# NiMH cell charging

E

#### Engineer

Jan 1, 1970
0
Perhaps some of the experts here could address this - I am not a
battery expert!
We have two digital cameras, both Canons - an A75 and an SX100IS.
They gobble up AA MiMH cells, particularly the SX100IS which uses only
two. I have one NiMH charger and one old NiCAD charger.
I also have a variety of NiMH cells, from green "no name" ones to
state-of-the-art Sanyo "eneloop" types, with some other brands in
between.
Some questions:
Can I charge the NiMH cells in the NiCAD charger? I think this
charges them more slowly as they don't get as hot as in the NiMH
charger.
Could I even leave them in the NiCAD charger to stay fresh? Not so
could regulate the input AC voltage to turn it into a trickle charger
(but NiMH's might not like that, either.)
So, all comments or suggestions elcomed... also any other other
proven, established NiMH lore or sources!
Thanks for all replies
Cheers,
Roger

B

#### Blarp

Jan 1, 1970
0
Perhaps some of the experts here could address this - I am not a
battery expert!
We have two digital cameras, both Canons - an A75 and an SX100IS.
They gobble up AA MiMH cells, particularly the SX100IS which uses only
two. I have one NiMH charger and one old NiCAD charger.
I also have a variety of NiMH cells, from green "no name" ones to
state-of-the-art Sanyo "eneloop" types, with some other brands in
between.
Some questions:
Can I charge the NiMH cells in the NiCAD charger? I think this
charges them more slowly as they don't get as hot as in the NiMH
charger.
Could I even leave them in the NiCAD charger to stay fresh? Not so
could regulate the input AC voltage to turn it into a trickle charger
(but NiMH's might not like that, either.)
So, all comments or suggestions elcomed... also any other other
proven, established NiMH lore or sources!
Thanks for all replies
Cheers,
Roger

Charger: if it is an old < C/10 charger - no problem.
(I am doing it for years now, occasionally forgetting to take the
cells out etc. Very bad procedure, but does not seem to hurt cells
much)

If it is a fast charger - don't! delta V is different.

Most batteries fail in cameras due to Ri being too high, not due to
lack of capacity. Failing batteries may work well in e.g. a radio, but
not in the camera.

I seem to observe that *lower* capacity batteries perform *better*
with respect to Ri and lifecycle.

E

#### Engineer

Jan 1, 1970
0
You need to know this!

C is the cell's capacity in mAh. This is usually right there on the cell.
not very high capacity, compared to recent cells.)

If you charged the cell at 50mA, that would be a 0.1C charge rate.

Indeed, yes... a bit arcane!
Typical NiMH's today (2008) are 2100 mAH so "0.1C" would be 210 mA.
I should check my Sanyo charger - my guess is that it exceeds "0.5C",
i.e. an amp, or so.
Still looking for a Maha/Powerex MH-C9000 charger.
Cheers,
Roger

U

#### UCLAN

Jan 1, 1970
0
William said:
Thomas Distributing is a good company, but you can find it cheaper
elsewhere.

I've been a Thomas Distributing customer ever since I had an intermittent
problem with a Maha battery charger and they sent me a new one (next day),
and didn't request I send the faulty one back. You can't beat their customer
service. Plus, they usually include batteries, battery cases, and charger
travel cases and cigarette lighter plugs with their chargers. Lowest price
isn't always the best deal.

U

#### UCLAN

Jan 1, 1970
0
William said:
Agreed, but the price difference is big enough to consider buying elsewhere.

Really? A C9000 and deluxe case is $65 including shipping at Thomas. Newegg wants$66 with shipping but no case. The cheapest Amazon vendor wants $65 including shipping, but again no storage case. 17StreetPhoto wants$67.40
including shipping, but no case. Thomas is looking good to me.
I buy most of my rechargeables from Thomas. They have good prices and good
deals.

I bought a dozen of the new type low-discharge NiMH AA cells from Thomas.
Love them. I'll never buy regular NiMH cells again.
If you need lead-acid batteries, try www.batteryplex.com.

Don't use 'em, but thanks.

U

#### UCLAN

Jan 1, 1970
0
GMAN said:
Hey UCLAN, would you suggest the MH-C9000 or the MAHA MH-C801D ????

I guess to me the only advantage with the C801D is the 8 cell capacity? The
drawback is not car charging.

And the extra cost. Main question is do you *need* an 8-cell charger? If so,
get the C801D, and get a cheaper charger for the car. The heavy duty power
supply for the C801 is nice. I used to have a MH-C808M charger that had the
same type of supply. The C801 is the Cadillac of chargers, no doubt, but
unless you need the 8-cell capacity, I'd go with the C9000.

U

#### UCLAN

Jan 1, 1970
0
GMAN said:
Good suggestion, then if i needed more capacity i could just in the future buy
a second one.

One more consideration: The C801 and its power supply require about FOUR
times more bench space than does the C9000.

U

#### UCLAN

Jan 1, 1970
0
GMAN said:
But technically does it do a better job or is the firmware and its capabilities
very similar to the C9000?

Dunno. Have neither. I get by just fine with my ol' C401FS. I didn't like
the cell contacts in the 808. Don't know if the 801 uses the same contacts.

As I said, if you need 8 cell capability or want to spend 50% more money,
get the C801. Otherwise, go for the C9000. JMO.

Visit http://www.mahaenergy.com/store/viewItem.asp?idProduct=423 and
http://www.mahaenergy.com/store/viewItem.asp?idProduct=422 and compare
the two. Why not compromise and get the C800S?

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