Solar Charging!

A friend said to me, and now I am going to claim it for my own.

Could the roof not have had a solar panel fitted that would either charge when idle, or help power the car when moving easing drain from the battery.

Then it got me thinking, ages ago i remember seeing panels you could buy tha plugged into car ciggie lighters, could that not somehow be modded in?

I don’t have a twizy yet and also not a auto electrician but if the car is plugged in charging, it the engine disabled? If this is the case then a panel that charges at work or elsewhere could be a fairly simplish mod?

It could be hard wired or maybe somewhere there is already an item that is a solar panel tha has a 3 pin socket attached.

Hows this for blue sky thinking?

It might make sense to keep the 12V battery fully charged - if it discharged, you’d have trouble starting the Twizy. And there might be some advantage to trickle charging the main battery to avoid it ever becoming fully discharged. However, as a major source of power, particularly while on the move, there really isn’t enough space on the roof to make a significant real-time contribution. A Twizy typically draws 2 to 3 kW while cruising, and much much more when accelerating or climbing. My house roof is 60% covered with solar panels which, on a very sunny day, only generate 4kW max.

OK Question answered.

We’re gonna need a bigger roof! :lol:

Might be worth checking some of the other threads on this as it has been covered before.

But as ecofunckytavel states you need a big roof on a car to make any difference. A twizy roof will take 100W solar panel, assuming no problems with weight.
The charger draws 10amps at 220v ie. 2200W. So if the Sun is in the the right position and no losses you would need 22 twizy roofs to charge the car! More like double due to the angle of the sun, losses etc. Also the cost! A 4KW house system including installation is about the cost of a basic Twizy.
So basing a full charge costing about £1 then you can recharge every day for approx 18 years! Uk weather means in the winter the 4KW system would not produce enough power in a single day to recharge the car. Summer no problem even this summer.

However for the 12V system then a 50w panel would be fine even in the UK if parked out side and not in the shade.

Again I think I will leave it there.

I’m about to buy a Twizy for use in an off-grid part of Spain. I have about 1,600W of solar panels and about 1,200Ah of 12V batteries, which is more than enough for current domestic use. I want to be able to ‘divert’ the solar power (which runs though a regulator) to the Twizy instead of charging the home batteries and then have to run it through an inverter to generate 240V AC power, which the Twizy charger would then convert back(!) to DC for the car battery. Can anyone confirm that the Twizy battery is around 50V? If so, do you think I can charge it with a 48V DC current? Or maybe 60V is better. The panels are 12V but I can run them in series to produce 12V, 24V, 36V, etc.

Good luck finding where to tap into the charge circuit without by passing the bms.

Certainly an interesting project.

The Fisker has a solar panel on the roof to power the elektronics of the interior.

A standard Twizy main battery shall be charged with 57.4 volts maximum.
You can not charge with 60 volt but yes you can charge with 48 volts but it does not get the battery fully charged.

To be able to charge your battery then you can connect the solar panel to the + and - on the Sevcon controller. This is the main power cord out of the battery box. To achieve this as there are 3 things that are important. you have to use diode between on the Sevcon contacts and Solar panel (so you do not get power up the solar panel from the battery). you must also use a contactor that activates charging only after the Sevcon controller has activated the out contactor in the main battery. and finally you have to have the ignition key in on position when it should charge.

this is the easy way to do it.

the difficult and more proper way to do this you must be able to manipulate the can-bus to activate the charging contactor and then connect the solar panel in on the charging cable between the charger and the battery. that it is no easy job to do, but not impossible :slight_smile:

I would probably rather have used a DC-AC inverter and then used the twizy own charger. much easier :slight_smile:

@kennethnilsen69 Very useful and interesting information. The problem I see with the DC-AC and into the Twizy is that the current from this route will not always be 10amps. Is there a way to limit the current being drawn by the Twizy?. It will take longer to charge but would be a better match to most Solar setups.

well i meant only DC-to AC inverter method when charging from a solar panel that is permanently installed home or for example at a cabin. Then I suppose surely a battery bank that supplies the inverter with the power so then it should be able to give Twizy charger the 2,000 watt that it needs.

I am not aware of a way to adjust the Twizy charger so that it charger with lower amp.

This method can not be used by a solar panel mounted on the Twizy.

Hi !
I am also in the same problem. I am on a solar Pv 2 kW system and it is not wise at all to draw the system at 2kW to charge the twizy.

It is not wise for my inverter, not wise for my house battery, and even not optimal for the twizy battery itself as it is always better to charge slow if you have the necessary time, and I have.

My question 1: if someone already open a twizy charger to see how to control its charging capacity, like insert some device to lower the current ?

The charger of course have to adapt itself to the batt level.
It’s a switching supply system.

Maybe insert an impulsion counter at gate pin of IGBT, use some TTL ic to skip % ON state ?

Another question 2 : when charging normally, what components are active on CAN bus ? Charger, battery, something more ? Main controller too ?

Question 3 : we can find cheap PV charger on AliExpress, voltage totally adjustable, compatible lithium ion, with good quality. I never get into the battery itself.
Why not just insert a cable inside the battery just before the charging/power out relays ?

With these options it would just need a special cable + a plug. Don’t know how the bms would behave if we don’t give them any charging info, but normal bms are autonomous, maybe they would be active too ?

Thanks !