Yes, the one bad apple will cause a problem since it forms part of the
circuit. It not only doesn't contribute but likely puts a drag on the
others. If they're more than a few years old you might want to replace
all of them as NiMH battery capacity has increased about 30% or more in
the past few years. Whatever you bought might not be the same capacity
as what you had and that's not good either. Best that the capacity
matches. I use Panasonic 2300 mah from BJ's (good price) but I know
that 2500 mah are available now and possibly even higher.
Incidentally, the batteries will self-discharge whether they're in the
flash unit or not. For high capacity batteries you may have to allow
3-4 hours for a full charge even with a high quality charger such as the
Maha MH-C204F. Longer for a cheap charger. I don't know this seller
but here's the Maha. Also available elsewhere with a 12 volt lighter
adapter and in kit form with 4 to 8 batteries.
<http://cgi.ebay.com/Maha-Powerex-MH-C204F-Intelligent-Battery-Charger-New_W0QQitemZ280020245505QQihZ018QQcategoryZ50511QQssPageNameZWDVWQQrdZ1QQcmdZViewItem>
I own two of these and I think there are others on the list with Maha
chargers as well.
I don't know what kind of charger you have but the Maha charges in
pairs. Generally a bad cell shows up as a pair where the charge light
never changes from red (charging) to green (charged). By marking and
pairing the two from the side that never reached full charge with those
from the side that did reach charge you can tell which cell is the bad
one. eg; assume cells numbered 1, 2, 3, 4 and that number 2 is bad (but
you don't know it yet) Assume that they are paired 1/2 and 3/4 in the
charger. Pair 1/2 never reaches charge after even 4 or 5 hours. You
know one of them is bad. Mark cells 1 and 2 and then place them back in
the charger paired 1/3 and 2/4. Since 2 is the bad cell the 2/4 pair
will not reach charge and you know the bad cell is 2.
Chuck Norcutt
They'll
Candace Lemarr wrote:
> Thank you, Chuck.
> I just took them to the local battery store, and they tested them for
> me. All but one were good. Could be that one bad apple was spoiling the
> bunch ;-)) I try to make sure I take them right out of the charger when I
> use them for the FL-50. It's good to know that I can just "top them off",
> that makes a lot of sense, i.e., I have them in the FL-50, but haven't used
> it for a day or two, so they are draining themselves.
> I did go ahead and pick up the lithium batteries as well. It will be
> interesting to see how those work. Have a young lady who wants her senior
> portraits done up on the Grand Mesa (for those of you familiar with G.J.),
> so I want to be sure I have everything I need, and then some. (now I just
> have to remember not to throw those in the charger!!!!) hahahaha
> Thank you for the info...there you go again being so wise ;-))
> Candace
>
>
> ----- Original Message -----
> From: "Chuck Norcutt"
>
>
>>It could be that the NiMH are old and tired but it may also be that you
>>don't understand the oddities of NiMH batteries. While they pack a lot
>>more power than an alkaline or NiCad cell they also have a very high
>>self-discharge rate. Just sitting on the shelf doing nothing they lose
>>about 3% of their charge *per day*. Let them sit around for a week or
>>two and they begin to look like weaklings.
>>
>>If it's been more than a few days since you've used them it's always a
>>good idea to top them up. Topping up was a no-no for NiCad cells
>>because of their "memory effect" but is a necessity for NiMH.
>>
>>The memory effect on NiCad cells is that if you only drain them to, say,
>>half power then they come to "remember" that half power setting as the
>>zero power setting. The more frequently you top them up the less
>>capacity you get from them. Resolving the problem requires multiple
>>full dicharge cycles to reset the "memory". NiMH do not suffer from
>>this problem but they're happy to use up the power all by themselves.
>>
>>Chuck Norcutt
>>
>>
>>Candace Lemarr wrote:
>>
>>
>>> The thing is...the NiMH battery is not giving me much life at
>>>all...perhaps they are tired and I need new ones.
>>
>>
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