Changing batteries


I’m planning to get rid of my Zero Fx 5,7 and buy a new Twizy. However, as many of you here in this forum, I don’t like the battery rent. The plan is to use the vehicle with rented batteries for a while and then find out how the BMS works/is connected inside the battery box. When I have found out, the plan is to buy the base plate and cover including the contactors and bms system. In theory I would then only need to get some cells that would fit the box (14 cells in series). I know that the base plate and cover can be purchased for approx. 250€. How it is with the contactor and bms ecu, I do not know. However, I do also have another issue to consider I think; will I be able to connect the “home made battery” to the Twizy or does it mean that I will have to remarry the bms with the rest of the twizy electrical system? (To conclude, I will purchase all things except the original battery cells). Anyone having experience when it comes to changing new parts to the electrical system? Does new electrical parts always need to be remarried to the Twizy? Br/Michael

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Welcome to the group.

I lot of people will be very interested in your project and we do have a member who has made their own battery inside the standard Twizy battery box. I’ll let @kennethnilsen69 explain more (or search for his power box).

Hi battery is a lot bigger, but he did change the BMS and added two new charging circuits. Although he now doesn’t have the rental it was not a cheap build.

Thanks Osbrook,

Yes I will contact Kenneth to see what experience he have had. My project will hopefully be much cheaper, because I will initially re-build it as close to the original twizy as possible. The cells that will be used is either leaf cells or A123 since I have both of them in my garage. However, working/fiddeling with the BMS could also be a NIGHTMARE and this is still in investigation stage.

I think that there are two potential stoppers here:

Nr 1: IF I get my hands on all parts, like box, bms ECU, contactors, interface an powercables. Is it possible to connect the new BMS to the can bus without having it remarried?

Nr 2: can I buy the above parts separate? The box should be possible to buy, but the rest…? IF not, I’m smoked. Or forced to buy a battery for 4500€…

Can anyone perhaps spread some light over these two potential stoppers? Maybe someone has experience of electrical parts being remarried or did not need to be remarried to the can bus? :slight_smile:

Stick me on the list. I also have 4 engineers that may be able to assist/contribute in some way if required. Located in Staines, Middx. UK.

Hello Martin,

and thanks for the back up. I will see IF I can find some parts at Renault tomorrow. I guess I can start there first.

If you look through these threads all the part numbers are already listed with the prices. I did get a reply from these guys though in the USA reference alternative battery packs;

Hi Martin,

I don’t have Twizy, but my brother had it in Bulgaria, so I know it.
We have offered and used our batteries for all kind of projects and EV / hybrid cars upgrade, so probably will be possible for Twizy.
But the main problem here is the shipping to Europe. We already shipped to UK and the other EU countries via Air Freight, but is complicated and expensive. For example a 9kWh pack for Vectrix – just the shipping goes to $800-$1000. We use to ship batteries to Australia by the sea, but still was complicated and not so cheap.
The reason is the batteries are considered Hazardous Materials and there are not so many shippers agree.

I don’t understand only why the Twizy needs new battery? It’s pretty new car.
What kind of battery capacity the Twizy need? Voltage, number of cells, capacity?

Best Regards
Nick Tranakiev
Hybrid Auto Center LLC
Tel./fax: (866) 516 5066
Cell: (702) 374 8692

I checked the prices for different battery components today:

  • Part no 293A01412R - BMS unit: 1100€
  • Part no 293890462R - cable for BMS (balancing cables from BMS to each cell):220€
  • Part no 295F00162R - Battery base plate (named oil sump… The big casted aluminium plate underneath the battery cells):129€
  • Part no 295F19016R - Battery box cover: 216€
  • Part no 295107900 - Complete battery (but the computer said contact warranty, so something is definitely wrong): 6234€! (Maybe price for a complete Twizy)

I did see something in the picture displaying the battery parts that could be both a hose or a cable (could not identify it). My guess is that it was the battery temp sensor, but i don’t know. This will probably also be needed… And If the contactors speaks to the can system, I will need those as well.

All in all, it seems to cost me 1700-2000€ just to prepare before adding my own Nissan leaf cells…

Anyone seen different prices? (I think someone showed a price of approx. 250-270€ for the complete box which seems to be almost 100€ cheaper than the price i got…)


One comment about the total cost:

It should be possible to make your own battery box also. I think that the car testning station will not notice the difference anyway. The base plate is anyway to narrow for the leaf cells that I’m planning to use and it seems to be “a lot of air” between the standard base plate and the frame.

So minimum “starter cost” if only bms, bms harness and temp sensor is bought should be approx 1300-1500€. (That is if contactors are not intelligent).


Come on. Someone must know something??? :wink:

See Kenneth on Power Box thread/

Yes, and it is confirmed by Kenneth that IF we do not want everything on the instrument panel to “go black” we still need the bms and perhaps a few components more. With that in mind, are there anyone here that has experience from changing a charger, instrument panel, Sevcon controller etc? I guess that some people do, but perhaps without asking Renault if they were forced to get it remarried… Ofcourse… :slight_smile: And no one changes these kind of components by them self… :slight_smile: I guess…

So, I will try to ask someone at the Renault workshop. Problem is just that in Sweden there is only 20 cars sold every year, so the staff from the workshop have little or none experience of these cars…sorry, motorcycles…

Last week when I asked about the BMS etc., the “spare part person” had never opend up the spare part list on his computer… (and the Twizy has been for sale in Sweden since 2013…)

So, with this in mind: is there anyone in UK or other parts of Europe that have a good relation to someone in the Renault workshop with good experience/knowledge of the Twizy function? If yes, is it possible fore “someone” to ask them if “bigger” electrical components can be changed without being forced to have them remarried?


Also: i forgot to say that the lights and turning indication will still work and it seems like the Twizy will still be able to run if Kennets invention is used, but the blue panel in the middle of the instrument cluster will still “go black”. But there is also another good reason for trying to get the standard BMS to work and that is that otherwize the charger will not work, and chargers are quite expensive… At least when providing >2000W :slight_smile:

Having that said, I think that Kenneths invention is absolutely great (I will actually buy a powerbox my self, because yesterday I bought myself a Twizy!). But I guess it’s perhaps a bit much to ask that he will also provide us with a software function that replaces the BMS. And so, if I did not totally misunderstood him on this point, we need to find out if it is possible to buy just the BMS and use it in combination with other cells, like 18650, Nissan leaf etc.

Martin: I saw now that I missed your question about the battery. It shall be:
14 cells with 3,7V each resulting in 51,7V (nominal).

What fully charged (100% SOC) or fully drained (0% SOC) will mean I do not really know, but I’m pritty sure that the cell voltage will be approx 4,1-4,15V fully charged and 2,5-3V fully drained.

@Michael Nilsson:
About chargers>> HERE is a 230V to max 60V 3000W charger for €160,-

160€ is really a nica price for 3000W. Question is just if it can provide charging without risking flames :slight_smile: Don’t get me wrong, it could very well be a good quality charger, but can we really be sure that it can be trusted at that price?

I have had an adjustable china charger before that unfortunatley blew up… And the Twizy charger has been tested… Again and Again… I can connect the chager to the network and go to bed without worries. :slight_smile:

But it’s not only the charger that is the problem. When the instrument cluster stops working because a missing standard bms, you also need to replace and tune a lot of other components.

So, I would like to ask all people on this forum: - do you know any mechanic at Renault or other workshop that has worked more than once on a Twizy? (Meaning also electrical work, not only mechanical).

Please… anyone…?

Unfortunatley I need to know that before I can get to work…


While I used to venture in engine upgrades on petrol vehicles… Take them to the track, and have a blast. Given the simplicity of the Twizy I find it in expensive to drive, maintain, and for my monthly stipen of the battery charge, headache free. If I get a failure of my battery pack, it’s replaced for free. If it under performs to 80% of new in retaining charge, it gets replaced. Given the cost of a new battery, and its labor regarding replacing it, I am not seeing the cost-benefit of building your own battery pack given the risks and costs associated with doing so. Has anyone ventured in seeing if it actually is worth while? I mean, the Twizy is aimed at a simple means of transport with fun factors thrown in… It was not designed to be modified, upgraded as such and with only a few accessories available. Evaluating such a platform so as to build-to-own the battery pack and carry the financial burden from the get go voiding all warranties, etc… May not make sense for most of the owners. Given I went through a full replaced right from my purchase, I sure was glad I was covered by Renault. Bought the Twizy for £3k, had lots of free repairs with a new battery, new inverter, and full service which would have cost more in parts and labour than the amount spent on the car. Checking out the BMW i3, costing 10x what I spent on the Twizy… My evaluation of use and capabilities other than the luxuries still makes the Twizy a much better value for the job it is meant to do - simple transport with the element of fun :smile:

CrazyTwizy: You got a point… If you don’t like to fix with cars, motorcycles, bikes, house etc…

Problem is that I hit my head REALLY hard (I think) when I was young, and the effect is that i like to modify/tune more or less all things with a motor in it.

However, it could also be worth mentioning that i buy and sell lithium batteries all the time and that i can build a 10kWh battery for the same price as 2 - 3 years of battery rent. Finally: mine is not a new one - so no warranty left.

Just to put so context around this.

Renault are expecting the batteries to last 10 years, before needing any fixes (NOT complete replacements). The 75% figure is when Renault will repair the batter back to above 75% not always back to 100%.

So provided the battery is damaged by some external element then most will be looking to spent £5400 over 10 years. With a battery cost of £2700 plus fitting it looks as if owning a battery is a better bet.

As a larger capacity batter can be fitted into the space at a similar cost to Renault then it is worth looking into for some.

The problem so far is the replacement battery costs are either too expensive (£3700) and often need too many changes that can only be done by specialists.

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