Dave, the batteries are called Supreme Power 2600mA standard charge
14-16 HRS x 260mA, quick charge 4-6 HRS x 550mA. REG USA Made in China.

Hmmm. I see various web sites offering that brand, but I don't see
much in the way of comments about their quality (good or bad).

I am waiting for a friend to bring by his old NiCad charger and I will
give it ago. I will let you know how I got on.

Please do - I'm curious.

For future reference would you have an idea on how long I should charge
the batteries for using the MFJ?

Depends on the charger. In general, a fully-discharged NiMH cell will
need to be "fed" somewhere around 150% of its rated capacity in order
to reach full charge - some of the energy fed into it is dissipated as
heat and doesn't go into rebuilding the electrochemistry. The
"standard charge" recommendations you quoted are feeding the battery
at a rate of .1C (10% of its capacity per hour) for 14-16 hours, so
that's just about right.

If you're using a different charger, you'd need to determine the
amount of current being fed to each cell, divide that into the cell's
rated capacity (to get the time required for 100% capacity delivery),
and then add around 40-50%.

These calculations apply *only* to cells which are fully discharged!
If a cell is partially charged when you start to recharge it, it'll
reach full charge sooner than these calculations indicate... and at
that point the cell starts to heat up pretty rapidly.

Most of the NiMH technology sheets I've read, seem to recommend
charging these batteries at a relatively fast rate (no less than .2C,
with .5C and 1C being common) and using a temperature sensor as the
primary means of figuring out when to turn off the charge.
Zero-delta-V is often used as a secondary method, with a timer being
the final fallback.

I don't know who or how the charger circuit has been modified. I could
ask W&S what sort of circuit has been used.

That would be a good idea!

The 259/269 have a simple slow/trickle-charge circuit built in... it's
OK for NiCd cells but isn't ideal for NiMH. It would be very
interesting to know how this was modified for NiMH in the 259Z model.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Apr 2, 6:08*pm, (Dave Platt) wrote:
Dave, the batteries are called Supreme Power 2600mA standard charge
14-16 HRS x 260mA, quick charge 4-6 HRS x 550mA. REG USA Made in China.

Hmmm. *I see various web sites offering that brand, but I don't see
much in the way of comments about their quality (good or bad).

I am waiting for a friend to bring by his old NiCad charger and I will
give it ago. I will let you know how I got on.

Please do - I'm curious.

For future reference would you have an idea on how long I should charge
the batteries for using the MFJ?

Depends on the charger. *In general, a fully-discharged NiMH cell will
need to be "fed" somewhere around 150% of its rated capacity in order
to reach full charge - some of the energy fed into it is dissipated as
heat and doesn't go into rebuilding the electrochemistry. *The
"standard charge" recommendations you quoted are feeding the battery
at a rate of .1C (10% of its capacity per hour) for 14-16 hours, so
that's just about right.

If you're using a different charger, you'd need to determine the
amount of current being fed to each cell, divide that into the cell's
rated capacity (to get the time required for 100% capacity delivery),
and then add around 40-50%.

These calculations apply *only* to cells which are fully discharged!
If a cell is partially charged when you start to recharge it, it'll
reach full charge sooner than these calculations indicate... and at
that point the cell starts to heat up pretty rapidly.

Most of the NiMH technology sheets I've read, seem to recommend
charging these batteries at a relatively fast rate (no less than .2C,
with .5C and 1C being common) and using a temperature sensor as the
primary means of figuring out when to turn off the charge.
Zero-delta-V is often used as a secondary method, with a timer being
the final fallback.

I don't know who or how the charger circuit has been modified. I could
ask W&S what sort of circuit has been used.

That would be a good idea!

The 259/269 have a simple slow/trickle-charge circuit built in... it's
OK for NiCd cells but isn't ideal for NiMH. *It would be very
interesting to know how this was modified for NiMH in the 259Z model.

--
Dave Platt * * * * * * * * * * * * * * * * * AE6EO
Friends of Jade Warrior home page: *http://www.radagast.org/jade-warrior
* I do _not_ wish to receive unsolicited commercial email, and I will
* * *boycott any company which has the gall to send me such ads!

You may want to use the NiCd charger on them for a few minutes and
then move them to the NiMH charger.

Jimmie

A NiMH or NiCd cell reading of zero volts usually indicates an internal
short, caused by metallic dendrite growth. If this is the problem with
the cells, they won't respond to any ordinary attempt to charge them.
It's sometimes possible to "zap" a shorted cell (by discharging a very
large capacitor into the cell) to burn out the shorts, but you end up
with a cell that has higher than normal self-discharge and a tendency to
grow shorts again. So if they don't respond to normal charging, I
recommend tossing them and getting some new cells.

If the device has a charger designed for NiMH cells, that is, one that
charges at a fairly high rate and properly detects the end of charge,
then I highly recommend one of the newer low-self discharge cells such
as the Sanyo Eneloop. If it doesn't have a proper NiMH charger and just
pumps in a constant current charge without end of charge detection, you
should use NiCd cells because they can tolerate that charge regimen much
better than NiMH cells can. I've had very good luck with Sanyo and
Panasonic NiCd cells. Don't be suckered by inflated capacity claims
which the minor brands liberally use. Even with the better brands, the
highest capacity cells have historically had more problems with overly
fast self discharge and premature cell failure.

Roy Lewallen, W7EL