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The battery!

Where is the accessory battery in the Twizy? is it possible to upgrade this?

Kind regards,

It’s in the front. Undo the 2 bolts under the front panel and unclip. It’s behind the number plate. Your hand book should show how to get to it to check it.
If you can find a bigger capacity 12V battery that will fit in that space it can be upgraded.

Behind the front number plate. 2 bolts under front bib, 2 pop studs round either side of nose cone (they are a fiddle to pull out) and battery is behind it when whole panel is removed. There’s 2 bolts either side of battery to release and it’s out. You could put a replacement lithium race bike battery in there, but they are a bit pricey!!! There is space for a bigger battery but I haven’t had time to work out the best possible mods for it yet… Theoretical maximum size for a battery in there is 155x165x125 but you would need to fabricate your own mountings and protection for the terminals (you don’t want them possibly touching anything metal after a crash, that’s how many vehicle fires happen.) The DC-DC converter (charger) for it can supply 25amp max, which is a good charging rate. Do check things for yourself before doing / buying anything as I haven’t done any testing on battery upgrades, just checked out a few possibilities. :slight_smile: M

Yes the race batteries are good, I suppose its finding out the Amp Hour of the battery and going from there, I have seen a lot of Bluetooth speakers like this http://www.sony.co.uk/support/en/product/SRS-BTX500/specifications but they only run for 5 or 6 hours, its say its a 12.5v 2.5w input to charge it, I figure it could be hard wired to trickle charge it all the time, and the bigger battery would be better if you want to run other stuff or maybe something similar to above.

You said the DC-DC converter (charger) for it can supply 25amp max, does this charger come with the car? is this how you just charge small battery and not the traction battery? sorry for all the questions on these cars.

My Blue tooth speaker run for about 20 hours, and the surface drive runs when plugged in to the accessory socket. As I charge the Twizy and the speakers at the same time and the run time for a twizy is no where near 20 hours - more less than 2 hours, I have never needed a bigger 12v supply. But if you are running a big amp etc then yes go for a bigger battery.

The DC-DC converter is part of the charger unit, it powers the 12v battery from the traction battery to keep it topped up as you drive (it acts in the same way an alternator does in a standard car). The 12v Accessory battery is 14ah (according to Renault) but it looks just like the 12v 12AH batteries everyone else uses and I don’t figure Renault have magically made them bigger capacity (because that would be miraculous) treat it as a standard 12v 12AH.

I have been looking around, finding it hard to get something like a 20ah or 24 ah that will fit, without paying silly prices. Is it just a normal battery in there, not a sealed one? Just lead acid?

I have been looking around, finding it hard to get something like a 20ah or 24 ah that will fit

Why do you want to fit a bigger 12v Battery?


Probably because it is better to have than have not? You may never need it, but here will be occasions where you’d be glad you did. Down the line, when capacity starts to falter with age, you could be at the stage where te battery is exactly the same as a factory-fit.

Of the three bikes I use, I invariably got little more than 28 months from each, whether standard, glass mat or Gel. In 2010 I switched to a different brand, MotoBatt - which in addition to its no-maintenance credentials and good reputation, is yellow in colour. I’m still on this battery after 3 years, so that’s the route I’ll go when the one in the Twizy needs replacing. It also has a greater Ah in the same-sized package.

Solar is a great addition here for the accessory battery. I’ve yet to do the calculations to work out the best set up and system loads for the Twizy. But it does reduce the likely hood of battery failure (and the consequences of) by having that extra power source.

My MR2 I know that can sit for months on end and always starts first time, the lights could run permanently without draining and a flat battery can recharge itself in 45 mins in the day time enough to get it started even if you were in the middle of nowhere without a jump. I can also go to the beach and run my stereo and mobile office for the day without running the engine. The MR2 runs 2x 20watt panels mounted on the rear engine bay cover, the electrical system has been reworked for minimal electrical energy consumption and it doesn’t run an alternator at all, it uses fuel (LPG) purely to move the car. It revs quicker and when you work out the electrical energy consumption of a conventional car electrical system in kWh and work back to what that costs in petrol, solar panels are a much better option anyway. They were also cheaper than a new alternator after mine seized and exploded and I no longer need to worry about an unreliable rubber band like a fan belt. But then it was easy to do the calculations and set it up specifically for my usage patterns as I know my typical energy consumptions from my sustainability research. :wink:

With solar panels and the right charge controller the battery will last for many more years than expected. But it is no use using little ones say less than 10w. In fact 10w would be the minimum.

I’ve got a spare 10watt and charge controller here to test with when I have time (it’s on the golf at the moment).

I have been told that Yuasu is a good brand, have a look at this http://www.yuasaeurope.com/images/uploads/uk/downloads/Motorcycle_Battery_Application_and_Specification_Catalogue.pdf

It has all the sizes too, the high performance range looks good.

so if I use a more powerful battery how will the on board charging system see this? Will it just take longer before it starts having to use the traction battery?

People may say why did Renault not just fit a better accessory battery, but as we know, things are done because of cost.

Yuasa is one of the top brands. No I think you’ll be using the traction battery pretty much the same, unless the ignition and charging is off. I need to do some monitoring to check it and confirm it, but AFAIK as soon as you power up the ignition the DC-DC provides a set voltage and therefore the battery while the car is in use only provides of brief peak loads and voltage smoothing.

I think the charger unit is the cars worst bit of design for several reasons. Renault could have done much better with that and I believe it’s actually flawed with a programming fault or sub standard mains side components causing these cars not to charge over 248v mains input voltages without showing a problem, which of those is the cause, I haven’t worked out yet. I’m hoping to get a second opinion shortly that Renault Customer Service or Technical won’t be able to ignore, but the consensus of all the knowledgeable people I’ve spoken to, the car has a flaw.

I know there’s been cost savings on the car, and we as customers want cheep cars, but it’s a balance of is a few extra £ worth the difference or not. I totally agree with the philosophy, but once you get to know the Twizy very well technically and understand it’s flaws… Hmm.

I still think it’s a fantastic car. There’s bits of it I would have done differently. Charger fan for example. dumb place to put it. If it had been put in the dashboard with a duct to the charger, you could have a clear windscreen in the morning (from the charger waste heat) and a fan for the screen anyway by double using the same device (the reason the Twizy couldn’t have windows was by European law if it did it would need forced ventilation if it had them and it would have added cost, it could have in fact been done very cheaply). Also it’s too vulnerable a device to have where it is, it actually limits the depth of water you can take the car through.

Out of this list http://www.yuasaeurope.com/images/uploads/uk/downloads/Motorcycle_Battery_Application_and_Specification_Catalogue.pdf what one do you think would fit, and be a big upgrade?


I have measurements of the accessory battery bay, I’m not sure you’ll get any noticeable improvement using another lead acid battery, the mountings would have to be changed to put a bigger battery in. I think there would be a little gain with an Lithium battery, but I’ve yet to do the power monitoring to calculate it’s real value. I’m sure we can get something in there that is lighter and of bigger capacity. Voltage is quite key though, different battery techs have different nominal voltages. A direct change between a lead acid to lithium can actually result in lower usable capacity as a lithuim has a different nominal voltage and different 0% state of charge voltage, I have seen lithiums give less usable capacity because of that if you don’t get the maths right.

If yours is still ok I’d leave it there. Renault had to swap my accessory battery under warranty as when I got the car (260miles old) I found mine was badly expanded. I did have a charger fault though (other than the charger fault I still have with the car).

What are the measurements please?

There has got to be a bigger and better one on the link I posted above, that will fit.

I measured (in mm) the space to be 165 long 155 wide and 125 high, but you want to make your own measurements before buying anything, make sure you have clearance space to wiggle something in there (duct tape up a cardboard box the same size and try it and remember the battery won’t bend).

You also need to ensure strong mounting (as if a battery is physically bigger you won’t be able to use the original mount) and it REALLY is a must that the positive cable has on insulation on the connection that cannot be displaced in the event of the front being physically bent in an accident.

I haven’t got a handbook, do you know where I can get one, not an online version but paper? thanks