Re: GE/Sanyo Model MFC NiMH / NiCd charger

On Sun, 24 Jul 2005 11:04:41 +0900, H. Dziardziel
<hdzi@xxxxxxxxxxxxxxx> wrote:

>On Fri, 22 Jul 2005 10:59:19 -0500, Scott Willing
><NOTwilling2BSPAMMED@xxxxxxx> wrote:
>
>>I picked up this sweet little 4-cell NiMH/NiCd charger (folding AC
>>plug, 12V DC input) but have cleverly recycled the package card that
>>had the instructions. No info on the Sanyo site for model MFC.
>>
>>The unit has a bicolour LED that shows green when power is applied but
>>no cells are loaded up, and orange (both colours lit) when charging.
>>All I want to know is if it changes colour again to red, or flashes,
>>or what, when it figures the cells are done.
>>
>>I've had it plugged in for several hours charging NiMH cells (the
>>first I've ever purchased) and it just stays orange... but then it
>>only delivers 120mA / cell and the cells are 2500mAhr so maybe I just
>>haven't seen it complete a full charge cycle yet.
>>
>>BTW, where do I find the FAQ for this group?
>>
>>-=s
>
>I have a couple of Sanyo chargers (and others). Does this unit
>have a 12V input and an ac line input?

Yep, as stated, "folding AC plug, 12VDC input." To clarify, the AC
power supply is built in, and unlike most similar chargers, you can
fold the plug flush with the back of the unit so that it isn't a
challenge for packing or storage.

> How heavy is it? A light
>weight compact unit implies it not being a simple timed charger as
>does the 12V input. Is it NiMh only? Where did you buy it?

It's very light, universal voltage (100-240VAC) and also handles NiCd.
I bought it at Princess Auto, a Canadian retailer of a wide array of
surplus stuff and cheap tools, for the equivalent of about US$8.

>How did you measure the 120mA?

I didn't. That's what is stated on the back of the unit:

Output: 1.8VDC 120mAx4

> If it's a compact quick charger it
>uses pulsed charging so only an oscilliscope or professional meter
>will give true current..

I don't think that will be necessary (see below).

>Cell temperature (taking into account
>charger body temerature) may give a good idea instead . At 120 mA
>they will remain at room or charger body temp.

They did get a little warm, but I didn't note the temperature of the
charger. Next time.

>A timed charger needs fully discharged cells to start with and is
>designed for a specific cell capacity. Blinking implies a "smart"
>pulsed quick charger. They however can have problems detecting
>some cell states, lower capacity cells and just inserted warm
>cells.
>
>Blinking red would usually be a cell check in progress (several
>seconds), red a problem or a charge in progress, green charged or
>ready, and orange is very likely is just charging. Yes, Sanyo
>has the full spectrum since these are all made in China for/by
>various OEMs/resellers who seem to modify basic designs.

Typical.

>Sanyo's got several similar looking chargers out, each with
>different LEDs and functions

I'm kicking myself that I let the card with the instructions get away
on me, but thanks to the information in this forum I'm leaning towards
the conclusion that I just bought a fairly simple charger.

I've just had a look inside and the only IC's are an LM358 dual op-amp
and a Sipex SP34063 regulator wired in buck mode to provide the cell
voltage. No evidence of intelligence per se. I'll put a scope on it in
an idle moment but it's looking like this is a simple, if elegant,
trickle unit that I should probably throw in my pile of assorted NiCd
chargers. <sigh>

Thanks very kindly,
-=s

.

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