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What type of batteries should I use?

Pascal666

Aug 20, 2012
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I only use my fiber cable test set every other year or so. Charging them the day before I need them doesn't seem to work. It looks like the batteries self-discharge over the intervening years and cannot be recharged.

The units came with 4.8v 600mAh NiCd battery packs (4 AA cells) soldered to the PCBs inside each sealed unit and 6v 300ma chargers. The different units use two different battery pack configurations, one flat and one square.

I'd like to replace the battery packs but am having trouble figuring out what type to use. Any suggestions?
 

jpanhalt

Nov 12, 2013
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NiCd's are about the worst for self discharge. Newer NiMH are very good, but after a year, you may need to charge them. I use Sanyo eneloop. There are other brands that also claim very low self-discharge.The ones in my models last for at least 6 months and are still usable, but I still recharge them before flying.

Is there any current draw during storage? A little trickle can do a lot over 12 months.

John
 

Pascal666

Aug 20, 2012
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I doubt there is current draw in storage. Each unit has a power switch.

By "after a year, you may need to charge them" do you mean they will no longer take a charge if I do not charge them yearly or they simply will have no charge left after a year?

I don't mind the batteries being fully discharged after sitting for a couple years, I would expect that, but I need a type that can then be recharged. It looks like NiCd's can't be recharged after sitting dead for years.
 

jpanhalt

Nov 12, 2013
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I forget the exact details, but let's say a four-cell battery pack is made of 2300 mAh batteries. After six months storage, I recharge them, and they take something like 300 mAh, i.e., 13% loss. One could certainly use them at that point, but why risk a $1000+ model when it is so easy to recharge. They are supposed to keep charge for a year, and I suspect that is true. I should also note that even after only a week or two of storage, my charger will show a minimum of about 200 mAh added.

I would not be concerned that they would become flat and non-chargeable after a year.

John
 

Pascal666

Aug 20, 2012
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Over what time frame would you be concerned?

Would I be able to use the original chargers? Though I use the word loosely, as far as I can tell they are really just dc power supplies. Is it possible to overcharge NiMH's?
 

jpanhalt

Nov 12, 2013
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Over what time frame would you be concerned?

I am always concerned. That is why I test things before relying on them.

Would I be able to use the original chargers?

Don't see why not. When I bought mine, I just bought batteries, not a charger.

Though I use the word loosely, as far as I can tell they are really just dc power supplies.

Loosely? What else are you thinking of?

Is it possible to overcharge NiMH's?

Yes, don't do it.

John
 

Pascal666

Aug 20, 2012
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I am always concerned. That is why I test things before relying on them.
I meant how often would I have to take them out of storage to charge them so I don't have to worry about them not taking a charge next time I need them.

Loosely? What else are you thinking of?
All of my other chargers monitor the charge level of the battery or battery pack and automatically shut off once it is full.

Yes, don't do it.
So if I just connect the new battery packs to the dc power supplies, how will I know when they are full?
 

davenn

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Sep 5, 2009
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Originally Posted by jpanhalt
Yes, don't do it.
So if I just connect the new battery packs to the dc power supplies, how will I know when they are full?

John is telling to use a proper NiMH charger

Dave
 
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