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Twizy Charging Logic


A few quick, but maybe difficult questions on the charging logic of a 2012 Twizy…

When on Charge:-
60v battery charges through the Mains Charger
Does the 12v battery charge through the main charger directly (i.e. 240vac -> 12vdc),
Or through the DCDC converter within the main charger? (ie. 240vac -> 60vdc - 12vdc)

When not Charging
Nothing happens, 60v pack and 12v pack are completely dormant?

When driving
60v pack supplies power to the 12v pack via the DCDC converter within the charger?

So effectively, what i am asking is… is there a 12v charger AND a DCDC converter within the Mains Charger?

Struggling to find a wiring diagram, even paid for the service manual and trawled through 1800 pages!

Many thanks in advance

If you still have the MK1 charger then:-
All charging of the 12V battery is done via the charger. That is both DC-DC and when charging from the Mains.

The MK1 charger only operates the DC-DC charger when the ignition is on, which is the same as when mains charging.

The MKII charger does not need the ignition on or mains voltage to operate the DC-DC converter.

What I didn’t answer was - when on mains does the Twizy charger use the same DC-DC converter. I would guess it does. All of it is in the one charger unit.

When not charging there is always some 12V power use, but very minimal (unless you have the power box plugged in). But if you have a MK11 Charger then the traction battery will top up the 12V battery.

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Thanks Osbrook

So its a possibly a bit unknown if there are two paths through the black box that is the charger to the 12v battery.

If the charge is ALWAYS through the DCDC converter within the charger (IGN on and 240v supply) and the DCDC converter fails, then the 12v battery will never charge.

However, if there are two routes and the DCDC converter has failed then it will charge at 240v. If the 240v to 12v charger has failed, then it will still charge with IGN on.


Get the car today, will do some digging. In the meantime i have a Ctek-style charger and a 60v to 14v DCDC converter arriving shortly (that i might try to run in parallel to the original unit) - worth a try!

Hi there,

By any chance did you buy a red Twizy with some body work needed? It had some holes in the rear panel? I saw that one and chatted to the seller - I advised them to check the battery health before they bought out the lease but they just went ahead and bought it out, and the battery might be in a poor state from being sat fully charged for so long…

It needs a new charger unit most likely, no one has yet managed to fix one as far as I’m aware. They are approx £800 from Renault !

The charger does 2 things - rectifies ac to dc to charge the main battery and the dc-dc converter to top up the 12v battery. They are 2 separate circuits in the same box, when driving obviously only the dc-dc converter part is active. When charging from the mains both are active.

You could theoretically replace that charger with a mains dc rectifier and a dc-dc converter but you’d need to also build and program an ardunio to communicate with the car via the can wires so the car is happy with it.


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I would love to know how many experts have tried to fix the charger. I not sure Kenneth has ever tried? It seems like it must be feasible with more people in the EV industry and.more people repairing things. It wasn’t too long ago that body shops wouldn’t touch a zoe as they were scared of being electrocuted!


Yep - thats the one…

I will be giving it a go to by-pass the dc-dc converter in the big black box.
I guess that it measures the voltage sag of the 12v battery and throws up the Battery light then.
I have some clever chaps at work that might be able to work out whats wrong inside the box and I have contacts in Renault Technocentre Paris, I will see what i can find out. Its obviously a supplier issue that should in theory be repairable, but if its due to water ingress then there can be a multitude of failures and there is no hope. I have seen a few pictures and videos of a couple of blown FETs and one with a blown fuse too.

My Jan 2015 Twizy seems to charge the 12v when the ignition is turned on (I can see the voltage on the 12v aux socket rise), I suppose this means that I have a mk1 charger?
Does anyone know when the mk2 charger was released?
Many thanks

most of the mk 2 chargers i have seen have been date coded 2019 but they could have been fitted to earlier Twizys but its a bit unknown , seems to be plenty of 2012-2015 Twizys needing the mk 1 charger replaced.

I am one of the unfortunates who experiences the regular combination of the beep, the red STOP signal and red battery light. I changed the 12V battery for a new one, but the frequent message combination keeps coming back. In this forum and on the net I have read that the most probable cause is a malfunctioning charger module.
Typically, and what I cannot find is an OEM type specificaltion of this specific module. Anyone?

I enquired with my local Renault dealer but they went blanc already after me mentioning Twizy and charger. LOL

This is what a brand new charger/dc-dc converter has on it.

So that is charging from the mains at 60v 40A and it supplies 27A at 12v for the 12v battery/systems.


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In most cases, the charger is strong, but most “EXPERTS”
consider it not working if it is not charging. It does not work because the kan bus is not operated. If the cells are visibly buried, 90% of the problem is in the temperature sensors of the cells?

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This dc / dc is complex electronics. on request it is divided dc / dc, ie has no common zero and works in a certain range. however, it is not managed. It works or does not work. Unlike the large battery charger.

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