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.
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.
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).
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.