1992 Mini-EL Motor and repairs

imval

Neues Mitglied
06.12.2021
11
Hi everyone,

I've been browsing this forum for a few weeks and recently bought a Mini-EL.
I live in the Netherlands but I'm French, I hope it's okay that I write this in English.

The Mini-EL had been previously "converted" to 48v by simply adding another battery in the cargo area and wiring the motor controller to the fourth battery while keeping the electronics powered by the third battery. All the batteries were completely dead when I bought it, so I started converting it to Lifepo4.

I am considering upgrading the motor to something more "recent" and efficient, and was considering a brushless DC motor with a three phase controller. I have some experience with them and I like the fact that they are silent, efficient and require almost zero maintenance.
Has anyone here done that? Would I need to certify it? What if I simply configure the controller to the same power as the thrige motor I had before?

Also regarding the DC-DC converter and various electronics, are they compatible with 48v?
For now I've built a 12S pack but I'd like to build a 16S pack as the voltage would be compatible with my ebike charger.

thanks for bringing so much content to this community, hopefully I'll be able to share more soon and help others!
Valentin.
 
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Sascha Meyer

Bekanntes Mitglied
18.05.2007
4.385
Bonjour Valentin,
what motor do you use currently? If it is a Titan Thrige or a Perm, i would rather consider not to change them for beeing quite efficient and robust. No need to change.
What age does your Mini-EL have?
Converting a 36-V-EL to a 48v one, there should be more adaptions than simply put an additional battery in the back.

You can get lots of informations in our ELWIKI, unfortunately in german. And there are other CityEL-Owners in the Netherlands. It is quite good to have someone near by.

Bienvenue ici et beaucoup de salutation de la region de la sarre, Sascha
 
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imval

Neues Mitglied
06.12.2021
11
what motor do you use currently? If it is a Titan Thrige or a Perm, i would rather consider not to change them for beeing quite efficient and robust. No need to change.
It's indeed a Titan Thrige with a Curtis controller.
My Mini-EL is from 1992. It has over 170'000km.

I have found the ELWiki, which is an incredible source of information, it's really nice to have this! I read a lot on it.

For now, I'm reverting changes made by the previous owner as his sense of electrical safety is very far from mine (For example, fuse bypassed for the motor controller...).
 

Sascha Meyer

Bekanntes Mitglied
18.05.2007
4.385
Oh dear, so you have lots of work to do and to discover.
Speaking of the Thrige, this motor is veeery robust. As we say here in Germany about this Thrige, it behaves like a wild hog. I have one by myself and i wouldn´t change it.
170 000 kilometers, i am impressed. There are some drivers here in Germany with a lot more, but not many of ´em. Mine did just drove about 130 000 km.
If you encounter trouble in understanding our german elwiki, please just ask. We will translate it in English or French, si c´est nécessare ou possible du tout..

Oh, and you might want to have a look into the great danish Ellert community..

Greetings from Germany, Sascha
 

imval

Neues Mitglied
06.12.2021
11
Good morning everyone,
I have made some progress on my MiniEL, but I'm facing some issues, which I'm solving one after the other :)

Batteries and rat nest
The previous owner had wired 4 lead acid batteries in the City-EL, taping the electronics on the 3rd battery without balancing the batteries and with vampire draw on the batteries due to the permanently on voltmeter he installed.
The lead batteries were totally dead and will go to the recycle center soon.
I quickly put together a 12s Lifepo4 battery to test and play a bit with my vehicle. Now after the freeze the previous weeks, I realized that I have to make something a bit more insulated if I want to be able to charge them! So I'm making boxes with cement/hardfoam insulation material and a heater at the bottom. I'm going to use a DIYBMS with custom cell modules that I made initially for my powerwall. This allows me to control the charger and relays to turn on heaters/stop the charge depending on the conditions. Also allows me to see the battery status from my mobile phone.


Now for the wiring, this picture above is a temporary setup to see how I am going to place everything, so don't mind the mess ;) I will make better pictures when it's finished and cabled properly!

Here is a picture of my new boxes, with a 15S setup, I'm currently working on converting the electronics to support this voltage:


I'm also cleaning the wiring under the seat as I'm not using the battery monitor and the current limiter in my setup.
I will place the charger under the seat soon. I bought a Huawei power supply capable of providing 50A to charge the battery. I'm planning to enable this vehicle to charge using Level 2 public chargers.


Mirrors
My mirrors had been repaired by the previous owner in a very original way, putting silicon glue in the hole and hope for the best. That didn't work for me. I tried to fix the plastic joint multiple time but it didn't hold.
So I drew on Fusion 360 a part, 3D Printed it with resin and glued it to the mirror support, and now it's working perfectly! I will see how it holds to the elements, maybe I will redo it with a different resin.
received_1085285932233146.jpegreceived_696197584700569.jpeg
received_501490624540211.jpegreceived_426876345885051.jpeg

Leaks
- I have a big leak on the windshield. I believe the rubber gasket between the canopy and the glass windshield is not doing its job correctly.
- I have another leak on the sunroof, also due to the rubber gasket not doing its job.

Do you have any recommendation on where I could find these rubber seals or should I just use some silicone paste?
Or is there maybe a way to treat the rubber to give it back its properties?

Thanks again for the amazing inspiration and community that you built, both on this forum and on the wiki!
Happy new year to everyone!
 

Kamikaze

Aktives Mitglied
Remember to compress the Battery-cells properly to prevent premature degradation.
If used and shaken without compression the electrolyte tends to separate from the Cathode and/or Anode which leads to increased degradation over time.
If I remember correctly the Whinston-cells are not extremely prone to this behaviour, but maybe better safe than sorry.
For my new EVE-Cells it is strongly recommended by the manufacturer.

Best of luck with your project! :)
 
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imval

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06.12.2021
11
I have compressed the cells with some duct-tape, I know it's not ideal, I will probably make a brace out of metal in the summer, when working outside is easier :)
Indeed these cells already have a quite sturdy case and don't really require compression. EVE-cells or aluminium shell cells require the compression, I have a few of them as well and they bulge otherwise.
 
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laase

Aktives Mitglied
08.10.2009
1.181
For several battery projects I already used "Umreifungsband" from the packaging industry: https://www.ebay.de/itm/321311698824?hash=item4acfab6f88:g:0c8AAOSw0vBUju4a
A special tool is needed to tighten the strip: https://www.ebay.de/itm/292289639649?hash=item440dd1f4e1:g:WNcAAOSwEWJZ24kT
Make sure you take the white "Textil" one (guess its Nylon?), cause its far better than the black PP one. The small tool is enough. Sets with strip and tool usually start at 35 or 40€, but with the mobile i didnt find it in the hurry. For specially pressing the "foreheads" of cell stacks, I introduced a vertically positioned 10x10 Al profile with 1mm wall thickness in each side. On smaller cells this might not be necessary.
Of course having Al plates tight-welded all around the stack would be the best option when it comes to space usage, but this is for my next workshop in my next life ;-)
 
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