Thanks, I already designed a fan control with a little trick. Normally no High Voltage on charger connector, only when switched on the 12V from supply, and totally disconnect the Fan from vehicle's 12V, because the grid charger has automatically switch between 700mA and 300mA charging mode. ( below 150V DC, charge 700mA and topping at 300mA )
IPU Fan driver

 

ah, then you are greatly more capable with electronics than I am.

I probably have more experience than you do with NiMH batteries. You can run 700mAh up to 185V with no problem. The pack's nominal voltage is 158V. It will always be higher than 158v if it has any charge in it at all. A completely discharged pack should go over 150V in seconds when charging at 700mA.

Pack should be cooled at all charge currents.

 

Thank you,
I admit your knowledge in NiMH batteries. I prefer digital technology.
So You say, i run to 185V at 700mA and after switch to 350mA mode?
How much is its voltage when it is totally discharged? 132 or 145.2V (1 or 1.1 Volt / Cell) ? Can i use deep discharge? (0.8V / Cell)

Here is the charger's controller:
Dual stage charger controller from
Mike Dabrowski's idea

 

Ah... I see you used the 99mpg.com design as a basis. Good. IIRC, that design runs them both for 1050mA and then cuts out the 700mA to top off with 350mA. If you go with 1050mA, I would go to 187V before cutting to 350mA.


Yes. 700mA (or 1050mA) to 185V (187V) and then cut to 350mA. Peak voltage varies from pack to pack as well as temperature. 192-195V is typical, can be as high as 200V on a freshly reconditioned pack.


For grid charging purposes, terminate charge the sooner of 8800mAh input or peak voltage for 8 hours.


RESTING voltage of a completely discharge pack will typically be very near nominal, 158V. For reconditioning purposes, discharge to 158V at max current, 132V @ up to 500mA, 106V@ 300mA max.


Example:


1) Grid charge to sooner of peak voltage for 8 hours or 8800mAh input.
2) Discharge to 158V at maximum current you can use (typically 1-2A).
3) Discharge to 132V at 500mA max.
4) Discharge to 106V at 300mA max.
5) Repeat 1-3
6) Discharge to 66V at 300mA max.
7) Repeat 1-3 and 6 as needed.


If you record the times and currents in each phase, you can compute capacity and see any improvements.

 

Yes. Mike's webpage is a good base.
This method same as the per stick reconditioning, but higher voltage and higher threshold voltages I finish my grid charger and maintain my original pack.

Thank you so much for the helping and instructions.

Chris.

 

Mike did some amazing work. he's completely out of it now... IIRC, he has the Chevy Bolt pure EV now.


Good luck!


Steve

 

Wow pure EV... ! Mike is an amazing man! Very accurate and persistent.
So thank You again!

Chris