Sunday, August 18, 2013

E+ (EMS) motor and battery disassembly

I had a very generous E+ electric bike owner send me his non-functioning motor and battery to test and do a post-mortem.

I received it a couple of weeks ago but I finally bought a 3-jaw puller and was able to open both of them up. Here are some photos and observations.

Here's the 3-jaw puller about to open the motor.

The rusty battery ring. There is a powdery material lining the inside of the casing which is quite curious. At first, I thought it was salt but the motor is from Austin which doesn't use salt on the roads since it doesn't snow there often.

The very rusty coils of the E+ motor. Interestingly, seeing the inside of the motor confirms that the motor is a 3 phase motor. The Tidalforce motors have 7 phases.

Better photo of the rusty coils. Rust alone would not stop the motor from working but it probably would be good to stop it or at least slow it down. Perhaps a slight clean up and conformal coating is in order.

Close-up of the 3 hall sensors placed between the coils and on a circuit board.

In order to open the battery hub, you'll need a snap ring tool or very good needle nose plier skills.

First impressions. This is a beautifully made battery. The tabs are welded very cleanly and the circuit board and cast casing are beautifully made. This looks brand new compared to the motor!

The axle casting and frame to hold the batteries are really high quality.

Again, the circuit board (BMS) and wiring are truly first rate.

The battery segments are joined by heavy heat-shrink wiring that is bolted in place. There are other segments joined by welded tabs.

The cells are not the SAFT French NiMH cells but are slightly higher capacity 10000 mAh Chinese made cells.

The 30 D sized NiMH cells are arranged into 6 5 identical cell groups for easier replacement.

The battery and motor side-by-side.

More later,


  1. Hi Ambrose, I've read a lot of your posts. They're full of useful stuff. Thanks for sharing. I recently acquired a TF motor that spins but runs rough and with a knocking sound. My attempt to open the casing to investigate got only as far as removing all screws, torgue arm, etc. and about a 1/2" separation. It would not come apart any further. Based on your 3-jaw-puller caption, should I assume that my bare hands won't do the job? Also, do I need to undo anything on the cassette side of the wheel? Thanks!

  2. The magnets in the motor are VERY powerful (as they are in all ebike motors). You'll need the 3 jaw puller unless you can come up with a creative way to do it. Be VERY careful when pulling it apart and putting it back together since any fingers caught between the halves are liable to be severely cut or even DISMEMBERED!

    As for what's on the cassette side, I'm not certain but just check as your pulling with the 3 jaw puller...

  3. Sounds like I'm biting off a lot more than I can chew... If a motor runs with good power albeit roughly and knocks, is it likely a straighforward issue to correct, based on your experience?

    Battery wheel topic: I've been thinking about mounting LIPO packs inside a dead front wheel. Questions: 1) Once existing contents are emptied out, are there mounting points (screw holes, metal hooks/loops, etc.) by which LIPO packs can be securely strapped in? 2) Would the absense of magnets make the front wheel cover openable without special tools?