Charging question

[HoDo]

I just want to confirm: You should never charge your batteries in the scanner ALWAYS OUTSIDE the scanner (better to blowup a $30 charger than a $500 scanner). So I bought 12 Energizer 2500 batteries and a Maha MH-C401FS charger to do the job. So should I always just run the scanner on battery power and never use the wall charger, or if I want to save the battery power, take the batteries out of the scanner and then plug it into the wall? If you plug it into the wall with the batteries installed it will start the charge process and stop it when you unplug then restart it again when you plug in, and isnt that bad for the batteries? Shouldnt I charge, then completely discharge all the time to keep the battery capacity to the fullest?

 

[MarkWestin]

Hello,

Good Question.

Your plan is good.

There is a switch in the battery compartment "Alkaline or NiMH". Just set the switch to Alkaline. Then you can plug the AC adapter in and not worry about overcharging your batteries. I am using the same charger and batteries that you are. I always run the batteries down (almost) completely before recharging them. Also your batteries will have a longer life if you charge the in the slow (5 hour) setting (more charge cycles before they won't charge anymore) Heat is the enemy of your battery.

Mark

 

[rhutch]

Just move the switch in the battery compartment to Alkaline and it shuts off the charging circuit. NiMH batteries don't have any type of "memory effect" so you can charge them any time. I run mine using the AC adapter when I can I really don't see any harm in it.

 

[John_M]

HoDo Wrote:

Shouldnt I charge, then completely discharge all the time to keep the battery capacity to the fullest?

I don't beleive that you have to discharge a battery completely before recharging
(NiMH). But, I have read that if you do it extends the life of the battery (Charging Cycles).

 

[HoDo]

So switch it to Alkaline and it turns off the charging, then I can plug it into the wall and not worry about it charging the batteries as I am listening. Is that what you guys do have it plugged in with it set to alkaline? It would only be a problem if you had alkaline batteries in and had the switch set to NiMh and then they would what, blow up or something?

 

[rhutch]

Probably overheat and leak all over and in the worst case start a fire.

 

[HoDo]

I called Maha and they said it is okay to charge 2500 mah batteries on fast charge since it charges at 1 amp per hour and a fast charge will be 2.5 hours and it wont hurt the battery at all. Slow charge will be 5.5 hours. I think I will still do it on a slow charge so I wont have any problems with overheating or hurting the battery.

 

[jpm]

I myself completely have batteries dischared before I charge them up again.

 

[Navycop]

I have a PRO-93. It is suppose to have a "Black" battery holder (alkaline) and a "Yellow" (Nimh) battery holder. I got it used so it didn't come with the Yellow one. I had alkaline batt. in the black holder. After lisening for awhile with it hooked up to AC power, I opened the battery compartment for some reason (after disconnecting it from the power). THere was alittle bit of WATER and the words inside where smudged off. Is this a concern??? The batts were brand new. I don't see a switch except for the battery holders being different colors. It still works though...
Thanks.

 

[MarkWestin]

Pro-93 Battery Holder

Hello,

This might not have been the best place to ask this, but since you did, I will try to answer as best I can. There is very little difference between the Black and yellow battery holders. The Yellow one has a third contact (which is connected to the second contact which is next to it) The battery box has three contacts. The third one is used only for the charge function. Having your unit plugged in with alkaline batteries in the black battery holder will not affect the batteries in any way. When alkaline batteries leak the fluid is alkaline (obviously). You can test the liquid by putting some vinegar in with it and then watching to see if it bubbles. If no bubbles, the batteries didn't leak. While I have seen unused batteries leak, You can see a discoloration on the plastic wrapper that is dark and nasty looking. One scenario I can think of would be if it was very warm and humid outside and you took your unit there from a cool (air conditioned) area where it had been for some time. I used to have to store my camera in a non air conditioned area to prevent the lens from fogging up for this reason.

I hope this helped at least somewhat.

Mark

 

[Navycop]

That sounds about right. It was in an air conditioned space then outside (humid) to another a/c space. It just freaked me out when I saw the inside of the battery compartment. So I do need the yellow holder to charge? I did buy some rechargable batteries.
Thanks.

 

[MarkWestin]

Battery Charging

Hello,

When I had my Pro-95, I cut the third terminal off the yellow battery holder so that I wouldn't have to worry about the scanner charging the batteries. A second battery holder is convenient, but I would just get another Black one. I never charge batteries in the scanner. I use the Maha (Powerex) MH-C401FS battery charger(s) (I have two of them) Each can charge from 1 to 4 batteries at once. It has two settings: slow (5 hours) and fast (1 hour). I normally only use the slow setting because on fast the batteries get hotter than I would like. I had a Powerex 2200 mah battery split its wrapper while charging on fast speed, so I don't do that any more. Also the batteries will have a longer life (more charge / discharge cycles) if they are charged on the slower setting. One reason for not charging in your scanner is if a cell blows, you only potentially damage a $40 charger, not your $$$ scanner. I am using the Energizer 2500 mah batteries (about $19.00 for 8 at Wal-Mart) with great battery life at minimum cost. A Google search for this charger will return several dealers and some reviews.

Mark

 

[John_M]

You can buy yellow (Charging) battery holders through RadioShack. I bought a couple extra for my Pro-96. Just go to your local RS and have them order one for you.

 

[Al42]

I called Maha and they said it is okay to charge 2500 mah batteries on fast charge since it charges at 1 amp per hour and a fast charge will be 2.5 hours and it wont hurt the battery at all. Slow charge will be 5.5 hours. I think I will still do it on a slow charge so I wont have any problems with overheating or hurting the battery.

It won't "hurt the batteries" to charge them at a 1 Amp rate, but they are designed to be charged at a 1/4 Amp rate (C/10). But the slower the charge the less heat generated, and the less heat the longer the batteries will last.

So it's your choice, but I never recharge batteries at more than C/10 and I've had batteries last for 4 or 5 times as long as they're supposed to last.

 

[Voyager]

NiMH batteries don't have any type of "memory effect" so you can charge them any time.

NOT TRUE!

NiMHs are LESS PRONE to memory effect than NiCADs, but they are not immune to it.

Joe M.

 

[DPD1]

NOT TRUE!
NiMHs are LESS PRONE to memory effect than NiCADs, but they are not immune to it.

Yes, I've found they both can suffer from the effect... Sometimes you can bring them back by forcing them to drain down as far as you possibly can. But doing that each time to begin with definitely helps.

Dave
-DPD Productions - Featuring the TrainTenna LP Gain RR Scanner Antenna-
http://eje.railfan.net/dpdp/

 

[Al42]

From Batteries in a Portable World (Chapter 2, Page 3):

The NiCd battery is least affected by repeated full discharge cycles.
Several thousand charge/discharge cycles can be obtained with this battery
system. This is the reason why the NiCd performs well on power tools and
two-way radios that are in constant use. The NiMH is more delicate with
respect to repeated deep cycling.

I can't find another document of his, but he also dispells the "memory" myth - it has more to do with overcharging NiCds than with any memory. (Cells not fully charged tend to get overcharged in fixed-time chargers. More modern chargers - which came out at about the same time as NiMH cells - tend to stop charging when the cell is fully charged.)