For an inexpensive option you could see if the Vapcell U2 is still available? Mine works pretty well with NiMh AA cells, I charge at 1A or 0.5A though.
I wonder if it would be more electrically efficient to have the solar panel charge 12v Pb Acid or a battery of LFP cells then take the c.12v and use that in a 12V charger?
Assuming your panel is 12V, you’re going 12V>5v charger input> charger converts to 4.2V to charge the lithium cells>5v usb output>NiMH charging.
Possibly one of the solar charging gurus can chime in.
Not many chargers do it that way, I have the Ansmann Powerline 4.2 Pro which start with the selected current, make a pause of 10 minutes and charge 1 h with 200mA, then it shows full.
Dunno if the C980 also use Top-off, but the times zoulas mentioned are only realistic with low-capacity-cells, not very empty cells and a much to high charge current. And the to high times he stated for every multi-chemistry-charger is also not realistic.
OK, it´s your decision. But the -dv/dt termination don´t works with very low charge current.
I dunno if you know this page, there are some information about the strategies
Yes, I have observed that in the past, but I never understood why until now. The Gyrfalcon All-88 would often keep going until the 10 hour limit and then stop. I will use higher amperage in the future to prevent this. However, I will still try to use the lowest effective amperage for termination. And I will study that HJK explanation, thank you.
From HJK about how the Powerex MH-C9000 charger works:
The charger charges until the voltage increases, then it changes to a top-off charge for two hours. The battery is reported ready when the main charge stops.
So it seems likely that, when your C980 charger says “Done” after 20-30 minutes, it’s not really done. It just says that it’s done, but the battery isn’t really full yet.
Jep, bt not sure whether the C980 do it the same way. In the manuals of the C9000 and C9000 Pro the top-off-charge is mentioned, I don´t find that in C980-manual.
I have the C9000 Pro but I´m not sure it uses Top-off, even it´s mentioned. HKJ shows the typical temp raise at the end of NiMH-charging is missing with the C9000 while my C9000 Pro (own experience) show it clearly.
But overall, zoulas charging times are not very realistic, except the reasons I mentioned are fact
This isn’t relevant for my C-cell tests, but one of the top USB-powered NiMH AA/AAAchargers on HJK’s list is the Woyum ZK6. It charges the slots independently, has selectable currents, and has good termination criteria.
However, I can’t find these for sale anywhere in the US.
I’ve been in touch with the Woyum guy, and it seems like they’re still making them. I’m guessing that there’s a market for these?
Well, given that they are supposed to be good, I’m thinking about selling the Woyum ZK6 here in the states. They’re sending me a sample soon, and I will test it and report back.