MH-C401FS charger turned to smoke.

I bought a a Maha MH-C104FS and the first time I plugged it in a did a
fast charge on the included 4 x AA 2200mA NiMH batteries, it burned out
one of the charging circuits after 10 minutes. Opened it up and found
one cooked power transistor in the constant current converter circuitry
of one of the channels. The other 3 channels still work but the
circuitry runs too hot for my liking in "fast" mode.
I bought this charger because it had good reputation on the web. Its my
first charger.

Manufactures don't give details of the charge methods, and we are stuck
with marketing babble written on the packaging. Does anyone know of a
charger that follows the known reliable methods of charging NiMH
batteries, such as described in

http://www.panasonic.com/industrial/...rgeMethods.pdf

As far as I'm aware no small charger built for charging 4 AA's utilize
the delta T method of fast charge termination. Where delta T is supposed
to be the primary termination method, not negative delta V, because then
the cell has already gone too far in the charge. There are no
temperature sensors in the MH-C104FS !

Adam

In article ,
Adam. Seychell wrote:

As far as I'm aware no small charger built for charging 4 AA's utilize
the delta T method of fast charge termination. Where delta T is supposed
to be the primary termination method, not negative delta V, because then
the cell has already gone too far in the charge. There are no
temperature sensors in the MH-C104FS !

See http://nordicgroup.us/chargers/ for alternatives.

"Adam. Seychell" wrote in message
u...
I bought a a Maha MH-C104FS and the first time I plugged it in a did a fast
charge on the included 4 x AA 2200mA NiMH batteries, it burned out one of
the charging circuits after 10 minutes.

I've been very happy with my Maha MH-C401FS. I was looking for a second
similar charger to keep in my truck and picked up a Panasonic BQ-830 based
on what I read on a comparison site on the web.

The first time I used it, it cooked one of the batteries. The second time I
used it, it cooked ALL the batteries until they ruptured and the unit was
deformed by the heat. I consider it lucky the thing didn't cause a fire. I
currently have an inquiry in at Panasonic to find out if they'll replace it.

I guess the thing to learn from our experiences is NEVER LEAVE ANY OF THESE
CHARGERS UNATTENDED!

The best chargers I have found are the expensive ($100+) units I use in my
remote control model airplane hobby. They aren't very practical for
charging loose AAs for household use, although I did buy an eight-cell AA
holder and sometimes charge eight at a time on one of these hobby chargers.
I have been using two different brands/types for a couple of years and have
never cooked a battery pack with either of them.

I was thinking the Maha charger was the best quality of the bunch of
household chargers. Now you have me wondering....

Good shooting,
Bob Scott

I have one, and never had a problem with it. I've noticed the batteries do
get quite warm when it's set to fast charge, but as soon as they charge up
they cool right down. One of the things they tell you is to make sure not
to close that plastic cover when charging batteries.

I also did a lot of research on the Net before buying that model, but I've
never used Maha batteries.

"Adam. Seychell" wrote in message
u...
I bought a a Maha MH-C104FS and the first time I plugged it in a did a fast
charge on the included 4 x AA 2200mA NiMH batteries, it burned out one of
the charging circuits after 10 minutes. Opened it up and found one cooked
power transistor in the constant current converter circuitry of one of the
channels. The other 3 channels still work but the circuitry runs too hot
for my liking in "fast" mode.
I bought this charger because it had good reputation on the web. Its my
first charger.

Manufactures don't give details of the charge methods, and we are stuck
with marketing babble written on the packaging. Does anyone know of a
charger that follows the known reliable methods of charging NiMH
batteries, such as described in

http://www.panasonic.com/industrial/...rgeMethods.pdf

As far as I'm aware no small charger built for charging 4 AA's utilize the
delta T method of fast charge termination. Where delta T is supposed to be
the primary termination method, not negative delta V, because then the
cell has already gone too far in the charge. There are no temperature
sensors in the MH-C104FS !

Adam

Robert Scott wrote:
"Adam. Seychell" wrote in message
u...

I bought a a Maha MH-C104FS and the first time I plugged it in a did a fast
charge on the included 4 x AA 2200mA NiMH batteries, it burned out one of
the charging circuits after 10 minutes.


I've been very happy with my Maha MH-C401FS. I was looking for a second
similar charger to keep in my truck and picked up a Panasonic BQ-830 based
on what I read on a comparison site on the web.

The first time I used it, it cooked one of the batteries. The second time I
used it, it cooked ALL the batteries until they ruptured and the unit was
deformed by the heat. I consider it lucky the thing didn't cause a fire. I
currently have an inquiry in at Panasonic to find out if they'll replace it.

I guess the thing to learn from our experiences is NEVER LEAVE ANY OF THESE
CHARGERS UNATTENDED!

The best chargers I have found are the expensive ($100+) units I use in my
remote control model airplane hobby. They aren't very practical for
charging loose AAs for household use, although I did buy an eight-cell AA
holder and sometimes charge eight at a time on one of these hobby chargers.
I have been using two different brands/types for a couple of years and have
never cooked a battery pack with either of them.

I was thinking the Maha charger was the best quality of the bunch of
household chargers. Now you have me wondering....

Thats what I don't understand. I cannot find any reference of others
reporting a problem with the Maha's. I've replaced the transistor
(2SA1020) with a something a bit more powerful (Zetex FZT749) and its
working again, but I feel a bit iffy doing another "fast" charge again.
I have a question, do you often charge using the "FAST" setting ?

If so have you noticed a fair bit of "warmth" from inside the charger
itself ?

I've seen the airplane hobby chargers your talking about. They are
defiantly good chargers, but as you say an overkill for household use.

I was thinking the Maha charger was the best quality of the bunch of
household chargers. Now you have me wondering....

I've got a Maha 204W (the latest & greatest), a Maha 204FS (still going
strong) and a Maha 204F which burned out its power supply a while ago. Never
had a problem with any of them damaging batteries or running too hot.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


"Robert Scott" wrote in message
ink.net...

"Adam. Seychell" wrote in message
u...
I bought a a Maha MH-C104FS and the first time I plugged it in a did a
fast charge on the included 4 x AA 2200mA NiMH batteries, it burned out
one of the charging circuits after 10 minutes.

I've been very happy with my Maha MH-C401FS. I was looking for a second
similar charger to keep in my truck and picked up a Panasonic BQ-830 based
on what I read on a comparison site on the web.

The first time I used it, it cooked one of the batteries. The second time
I used it, it cooked ALL the batteries until they ruptured and the unit
was deformed by the heat. I consider it lucky the thing didn't cause a
fire. I currently have an inquiry in at Panasonic to find out if they'll
replace it.

I guess the thing to learn from our experiences is NEVER LEAVE ANY OF
THESE CHARGERS UNATTENDED!

The best chargers I have found are the expensive ($100+) units I use in my
remote control model airplane hobby. They aren't very practical for
charging loose AAs for household use, although I did buy an eight-cell AA
holder and sometimes charge eight at a time on one of these hobby
chargers. I have been using two different brands/types for a couple of
years and have never cooked a battery pack with either of them.

I was thinking the Maha charger was the best quality of the bunch of
household chargers. Now you have me wondering....

Good shooting,
Bob Scott

Adam. Seychell wrote:
Robert Scott wrote:

"Adam. Seychell" wrote in message
u...

I bought a a Maha MH-C104FS and the first time I plugged it in a did
a fast charge on the included 4 x AA 2200mA NiMH batteries, it burned
out one of the charging circuits after 10 minutes.



I've been very happy with my Maha MH-C401FS. I was looking for a
second similar charger to keep in my truck and picked up a Panasonic
BQ-830 based on what I read on a comparison site on the web.

The first time I used it, it cooked one of the batteries. The second
time I used it, it cooked ALL the batteries until they ruptured and
the unit was deformed by the heat. I consider it lucky the thing
didn't cause a fire. I currently have an inquiry in at Panasonic to
find out if they'll replace it.

I guess the thing to learn from our experiences is NEVER LEAVE ANY OF
THESE CHARGERS UNATTENDED!

The best chargers I have found are the expensive ($100+) units I use
in my remote control model airplane hobby. They aren't very practical
for charging loose AAs for household use, although I did buy an
eight-cell AA holder and sometimes charge eight at a time on one of
these hobby chargers. I have been using two different brands/types for
a couple of years and have never cooked a battery pack with either of
them.

I was thinking the Maha charger was the best quality of the bunch of
household chargers. Now you have me wondering....


Thats what I don't understand. I cannot find any reference of others
reporting a problem with the Maha's. I've replaced the transistor
(2SA1020) with a something a bit more powerful (Zetex FZT749) and its
working again, but I feel a bit iffy doing another "fast" charge again.
I have a question, do you often charge using the "FAST" setting ?

If so have you noticed a fair bit of "warmth" from inside the charger
itself ?

I've seen the airplane hobby chargers your talking about. They are
defiantly good chargers, but as you say an overkill for household use.


I have had two MAHA chargers, and have had excellent service from both
of them. One bad experience among the thousands of users shouldn't give
you any pause. The 401 does heat the batteries somewhat, but not so hot
that I can't take them out by hand. Leave the cover open, and charge
the batteries in a cool place away from direct sunlight.



--
Ron Hunter

In article ,
"Adam. Seychell" wrote:

I bought a a Maha MH-C104FS and the first time I plugged it in a did a
fast charge on the included 4 x AA 2200mA NiMH batteries, it burned out
one of the charging circuits after 10 minutes. Opened it up and found
one cooked power transistor in the constant current converter circuitry
of one of the channels. The other 3 channels still work but the
circuitry runs too hot for my liking in "fast" mode.
I bought this charger because it had good reputation on the web. Its my
first charger.

Manufactures don't give details of the charge methods, and we are stuck
with marketing babble written on the packaging. Does anyone know of a
charger that follows the known reliable methods of charging NiMH
batteries, such as described in

http://www.panasonic.com/industrial/...onic_NiMH_Char
geMethods.pdf

As far as I'm aware no small charger built for charging 4 AA's utilize
the delta T method of fast charge termination. Where delta T is supposed
to be the primary termination method, not negative delta V, because then
the cell has already gone too far in the charge. There are no
temperature sensors in the MH-C104FS !

Adam

Ansmann

--
To reply no_ HPMarketing Corp.

"Robert Scott" wrote in message
ink.net...

"Adam. Seychell" wrote in message
u...
I bought a a Maha MH-C104FS and the first time I plugged it in a did a
fast
charge on the included 4 x AA 2200mA NiMH batteries, it burned out one of
the charging circuits after 10 minutes.

I've been very happy with my Maha MH-C401FS. I was looking for a second
similar charger to keep in my truck and picked up a Panasonic BQ-830 based
on what I read on a comparison site on the web.

The first time I used it, it cooked one of the batteries. The second time
I
used it, it cooked ALL the batteries until they ruptured and the unit was
deformed by the heat. I consider it lucky the thing didn't cause a fire.
I
currently have an inquiry in at Panasonic to find out if they'll replace
it.

I had a BQ-830 deform by heat, and the store (Costco) gave me a refund. The
new one has been fine. I noted this on my web site. I have tried defective
cells in this one, and it doesn't try to charge them.

I guess the thing to learn from our experiences is NEVER LEAVE ANY OF
THESE
CHARGERS UNATTENDED!

I agree.

"Adam. Seychell" wrote in message
u...

Thats what I don't understand. I cannot find any reference of others
reporting a problem with the Maha's. I've replaced the transistor
(2SA1020) with a something a bit more powerful (Zetex FZT749) and its
working again, but I feel a bit iffy doing another "fast" charge again. I
have a question, do you often charge using the "FAST" setting ?

I think I used the fast-charge setting once. I have enough batteries around
to use the slow charge.

If so have you noticed a fair bit of "warmth" from inside the charger
itself ?

Not in the Maha, but definitely in the Panasonic (which was fast charge
only).

I've seen the airplane hobby chargers your talking about. They are
defiantly good chargers, but as you say an overkill for household use.

They are designed to charge battery packs of NiMH or NiCad, or lead-acid
batteries. They work great for charging a whole bunch of identical
batteries at once if you have a way to hook them up properly. I've used
them extensively without one single problem!

Good shooting,
Bob Scott