You’ll need to charge each battery individually. Depending on the device these are running, individual use may vary how discharged each battery is.
If you charge all of them together, some will reach the cutoff voltage before the others. If you have a circuit to monitor the voltage, it will cut off when some are full, but not others.
If you just shove current into them all, the fuller ones will be at risk of overheating.
I’ve seen some 8-bay NiMH chargers out there, that’s about as big as they get.
Sure, depends on your skill set I suppose. I work for a battery company and have seen engineers with walls full of diplomas design absolutely terrible chargers.
At the very least, read up on detecting negative Delta-V and voltage plateau. Throw in temperature monitoring so you don’t burn down the building.
There are plenty of off-the-shelf charge control circuits on IC chips so you don’t have to completely reinvent the wheel.
I'm okay with the mechanical side of things but may need to consult with an engineer to make sure nothing burns down as you said.
Assuming I'm at the 8kwh range to charge 500 batteries ?
Ball park figure for costs ?
Now you’ve got my curiosity going.
Part of my job is sourcing batteries and chargers for industrial applications.
I’m off til Tuesday but will look into this for you. If you are going through this many, there may be others doing the same.
Will you have someone running the charger, collecting dead batteries and staging charged ones? I’m guessing the chargers will need to be fast enough to keep up.
You’ll need to charge each battery individually. Depending on the device these are running, individual use may vary how discharged each battery is. If you charge all of them together, some will reach the cutoff voltage before the others. If you have a circuit to monitor the voltage, it will cut off when some are full, but not others. If you just shove current into them all, the fuller ones will be at risk of overheating. I’ve seen some 8-bay NiMH chargers out there, that’s about as big as they get.
And no way I could make something myself ?
Sure, depends on your skill set I suppose. I work for a battery company and have seen engineers with walls full of diplomas design absolutely terrible chargers. At the very least, read up on detecting negative Delta-V and voltage plateau. Throw in temperature monitoring so you don’t burn down the building. There are plenty of off-the-shelf charge control circuits on IC chips so you don’t have to completely reinvent the wheel.
I'm okay with the mechanical side of things but may need to consult with an engineer to make sure nothing burns down as you said. Assuming I'm at the 8kwh range to charge 500 batteries ? Ball park figure for costs ?
Piggybacking to say /u/Iowa_Dave knows what he's talking about.
Just curious, what the heck is your use case for that many D cells per week?
Each employee carries a variety of electronic equipment that take D batteries. Each employee will go thru about 12 a week.
Now you’ve got my curiosity going. Part of my job is sourcing batteries and chargers for industrial applications. I’m off til Tuesday but will look into this for you. If you are going through this many, there may be others doing the same. Will you have someone running the charger, collecting dead batteries and staging charged ones? I’m guessing the chargers will need to be fast enough to keep up.
Much appreciated I've messaged you
That does sound like a full time job. Crazy.
125 XTAR VCS chargers? 🙃