Use dummy cell in two cell battery charger?

At home I use an "intelligent battery charger" which charges cells two at a time and both must be present for the charger to work.

--------------------

THE PROBLEM ..... Sometimes I want to charge just one cell on its own.

Maybe that one cell is an AA or AAA from a single-cell MP3 player. Or maybe I have to recharge cells which have very different capacities or charge levels.

--------------------

To charge only one cell, can I put a resistor in the place of the second cell as a sort of dummy cell? If so then what values might I use?

I figure the Negative Delta V sensor would still trip correctly with one cell as it's unlikely that two cells would reach their voltage drop simultaneously.

Tech details are below. Thank you for any info.

Alex

--------------------- TECHNICAL DETAILS ------------------- INFO ABOUT CHARGER ...

The charger is a Vanson V-1000 charger which uses Negative Delta V.

The spec says AA cells are charged at 350mA and AA cells at 750mA. I read 1.45 volts across one 900mAh AAA whilst charging 2 of them. I read 1.35 volts across one 2000mAh AA whilst charging 2 of them.

Manufacturers info:

Wholesaler's info:

INFO ABOUT CELLS ....

Use mainly NiMH with some NiCd AAA cell capacity ranges from 300mAh to 900mAh. AA cell capacity ranges from 1000mAh to 2800mAh.

-------------------- END OF TECH DETAILS -------------------

Buy a charger that charges and monitors each cell individually.

Try

for a huge selection (no relationship with them; just a longtime customer). The Maha/Powerex chargers are particularly well regarded.

Carbon Zinc is a dead form factor.

Not on modern chargers.

"Battery" chargers charge individually. Even the old ones like that which you mentioned charged in parallel.

You should look into modern cell charging systems.

Take a cell, and measure its internal resistance when fully charged and when ready to avalanche over to "deadness".

Archimedes' Lever wrote in news: snipped-for-privacy@4ax.com:

Why do you think xinc carbon cells were implied? Those cell formats (AAA,AA,B,C,D) are also used for alkaline and NiCD and NiMH.

Only true if they charge each cell independently. Otherwise the risk is there.

Not true. Many charge in pairs, two series pairs in parallel for charging two or four cells at once. That's a widely standardised form, and it DOES cause charging imbalances after a while, I've got NiMH cells with this problem, and they've only been charged in one charger.

Probably true, but without carefull assessment of the problem, it's just as easy to choose a new charger with problems, as an old one. It costs more to monitor and charge each cell on its own, so unless governments enforce it to avoid waste going into landfill, there will always be chargers that offer less effective methods, and many of them will come with misleading claims to persuade people to buy them.

Archimedes' Lever wrote in news: snipped-for-privacy@4ax.com:

I don't get it... What is 'deadness'? It's not a state than any cell capable of taking a full charge is likely to 'avalanche' into.

Testing the internal resistance, perhaps by short timed pulses of high drain through known tiny resistance and montoring chages in voltage might be revealing, but I don't know enough about them to know if it's more useful than other methods.

Alex, does your charger only use NDV to detect full charge? If so, be wary because NiMH doesn't drop voltage as gas begins to be produced, as much as NiCd. One NiMH cell could be too difficult to detect to be trusted, unless the charger also monitors temperature.

Lostgallifreyan wrote in news:Xns997F43E69C28Azoodlewurdle@140.99.99.130:

Do you mean the sharp drop in NiCd at full charge? If so, bear in mind that NiMH doesn't drop so sharply, and either way you can't make the test without NDV detection telling you when to test, so you must test frequently until you detect NDV. That might need microcontrollers or other major increases in cost and complexity.

Make a cell out of a bit of wooden dowel.

Drill a hole through the wooden cell

Connect two 1N4001 diodes in series

Pass the diodes through the hole in the wooden cell

Coil the ends of the connection to the two diodes so that they lay flat on the ends of the wooden cell.

Fit the wooden cell in place of one cell, the diode "cathode" is the minus terminal.

Arthur

However, the Rat Shack charger that was mentioned IS NOT. They are the last vestige of folks still pushing Carbon Zinc cells. Do try to keep up.

Know much about cells, boy?

There is a useful life curve they all have. It varies from one cell technology to another.

Alkalines keep their full voltage (FAIAP) right up until they AVALANCHE down to near zero volts.

Other cell types have different curves.

ALL cells exhibit a different internal resistance when fully charged than they do when discharged, and beginning a charge cycle, and also at the point at which they avalanche.

The sentence was quite simple, and it takes a real dipshit not to see what was meant by it.

This is obvious.

Archimedes' Lever wrote in news: snipped-for-privacy@4ax.com:

Are you dense or what? Talking like a teacher while prating spastically of xinc carbon being a dead format, then talking of a charger in the same discussion. What is this guff of assiciation of one firm's habits? You won't solve technical problems with weird innuendos about one firm's selling habits. If you can't address the specific point raised meaninfully, don't post.

Archimedes' Lever wrote in news: snipped-for-privacy@4ax.com:

Troll. That's all I need to know, you're a troll, and unlike Phil Allison, who writes things worth reading despite his invective, you don't because unlike him, you don't have the clarity needed to stick to the point.

Archimedes' Lever wrote in news: snipped-for-privacy@4ax.com:

Yep, a troll. Thought so.

Archimedes' Lever wrote in news: snipped-for-privacy@4ax.com:

The original poster asked about the reaching of full charge, so one cell could be charged. He said his charger uses NDV to detect full charge. That has nothing to do with the cell resistance at discharge. Focus on what was asked, and be a bit more explanatory too, if you want to justify your asshat attitude. Talking like a teacher slapping a pupil fopr innattention, saying as little as possible, strining in unrelated issues the moment you do speak of more. You're no teacher. Any teacher who was that bad at it wouldn't last long in a class.

Fuck you, LostGalliRetard. Go find a tall bridge, you retarded twit.

Archimedes' Lever wrote in news: snipped-for-privacy@4ax.com:

Like I said, a troll. At least that's settled. *Plonk*.

Looks like IT has morphed, again.

-- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85.

Michael A. Terrell Central Florida

I'd like to hear more about that. The alkalines I use all gradually ramp downward in voltage. I could ship you all sorts of alkaline AA batteries with voltages between 0.8 and 1.5 volts.

--
"Liberals used to be the ones who argued that sending U.S. troops abroad
was a small price to pay to stop genocide; now they argue that genocide
is a small price to pay to bring U.S. troops home."
  -- Jonah Goldberg