot » Jul 25 2010 6:58pm

swbluto wrote: My scooter weighs a total of ~29 pounds with its a123 batteries. It only gets 6-7 miles range though (Good for one-shop trips, but not for multiple stops, unless I charge in between.). I have an external battery port to extend the range if desired with my "backpack battery" - that extends the range by another 24 miles or so.
Ah yes, I have long appreciated the virtues of an external parallel connectable pony pack for range extension. Sure simplifies things when they internal and external pack are the same battery type and equally charged from the take off point. Even using mixed battery types is a good way to go sometimes if certain additional precautions/procedures are taken into account.

I sure am happy this thread is drawing in some diversity of experience and ideas as I hoped it would. :)

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Re: DIY Battery Upgrades for Goped ESRs

Post by scoot » Jul 25 2010 7:13pm

mwkeefer wrote:My ESR runs 6S 20C 4P 20AH but I have them split into 3S portions and wired as 3S2P block (to replicate the stock setup, I have tons more space left over)... This allows the internal charge to be used (I upgraded by replacing it in the end, but it worked for months without issue) as it will just require a slight reduction in output voltage to keep it within a safe limit for 6S @ 24.96.

-Mike
Guess I never picked up on in my forum readings, or remembered you were an ESR guy :lol: Those of us using the 8s LFPs (Headways) found we need to snip the sense wire between the controller and the charger to get a safe 27.5 max charger voltage in order to prevent over-volting any individual cell (credit to Walls99 on that one). We miss out on only a small amount of total pack capacity in doing so in a routine bulk charge with the onboard charger. 8)

It's was very interesting to me to hear about your successful experience with a lower voltage / high discharge capable pack :) Thanx for your input MWK!!
Last edited by scoot on Jul 26 2010 8:52am, edited 1 time in total.

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Re: DIY Battery Upgrades for Goped ESRs

Post by mwkeefer » Jul 26 2010 12:29am

No problem - I will try to bring the ESR home from the shop this week and take photos / document how I went about altering the charger output voltage to the 24.9v - it was just a few resistors and I added 100 ohm 10 turn kinda just glued in place.. Took a while to figure out but it works great... I can alter them up or down about 8 volts (maybe more with some playing). You do have to alter the "sense" resistor network too :)

swbluto - I have an old (first gen) ESR 750 ex, the motor is about 3.5" long and I would guesstimate 2.5" OD - the problem is it must insert into the frame (cantilever designed rear) and becomes a structural part - the gearing should be okay... stock is 15t to 86t if I am not mistaken (on my generation with 10" wheels)... I am really less concerned with gearing (I've run it with an outrunner already as a test, just a clamp on mount aft of the normal motor mount and straight chain drive.. got it working well enough but then there is a gaping (round sadly) hole in the frame intended to not only contain but heatsink the proper motor...

I figure I can start with any motor (inrunner) which meets the required OD, shimming to add heatsinking where required.. I really want to do this without altering the frame (or creating a structural weak point) but there is another option I haven't really toyed with too much...

The second option is an outrunner but with the bell mounted internally so the shaft comes out the end as it does on teh stock esr but... the front bolts into a circular mounting bracket / plate...

If I go the RC direction with the next incarnation - I think I will look for a motor appropriate for running at 12S and either going wye (or buying wye) to get better (lower) kv... I could increase my rear sprocket a tad, maybe go 80 but any more and I'd risk bending the sprocket on landings...

I have another scooter here uses skate wheels I think it was called the Transporter 2000 ( I have both the SLA and Nimh versions) and it's kinda neat for what it is but it uses a twin motor friction drive and that just about kills the darn wheels every time... Since I have hacked it apart (trying to build a friction drive about a year ago) - I have decided I can rework the rear to use dual chain drives... Within the existing space, I can mount a tiny inrunner (and I need a tiny one) and someone here on the forums prompted me to the idea of fixing a little #25 sprocket directly to the scooter wheel..

If this transporter won't work... my next "Real" scooter project simply must be along the same design lines as the above Transporter - the idea is you can't tell it's electric (you really can't tell at all) and I rode that thing in train stations, malls, sidewalks, roads and just acted like I was kicking (who am i kidding it was topped at 12mph) but it was my second or third standing scooter so what did I know... first was some 350w piece of junk, bought a pair of them for me and my dad (wish we had kept them) they had massive #35 chain, weighted about 80lbs each 48v (4x12v SLA) and would do about 18mph for 8 miles - he got the blue, I kept the black... Then this transporter, then I got lucky and found a goped at a skate shop in Philly... it had a bent rear sprocket and dead batteries... I bought it for 200.00, used his bench vice on site to straighten the sprocket enough to ride (it had been kurbed) and off I went home... made it to 30th and it died (needed batts). First set of batts were BB9-HR12 x 4 (I think) and since the deck was knarley I ordered instead of the batts... just a new ESR to ESR EX conversion kit (raises the deck 3/4 inches and came with batteries for less than the price of batteries).

If I could ride my GoPed here in my home town still (I did for 3+ years) I would be more interested in geeking it up, now that I actually know what it is I am doing.. I am thinking onboard bulk charger with a reformed ESR EX deck (reworked water seals for sure) and perhaps (I need to look at the frame)... I could actually build a simple internal jackshaft using an SA3 on the output of the motor I choose @ say 3:1 then further reduce at the other end... then it would be UBER efficient.

Again - I will likely begin working on a razoresque (the kick type) scooter in the very near future, somthing folding, light weight, 20mi range (no kicking) @ 20-25 mph and sufficient torque for say 300lbs max weight (should cover everyone right?)... I could get away with that no problem all around here and in the city and due to the nature of such a frame, it would weigh about 10-15lbs max with 20mi of battery :)

-Mike
Regards,
Mike

{My Rides]
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w

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Re: DIY Battery Upgrades for Goped ESRs

Post by swbluto » Jul 26 2010 1:23am

mwkeefer wrote: Again - I will likely begin working on a razoresque (the kick type) scooter in the very near future, somthing folding, light weight, 20mi range (no kicking) @ 20-25 mph and sufficient torque for say 300lbs max weight (should cover everyone right?)... I could get away with that no problem all around here and in the city and due to the nature of such a frame, it would weigh about 10-15lbs max with 20mi of battery :)

-Mike
That would be really impressive! It's hard to imagine what kind of urban terrain such a lightweight scooter would be appropriate for at 20 mph and 20 miles except for race tracks. I'd imagine it wouldn't have pneumatic wheels? Or maybe it could.

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Re: DIY Battery Upgrades for Goped ESRs

Post by mwkeefer » Jul 26 2010 1:46am

sw,

In theory it could have em, but remember this is to be about 15, maybe 20lbs with packs... with 4-6" wheels, and that light a frame... I should be able to hop over anything too serious in my path.

Im also planning on using some modified RC style parts for a front suspension and may (may is operative, only if I can do it without the drive system being discernable) go with some form of limited poly bushing rear link suspension...

I've been looking at the DIY Instructable (Don't laugh, they are good for ideas from time to time!) at the DIY hub motor for such a beastie... between the parts for the Battle Bots (good source for small pneumatics too) specifically all the various neoprene wheel skins or tires... I figure an inline skate wheel could be bored to leave about 1/2" of roller surface (the stock scooter inspiration for this has mag centers and neoprene hard outters) hub motor could be press fit and set screwed (aluminum so they would wear with the wheels) which would provide sufficient holding power for the torque level... also with the little 6" or smaller wheels, it will look like a kick scooter for sure and with lipo in deck (as of now planning 1/4" thick rectangular 6061 stock from McMaster for Main subframe... 2 x 2x4 sections joined together and seamed to form a long cinder block design (should be stronger than a single channel...).

Again - I may not even get past the, hey that would work... but the idea of dual mini hub motors or even DD motors (what kinda gearing does 20mph require on a 6" wheel? -- Answer 1120 RPM = 20 mph @ 6" so assuming outrunner (just throwing stuff around here) positioned above rear wheel (hidden with maybe a tailfin looking thing) and with a kV of say the 5330 9t (235kv in Delta stock) - and assuming say... 10S for starters (since it's easy to charge!):

In delta we can assume 83% efficiency from the motor... so kV becomes 194.05 for calculating drive train...
10 * 3.7 = 37v
194.05 * 37 = 7216.85 RPM
Now my trick - I want 25mph all the way to LVC...
25 * 336 / 6 = 1400 RPM.

Now 7216.85 / 1400 = 5.15 : 1 reduction

Using the no load kV, we can calculate the kV in Inch Ounces:
1355 / 235 = 5.7659574468085106382978723404255 kT

Use hi precision or the numbers will be far off...

So if we assume to allow 53A maximum and nominal voltage:

53 * 5.7659574468085106382978723404255 = 305.59574468085106382978723404255 in oz of torque at motor shaft

now the reduction:

305.59574468085106382978723404255 * 5.15 = 1573.8180851063829787234042553191 in oz
1573.8180851063829787234042553191 / 12 = 131.15150709219858156028368794326 lb oz
131.15150709219858156028368794326 / 16 = 8.1969691932624113475177304964539 ft lb of torque

@ 37 * 53 = 1961 watts...

Obviously 8.18 ft lbs is not enough for a 300 lb load @ 25 mph...

Again.... this is a thought in progress...

-Mike
Regards,
Mike

{My Rides]
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w

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Re: DIY Battery Upgrades for Goped ESRs

Post by swbluto » Jul 26 2010 1:52am

mwkeefer wrote: Obviously 8.18 ft lbs is not enough for a 300 lb load @ 25 mph...

Again.... this is a thought in progress...

-Mike
I can't tell, but is that sarcasm? I just did a calculation with a 3 inch radius and that comes out to roughly 142 newtons. My last 25 mph calculation suggested about 74 newtons is needed to sustain 25 mph on flat-land (or 50 if you're bending over).

Btw, "hiding an outrunner". I don't think they want to be hidden! :wink: (They make a little noise, though they're pretty quiet if you're going slowly)

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My LiFePO4 Adventures

Post by wit9000 » Jul 27 2010 5:44pm

I've had an ESR (Hoverboard variant) for a couple years and recently converted it to an 8s2p configuration using Headway 38120 cells. Personally, and with many thanks to a number of selfless contributors to an ESR scooter thread on another forum, I found the modification easy to do even for a novice (that's me). I've had nothing but good experiences thus far and hope to continue that trend. I do try to take the time to manage the battery health properly - maybe that's been why I've had no issues. I use two chargers...have balance wires on each of my battery packs...built a charging station...hinged my scooter deck to make it easy to 'pop the hood'...and basically treat my cell packs as large rechargeable batteries that I pop out an onto the charger each evening after I get home from work...and I regularly log data when riding or charging using CellLogs or charger and LogView. I assembled a number of reliable supplier sources along the way and believe I've now got a sustainable process for use of LiFePO4s in my Go-Ped Hoverboard. I use a Cycle Analyst presently to monitor my battery performance while in motion, though I'm now evaluating how best to use my CellLogs in conjunction with a piezo buzzer to work as an effective LV warning system. Anyway, I've attached a few pics to illustrate what the scooter looks like at this point in time. I have MUCH to learn, so any comments and/or advice is most surely welcomed.
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battery pan
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battery packs
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DSC04858.JPG
with the hood up
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DSC04854.JPG
cam lock on rear of deck
DSC04854.JPG (15.37 KiB) Viewed 2417 times
DSC04855.JPG
hinged front of deck
DSC04855.JPG (18.69 KiB) Viewed 9696 times
DSC04848.JPG
charging station
DSC04848.JPG (14.15 KiB) Viewed 2417 times

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Re: My LiFePO4 Adventures

Post by swbluto » Jul 28 2010 7:38pm

wit9000 wrote:I've had an ESR (Hoverboard variant) for a couple years and recently converted it to an 8s2p configuration using Headway 38120 cells.
Is that roughly 24V 18 Ah? (The "10Ah" cells seem to measure around 9.2 Ah in real life usage.)

That's pretty impressive battery capacity. Of course, the Goped ESR is a larger scooter type.

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Re: DIY Battery Upgrades for Goped ESRs

Post by wit9000 » Jul 28 2010 10:34pm

Roughly yes...in real world usage...while enough capacity for my normal commute...I'm seriously considering gifting the 38120 packs to my wife and building 9s2p setup using 40160 cells to (1) get the most "go" out of what the stock controller will handle in terms of voltage, while (2) increasing my range to a comfortable level where I can run extra errands without worry...I just have to make CERTAIN I can fit those cells into the battery pan before I commit...

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scoot   1 kW

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Re: DIY Battery Upgrades for Goped ESRs

Post by scoot » Jul 28 2010 11:12pm

yea, we already know we can fit the 12ah cells in there for a total of 24ah (or 22ah if you want to consider the correction factor). My bench tests yielded 90% + on Headways when they were new (breakin' them in). Of course we also know that they liven up some with use, except taking them to their limits on a daily basis to find out is not the best of ideas... especially when running them partially naked :oops:

Hey wit... RE those 16ah cells, I remember trying dry fits early on with various PVC plumbing couplers that were close to the diameter your talking about (like the old BMI cells) to see how they would position/stack in the pan with as low a profile as possible. Then of course avoiding the deck mounting studs length wise. I sure am hoping you can sort it out... and like said in the first post, fitting the cells in nicely especially without raising the deck too far is probably our biggest challenge. :evil: Message me for more detail. :wink:

BTW, i simply love your hinged deck :twisted: based on your inspiration, I picked up some cabinet hinges yesterday and am going to attempt a sideways hinged install.... I think it will be tricky but possible. :mrgreen:

Did you just paint your deck spacer black? 8) Looks Cool :wink:

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Re: DIY Battery Upgrades for Goped ESRs

Post by wit9000 » Jul 29 2010 9:37am

Scoot - My spacer has an actual height of 1.7" as I added a layer to the factory spacer to allow clearance for the 2s2p BB EVP1212 SLA configuration that I was running before converting to LiFePO4 cells. Add in the top deck layer at basically 0.5" and I have a total of 2.2" atop the battery pan.

As for the spacer, having a bit of woodworking experience and a reasonable set of tools, after fabricating and attaching the add-on layer to the factory spacer, I routed and sanded the whole spacer assembly to clean it up and ensure a proper fit and match to the top deck. Being an 'old guy' used to 'old school' paint, on my black scooter I used a black lacquer base coat, followed by a quick mid-coat of metallic flake, then topped off with clear. On my wife's, because I care so much :D , I did a red base to match the scooter frame, then an air-brush silver top-to-bottom fade, then clear top coat. (pics attached).

I think the paint techniques helped integrate the spacer to the battery pan visually so that it doesn't appear out of proportion while giving me plenty of height under the deck to work with once I switched from BB EVP1212 SLAs to the LiFePO4s.

Hope this helps... wit
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DSC04878.JPG
black scooter deck spacer
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DSC04882.JPG
red scooter deck spacer
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scoot   1 kW

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Re: DIY Battery Upgrades for Goped ESRs

Post by scoot » Jul 29 2010 9:55am

Very nice wit :mrgreen: So you have oodles of space/room to play with :lol:

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DIY Battery Upgrades for Goped ESRs

Post by wit9000 » Jul 30 2010 12:08am

So...I thought maybe for the ESR folks that haven't built battery packs using Headway cells it might be helpful for me to post up a few pics of that process...again...I'm a real novice...but with a little research and planning...it's a straightforward process. I attempted to make the pic titles self-explanatory, but if anyone wants more detail...just ask.
Attachments
DSC04865.JPG
8 38120 cells labeled; ready to assemble
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cell connectors for 8s configuration
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balance harness - 9 wire, 18 awg, 1/4" rings, 15A powerpoles
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main wire harness, 10 awg, 45A powerpoles
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cells connected in series with numbered balance wire attached to each cell
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cells stacked for nylon ties; balance wires tucked in central space between cells
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nylon ties in place
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bars added to connect C2 to C3, C6 to C7
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bar added to connect C4 to C5, main wires to C1 (-) and C8 (+)
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finished pack!
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Green Machine   100 kW

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Re: DIY Battery Upgrades for Goped ESRs

Post by Green Machine » Jul 30 2010 5:53pm

Do you guys think this batter would work in the esr?

Please let me know as soon as possible i am fixing to order 2...

http://www.batteryspace.com/highpowerpo ... ntbag.aspx

Also does anyone know where i can buy a torkinator motor?

swbluto   100 GW

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Re: DIY Battery Upgrades for Goped ESRs

Post by swbluto » Jul 30 2010 5:54pm

extremegreenmachine wrote:Do you guys think this batter would work in the esr?

Please let me know as soon as possible i am fixing to order 2...

http://www.batteryspace.com/highpowerpo ... ntbag.aspx

Also does anyone know where i can buy a torkinator motor?
Hobbycity Lipo is SOOOOO much cheaper.

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scoot   1 kW

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Re: DIY Battery Upgrades for Goped ESRs

Post by scoot » Jul 30 2010 6:28pm

extremegreenmachine wrote:Do you guys think this batter would work in the esr?

Please let me know as soon as possible i am fixing to order 2...

http://www.batteryspace.com/highpowerpo ... ntbag.aspx

Also does anyone know where i can buy a torkinator motor?
Here is the link to the t2v3 "torkinator" motor: http://www.torkinator.com/ordering/shop.html

Those packs appear similar to PMW's Lipo packs, except the PCM on those packs is limited to 40 amps, so at a minimum you would want at least three to avoid regularly tripping the PCM's current cut off (usually you have to disconnect the packs to reset them... PITA)... 4 would be better especially with the torkinator motor, but they are rather expensive. They appear to be the same dimensions as the stock SLA battery HR9-12 in the EX ESRs so 4 of them should fit OK. For safety reasons, I am not a big fan of Lipo personally, especially for use/transporting on public transportation, or when charging unattended in the garage, apartment or work cubicle... but that is your call obviously. I suspect they would work though.

FYI, the LiFePO4 upgrades, such as the Headway cells (A123 also), are considerably cheaper, much safer, last longer, and you can still have over 20ah by the time you are done. They also deliver plenty of punch for the torkinator. Assembly is a little interesting... not exactly a plug and play affair. But then that is why this thread was started... to help people along with that and other options. 8)

Edit: you WILL need to come up with another off board charger to ensure they balance and completely charge up.

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Green Machine   100 kW

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Re: DIY Battery Upgrades for Goped ESRs

Post by Green Machine » Jul 30 2010 6:54pm

I got my sources i can get those batteries on the cheap :) ...they are a very nice solution with balancing board built on and nicely packed together soft cells. Much tighter package then strewn together lipos from hobby city and without all the hassle.

I have some now 48 volt versions i use on my ebike. I am thinking of ordering some bullk lipo batteries very similiar to the ones i posted link on and then be able to sale them to other gopeders who want a quick and easy solution.

40 amps is not enough draw??

I was thinking of putting 2 batteries in there to get 16ah which should be plenty for my needs. 32 amp hours would be just obscene...what would that be a 50 mile range?

I like lipos because of there low weight and compact size...i think they will be safe when contained inside the goped deck and cage. Because this pack a balancing board built in i think it is pretty safe.

I can get a 6 amp smart charger for these packs for 40 bucks which will be an out board charger.

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scoot   1 kW

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Re: DIY Battery Upgrades for Goped ESRs

Post by scoot » Jul 30 2010 7:11pm

Be sure to let us know how they work out for you. BTW, don't be surprised to see the t2 pull 100+ amps on a steep grade, or at top speed when geared tall for 28 MPH. :mrgreen:

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Re: DIY Battery Upgrades for Goped ESRs

Post by wit9000 » Jul 30 2010 8:59pm

Extreme - please do keep the folks on this thread informed about your experience with the lipo packs. I'll admit I just couldn't muster up the courage to take that leap. I saw a lot of comments that made me think about the potential volatility of the chemistry and I didn't see a way to self-service a pack if anything happened. So I went the LiFePO4 route as it at least seemed safer to me and I could service a pack (i.e. replace an individual cell) without a lot of expertise.

Scoot - I posted a basic 8s pack build process earlier in this thread - didn't you pair your cells first, then in series? That's for sure another alternative for folks to consider. There are certainly times I wish I would have done that - just one reason is that I have a CellLog on each of my two packs while you only need one.

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