Motenergy 86v E-Kart ME1306 Build

journeyman846

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Figured I would start a thread this time to document the progress on my 2nd electric gokart conversion. Wife got me the frame off Facebook for $50 as a birthday present. It had been sitting in a field for about 5 years. I was able to get the engine running by replacing the carb with a $10 ebay replacement and sold it for $70. Currently the planned build is going to be a 24s2p Lifepo4 battery pack, Motenergy ME1306 motor, and a Kelly KLS7275H controller. Currently waiting on the controller and BMS. I am curious to know from some of the smarter people on here, my other build was 72v LiPo and I have this charger for it. Since in theory the Lipo battery would charge to a max of 84 and the Lifepo4 being a max of 86, could I re-use that charger?

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Functional Artist

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Very interesting project :sifone:
...& that's a kool looking kart too ;)

How about some more pics of the motor mount :thumbsup:
...that looks interesting too 😎

In theory the charger should work (as you said, it just won't fully charge the battery pack)
 

EpsilonZero

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The charger should work fine and you will actually have near 100% of your power available at 3.5v per cell (84v total) while improving cell life.

You may already be aware, but be careful with that battery. Both your motor and controller are rated to pull more current than your battery pack is. Your peak current draw under full throttle will hit 500A with the controller current settings at 100% and your batteries in 2p can handle only 250A for 10 seconds according to their spec sheet. If you adjust the controller settings down it should be fine and you won't just be relying on your BMS to protect the battery.
 

journeyman846

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The charger should work fine and you will actually have near 100% of your power available at 3.5v per cell (84v total) while improving cell life.

You may already be aware, but be careful with that battery. Both your motor and controller are rated to pull more current than your battery pack is. Your peak current draw under full throttle will hit 500A with the controller current settings at 100% and your batteries in 2p can handle only 250A for 10 seconds according to their spec sheet. If you adjust the controller settings down it should be fine and you won't just be relying on your BMS to protect the battery.
Yep already planned for the amp constraints, I didn't originally plan to go so big with the motor but the cost differences were too close so I decided to just go big. I might even end up swapping over the LiPo pack from my other build as they are rated much higher.
 

EpsilonZero

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Trying to get a closer to 60mph, I guess in theory that combo should already be close to 50. Not sure why I am not hitting that, need to hook up and monitor the controller readouts.
How tall are your rear tires?
 

EpsilonZero

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I think the ME1306 is good for 81.25rpm per volt from looking at the plot. You should be hitting your rated 5000 rpm and more like 48 instead of 38mph. At least some of the controllers default to 4000 rpm max; did you change it to 5000?
 

journeyman846

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I think the ME1306 is good for 81.25rpm per volt from looking at the plot. You should be hitting your rated 5000 rpm and more like 48 instead of 38mph. At least some of the controllers default to 4000 rpm max; did you change it to 5000?
Here are the current setttings. Let me know if you see anything that can be improved.

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EpsilonZero

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Your acceleration could be improved with adjustments to Torque Speed KP/Ki and Speed Err Limit (e.g., 9500,500 and 4000 on mine). Top speed could be affected by your low speed switch. Try setting your MidSpeed Forw and LowSpeed Forw to 100 as a test. You can also connect via bluetooth or serial port and watch live what the controller is seeing and doing (e.g., throttle, motor rpm, switch detection, etc). Your throttle settings look fine as well as long as you're actually hitting 80% for full throttle (which you should unless the throttle is bad).
 

EpsilonZero

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Also... you appear to have field weakening on your controller, which wasn't previously available on KLS-H models (just KLS-NR). If you set your Min Excitation to a positive integer it should enable it. The suggested starting point was 40 when I enabled it. Be advised that you could run into sudden deceleration if the field weakening current collapses (simply letting off the throttle in my experience), which was an issue I had no matter what settings I tried above a certain excitaiton threshold (including just 40). You shouldn't need field weakening to increase your RPM to even 6k though with your available voltage. Be careful with your max RPM setting when you get this working since your motor is rated at 5k and you have it set to 6k. Shorter bursts at 5.5k will be fine but I wouldn't cruise along at 6k if I were you.
 

journeyman846

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Thanks, I will make those changes and see how it goes. Also, could you explain the motor nominal current and what it should be set at? The user guide doesn't list this setting.
 

EpsilonZero

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Thanks, I will make those changes and see how it goes. Also, could you explain the motor nominal current and what it should be set at? The user guide doesn't list this setting.
That would be your continuous current rating, which is 150A. My understanding is only used during the motor detection routine, so if detection was successful and your motor is running smoothly you should be fine.
 

journeyman846

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Almost finished with the kart. Just needs some brake lights and maybe a windshield. I finally got around to testing with a laptop connected and found out the reason I am not reaching my expected speeds. Seems the motor is not going over 3000 RPM. Not sure what could be causing that except for maybe not having a fully charged battery pack (still waiting on the BMS from China). IMG_1165.jpgIMG_1164.jpg
 

EpsilonZero

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Not sure what could be causing that except for maybe not having a fully charged battery pack (still waiting on the BMS from China).
Did you check your battery voltage? Did you charge those cells individually or in parallel with a bench power supply? Be very careful with using the battery without a BMS. Overcharging and over-discharging can easily damage individual cells, but individually charging the cells for assembly and testing is safe; just don't go too long and risk over-discharge when you aren't monitoring the cell voltage.
 
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