Looking for the battery pack for the Realistic Pro 35 (20-136)

[spdfile1]

I started a collection of vintage scanners that I used to own back in grade school and the Realistic Pro-35 (Catalog #20-136) was one of them. I picked one up and that works and looks great but the original battery is shot of course. I've spent some time searching on the internet to see if anyone might still sell an aftermarket replacement with no luck. If there's one to be made anyone know where I can find it. Thanks
Scott (N4SYR)

 

[doctordialtone]

If there's one to be made anyone know where I can find it. Thanks

Here:
https://www.batterytex.com/product/...canner-20-136/cnb-20003-10457083-wwn-cnb20003

 

[bb911]

From what I can tell from the pic on ebay (link at bottom), the Pro-35 must have been made for Radio Shack by Uniden. It appears to be identical to my Uniden BC 200xlt - only my BC 200xlt has 200 channels. I replaced the NiCD pack in my 200xlt with a 7.2v, 1650 maH NiMH batt many years ago. (I purchased it from The NICAD Lady Co. which some Hams and scanner buffs living near Riverside, CA may remember. Now out of business). It still works but it can't possibly be at 1650 mAH any longer because it discharges too fast and doesn't hold a charge when sitting idle for as long as it should. I see lots of the BC 200xlt complete batts and inserts online (BP 200 - which also fits several other BC scanners), but the prices are outrageous ($40 to 80). Pro -35 on ebay and BC 200xlt.

 

[kruser]

If that battery pack is like the 200XLT battery, it can be opened easily and rebuilt with new cells for under $20 dollars.
One thing I don't know is if the internal charging circuit will handle NiMH cells or burn them up. I rebuilt a few over the years but always used NiCD cells. They always worked just fine and it was much cheaper than the crazy prices they get for a new pack today.

I used to get the flat top cells from Batteries Plus. They would even spot weld the solder tabs on them and shrink wrap them together in the same configuration as the originals cells, all for free. You just needed to solder the original cells power wires to the new cells and screw the housing back together and you were in business.

I'm pretty sure BP still sells the flat top cells today in both chemistries. They are standard AA size cells but called flat top cells. A pack needs 7 cells and BP cells the original 900mA size cells for a whopping 0.99 cents! So, for $7 dollars, you could rebuild a pack at 900mA. They also sell an 1100mA flat top AA cell for maybe 25 cents more but are usually out of them. Or if you want to take the chance that the internal charger will shut off before damaging a NiMH cell, they sell those as well but more around $2 dollars each.

Anyone handy with soldering, this is an easy project for these older battery packs.

 

[spdfile1]

Here:
https://www.batterytex.com/product/...canner-20-136/cnb-20003-10457083-wwn-cnb20003

I saw that one but the price is higher than I’d like. However Begger’s can’t be choosers lol

 

[spdfile1]

From what I can tell from the pic on ebay (link at bottom), the Pro-35 must have been made for Radio Shack by Uniden. It appears to be identical to my Uniden BC 200xlt - only my BC 200xlt has 200 channels. I replaced the NiCD pack in my 200xlt with a 7.2v, 1650 maH NiMH batt many years ago. (I purchased it from The NICAD Lady Co. which some Hams and scanner buffs living near Riverside, CA may remember. Now out of business). It still works but it can't possibly be at 1650 mAH any longer because it discharges too fast and doesn't hold a charge when sitting idle for as long as it should. I see lots of the BC 200xlt complete batts and inserts online (BP 200 - which also fits several other BC scanners), but the prices are outrageous ($40 to 80). Pro -35 on ebay and BC 200xlt.

Your right Uniden did make there own and probably Radio Shacks. Maybe I can get away with using a battery for the BC200xlt!!!!!!!

 

[bb911]

One thing I don't know is if the internal charging circuit will handle NiMH cells or burn them up.

I don't want to open up my battery holder due to it's age, but I recall modifying the internal circuit by adding a resistor across an existing one (the only resistor in the circuit large enough to solder to, as I recall) in order to decrease the charge time for the higher mAH NiMH cells. Also, the circuitry triggers the low battery indicator unnecessarily early with the original cells and the NiMH cells. There's a mod for that, but most users simply continue to run the radios after the indicator appears for x amount of time, until the signs of a need to recharge appear. I don't run my radio very long after the indicator appears.

A pack needs 7 cells..

Only 6 cells for the 7.2 volts pack

...and shrink wrap them together in the same configuration as the originals cells...

Yes, and the 6 cell configuration is not in a square shape, but rather an oblong one, in order to fit in the holder (a tight fit).

 

[kruser]

Only 6 cells for the 7.2 volts pack

I need to open one back up from my 200xlt. I swore I counted 7 cells!

I also did something with one of my 200XLT packs so I could use NiMH in it. I don't recall what I did but it worked and those NiMH cells still work to this day after several years of charging them. That's charging with the old OEM unregulated Uniden wall warts that put out near 19 VDC under a no load condition.
I'm thinking the 200xlt pack may have a zener diode in it to regulate the charge voltage and probably a resistor to help keep the current down. It's been a long time though so I could be thinking of something else.

edit: I looked in one and you are right, six cells. I saw the three on top offset between the rear three which made it look like there were four cells in the rear of the pack.

 

[spdfile1]

I ended up purchasing a BP-200 battery pack which works for the Uniden BC200XLT. There were plenty available compared to none available for the Realistic Pro-35. It's still 7.2V but 1800 mAh (instead of 600 mAh) and it's a NiMH. What I'll end up doing because the Uniden BP-200 battery has these flares on one side is using a dremel tool to cut/shave them down to get them to where they are on the Realistic battery so it's a good fit. So by using the Wall Wart I've got for this new NiMH battery will it make the battery unusable? I wanna say the wall wart is 12V at 800 mAh if I remember correctly.

 

[spdfile1]

Ended up getting the Uniden Battery (BP-200) for there version of the Pro-35 which is the BC200XLT. Had to use a dremel to thin out the rails because the battery slid onto the radio a little too snug. Also trimmed the flared parts of the battery so it would fit. Not the best work but it's almost perfect and works!!!!! By the way the Pro-35 owner's manual mention's the replacement Radio Shack Battery for the Pro-35 can (or could) be ordered at your local Radio Shack. It was part # T20-003. Not sure if the replacement batteries had that model number on it or not because I know the battery that came with the Pro-35 has the radios model # on it.

 

[kruser]

Good deal getting the 200XLT pack to fit and work!
I'm not sure on the charging part. See @bb911 post above. He recalls bypassing a resistor in order to charge the higher capacity NiMH cells.
I remember doing something but not sure if that was it or not. As far as the wall wart goes, 12 VDC at 800 mAh sounds about right. I have six of them and they all put out between 18.5 and 19.5 VDC with no load according to the open circuit voltages I'd marked on them.
Inside the batt pack is a small charging circuit that probably regulates the voltage. Current would be regulated by the resistor @bb911 mentioned as well as the current limit of the wall wart. I seem to recall a zener diode in one or more of my packs that set the charge voltage. I don't recall that voltage though.
You can just let one charge for a day or two and keep an eye on the voltage at the contacts on top of the pack. If you feel it getting really warm, it could be a sign it is overcharging the NiMH cells.
The only bad thing is there is no way to tell if a cell has shorted other than the pack no longer supplying decent power.
I did look at a couple of the packs I'd rebuilt years ago now and I did use NiMH cells in some of them. Those packs still seem to work fine to this day so it's very likely the charging circuit will not harm them as it is. It may just take twice as long to fully charge a pack compared to an old NiCad pack.

 

[bb911]

I have a vintage"BC XLT Taper Box II" made by MetroWest (apparently out of business) that is inserted between the stock charger and the radio (it plugs in right behind the radio). It was designed so that it sits at the same level as the radio and acts as a "stabilizer". It wasn't mass produced by MetroWest, a small company. The enclosure is an aluminum hobby box that was sold by electronic suppliers. (The brand which made/makes those 2 color aluminum boxes in a wide variety of shapes and sizes - plastic boxes, too).

The leaflet that came with it states, "Due to the current regulator circuit in the Bearcat battery pack, the charge level of the batteries cannot be sensed from outside the pack. Furthermore, the level of charge current, while limited by this regulator to the recommended 60 ma , cannot be reduced to a taper level at the end of a charge cycle, nor does the Bearcat module or pack circuitry end the charge cycle - they just keep pumping 60 ma into your NiCads. The Taper box II will determine the end of charge (by timeout) then "tapers" the charge by time modulating the 60 ma input current. Since the pack will not allow a 15ma holding current, the Taper Box provides 60 ma for 25% of the time (thus the pulsing LED on the pack in this mode) for an equivalent 15 ma continuous current. According to NiCAD manufacturers, this is just as effective at maintaining the charge on the NiCADS".

The taper box timer is set for 15 hours (+/- 10%) and works fine with NiMH packs. The resistor mod that I made inside the internal batt circuit increases the charging current and reduces the charge time to about 12 hours. (My NiMH pack is rated at 1650 maH). Plugging the supply into the taper box before plugging it into the batt pack starts the timing cycle. Doing the reverse puts the charger immediately into the taper charge mode.

 

[kruser]

I have a vintage"BC XLT Taper Box II" made by MetroWest (apparently out of business) that is inserted between the stock charger and the radio (it plugs in right behind the radio). It was designed so that it sits at the same level as the radio and acts as a "stabilizer". It wasn't mass produced by MetroWest, a small company. The enclosure is an aluminum hobby box that was sold by electronic suppliers. (The brand which made/makes those 2 color aluminum boxes in a wide variety of shapes and sizes - plastic boxes, too).

Good info! This is a product I never knew existed back in the day.