svenomous Posted March 31, 2019 Share Posted March 31, 2019 OK, here's an odd concept I'd like to explore: I live in a condo where I can't use a generator, so I have a 700Wh Lithium Ion (LiFePo chemistry) battery pack I keep charged up specifically as an emergency power source for power outages. It can run small electronics like my laptop, can charge cell phones and other USB power needs, and even has an inverter that can produce household AC power for smaller appliances. I also take this power pack on camping trips where it comes in handy to power the tent and campground to my 21st Century standards. An EUC like the one I've got on order (KS18XL) has about double the power storage capacity of this dedicated battery pack. When fully charged it contains a whole lot of stored energy! So, in an emergency it would be nice to know I could drain the stored power from the EUC and use it for something other than routine locomotion. I like tinkering with electronics and DIY projects (such as the battery pack I mentioned above, which I put together myself), so I'm wondering about what could potentially be done with the charge port on KS wheels, even if it's "not supported" and "not recommended." My understanding is that a KS wheel does not have a built-in charge controller, and that the external charger has all the charge circuitry built-in to it (the CC-CV circuitry that controls voltage/current, tapers the charge, etc.). This implies that the charge ports just connect more or less directly to the batteries, with nothing in the way except the BMS's. So, is it theoretically possible to connect something to the charge port of a KS wheel and discharge it, instead of charging it? My whole emergency power setup is 12V automotive power based (full charge resting state is around 13V, fully discharged state is around 11V, and the charger brings it up to about 14.6V, which is the recommended cutoff voltage for the 4S LiFePo packs i'm using), so obviously 84V would need to be stepped down to be compatible, but: if the amperage draw is controlled, as is the discharge cutoff voltage, and if voltage is converted correctly, could it be done? Just wondering for now, as I don't even have the wheel yet (it's ordered but awaiting stock at eWheels). I think too much, sometimes, and I have concepts for voltage converters with Lenovo square plugs and inline voltage cutoff switches dancing in my head! Link to comment Share on other sites More sharing options...
esaj Posted March 31, 2019 Share Posted March 31, 2019 4 minutes ago, svenomous said: OK, here's an odd concept I'd like to explore: I live in a condo where I can't use a generator, so I have a 700Wh Lithium Ion (LiFePo chemistry) battery pack I keep charged up specifically as an emergency power source for power outages. It can run small electronics like my laptop, can charge cell phones and other USB power needs, and even has an inverter that can produce household AC power for smaller appliances. I also take this power pack on camping trips where it comes in handy to power the tent and campground to my 21st Century standards. An EUC like the one I've got on order (KS18XL) has about double the power storage capacity of this dedicated battery pack. When fully charged it contains a whole lot of stored energy! So, in an emergency it would be nice to know I could drain the stored power from the EUC and use it for something other than routine locomotion. I like tinkering with electronics and DIY projects (such as the battery pack I mentioned above, which I put together myself), so I'm wondering about what could potentially be done with the charge port on KS wheels, even if it's "not supported" and "not recommended." My understanding is that a KS wheel does not have a built-in charge controller, and that the external charger has all the charge circuitry built-in to it (the CC-CV circuitry that controls voltage/current, tapers the charge, etc.). This implies that the charge ports just connect more or less directly to the batteries, with nothing in the way except the BMS's. So, is it theoretically possible to connect something to the charge port of a KS wheel and discharge it, instead of charging it? My whole emergency power setup is 12V automotive power based (full charge resting state is around 13V, fully discharged state is around 11V, and the charger brings it up to about 14.6V, which is the recommended cutoff voltage for the 4S LiFePo packs i'm using), so obviously 84V would need to be stepped down to be compatible, but: if the amperage draw is controlled, as is the discharge cutoff voltage, and if voltage is converted correctly, could it be done? Just wondering for now, as I don't even have the wheel yet (it's ordered but awaiting stock at eWheels). I think too much, sometimes, and I have concepts for voltage converters with Lenovo square plugs and inline voltage cutoff switches dancing in my head! Likely the BMS has reverse protection on the charge side, on some wheels you can draw power out from the charge port, but probably not on King Songs. If you can't read out voltage from the charge port, likely you can't draw current through that either. What you could do is splice wires to a separate connector from the discharge-side (easier and safer than trying to modify the BMSs for disabling the charge-side protections IMO ) and make a hole for it in the shell. Link to comment Share on other sites More sharing options...
svenomous Posted April 1, 2019 Author Share Posted April 1, 2019 Well...how inconsiderate of KS to not anticipate my completely random desire to do something unsupported with one of their wheels! Next you'll tell me it can't be used as a spare motor for my washing machine either. My congresswoman will hear about this! Thanks esaj. On a serious note, I probably won't act on this particular impulse, but if I ever do I'll report back about my warranty-voiding modifications. Link to comment Share on other sites More sharing options...
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