ATW Ligier Optima Sun Microcar Project

[Sachs]

Hello everyone,

I've recently bought a '94 Ligier Optima E Sun. Normally this microcar was sold as a mopedcar with a variety of single cylinder diesel or gasoline engines and a top speed of 45km/h. In the early 90's, a German company called "ATW" converted about 150 of these to an electric drivetrain.

The 15kW electric motor was a massive improvement in power and increased the top speed to a rather impressive 105km/h. Unfortunately, the originally implemented lead-acid batteries were expensive, didn't last long and made for a rather short range. Which became the downfall for these early German EV projects. But fortunately, lead is dead so to say.

This specific one was previously used for research purposes at an university and a college school. It appears to be in fairly good condition and was mostly stored inside. Unfortunately, the luxurious metallic blue paint has been replaced with a white base coat, and the electronics need a refresh. Fortunately, the steel frame is still in good condition and shows no signs of (excessive) rust, and the brakes seem to work perfectly.

The Ligier is equipped with the following components:

– GenLab VPA 230 motor inverter
– 168V lead-acid battery (14 x 12 V)
– Thien 15 kW three-phase asynchronous motor (105 km/h)
– DCC 4000 BMS-ish device
– Trumatic 1800e LPG heater
– Zivan K2 charger (~1.5 kW)
– Zivan K02 168V->12V 20A DC-DC converter

The suspension was upgraded with stronger wishbones, disc brakes at the front, and a stabilizer bar – a good base, I believe. Alright, enough chit-chat about the Ligier itself. Let's start with the interesting stuff.

My plans
My current plan is to modernize it to modern standards so i can use it on a daily basis.

Batteries
There are 12 brand new Nissan Leaf battery modules on their way to replace the lead-acid batteries. These are 180Ah 4S1P CATL NMC modules and make for a combined battery pack of 177V/32kWh. This should drastically improve the range to ~200+ km. (125+ miles)

BMS
The DCC 4000 BMS is going to be replaced with a cheap-ish BMS system called GhostBMS. This BMS handles up to 200A of current, supports cell balancing and comes with CANBUS, pretty nice for a budget BMS.

Charger
The original ~1.5kW charger is rather lackluster for a 32kWh battery pack. This charger will be replaced with a three-phase 10 kW charger compatible with Type 2 charging stations and CANBUS.

Heater
The LPG heater will be replaced with a diesel heater for safety reasons and to save weight, eliminating the need for a gas cylinder behind the driver's seat.

Progress
I'm currently stripping the vehicle as far as neccessary to remove all the old tech and inspect some of the wiring. The next time i'm doing some work to it, i'll take some more pictures to share with you guys.

 

[neptronix]

Looks cool, i'm kinda shocked that a 15kw rated motor can drive such a vehicle that fast!
With an upgrade to lithium, you should be able to get a notable torque boost over stock due to MUCH less voltage sag, should be a fun ride!

 

[harrisonpatm]

This looks great! Can you discuss legalization plans for it, if you have any?

 

[Sachs]

Looks cool, i'm kinda shocked that a 15kw rated motor can drive such a vehicle that fast!
With an upgrade to lithium, you should be able to get a notable torque boost over stock due to MUCH less voltage sag, should be a fun ride!

Thanks! It would probably take a while to get it all the way up to 105km/h, but it should be possible. I'm really excited for how it will drive since i bought it with dead batteries.

This looks great! Can you discuss legalization plans for it, if you have any?

Yeah, of course. It was registered as a normal (EV) car in Germany, and came with the registration paperwork when i bought it. I've sent a copy of the registration to the RDW (the Dutch vehicle authority for registration and such) and they will register it here without any problems because it's got a registration from an EU country. This was an important selling point to me since i can't do much with it when it's not road legal.

 

[jonescg]

With 32 kWh of lithium I reckon you'll go further than 200 km. Awesome find!

 

[Sachs]

Aaaand here's the next update. I took some pictures of the dismantling progress, and found some older pictures. Picking the Ligier up from the south of Germany was quite the adventure, it was winter time and there was lots of ice and snow in the mountains. Sounds fun, until you have to drive up/down 10%+ slopes with an old manual Volvo 240, a large trailer and summer tires to top it off. But we made it


I've started the dismantling process under the hood, where the old charger, dc-dc converter and LPG heater were mounted. Removing them gave access to the motor and gearbox:


It looks like an industrial motor coupled to a modified Comex gearbox, fun fact, the gearbox design was later used in the much more modern Renault Twizy as well. I've still got to remove the LPG lines and clean up the wiring, mostly cutting out the unneccessary stuff. The front shocks seem to be a bit stiff and probably at the end of their life, but replacements aren't being made anymore and seem to have become unobtanium....

The interior got partly stripped as well, i've removed the seats, dashboard and middle console for access to all the wiring and measuring up the battery bays. There is quite a lot of room for batteries, and they sit nicely low into the floor for a low-ish center of gravity. Still got to clean the goop from prior lead acid battery leaks and shards of glass from the shattered rear window... (it wasn't me, i swear)



I've opened up the GenLab motor controller as well to see if it's alright in there, and it looks to be in great condition. Always love to see some vintage electronics:



The charge port will need some attention though. An upgrade to the type 2 connector will make life a lot easier, and that slab of wood it's mounted in.... Not my style so to say But that's easily fixed with some Solidworks and 3D printing.

The stickers also had to go, i've removed them on one side for now to see the difference. (or because i was too lazy to do the other side as well ) And fitted some wheel covers for that slick *premium* look:

 

[offGridDownUnder]

The front shocks seem to be a bit stiff and probably at the end of their life, but replacements aren't being made anymore and seem to have become unobtanium....

Take many measurements while it's clear and consider replacements that are broadly available?