396 charger ?

[BigC801]

I was looking at the other thread on this but people started getting mad, so ill just ask here, is it safe to use a 6v 1000mha dc car charger for my scanner in the truck, i saw that uniden is selling the same one for several scanners, i just dont want to fry my scanner with to many amps. Thanks

 

[consys]

The scanner will only take the amps it needs. The rating (1000mA) of the charger is the maximum it can supply without damage to itself. So, for the 396 the charger must be at least 800mA per the numbers on the case.

I haven't done it with the 396 yet, but this logic never caused me any grief with three other scanners, and I never owned the "factory" car charger for them.

 

[BigC801]

Thank you, thats what i thought but wanted to hear someone eles say it before i started using it again ty for the responce

 

[slicerwizard]

The 396T is fussy about the voltage of any external supply connected to it. One of the reasons for this is that it doesn't have a good regulator to control the charging rate of its batteries. Instead, it depends on the external voltage supply being very close to six volts, which will then result in its NiMH cells getting about 240mA pushed through them (which is roughly C/10 for today's AA NiMH cells)

Somewhat higher voltages (like ten volts) won't hurt the 396, but the CPU will refuse to work with them (no full poweron and no battery charging) and will instead display "Illegal Voltage" on the LCD.

The main criteria for an external supply for the 396 is _regulation_; the voltage must remain near six volts under all loads. These loads range from about 70mA with the scanner "off" and no charging in progress to about 450mA with the scanner on, backlight on and fully discharged cells being charged.

Any regulated six volt supply capable of delivering 500mA or more will work fine with a 396T. If battery charging is not used (charging switch set to ALKALINE or no cells installed) a 250mA or better regulated supply can be used.

Anyone considering the use of an external supply in a vehicle should be aware of the fact that if rechargeable batteries are installed and the charging switch is in the Ni-MH position, the CPU will initiate a 14 hour charge cycle each time external power is supplied (e.g. each time the adapter is plugged in or when the vehicle is started). Overcharging of NiMH cells in this manner will eventually ruin them.

 

[BigC801]

ty, yep thats why my batteries only last a few hours now im sure, wish they would make a better batt charger in these but o well thats why i keep my old one in there i guess, thanks for the reply.

 

[ems170]

I use a radioshack multi-volatge dc-dc plug. I have it set on 6V. I have used this since I got the radio last year. I have had no problems at all with it. Your best option is to keep a couple sets of batteries and not use the radio as a charger. Buy a smart charger for your batteries so you dont fry them. I have had the same NMH batteries for 3-4 years now and I still get about 6-8 hours on a charge in the 396, let them run till the radio shuts off every time, then fully charge. So When I am in the house I use the house adaptor and The car adaptor inthe car. But again I never use the radios charger, no sence having a battery pop or overheat and ruine my $500 battery charger when I can pick one up for about $15 at walmart. As an end note as you know NMH batteries are not that cheap so the added life of the batteries basicly pays for the charger itself.

 

[Randall]

I was looking at the other thread on this but people started getting mad, so ill just ask here, is it safe to use a 6v 1000mha dc car charger for my scanner in the truck, i saw that uniden is selling the same one for several scanners, i just dont want to fry my scanner with to many amps. Thanks

make sure the voltage is right and the polarity, as long as the current rating is as high or higher than what the radio calls for it will work. so if the original power source was 6 volts @ 500 ma with + tip polarity you can also use one rated at 6 volts @ 750 ma as long as the tip polarity is still + .....If the tip polarity is - you simply have to cut the wires and connect them to the opposite sides to change polarity.

 

[Randall]

I was looking at the other thread on this but people started getting mad, so ill just ask here, is it safe to use a 6v 1000mha dc car charger for my scanner in the truck, i saw that uniden is selling the same one for several scanners, i just dont want to fry my scanner with to many amps. Thanks

i also would agree with the post that says to get a NIMH charger and two sets of batteries from walmart. the Nimh or nickle metal hydride batteries work great, ive been using them in my portable scanners for years.

 

[ems170]

the dc adaptors I have from radio shack and walmart have selectable tip polarities. It is very important that you match the right polarity with the unit. otherwise you could have an expensive desk ornament.

'''''''''''''/----\
(-)---------. |-------(+)
,,,,,,,,,,\___/

Thats a very crude polarity indicator. The line that goes to the center (tip) will indicate the polarity. The example above indicates negative tip. I dont recall what the radio polarity is off the top of my head but the indicator is present.

 

[slicerwizard]

It is very important that you match the right polarity with the unit. otherwise you could have an expensive desk ornament.

Brief polarity reversals will be handled by the 396's built in protection diode. If the external supply is fused, a polarity reversal will blow the fuse. A fast acting 1 amp fuse will protect the 396 nicely.

If the supply isn't fused and the reversal is maintained long enough, the protection diode will fail. It will probably fail shorted, which would leave you with a scanner that only ran on batteries.

I dont recall what the radio polarity is off the top of my head but the indicator is present.

It's positive tip.

 

[TenRingMike]

Several people on the 396 yahoo group have reported that unless your power supply is *regulated*, it won't or might not work. The 396 is very sensitive to proper voltage.