Boost your electric windows for 20 quid

[Fefeu52]

Hi guys,

I 've owned my S3C for 7 years. Just after I bought it, I remove door cards to clean and grease all the mechanism of the electric windows to boost it up. All the electric connections was cleaned etc. But, that was not much better after. Since 7 years, the passenger side works well but is pretty slow ; the driver side is lazy and has great difficulties to reach the top without manual help. Before modifying anything, I timed them to compare :

Driver side down : 4 sec
Driver side up : 11 sec and stop 5mm before the top
Passenger side down : 4 sec
Passenger side up : 7.5 sec, stop on top

Here is my idea : When I put 13.5V at the beginning of the electric windows circuit, there is, at best, between 9V and 10V at the electrical engine do to poor harness and loss in connections, switch and wiring resistance. If I could level up the voltage at the beginning of the harness, voltage at the end will be higher and power loss will drop as current will be lower.

So I bought a DC to DC converter to go from 12V to 16V. I choose a 12A model but in reality, a 8A one is enough (3.5A by side)



Cost : 18e on Chinese market place.

To easily pickup the power in the main board, I bought a fuse extension lead for 2e



After 5 or 10 minutes to prepare this set-up :




Now it's time to test the windows :

Driver side down : 2.8 sec
Driver side up : 4 sec stop on top
Passenger side down : 2.8 sec
Passenger side up : 3.5 sec, stop on top

Perfect I just put a white point with paint to be sure not to invert the fuse extension way and close the panel

Edited by Fefeu52 on Tuesday 15th July 13:21

[GreenV8S]

It feels like you're overcoming the problem rather than fixing it, but that's an ingenious way to raise the operating voltage.

[phillpot]

A couple of relays, a decent 12 volt feed and the jobs a good 'un

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Fefeu52]

I know this "solution" since years and i've never done it because I think it's a bad idea to put 2 relays with several wires and connections in a door that bangs 2 times every time I drive the car.... not to mention the humidity inside the door and the wire added in each hinge. This mod take a long time to do properly and add trouble sources in the harness. My solution takes 10 min to prepare and install, the cost is pretty the same (pretty nothing), there is no modification of the genuine harness, and If there is a problem with the converter, in 5 seconds, I remove the system, put the fuse back in place and all come back to genuine. No doubt this system will help in a lot of nearly old cars with lazy electric windows.

[TwinKam]

I would be happier with the concept if you weren't 'over-driving' the frail old motors so much; converters with an output of 13.8v are available.

[Fefeu52]

Don't worry. If the voltage at the motor is only 10V when the fuse is feed at 13-13.5V, of course when you feed the fuse at 16V... There is not 16V at the motor. Only 13V feed the motor which is just the rated voltage. There is about 0.8 Ohm resistance in the harness.

[Oldred_V8S]

Fefeu52 said:

I know this "solution" since years and i've never done it because I think it's a bad idea to put 2 relays with several wires and connections in a door that bangs 2 times every time I drive the car.... not to mention the humidity inside the door and the wire added in each hinge. This mod take a long time to do properly and add trouble sources in the harness. My solution takes 10 min to prepare and install, the cost is pretty the same (pretty nothing), there is no modification of the genuine harness, and If there is a problem with the converter, in 5 seconds, I remove the system, put the fuse back in place and all come back to genuine. No doubt this system will help in a lot of nearly old cars with lazy electric windows.

If the relays are mounted in the footwells or under the dashboard and not in the doors there are no extra cables passing through the door edge and no vibration damage to the relays.