You don't HAVE to, but the current is so low, there's no point in swapping to a lower wattage bulb.

 

Ok thanks. I will continue with 100W bulb

 

I discharged the battery from 186V to 158V it took 7 hours 50 minutes. As you wrote, I did not change the bulb. And the battery started to drain faster and faster. I will present my records

10.50- 157.9 V
10.59- 156.7 V
12.13- 150.3 V
14.22- 124.8 V
14.54- 110.9V
15.12- 108.2V

I unplugged the bulb, I waited a few minutes. And I checked the battery level. Pointed out 116 V. In that case should I plug the bulb again?

 

1) 10.50 = 50 minutes past 10 am?
2) It took 4 hours, 22 minutes to discharge from 157.9V to 108.2V?
3) Absolutely not. Once the target voltage or time limit is reached, you are finished. NiMH voltage increases when a load is removed, and it will seek nominal voltage. The pack will eventually continue creeping up towards 158V when all the cells are truly healthy. It likely won't make it back there, but you don't want to wait to find out.
Charge for 25 hours and repeat.
7 hours, 50 minutes at about 350mA (estimated average) means you only extracted about 2750mAh or about 1/2 the rated capacity (5500mAh).
You pulled another estimated 1100mAh out below 158V at about 250mA (estimated average).
The second cycle should see an even longer discharge time to 158V and a shorter discharge time to 106V.

 

1,2) yes


Ok, I connected the charger. The battery after a few minutes indicated 160 V. I will continue to charge according to your instructions. Here I would like to thank you for your quick advice.
I appreciate every hint. So THANK YOU

 

LOL... I literally got the Windows Blue Screen of Death as I clicked the post button. Glad it made it.

The initial voltage rise is usually very rapid. As it continues to rise, it will slow.

Terminate charge at the first of:

25 hours
35°C (pulling it back from 40°C, assuming ambient of about 25°C)
a 0.5V drop from the highest voltage observed.

Do not be surprised if the voltage peaks at a higher level this time.

 

I charged the battery for 25 hours. At the end of charging the battery was at 189.2 volts. I left the battery for 4 hours without charging and without the bulb. After 4 hours the battery was at 183V. At this point, if I start discharging, will it affect the results? At the previous discharge, I connected the light bulb at 186V And it was right after the battery was fully charged

 

It will affect it, but it's hard to say how much. When batteries are full, they lose charge the fastest, so it will affect the results, and there's something of a "surface charge" that adds a little bit when discharging immediately after charging.

For consistency, I recommend you charge it the shorter of it hitting 189.2V again OR 90 minutes, then immediately proceed with discharge.

 

I connected the charger for 40 minutes. The voltage rose from 183 V to 188.8 V. And immediately I connected the light bulb. The voltage also quickly droped down . So I left the connected light bulb and i will check the voltage after 7 hours and 50 minutes

 

That should help get the data on a comparable level.

Hopefully, you're going to get frustrated with the 15 hours it takes to get to 158V