Here we go, I'll use my 700mAh AAA NiMH battery instead. That's only 2400 joules. If the JT can charge the UC from 0 to 2.6 volts, and then from 0 to only 1.5 volts that would be amazing. That's only 1.5 days to do that.

Darn, my AAA is not fully charged. It's 1.27 volts. I just read that the maximum recommended charging current for a NiMH is its rating. That is, if its rating is 700mAh, then it's okay to charge it at 0.7 amps, which is what I'll do. That should get it charged in no time.

I just realized what gadget was saying. He does not discharge the UC all the way because it's not as efficient charging something near zero volts. That makes sense. I'll charge the UC to about 1 volt with a power supply before using the JT, and use the JT to charge the UC to 2.6 volts. At 600 farads, that's 1730 joules. Do that twice & it's way over cop>1.

The AA has been charging a 610mA for about 25 minutes now. That's more than enough since it nearly charged to start with.

Paul

Quote from: PaulLowrance on December 10, 2009, 12:44:02 PM
Darn, my AAA is not fully charged. It's 1.27 volts. I just read that the maximum recommended charging current for a NiMH is its rating. That is, if its rating is 700mAh, then it's okay to charge it at 0.7 amps, which is what I'll do. That should get it charged in no time.

Paul,

Normally a battery is recommended to charge at its 1/10 of its Amperhour capacity i.e. in your case charge it with 70mA for 10 hours if you wish a normal treatment.  Otherwise you abuse the battery, its durabilty etc.
Even so called quick chargers do not give the same charge current as the Ah capacity number, max a few times higher than the 1/10 Ah rate, so do not charge yours with higher than say 200-270mA and notice its temperature too.

Gyula

I did. The temperature only went to 80F, but it was only on for 25 minutes. When I leave it on my battery charger, which is at 90mA for these AA, the temperature is far higher than 80F. I think the 1/10 rating is for long term battery life. Charging it 610mA is something I wouldn't do all the time.

Paul