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somebody
01-01-2005, 04:52 PM
Hi Guys,

First Question:
After some recent overseas shopping, I have purchased myself a cordless soldering iron, which runs of 3x AA batteries. At the time I thought that it would be a good idea to get rechargable batteries to go with it, so I bought a pack of 4x 2300mAH batteries to go with it. I obviously wasn't thinking properly at the time, because the only charger I have is a Sony one which is designed for 2100mAH batteries, on a 6hr charge cycle. These batteries are 4hr charge, at 2300mAH. Will there be an issue if I charge the batteries using this charger? (the charger is designed to shut itself off after the batteries are fully charged).

Second question:
The cordless soldering iron is designed to take 3x 1.5v AA batteries. The rechargable ones are rated at 1.2v. The salesman assured me that once the batteries are fully charged, they will actually provide 1.5v rather than the 1.2v specified. Now I think about it, I think I was a bit silly to believe him, but could he be telling the truth?

Final question:
I have a cordless mouse which came with rechargable batteries - AAA at 600mAH. The charger is part of the receiving unit, and takes 14hrs to charge a pair of batteries. I have discovered that the 5v supply from the PS2 ports stays on when I shut down my PC, but not turn it off at the wall, so I can effectively charge the batteries without having to listen to the droning sound of the PC overnight. If I interupt the charging process, will that cause permanent damage to the batteries? They are NiMH batteries.

godfather
01-01-2005, 08:05 PM
First Question:
After some recent overseas shopping, I have purchased myself a cordless soldering iron, which runs of 3x AA batteries. At the time I thought that it would be a good idea to get rechargable batteries to go with it, so I bought a pack of 4x 2300mAH batteries to go with it. I obviously wasn't thinking properly at the time, because the only charger I have is a Sony one which is designed for 2100mAH batteries, on a 6hr charge cycle. These batteries are 4hr charge, at 2300mAH. Will there be an issue if I charge the batteries using this charger? (the charger is designed to shut itself off after the batteries are fully charged).

The charger should be fine. They usually use a dv/dt sensor that looks for the minute change in voltage/time whan the cell reaches full charge, so the extra capacity will still be accommodated.


Second question:
The cordless soldering iron is designed to take 3x 1.5v AA batteries. The rechargable ones are rated at 1.2v. The salesman assured me that once the batteries are fully charged, they will actually provide 1.5v rather than the 1.2v specified. Now I think about it, I think I was a bit silly to believe him, but could he be telling the truth?

Porkies, I am afraid. Fully charged NiMh/NiCd batteries approach 1.4v, while alkaline exceed 1.5v fully charged. However it's unlikely to be an issue as the current that can be delivered is usually the key, and the rechargeables should be OK there. If the iron was designed to only use Alkalines at 1.5v, it would perform very poorly once the Alkaline batteries were partially discharged, and thats unlikely to be the case.

Final question:
I have a cordless mouse which came with rechargable batteries - AAA at 600mAH. The charger is part of the receiving unit, and takes 14hrs to charge a pair of batteries. I have discovered that the 5v supply from the PS2 ports stays on when I shut down my PC, but not turn it off at the wall, so I can effectively charge the batteries without having to listen to the droning sound of the PC overnight. If I interupt the charging process, will that cause permanent damage to the batteries? They are NiMH batteries.

Not enough info on the charger type, but if they also use dv/dt then its unlikely to be a problem. Also its likely that they just use a fixed current in a simple charge system, which will also be unlikely to be affected by interrupted charge. Given the very low cost of rechargeable cells, its not a problem anyway if their life was reduced by a few months, is it?

somebody
01-01-2005, 08:33 PM
A huge thanks Godfather - your information has brought a huge sigh of relief.


First Question:
After some recent overseas shopping, I have purchased myself a cordless soldering iron, which runs of 3x AA batteries. At the time I thought that it would be a good idea to get rechargable batteries to go with it, so I bought a pack of 4x 2300mAH batteries to go with it. I obviously wasn't thinking properly at the time, because the only charger I have is a Sony one which is designed for 2100mAH batteries, on a 6hr charge cycle. These batteries are 4hr charge, at 2300mAH. Will there be an issue if I charge the batteries using this charger? (the charger is designed to shut itself off after the batteries are fully charged).

The charger should be fine. They usually use a dv/dt sensor that looks for the minute change in voltage/time whan the cell reaches full charge, so the extra capacity will still be accommodated. excellent - I was worrying that I would have to buy a new charger.



Second question:
The cordless soldering iron is designed to take 3x 1.5v AA batteries. The rechargable ones are rated at 1.2v. The salesman assured me that once the batteries are fully charged, they will actually provide 1.5v rather than the 1.2v specified. Now I think about it, I think I was a bit silly to believe him, but could he be telling the truth?

Porkies, I am afraid. Fully charged NiMh/NiCd batteries approach 1.4v, while alkaline exceed 1.5v fully charged. However it's unlikely to be an issue as the current that can be delivered is usually the key, and the rechargeables should be OK there. If the iron was designed to only use Alkalines at 1.5v, it would perform very poorly once the Alkaline batteries were partially discharged, and thats unlikely to be the case.
phew - the iron states that if you use other batteries, performance might not be as good as using Alkalines, however it does not say you cannot use other battery types. I have since found however, that these particular rechargable batteries are physically larger, and don't fit in the iron - their external diameter is slightly larger, which is a bit of a problem.



Final question:
I have a cordless mouse which came with rechargable batteries - AAA at 600mAH. The charger is part of the receiving unit, and takes 14hrs to charge a pair of batteries. I have discovered that the 5v supply from the PS2 ports stays on when I shut down my PC, but not turn it off at the wall, so I can effectively charge the batteries without having to listen to the droning sound of the PC overnight. If I interupt the charging process, will that cause permanent damage to the batteries? They are NiMH batteries.

Not enough info on the charger type, but if they also use dv/dt then its unlikely to be a problem. Also its likely that they just use a fixed current in a simple charge system, which will also be unlikely to be affected by interrupted charge. Given the very low cost of rechargeable cells, its not a problem anyway if their life was reduced by a few months, is it?
Fair enough - they came with two sets of batteries, so even if I ruin a set I've still got some for backup - and if that fails, alkaline AAA batteries aren't too expensive either.

The unit has very little information as a)the information sheets are all written in Chinese which I cannot read, and b)does not have much information regarding technical specs at all - in any language. I do know that the charger says it delivers 120mA at 5V, while the batteries say that they take 14hrs to charge at 60mA. The batteries appear to be connected in series within the charger. The charger seems to stop charging (a red led goes off) after about 6-7 hrs, so it must have some kind of sensor in it.

Jeff
03-01-2005, 01:15 PM
One thing you may to keep in mind about your cordless soldering iron batteries. To create high temperatures it will need to pull alot of current from your batteries. This in turn will heat up your batteries and might "cook" them. Depending on how offen you intend to use it, you could be replacing your rechargable batteries a bit more often that what you would like.

Also they could go flat in the middle of a job. So you would have to make sure to have spares aways with it. If you don't use that often you may find your spare battries have gone flat.

The best cordless soldering iron I have seen was a gas powered one. Don't know if you can still get them.

Anyway it might be more cost effective just to buy a bulk pack of Heavy Duty batteries.

godfather
03-01-2005, 02:36 PM
Anyway it might be more cost effective just to buy a bulk pack of Heavy Duty batteries.
Oh no. Batteries marked as "Heavy Duty" would be lucky to do a single solder joint.

Alkaline are needed, not the "Heavy Duty" labelled zinc-carbon ones. Always seems strange that "Heavy Duty" type is not nearly the output of Alkaline, which are not labelled "Heavy Duty"...

DSE presently have 40 x AA Alkaline for $20. They are good quality.

However, I have (some years ago) had a rechargeable Wahl battery iron that went for about 7 years with steady use, on trickle charge 24/7.

The NiCd/NiMh batteries available today should have low enough internal resistance to ensure that they do not get overly hot, and if they do they are getting stuffed anyway. It may be one case where NiCd could be marginally better than NiMh.

somebody
03-01-2005, 07:13 PM
I won't be using it that often, so it shouldn't be too much of an issue. Any larger soldering projects, or if I am at my desk, I will use a corded soldering iron.

keng
03-07-2007, 05:49 PM
Hi Guys,

i have been reading the application manual of EnerSys Genesis lead acid battery. i have few question wanna ask.
1. what is permanent damage?
2. what is hour rate?
3. what is C/2?
4. what is specified charge regime?

Graham L
03-07-2007, 06:36 PM
"permanent damage" is just that. :( A battery will appear to reach full charge very quickly. But it will reach full discharge very quickly, too. This happens if the battery is maltreated (discharged below 10.5 volts or so -- causing sulphating -- or if it's charged with a "battery charger" of the sort sold to ruin car batteries. Over charging causes the electrolyte to be lost through the pressure release caps of the cells, and it's all over.)

The "hour" rating is simple. A 20 amphour (Ah) lead-acid/gel battery will give one amp for 20 hours. The "C" value for it is 20. But it won't give 20 amps for one hour, or even 10 amps for 2 hours. The manufacturer will give a table or graph of the nonlinear time vs current characteristic of a battery. (NiCd and NiMH, LiX, etc have a different rating system, because of the different chemistry).

C/2 for a 20 Ah battery would be 10A. For a 7Ah battery it would be 3.5A.

A simple way to charge a gel battery is to use a voltage regulated supply at 13.8 V. You can leave the battery on that permanently. "Proper " chargers use a microcontroller to give a constant current until the battery reaches about 14.5V, then a constant voltage at 13.8 until the current drops to about c/20. There might be (ideally) compensation for the temperature.

Have a look at the Battery University (www.batteryuniversity.com) site.

tweak'e
03-07-2007, 06:43 PM
battery operated soldering iron?

better off getting as gas powered one. much more usufull.

Graham L
03-07-2007, 06:46 PM
I wouldn't want to work on an expensive PC board with a gas soldering iron. The battery ones have a place. But if I was doing a lot of "field" repairs I'd use a couple of gel batteries to give 24V for a Weller temperature controlled iron. :D

tweak'e
03-07-2007, 08:49 PM
so true, fortunatly most of my field repairs where never to hitech ;)

keng
03-07-2007, 08:52 PM
thanks Graham,
i very appreciate this information. it help me lots.
i have one more thing wanna know,
what is C10, 10 is small letter.

zqwerty
03-07-2007, 09:31 PM
For instance the C/10 charge rate for a 500mAh NiCd cell would be 50mA.

This is known as the trickle charge rate and the cell will not be damaged if it is left on this rate for a long period, later model cells have higher trickle rates than this, sometimes as much as C/3.

Read the specs.

keng
04-07-2007, 05:59 PM
sorry zqwerty. actually want i want know is what is C10. 10 is inferior.
thanks

Graham L
05-07-2007, 04:38 PM
C with a subscript of 10 might be a capacity (Ah) rating on a 10 hour basis. A battery which will give 1A for 10 hours will have half the capacity of a battery which will give 1A for 20 hours.