DIY Open Source EV Charger

[jackbauer]

Water cooled resistor

[bones007]

I love your water cooled resistor, so illusive - but so obvious. Super idea.

[NiHaoMike]

For another design, what about half wave rectify both sides of the 240v AC line so the negative output would be connected to neutral? (For 120v use, you could either half wave rectify it or revert to a bridge rectifier.)

[jackbauer]

One problem there is the very high ripple on the dc that results from half wave rectification

[apowers]

I found this while looking for something else. But someone might find it useful.
The appl note for the 3906 seemed promising.
Battery Charge Management

[NiHaoMike]

Originally Posted by jackbauer

One problem there is the very high ripple on the dc that results from half wave rectification

Half wave rectifying both sides of 240v is essentially full wave rectification.

[jackbauer]

Yes if both waveforms happen to be 180 degrees phase shifted. However with this design it will run on any ac voltage from 90v to 260v as long as the battery full charge voltage is lower than than 90% of the dc bus voltage at whatever ac input. eg rectified 240v ac gives about 320vdc so will charge from 32v to 288v. half that on a 120v ac input.

[NiHaoMike]

Originally Posted by jackbauer

Yes if both waveforms happen to be 180 degrees phase shifted. However with this design it will run on any ac voltage from 90v to 260v as long as the battery full charge voltage is lower than than 90% of the dc bus voltage at whatever ac input. eg rectified 240v ac gives about 320vdc so will charge from 32v to 288v. half that on a 120v ac input.

Use a buck/boost design that dynamically switches between buck and boost operation.

[jackbauer]

yep that can be done. as my battery is only 96v and single phase ac mains in Ireland is 240v its not required. However i will look at a buck-boost type design once i get the present unit up an running and work out the bugs.

[jackbauer]

Well with the car back together i decided to finish up the charger. Just some metalwork. Naturally i was short one bolt!!! Will hopefully be installing the charger and batteries this week. By the way my apologies to the op i didnt mean to hijack the thread!