Re: Building a HCHII grid charger
 

Hummm, If that was the case then I should not have been able to power on the fan using the charger.

I'll have it opened up tomorrow and have a closer look at the diode.
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Re: Building a HCHII grid charger
 

Agreed.

Re: Building a HCHII grid charger
 

Edit: also just for reference yesterday I did a 100km trip back roads(hilly and sharp bends) 100km/h limit with the avg mpg reset at start. The car averaged 5.8 L/100km or 40.5 mpg. I was not hypermilling in any way probably averaged 70/80km/h

FYI, updated my schematic with the intended relay.
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https://cimg2.ibsrv.net/gimg/www.gre...f4f191a273.png
Harness schematic with relay

Re: Building a HCHII grid charger
 

So it seems the above resulted in the same issue....

I considered what the cause could be and decided to try a diode between the pwm generator and the fan. This did stop the fan running when the car was started but also stopped the pwn generator from running the fan.

I then decided to connect the 12v permanently and instead switch the pwm wire with the relay. Finally the whole thing worked as expected!!! Woohooo! :D

A short 5min test with the charger 200v supply turned on I seen a steady 295mA and a rise from 176 to 178v.

​​​​​​I also built a new enclosure for the pwm generator, see a new schematic and some photos below. (uploading)
https://cimg3.ibsrv.net/gimg/www.gre...19faccccbb.png
Final working schematic

https://cimg8.ibsrv.net/gimg/www.gre...b4368ffba5.jpg
https://cimg8.ibsrv.net/gimg/www.gre...f91ca403e2.jpg
https://cimg9.ibsrv.net/gimg/www.gre...25104977e0.jpg
https://cimg1.ibsrv.net/gimg/www.gre...5d60698435.jpg
Voltage before charge
https://cimg6.ibsrv.net/gimg/www.gre...b49e52a237.jpg
Voltage after 5 mins

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Re: Building a HCHII grid charger
 

looking good.

Re: Building a HCHII grid charger
 

So onto charging and discharging.

I have a 36 hour window twice a week.

​​​​​​Planning to start 6pm and have till 6am two days later.
1. 6:00pm - 6:30pm 3x reconnect 60sec 12v and start the car between to get highest SOC via car.
2. 6:30pm - 12:00pm grid charge, expected 180v -> ~190v note voltage and current.
3. 12:00pm - 8:00am continue charge overnight and expect little to no change in voltage. Current should be minimal >30ma by the morning.
4. 8:00am - ~4:00pm discharge 60w till 157v and 40w till voltage drops below 90v
5. 4:00pm - 8:00pm grid charge expected 90v - <157v
6. 8:00pm - 8:30pm 3x reconnect 60sec 12v and start the car between to get highest SOC via car.
7. 8:30pm - 12:00pm grid charge, expected 180v -> ~195v note voltage and current.
8. 12:00pm - 8:00am continue charge overnight and expect little change in voltage(maybe up to 198v). Current should be minimal >30ma by the morning.

Steve I'd appreciate your input. I think I have the sequence correct. Maybe some steps I have planned too little time or too much time. And I'd also like input on the discharge voltage. Thanks!

Re: Building a HCHII grid charger
 

I'm I'm seeing about 13.5 hours of grid charge time following the 12V reset/charges? I would add 4+ hours to that and cut your discharge time short for the first charge.

Confirming you have 220V rated bulbs, so current based on wattage should be about half expected. If that's the case, I would run the highest wattage bulbs possible down to 158V. Up to 100W down to 145V, 60W to 132V and 40W to 106V. Those are maximums. You can always choose to go lower. If you stick with your plan, you may not be able to do a meaningful discharge at the current that 30W of power yields.

Limit total discharge time below 132V to 5 hours no matter what voltage you hit.

#2, you should peak higher, though you may not in the 5.5 hour given.
#3, you should be > 190V, and the only way current will reduce is if the voltages raises above the power supply voltages, i.e., if they perform like normal power supplies, they will deliver their constant 292mA of current until their max voltage is reached.


#5, increase to 5 hours to ensure > 20% SoC. The first 1-2 hours of charging won't yield any usable capacity.
#8, see #3.

Try to allow about 30 minutes of sit time prior to driving after the final topping charge. During your first drive put it in neutral during engine braking/braking until you see the SoC bar move down by 1. You want to minimize/prevent regenerative braking when the battery is poked full of juice. The car will sense it, but there is a small delay where the car may spike the pack with 30-50A when it's full before it realizes it's full. Best to avoid that.

Re: Building a HCHII grid charger
 

I've created a new list for myself with your input, it's linked below as an xls to calculate your key times based on a start time and duration of each step.

Based on this I'll likely need to do it over the weekend.
https://cimg2.ibsrv.net/gimg/www.gre...0d2463747e.jpg

Re: Building a HCHII grid charger
 

Concerning step 5 in the sheet, do not be surprised if the voltage exceeds 157V.

The 30 minute wait prior to driving is optional, but it gives the voltages a chance to settle. Wait or not, the most important thing is to limit regenerative braking until the SoC meter drops, so you have some confidence that the car has a grasp of the true state of the battery.

Best results are obtained by logging time, voltage and current on a reasonable frequency - maybe hourly for charging and every 30 minutes for discharging. A mutimeter in 10A ammeter mode can be put in series with the discharge bulb. With time, voltage and current log data, you can calculate the capacity of the pack. If you couple pack log data with the 11 tap voltage readings, you can identify possible problem subpacks.

Wrapping my head around the 220V bulbs... a 100W bulb will likely only pull about 350mA in the operational range of this exercise (based on 450mA @ 220V). That's 16 hours of discharge time assuming a perfect pack. A 60W bulb will be about 0.2A at the prescribed change over voltage. Given that, I would skip the 40W bulb and just use the 60W bulb. Again, if you can get higher wattage bulbs OR put two 100W in parallel, I would recommend that to ensure you can do some meaningful work in the allotted discharge times allowed.

Again, you will only see a decrease in the charging current if the battery voltage hits the 200V peak of the PSU assuming they operate likely normal CC LED drivers. Since they are so much higher than the rated 90V, I would not be surprised by abnormal behavior above 180V. Along those lines, if you do not hit a peak voltage while maintaining the 292mA or so of charge current, the battery may never reach full charge, and discharging below 145V may be risky due to perpetual imbalance and excessive polarity reversal of the least full cells.

Re: Building a HCHII grid charger
 

I'll do my best to log regular voltages and current during charge/discharge and for now put my multimeter in line during discharge(wanna figure a way to use the charger display in both directions.)

I'll pay particular attention when charging to max voltage to see that the mA remains high.

​​​​​​I'll likely get two 100w bulbs running in parallel till 157v.

Also could it be a quick option to take the car out for a drive after charging and drain as much as I can using neutral during breaking to speed things up?