Baofeng UV5R accu eliminator part2
Received 2 very small DC-DC converters from China.
How is it possible 1€ free shipping from China?
Decided to break open the "accu eliminator" I payed 15€ local prize
loosing warranty but this type adapter does not work.
From China 5€ for the cartridge and power cord and 1 € for the dc-dc regulator still is a bargain
The plastic case had to be forced open with a knife
Inside as expected a linear regulator with a 7808
A much too small heath sink for 6W heath loss and thermal protection trips after a minute with a UV5R. I did not hear about problems with this adapter? must have been
first one sold?
The dc-dc converters need minimum 470uF elco on the output to filter switching ripple
I did not have a suitable 9V suppressor TVS diode for over voltage protection.
like a Unipolar Transient Voltage Suppressor Diode 5kW
10+€ 0,30 5KP7.5C but crazy 7.5€ shipping
The smaller regulator performs even better at low input Voltage.
10V -20V input 8V out drop 20-30 mV with 1A load
Impressive performance, much better then I could get with the emitter follower regulator.
at 1A the the switching IC off the smaller became hot 50C-70C about
the total conversion loss is 100-400 mW estimated
Precaution is needed these regulators have no short circuit- reverse polarity- over voltage- or thermal protection
For the UV5R I used the bigger regulator
with the original Cap's used with the UA7808
over the output extra 470u and input 100u
the original useless 7800 regulator
this tiny regulator performed best but heats up a bit at 1A
a tiny heat sink on the regulator IC would be enough or a very small PC fan
first result was okay had a long talk over the local repeater
No problem . the 7808 would trip thermal after 1 minute.
the small type uses the MPS MP2307N claimed to be better then the LM2596
the 1.5MHz switching frequency that was in some specs is a misprint
it's around 340kHz in the MPS specs. chip seems to have no internal protection.