Electric battery Earn £175 per month from your EV!
BMW i3 wrapped in adverts

DIY replacement of the Twizy charger

Shortly after buying my Twizy I discovered that despite being a 2015 registered model it was actually built in 2013 so was fitted with one of the earlier problematic chargers.

I soon found out my original charger wouldn’t charge when our solar panels were generating as the supply voltage pushed to around 253Vac. Also it didn’t keep the 12v battery topped up from the traction battery whilst parked.

Not much long after my charger developed what seems to be a common fault. It only charged the 12v battery whilst driving quickly. When ‘idling’ or plugged into the mains the 12v battery wasn’t charging and the battery indicator and STOP lights came on.

On reading the forum I got the impression for Renault to fit a new charger would cost in excess of £1000 so looked for a cheaper alternative. In the end the best option was to buy a replacement charger from Renault and fit it myself. The price for the replacement charger was £727.57 (2019).

As already mentioned my original charger was one of the very early ones.

The charger Renault supplied me with appears to be the latest version with the sticker suggesting it was made in this year.

Replacing the charger yourself is easy as with the exception of the earth wire, all connections are plug and socket.


Raise the front of the Twizy on ramps.

Remove the front under tray (6 large bolts and 2 small ones / 13mm socket and 10mm socket).

It’s best to remove the centre bolts last to prevent bending the tray.

Both the mains cable and traction battery cable have quite complicated connectors on them. To disconnect them you must first slide back the blue catch then slide the black casing back whilst first pressing button 1 then pressing button 2. The connector should easily slide apart with minimal effort!

Unbolt the earth connection and disconnect both the mains cable and pilot connection.

Disconnect the 12v lead

Disconnect the traction battery lead.

Disconnect the communications lead.

Unclip any cable fasteners that would prevent removal of the charger and pull off the vent pipe (if fitted).

With everything disconnected, remove the four mounting bolts and carefully lower the charger, which is quite heavy. I’d suggest leaving two nuts, diagonally opposite, on just a couple of turns until final removal. You’ll need a deep 10mm socket.

Charger removed.

Refitting the new charger is just a reversal of removal, making sure all cables are secure (blue tabs pushed in).

My workshop manual didn’t specify individual tightening torques so I just used standard ones recomnended for the bolt sizes. I also applied a spot of copper grease to the two small under tray bolts that had started to corrode.

On completion check all charging features are ok - traction battery charges when plugged in, 12v system at ~14v whilst running and no fault lights.


Another excellent and helpful post Peter :thumbsup:.

1 Like

How detailed is this? Excellent Peter, I just hope I’ll be able to find this post when and off my charger blows up. However the current installed charger was changed by Renault 2 weeks before the warranty expired (phew!) a few years ago so hopefully mine is the new type anyway.

1 Like

Following @peter-ss instructions I have now replaced my 7.5 year old Charger, Mark 1 with a new Mark 2.

Using Peter’s picture. Here is how to operate the catches to disconnect the Orange cables

You cannot practice (or at least I couldn’t make the catch work until plugged in). Disconnection as above, Slide the blue catch back towards the cable (Peter’s fingers in picture) . Then press button 1 on the side and start to slide the black sleeve back. Once it moves a little bit press button 2 and slide all the way back. The connection comes apart easily then.

Re-connection is a little easier - Plug the connector together and slide the black sleeve all the way over as far as it will go. Then slide the Blue catch toward the black sleeve. If the blue catch doesn’t move it means you haven’t got the black sleeve fully in place. Clever.

Other connectors - Squeeze the top of the connector nearest the cable to operate the catch and pull.
The 12V lead has a yellow catch - slide out and then pull connection apart it isn’t obvious where it comes apart at first.

There is NO vent tube connection pipe on the Mark 2 chargers.

All the new cables have the relevant clips on them so don’t panic if the 12V connector comes off the frame. It has to be replaced.

The only cable not supplied with the new charger is the communication lead. It looks like the all the cables would come off the charger but those are just the glands sealing the cables in.

Peter’s instructions are really good once you start. As long as you can see under the Twizy it doesn’t have to be any higher than in Peter’s pictures - simple ramps will do.

10mm Socket/spanner for tray (2 off) start with these.
13mm Socket for tray bolts (6 off)
10mm Socket/spanner for earth cable nut (1 off)
10mm Deep socket for the charger nuts (4 off)

ie. 10mm and 13mm sockets only.


Differences in the chargers:-
Mark 1 chargers are High mains Voltage sensitive and wouldn’t charge if voltage was over 246V.
The Balancing phase was done AFTER the screen went blank (100%) and would last between 20 mins and 7 hours. All the time the fan was running.
Charging rate was 1% every 2 mins up to 97% where it would slow to 5mins per percent.

Mark 2 Chargers cope with a bigger voltage range. The balancing phase is done during the charge to 100%. This means the charge is as quick to 98% and then can longer to reach 100% - depending on the balance level this can be 20 or more minutes.

The way the 12V battery is maintain as been explained else where although in 7.5 years I never had a problem with my 12v battery on a Mark 1 Charger. The current available to the 12V system is slightly higher 27amps on the Mark 2 version. However as the 12V battery is so small it cannot cope with that current level for long. The extra 2 amps makes little difference.


I took the top off my Mark 1 Charger that had failed. It looks in very good condition and the only thing I can see that isn’t right is the fuse shown below has failed. However I have yet to get the cooling panel off the front of the unit (Back of the picture).

Is it worth doing any more @grumpy-b? I was happy with the charger as it never gave any problems until it failed at over 7 years old.

You understand many things and give meaningful advice. I have a Twizy that doesn’t come with the original battery, but also with a charger. The control of the controller does not allow the not original battery to be inserted. I replaced the controller with a curtis 1234 … display … the cables and it worked. The engine started to run better than the original controller … it doesn’t heat up and it goes a lot more miles. This overheating of the engine to over 100 degrees consumes battery power. I’m trying to program a controller that, by tweaking it … to not touch anything else. And do not warm the engine. If you have an idea to share ???

greeted Dimitar

Dimtar not me I’m afraid. I own a very standard Twizy. however @kennethnilsen69 Knows a lot about programming the original controller and may be better positioned to help with the engine temperature issue.