Video

72v - 24 LiFePo4 in series.

Yeah, at 2:25 I mention that. 8 in parallel. 14.4X8 = 115.2 :)

Good idea. I will be adding some ventilation through the motor cover as well.

@@looperidepersonalelectrict7003 the cheap bldc motor I bought thought would have had active cooling via a fan on the shaft. If I get time I may 3d print a fan and mount it. I prefer that over others as it's always working but air cooled has its limits

Glad you are moving forward with it! Share the details or pics when you get it finished. Anyway I use 3/8 OD copper tubing that fit down into the impeller bushing, but not sure if that will work for you. Good luck.

I robbed them from my electric VW bug that I converted several years ago, haha. They are 160Ah lifepo4 cells. Sometimes you can find some here: batteryhookup.com/

Main questions are can you share a link to the motor? What is your shaft/prop ratio? What is your RPM Motor? I can't unfortunatelly build my own battery, full blast how long yours lasted? Do you have a link for batteries close to yours?

Hi, @@franklabs3766 here is the motor I used, or very similar. QS motor, 3000w nominal, EM150SP controller.www.aliexpress.us/item/3256805728846198.html?spm=a2g0o.productlist.main.13.4fd79abanTcRpx&algo_pvid=56e26e6d-c2ef-4840-8769-63edcf1738a1&algo_exp_id=56e26e6d-c2ef-4840-8769-63edcf1738a1-6&pdp_npi=4%40dis%21USD%21472.70%21425.43%21%21%21472.70%21%21%402101f49e17044061465024286ebb69%2112000034833275225%21sea%21US%212791305019%21&curPageLogUid=mfKuBAlaKvXj&utparam-url=scene%3Asearch%7Cquery_from%3A

not sure of shaft/prop ration, it was an old Johnson 9.9 2-stroke. Let me know if you have any more questions. You might need to add better cooling, or find a motor with a built in cooling sleeve. Mine still gets hot after a longer run.

@@looperidepersonalelectrict7003 is the cooling coil still works or its rubbish?

@@franklabs3766 It works, and helps, but you might consider adding air circulation to augment it because the cowling doesn't provide for a lot of air flow normally. Depends how long you want to run at heavy load for.

Be very careful! Although 72v DC probably will not give you a shock if your hands are dry, anything over 60v DC is considered dangerous, I think. Wear rubber gloves. If you are careless and let power wires touch, you'll get a lot of sparking, and possibly a fire if the short is maintained for too long. If you're not sure what you're doing, don't attempt this mod.

Are you having issues with the motor overheating? What do you have the phase amps set to?

@@DirtyFresh Wide open IIRC.

@@buckfiden2988No issues with your motor getting too hot? I’m set at 8kw and 650 phase amps. The KO app motor temp monitor keeps going into the yellow toward the top end of the temp range. I expect it to run hotter but am curious what others have experienced.

@@DirtyFresh Check your bike for drag in the chain or wheels.

Search for QS motor 138 3000w on Ali Express. I bought from SIA Ecosys. Cheers

Thanks. I think 48v might not be enough. I did that on a little 5.5 and it was OK for a Zodiac but kind of worked it hard to keep on step. 72v might be good, and would save you money compared to a 96v system. Depends on what you're putting it on, and what KW or HP equivalent you want. Good luck!

96 vopts

It's got to be an MX3. I wondered the same thing but the MX4 appears to have a 145 amp BMS. Way more punch than the MX3.

I think that would be ok-I don't think the BMS would be working at that point. The cells would just be at rest, as if you disconnected the battery. But really I'm not sure about that specific case. You could unplug the BMS entirely and then it would certainly not be doing anything... Bypassing the BMS is risky in that you are bypassing a safety feature of the battery in order to get more power, so it's up to you if you want to proceed.

Yep it's 72v, so a little over 20kw! I'm sure I could prop up even more if I wanted more speed...

@@looperidepersonalelectrict7003 Honestly incredible to squeeze that power out of that 3kW motor. What controller are you using?

@@AntonMakesStuff It's a Votol EM150SP

It was difficult to read the display so I installed a brighter one yesterday. Probably was pulling around 150 amps max, or around 10kw. After the new prop arrives, I'll post an update with more details. The most power draw is getting on step, then maintaining speed uses less power.

That depends on the controller not the battery layout, other than max battery amps.

I preordered the rush spec controller which is capable of 1800 phase amps…ko says you can only go up to around 520 so was curious how they obtained this figure..

@@Josho67 I guess that's a question for KO Moto, let me know what they say :)

The easy way to think of it is with layers and rows equal to the series and parallel amounts, but when trying to make a pack with a certain dimension, it becomes necessary to make a more complicated layout. But is behaves the same way, and is connected the same way throughout the pack, as if it were as you describe. You can search for 18650 battery pack design or similar and find more info about how cells can be connected to make a pack.

If you look at a discharge curve of a lithium 18650 cell, it would make sense. The curve is pretty steep at 2.5 volts, so it doesn't take much more current draw to pull it down below 2.5 which you don't want to do. The amount of extra ride time you'll get by lowering the LVC is pretty minimal, and not worth the risk IMO especially if you're drawing around the max that the cells are rated for. Also, the higher the current you're drawing, the lower the voltage due to sag, and also the less capacity the pack will have. Anyway, 3.25 per cell as the cutoff (52v) wouldn't lose much capacity and would help preserve your pack I think.

Yes, I would expect that running these cells at a discharge rate over the factory specs for extended amounts of time would overheat and/or shorten the life of the cells. Using a snowbike kit, it's often at WOT so it would be pulling the max amps allowed by the controller. You're correct, there is not a mention of a maximum burst current, that would probably have to be ascertained by testing.

I haven't encountered that. Did the battery get over discharged?

@@looperidepersonalelectrict7003 Not that I would think. I bypassed it and then tweaked my KO Moto Nano controller settings. Rode a couple times while dialing in the controller. The last ride was about 17 miles and then I parked it. Waited til the next day to recharge. I thought I heard it run for a couple hours. Then I tried to ride the next day and I got Error 08 on the display.

@@tomorrowtactical Not sure. Probably you should follow up with KO Moto. The 08 Charge circuit error could have something to do with the bypass, especially if that was the first charge after the bypass, you should probably double check wiring. You might also check your battery pack voltage as a reference for talking to KO Moto support.

@@looperidepersonalelectrict7003 I don't think its the controller. I was able to use another battery and it runs just fine. I have double and triple checked the wiring. Not seeing anything. What would be the safest way to undo the bypass? That's all I have left to try.

I have a bad news for you. I think your BMS bricked (sofware collapsed inside) I saw a few videos about battery bypassing, and in one of them the guy mentions we can easely brick the BMS because if you pull off the main voltage supply from the BMS or the balancer connectors, it can cause BMS to confuse and after that, will never charge your batteries.

I've added a KO Moto controller and a BMS bypass on the battery, will be testing and posting another video soon.

Hi. It's called MY1020 48v1800w. If you watch part 1 there is more info.

Also I just uploaded part 3. I've ordered a 72v motor and 3000w controller to try next.

@@looperidepersonalelectrict7003 thanks a lot for reply, I've found the motor, is a very cheap chinese motor. I'm wait the part with the 3kw motor. I've found other video about conversion, but I'm still try to found the motor that it's right for my use. Thanks for your sharing

Hi there, News about 3kw motor? Thanks

​ @Antonio Stefanelli I was able to get on step and go about 12 or 13 knots. I made a video, for part 4, just haven't had time to upload. Really, I'd say that a slightly bigger motor would be better for maintaining speed, and for not having to run at full power, but getting much bigger than this type of motor adds a fair bit of expense. maybe if the Zodiak were a little smaller this motor would be ideal.