Cole Posted April 3, 2020 Share Posted April 3, 2020 Hi All, I was wondering if anyone has successfully extended the range on a Z10 with an external battery. I know the wheel shuts off when the charger is connected, but I'm wondering if you could feed current through the XT60 that connects the battery pack to the controller either with a 14s pack in parallel or a lower voltage pack with a boost converter. From teardown videos I see that there are two XT60s on the Z10 - does that mean there are two batteries that are not in parallel? I'm guessing that would mean that I can't just tap into one of those connections. Cheers and thanks! Quote Link to comment Share on other sites More sharing options...
Chriull Posted April 3, 2020 Share Posted April 3, 2020 48 minutes ago, Cole Bishop said: From teardown videos I see that there are two XT60s on the Z10 - does that mean there are two batteries that are not in parallel? I'm guessing that would mean that I can't just tap into one of those connections. Seems so - here were many reports that with longer downhill parts only one of the two battery is charged by regenerative breakinf and the packs go out of sync. One has to drive afterwards a bit to get them in sync again. So it seems the controller only uses one pack at a time and switched between the packs. So the battery packs output is not to be connected in parallel ever! For charging both packs are somehow connected in parallel - so they had to disable the output! Regarding your external pack you'd have to make two, so both packs are extended similar (and not get a patallel connection!) A second problem could be/is that a fix connected external pack not only charges the battery pack but also supports while riding and get charged while regenerative braking! Ad riding: As ninebot uses low battery voltages (14s) and are quite powerfull expect "massive" currents to be drawn also from your external battery! Ad regenerative braking: Also in this case quite high currents can flow! Normally above "normal/healthy" charging currents. By this charging currents imo one has to be careful with/can forget boost converters - one would need one that can work bidirectional! Maybe the easiest solution is a portable charging pack with a step down converter with current limiting (if no power outlet is available at your tour to use a normal charger). Z10 were reported here to accept charging currents up to some 7-8A. So while within the constant current stage of charging one can recharge about 7A/18Ah*1h=39% per hour... Quote Link to comment Share on other sites More sharing options...
Cole Posted April 3, 2020 Author Share Posted April 3, 2020 Thanks for the insight! I currently have a portable pack made from 3 10s2p (36V) hoverboard batteries and a boost converter that can charge at 7.5A on a break. If I wanted to keep both batteries independent I would need two externals and two boosters which seems like a pain, although I'm not sure I see the regen current being a problem because it would be split between the internal and external packs. It sounds like the most elegant solution would be to have two 14S external packs with one in parallel with each internal pack, eliminating the need to change voltage Quote Link to comment Share on other sites More sharing options...
smallexis Posted April 3, 2020 Share Posted April 3, 2020 11 minutes ago, Cole Bishop said: It sounds like the most elegant solution would be to have two 14S external packs with one in parallel with each internal pack, eliminating the need to change voltage I have put an external plug on my Z10 and this plug is link to both XT60 inside the wheel. So Battery 1 and Battery 2 are linked together and the wheel works perfectly. With my externel plug I can link my external battery (14S4P that give 12,8Ah) that give power to both battery and I can have a faster load if it's needed. 1 Quote Link to comment Share on other sites More sharing options...
Chriull Posted April 3, 2020 Share Posted April 3, 2020 13 minutes ago, Cole Bishop said: although I'm not sure I see the regen current being a problem because it would be split between the internal and external packs. You have the specs of your boost converter? Can he take reverse current? Once the motor by regen braking raises the voltage the boost converter tries to prevent this by raising its voltage to max (and stops at his 67.2V or 84V or...). So both motor and the pack charge the internal battery. By this the internal pack gets (over)burdened even a bit more.... For the (short) moments of hard braking... Depending on the overvoltage alarm/tiltback/cutoff, the max boost converter voltage and the internal battery voltage there could be situations which the boost converter cannot withstand - from some people who use such devices this seems to be teorethical/no real problem? If all this limits work together going downhill with a full battery just the overvoltage alarm will come earlier.. Quote Link to comment Share on other sites More sharing options...
Cole Posted April 3, 2020 Author Share Posted April 3, 2020 5 minutes ago, smallexis said: I have put an external plug on my Z10 and this plug is link to both XT60 inside the wheel. So Battery 1 and Battery 2 are linked together and the wheel works perfectly. With my externel plug I can link my external battery (14S4P that give 12,8Ah) that give power to both battery and I can have a faster load if it's needed. Nice, thanks! Do you have any more photos of the wiring on your setup? That would be the most elegant solution for sure then. 3 minutes ago, Chriull said: You have the specs of your boost converter? Can he take reverse current? Once the motor by regen braking raises the voltage the boost converter tries to prevent this by raising its voltage to max (and stops at his 67.2V or 84V or...). So both motor and the pack charge the internal battery. By this the internal pack gets (over)burdened even a bit more.... For the (short) moments of hard braking... Depending on the overvoltage alarm/tiltback/cutoff, the max boost converter voltage and the internal battery voltage there could be situations which the boost converter cannot withstand - from some people who use such devices this seems to be teorethical/no real problem? If all this limits work together going downhill with a full battery just the overvoltage alarm will come earlier.. This is the one I have been using, adapted from VnR on a onewheel, it would have plenty of headroom at 14s (58.8V) as it goes up to 120V: https://www.amazon.com/Numerical-Regulator-10V-120V-Converter-Adjustable/dp/B01GFVI6R6/ I would usually just set the output voltage a bit lower than the internal battery full charge voltage and never had a problem with voltage spikes from regen - the boost converter just keeps sending charge regardless of the output voltage Quote Link to comment Share on other sites More sharing options...
Chriull Posted April 4, 2020 Share Posted April 4, 2020 17 hours ago, Cole said: This is the one I have been using, adapted from VnR on a onewheel, it would have plenty of headroom at 14s (58.8V) as it goes up to 120V: https://www.amazon.com/Numerical-Regulator-10V-120V-Converter-Adjustable/dp/B01GFVI6R6/ From skiming over some google searching it seems boost converters normally/most/many "block" reverse current(1). They seem to be just vulnerable to too high voltages forced on the output. Depends of course on the respective choosen detail implementation of the circuitry. I'd do some input/output voltage and current measuring (+oscilloscope should be helpfull) with different scenarios - or if one happens to know one experienced with this topic, gather reliable infos. (1) Synchronous boost converters could be vulnerable? I'd see no real reason why an boost converter like yours should be a synchronous one, but i'm not too much into this topic... 17 hours ago, Cole said: I would usually just set the output voltage a bit lower than the internal battery full charge voltage and never had a problem with voltage spikes from regen - the boost converter just keeps sending charge regardless of the output voltage Yes. The converter will raise the voltage (limited by max setting) high enough that the choosen current flows. As you set the limit below battery max voltage and there is no problem with fully charged batteries your converter seems to block and "withstand" higher voltages at the output. Did you check if the battery does not get discharged - it keeps this higher voltage? Ps.: The motor controller itself is a step down and boost converter. Some links mention to be carefull connecting converters together - depending on their control loop this can lead to (bad) oscillations. ... If ones setup worked some time wo probs chances are high this is not happening... Quote Link to comment Share on other sites More sharing options...
Cole Posted April 4, 2020 Author Share Posted April 4, 2020 On 4/3/2020 at 11:33 AM, smallexis said: I have put an external plug on my Z10 and this plug is link to both XT60 inside the wheel. So Battery 1 and Battery 2 are linked together and the wheel works perfectly. With my externel plug I can link my external battery (14S4P that give 12,8Ah) that give power to both battery and I can have a faster load if it's needed. I saw your wiring diagram from your other post and I think I'd like to replicate your build. Mainly I'm curious how you physically chose to connect the wires and where you drilled the hole to get the connector out. I'm considering either making an adaptor using XT60s or using posi-taps, so please let me know what you went with and any problems you might have encountered. I'm a little afraid of unplugging it because I've heard stories of people needing to "reactivate" the Z10 batteries after unplugging them. 9 hours ago, Chriull said: As you set the limit below battery max voltage and there is no problem with fully charged batteries your converter seems to block and "withstand" higher voltages at the output. Did you check if the battery does not get discharged - it keeps this higher voltage? Yes, with the onewheel the battery % would just decrease much much slower as the booster fed current into it from the hoverboard packs, so I'm hoping the Z10 will have the same behavior. Because it's such a small motor and only goes 17mph I could get something like 40mi with a 1kWh pack. The ideal scenario would just be to have a pack with a matching number of cells in series so you don't need a boost converter but I'd like to use the batteries and booster I already have. The boost converter method also has the added benefit of keeping the wheel near full charge for longer so you get more power for your ride. Quote Link to comment Share on other sites More sharing options...
smallexis Posted April 8, 2020 Share Posted April 8, 2020 On 4/4/2020 at 11:58 PM, Cole said: I saw your wiring diagram from your other post and I think I'd like to replicate your build. Mainly I'm curious how you physically chose to connect the wires and where you drilled the hole to get the connector out. I'm considering either making an adaptor using XT60s or using posi-taps, so please let me know what you went with and any problems you might have encountered. I'm a little afraid of unplugging it because I've heard stories of people needing to "reactivate" the Z10 batteries after unplugging them. I have no picture but I can say there is no other choice to link both batteries than to do it before the XT60 connector from each battery. I have directly soldered wires for external plug on it. And same problem for the external plug, no more possibility to put it on the shell due to the shape. open your shell and you will understand what I'm speaking about. Quote Link to comment Share on other sites More sharing options...
Cole Posted April 19, 2020 Author Share Posted April 19, 2020 On 4/8/2020 at 8:50 AM, smallexis said: I have no picture but I can say there is no other choice to link both batteries than to do it before the XT60 connector from each battery. I have directly soldered wires for external plug on it. And same problem for the external plug, no more possibility to put it on the shell due to the shape. open your shell and you will understand what I'm speaking about. Thanks for your help! Luckily I was able to add an external charge port for each battery using only connectors I had around already. I used two 2x male to 1x female XT60 adapters and ran the two extra male connectors out of the shell. For a long ride I can attach them together with a 3x female to 1x male adapter which I plug into my boost converter set to 58V and external battery (3x hoverboard 10s2p) in my backpack. Added a voltmeter too so I could keep an eye on it. The screw was able to catch on the threaded insert so I didn't even have to drill out the enclosure which means I can return the unicycle back to stock if I want It's working great so far, I did a 50mi ride and was also able to charge at 5A through the port and 7A through the connector simultaneously on a break with no issues. I highly recommend this mod if you need more range! It was super easy and took like 10 minutes to install. 1 Quote Link to comment Share on other sites More sharing options...
Boris Lämpel Posted October 6, 2020 Share Posted October 6, 2020 Hey @Cole, I recently read about Your Battery extension. Did it work? Did You use a battery with the same voltage or Your boost converter? What about braking? I just want to do the same... Quote Link to comment Share on other sites More sharing options...
Boris Lämpel Posted December 9, 2020 Share Posted December 9, 2020 (edited) Here is my setup for using a second battery while riding: I use an original Z10 battery in my bag. So the capacity is doubled and the same in both packages. First I connected both parts of the inner battery of the Z10 to only one xt60 port. So I have got a free input for my backpack battery. I laid the cable outside next to the trolley. I just had to grind two small holes for the cables to pass through the sidecover and the upper plastic part. The two outputs of the backpack battery are also connected together. Then there is a fuse, so that there is no chance for my back getting overheated in any case of a shortcut . Actually I use a 40 A MIDI fuse, but at hard acceleration with some Voltage difference at the batteries that could be too less. So there is the possibility of using MAXI fuses up from 50 A. To connect the second battery with the wheel I used 14AWG cables, the same as used inside the Z10. Around there is a sleeve. Till now I did not experience any heat in the cables (one of my fears in that project). In my first tries I used DC-connectors. I wanted something easy to loose in case of a fall. But the port completely melted at the very first hard acceleration... So I switched back to the XT60 ports which I just wore out a bit. The connection will break during a fall . Now to the biggest thing to look at: voltage difference. The Z10 has 2 inputs because of actually 2 batteries. I have 4 batteries and connected 2 of each together. So the power input goes to the motherboard first and then towards the motor / the other battery. At the input there is no voltage when I do not use it. There is no danger of getting a short circuit. I tested connecting the batteries to the wheel with a voltage difference of about 1 V. That could be dangerous because of sudden evening out. At ninebattery there was a max current of 2.5 A. Acceptable. When there are some voltage differences I just do not stop, so the most electricity is used by the wheel itself and not transmitted between the batteries. For charging the second battery I built a port that uses the original charging input of the battery and fits with the Ninebot charger. I use a digital voltmeter capable of the 58 V to check the voltage sometimes between the ride. So I can see that the batteries drain simultaneusly. Finally that is my riding setup: A backpack with the battery inside it, a cable going to the wheel. I used some kind of velcro to adjust the length of the cable. The riding feels a lot different now. I feel like there is a bomb on my back that could explode all in a sudden... So I am less brave in driving and have less fun. But the range is notably better. Edited December 9, 2020 by Boris Lämpel Quote Link to comment Share on other sites More sharing options...
Boris Lämpel Posted December 21, 2020 Share Posted December 21, 2020 Warning: That mod can destroy your electronics! I already tested the case of the cable being removed by accident. In every situation (stand still, accelerating, braking) I could unplug the battery and nothing happened. During a longer trip (38 km) I regularly checked the voltage of the backpack battery. I the actual case I unplugged it while I was braking gently to a standstill. At a sudden the light turned of, the wheel stopped balancing and there was a "puff" (capacitor exploded). My theory: While regenerating the Z10 regenerates only into one battery. It is not alway the same battery but it changes randomly. I suppose that just at the moment I removed the cable and was braking, the wheel regenerated the power into the backpack battery. With the battery removed the power had no way to go (I do not know how it is steered in just one battery) and the capacitors got too much voltage. So one after the other they exploded (the second one just randomly on walking the wheel home). Quote Link to comment Share on other sites More sharing options...
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