DSCF4706_RevA.jpgIf you are reading this post, you probably are experiencing decreased range and speed on your Go-Ped electric scooter. I too have experienced these problems, but I am going to share some solutions I came up with. I purchased a Go-Ped ESR-750 scooter this summer for transportation in Mountain View, CA for a summer internship. I rode that scooter every day to work on turbo-mode, which was about two miles. At the end of internship, I could not even get to work on econo-mode, and when I returned home I junked the batteries to lighten the shipping cost. Later, I modified my scooter to fit a larger pack size.

Two months into the internship I could not get to work any more. I opened the scoot scooter top to find 4 sealed-lead-acid (SLA) batteries with a pack configuration shown in Fig. 1.


Fig. 1. Stock Go-ped battery pack configuration.

From previous work I did with laptop batteries, I learned that manufacturers typically tie together parallel cells such that they form a pack similar to the one shown in Fig. 2, Step 4, which has two advantages. First, it halves the number of sensors that measure voltage. Measuring two voltages, one across B1A and another across B2A is essential for determining when to end charge and discharge, major factors that affect battery life. Unfortunately, the scooter model only measured the stack voltage, the total voltage across B1A and B2A. The second advantage is that it provides a balancing effect. If a cell becomes weaker, the adjacent cell gives it charge. Having cells reach end-of-charge and discharge in unison is the most beneficial situation. After two months my batteries were significantly damaged. I parallel tied my batteries, which allowed them to die more gracefully and it also gave me about 20% more range, both which helped me get to work and back until the end of the summer.

batterysteps.png
Fig. 2. Steps to extend Go-Ped pack configuration

IMPORTANT: Do not reconfigure the battery pack if you do not know what you are doing, and expect to void your warranty too. However if you want to take preventive measures follow these steps.

STEPS TO MODDING GO-PED BATTERY PACK

  1. Find a well ventilated area to work in.
  2. Disconnect the scooter from the charger and open the board with a torx screw driver.
  3. Remove the four quick-connects at the top and bottom of the batteries.
  4. Remove the two metal tabs that connect B1A to B2A and the one that connect B1B to B2B.
  5. Create a wire harness that replaces the function of the metal tabs and will tie together the cells.
    1. You will need two short pieces of stranded 12 AWG wire and four yellow T2 female quick connect terminals and one long 18 or 22 AWG.
    2. Strip the wires and crimp both an the 18 AWG and the 22 AWG terminal into the same terminal.
    3. Crimp the other terminals so that the harness forms an H shape.
  6. IMPORTANT: you must balance parallel batteries before you connect them together. Otherwise you will cause a spark and damage your batteries.
    1. Connect small resistors, about 100 Ω, between parallel batteries, and let them balance for a few hours.
  7. Once balanced you can proceed to reconnect your pack.

The final connected harness should look something like the one in Fig. 3.

IMAGE_128.jpg
Fig. 3. Completed wire harness

Once you have made these modifications to you scooter there are some other life extension options to consider. Re-configuring the pack was a simple form of cell balancing, where charge moves between adjacent cells. There are commercial active cell-balancing products such as BattEQ and Power Cheq that moves charge from different levels of a stack. Check your scooter dimensions for free space. Another option is higher quality, larger capacity batteries. Ultimately I choose the last option, which I will discuss in another article and describe other scooter modifications.

UPDATE:
My wife and I have been able to get a couple rides into work this summer. We have been very happy with the new pack. I am able to ride 5 miles to work all on turbo mode . I measured the pack once, which indicated that this distance depletes the pack by 50%. I live in Illinois, which is as flat as you can get. I recently added some packaging foam around the batteries as the bigger batteries were causing a lot of road vibration. This easy mod made our rides a lot more comfortable.

My chain was starting to get stretched out from use. I tried to use my bike chain tool to remove some links, but Go-Peds chains are much smaller. I the bought the chain tensioner add-on for the scooter which works like a charm. Looking back, I should have built my own. $40 for a piece for plastic is a bit pricey.

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31 Responses to “Go-Ped Electric Scooter Battery Life”  

  1. 1 Max

    Hi
    Nice work on the battery reconfiguration. I don’t have a GoPed, but am thinking of getting one. I live in NYC and getting around on one of these could be a blast and save a lot of time. Plus, they are building new bike trails all over the place. Ever since I got an electric scooter for my boy for Christmas, I want one too. I got him a cheaper 500W IZip which is fine for him now. I just want a super powerful one if I get one.

    Anyway, I was thinking, if your batter reconfiguation offers better performance, why doesn’t the company wire them like that in the first place? And, do you think this will work on the bigger model, the ‘EX’ model which they came out with? I know an electrical guy who could figure this out, I just have to decide when and where to get one. Thanks

    Max

  2. 2 Grant Pitel

    Make sure you read your state’s policy on E-Scooters. They are actually illegal in New York. California treats them as bicycles, which is convenient with all their bike lanes.

    The reason they do not wire batteries this way is because it adds slightly more labor cost. Initially, when all the batteries are fresh and about the same, you see no added performance. All manufactures spec their scooters when the batteries are fresh. The benefit is not clear until you ride the scooter for a while (after which point you already bought the and the manufacturer does not care).

  3. 3 Mike Daniels

    Thank you for this interesting experiment with your Goped batteries. I am eagar to read about the other modifications you have made as I too own a Goped (the new Hoverboard, it’s a blast but the range could be better even though it is the best of the bunch).

    -Mike Daniels
    Los Angeles, CA.

  4. 4 Karl

    Found your tips fascinating, including your oversized SLA battery mod. I just bought a hoverboard, but need to lighten it significantly for train commuting. The new goped Li battery models are just too pricey! I have been researching NiMH batteries. Given your experience with the laptop batteries, I thought you might have some insight for me. Check out the “scooter batteries” at batteryspace.com & all-battery.com and let me know what you think. Hope to hear from ya.

  5. 5 Matt

    Great suggestions – your idea inspired me to get out and purchase some tools and materials to modify my battery setup – searched the gopednation forum for your posts there, and some folks were looking for some more detailed photos –

    I have two questions -

    Could you draw a simple diagram / take photo of balancing batteries with resistors?

    Could you take a photo of your battery setup with the wiring spread out a little more? The yellow leads look like they are spliced into the control box…would be very helpful!

    I have almost no electronics experience, and would hate to mess up my batteries…looking forward to your reply!

  6. 6 Grant Pitel

    I uploaded a new step-by-step diagram that shows how to add that balancing wire and posted a status update on my pack. I hope what I did is clearer now. If not, please tell me. Thanks for your interest.

  7. 7 Karl

    Hi again Grant. I am picking up my new goped tomorrow and will use your new updated diagram and step by step clarifications to install the balancing wire on the new batteries. I went to the cell balancing device websites you had for us, but could not see imediate pricing available…oh well. I’m guessing your appraoch will help quite a bit for now until I have the patience to further attempt contacting these companies and getting quotes. Appreciate your sharing your knowlege with us.

  8. 8 Grant Pitel

    The BattEQ is available for purchase from Staab Battery. Their website no long lists their price, but they were around $120.

    The company that makes the BattEQ is located in town and was founded by my thesis adviser. If I can get about ten people interested I can try to negotiate a better price with the company directly.

    I had previously requested to get a freebie or discount for just myself, but did not get any bites :(
    Maybe if I get some more enthusiasts they will change their tune.

  9. 9 Karl

    Hi Grant,

    What do you think of the specs on this battery at http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1243

  10. 10 Karl

    Hi Grant,

    What would think of hooking two of these battery packs (see below) with one of these balancing devices?

    http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=995

  11. 11 Grant Pitel

    Karl,

    I recommended staying away from batteries that do not list a manufacture or provide detailed data sheets. My brother and I made such a blunder and purchased a whole lot of NiMH batteries, none which worked for very long. While you may pay 20% more for brand name, its very possible it will more than pay for itself in battery life. An associate of mine performed life cycle tests on Li-ion batteries from two different manufactures. One achieved 200 more cycles than the other, which for Li-ion, is significant.

    I would email batteryspace to find who manufactures those cells, I am actually curious myself, please post who if they response.

    Looking back at my battery article, a continuous discharge of 18 A (which I think is roughly turbo mode) will deplete a a 12 Ahr pack in 25 minutes, so roughly 2C. If you used two pack, each cell would see 1C, which is within the spec on the website (provided that pack uses the same cell given in that second link). HOWEVER, this is continuous discharge. The peak current draw (a.k.a pulse current and cold cranking amps) is in fact much higher on a scooter. They occur when you go up hills and accelerate. Lead-acid are wonderful in this category.

    As the pack was designed for electric bikes, I suspect that it would work. Go-Ped does bring the voltage above 24 V to extend lead-acid battery life. I would check Ni-Mh datasheets to make sure this chemistry can handle the over voltage. I have posted some data I have taken from my scooter that you may fine helpful. I think 27.3 V was the highest I have encountered.

    GO-PED BATERY INDICATOR
    3 = Red+Yellow+Green
    2 = Red+ Yellow
    1 = Red Blinking
    Supply (V) / Indicator
    27.3 / 3
    23.1 / 3
    23 / 2
    22.9 / 2
    22.77 / 2
    22.5 / 2
    22 / 2
    21 / 2
    20.9 / 1
    20.5 / 1
    20 / 1

  12. 12 Karl

    Under the link I gave you for the individual cell there is a PDF link

    http://www.batteryspace.com/prod-specs/MH-F13000.pdf

    to a specification sheet that contains oodles of information well beyond my interperative skills. While my profession is in analytical chemistry, I am signifcantly lacking in the area of elecrochemistry, electricity, and how it is related to electronic equipment. On the spec sheet it indicates that the manufacturer is “AA Portable Power Corp.” I quickly googled it and found their website. They seem to be associated with some Chinese manfacturers. I have e-mailed them asking them to confirm this.. will let you know when I hear from them.

    Anyways, when I initially reviewed there advertising claims, they indictaed for each pack a recomended discharge rate of 13 amps, a maximum continuous discharge rate of 40 amps (with reduced capacity) and a short term maximum discharge rate of 60 amps. I thought hooking up two packs in paralell would gives us the amperage needs for the scooter without needing to adjust the scooter’s controller and essentailly double the range for roughly the same battery weight. The physical dimensions of the pack(s) would require a similar modification of the battery box like the one you did for your ovesized SLAs. Based on my first correspondence with them, they said one would need a seperate charger (each with its own temperature sensor for each pack) but that the parallel hook up for running the scooter should be disconnected during charging to avoid inbalancing issues.

    As for your “overvoltage” question, I was not quite sure how to pose the question to them without revealing my ignorance on some of these technical issues.

    BTW, I successfully installed the balancing wire on my my new goped. what a fun vehicle!

  13. 13 Karl

    Just found this one on the batteryspace.com site:

    http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3847

    It might be a litte more suitable in terms of physical dimensions, a little more voltage, and cheaper to boot. The description actually specifies 25.2 V working and 30.45 V peak. It also uses the same F size cells, 21 instead of 20, and stacked a little differently.

  14. 14 Grant Pitel

    Glad to hear you got that balancing wire in.

    It seems that the NiMH pack will stay within voltage range. The goped battery charger is really slow. I expect the stock go-ped charger to work with that pack. I doubt the state-of-charge indicator would work.

  15. 15 Karl

    If you haven’t seen it already, there is a new thread under the electric scooter section of Goped Nation forum entitled “interesting lithium pack”.

  16. 16 GUIDEGUIDO

    Thanks Grant–

    A simple solution to a nagging problem– nice.

    I made some cables and connected the batteries. For the resiestor, I had one with long leads, so aligator clips worked just fine.

    After half-assembling the harness, I thought, “wait a second– this may not fit.” Sure enough, I could not get 2 quick connects tied together with a small enough profile so the serial batteries would fit in the tray. (The deck bolt posts were in the way.)Possibly, some sort of s-configuration would work, but I was running out of connectors. So I just jumpered directly to the pre-existing metal tabs. Happily, I found with the 18 gauge wire, there was no need to dremmel the underside of the deck.

    I believe my range has indeed increased on batteries that have had 25+ charge cycles. Must test more. Again, thanks.

  17. 17 Grant

    GUIDEGUIDO, glad to hear the mod worked for you. Please, let us know what your test results are.

  18. 18 Karl

    Hi agin Grant. Recently I have been trying to send some more folks in your direction from GPN to see how you are doing the balancing wire. I am convinced mine has helped extend my usable batt life. At least one person has actually done some semi-quattative comparison with and without the wire installed. You will find the discussion in this GPN thread:
    http://www.gopednation.com/forum/showthread.php?t=277709
    Take care!

  19. 19 GUIDEGUIDO

    Hi Grant–

    I linked to this page to the scooter wiki I visit from time to time. If that is not acceptable, let me know, and I will remove the reference.

    My range is still good, but I don’t have any data. Also, I went with shorter gearing, so it would be difficult to make an accurate comparison. gb

  20. 20 Grant Pitel

    Thanks for the link and acknowledgement. Very cool site.

  21. 21 SteveO

    Hi Grant,
    Nice write up. I take it you were a Googler?
    I’m not an EE and have a couple questions regarding this upgrade.
    1. in your schematic for the resistors (Fig 2.), can you explain exactly how/where to connect those resistors? would the 100 ohm resistor go where those yellow wires connect to the harness? (or connecting it to the ends of the yellow wires?) Also, would a 100 ohm take more than a few hours to balance?

    2. after balanced, your yellow wires seem to tap into that existing wiring harness. Is this true or simply done to keep that wire tied down to something?

    Thanks,
    Steve.

  22. 22 Grant Pitel

    Hey SteveO (is your name a reference to WildBoyz?)

    I balanced the two battery stacks by attaching one end of an alligator clip to the right-center battery terminal and the other to a resistor leg. I repeat the procedure for the left-center battery terminal and other other resistor leg.

    The stock scooter has metal terminals that connect the batteries together. I removed these and made custom harness with wire and crimp terminals.

  23. 23 SteveO

    Thanks Grant,
    For 2, i already made my H-harness with the yellow wires added to each set, but the other ends of the yellow cable – where do those go? In your pic, it looks like they attach to a junction right by the motor.

    Thanks again,
    Steve

  24. 24 Grant Pitel

    No. The wires connect directly to the other battery. I appologize for the bad picture. I took it with my cellphone.

    ~Grant

  25. 25 Erin

    Hi, I don’t understand how to add your site in my rss reader. Can you Help me, please :)

  26. 26 Adam Pitel

    Erin,
    Here is a direct link to the newsfeed: http://feeds.feedburner.com/pitelspot

    Best,
    Adam

  27. 27 joe

    The confusion in the NYC law was in regard to the Goped gas models and unfortunately the original code specifically stated “Goped” in the language to outlaw the gassers. City council amended the no “Goped” law several years ago and made allowance for electrics 750W and under. I don’t have the NYC link to the amended PDF code anymore but I do have a printed copy I carry.

    In NYC the ESR is considered a bicycle on the streets but the cool thing is that the moment you step off you become a pedestrian. As long as you kick power only (wink, wink…) it’s actually okay on sidewalks too as kick/foot scooters are specifically allowed on sidewalks.

    As far as the batteries are concerned you cannot use cheap standby lighting batteries for the ESR. BB brand is the only thing I’ve found that will provide reliable performance with the ESR controller/motor.

    The balance issue is interesting and I will investigate this more – I’ve always had pretty good luck with the stock batteries but maybe I’m not draining them severely?

    best, joe

  28. 28 Grant Pitel

    I just finished school and I am getting ready to move back to NJ. I was ready to cry when I found out that in NJ only mobility scooters are allowed. The law was recently amended to include Segways, but not electric scooters!. I hope they change this law in the future. Otherwise I may have to sell my prize scooter!

    If you have any links about NJ and scooters please send them my way :) )

  29. 29 Jacob

    If you go to gopednation.com go to the electric form and read some of the threads about battery switching and LiFe.

    Good luck

  30. 30 Dallas Electrician

    I keep read sites that talk about becoming hassle free or adding more features, and seeing your information is encouraging, because it is not so easy as they say it is..

  31. 31 Blair Jensen

    Very useful info & interesting. I had no idea there was so much to realize about Go-Ped scooters batteries, but I’ve wondered various of these information.

    Good suggestions, nice work! Thanks for sharing!

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