Panasonic ML621 or equivalent. Alternatively you can use the battery
pin (pin 6): remove the onboard battery and use en external primary
cell (CR2032 or equivalent). See pages 15 to 21 of the M12M user
manual.
http://www.ilotus.com.sg/~ilotus/sites/all/themes/zeropoint/pdf/m12m/M12M%20-%20User%20Guide%20%28Ver%201.0.0%29.pdf

On Mon, Apr 25, 2016 at 2:11 AM, Joseph Gray jgray@zianet.com wrote:

I have several 5V Oncore UT+ receivers of the type that did not
include a rechargeable on-board battery, but didn't want to bother
with lithium primary batteries or rechargeable batteries and their
associated holders so I opted to use supercapacitors. Specifically, I
use the Panasonic EEC-F5R5U105 supercap with a capacitance of 1F and a
max voltage rating of 5.5V.

Charging is easy: I simply run 5V power through a diode and a resistor
sized to prevent exceeding the diode's current limit and the capacitor
charges in about 20-30 minutes. The diode prevents the supercap from
discharging through the resistor when the power fails.

I use a 1N4148 small signal diode rather than a 1N400x-series diode
because the 1N4148 has a smaller reverse leakage current. A 240 ohm
resistor keeps the peak current to 20mA (the diode can handle up to
200mA forward current) and the capacitor is charged up in about 20
minutes after power-on. Adjust the values for your specific needs.
Once charged, it maintains the Oncore's RAM for several weeks with no
power.

On Mon, Apr 25, 2016 at 12:25 PM, Azelio Boriani
azelio.boriani@gmail.com wrote:

--
Pete Stephenson

Very handy,  I've picked up a few Oncore receivers recently and was
planning to test them all and then replace the batteries in the good
ones.  Has anyone worked out what the original charge circuit schematic is
though?
On 25 Apr 2016 13:01, "Pete Stephenson" pete@heypete.com wrote:

Another option for the UT+ (not sure it's applicable to the M12M) is to remove/disconnect a SMT resistor that connects the (+) terminal of the rechargeable onboard battery to pin 6 (IIRC) and use a non-rechargeable battery of the same form factor.  I've done that for one of my receivers and it's lasted for over a year now.  I don't recall the exact battery type but I can get it if anyone needs it.

Joe

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Pete Stephenson
Sent: Monday, April 25, 2016 6:34 AM
To: Discussion of precise time and frequency measurement
Subject: [Bulk] Re: [time-nuts] Oncore battery

I have several 5V Oncore UT+ receivers of the type that did not include a rechargeable on-board battery, but didn't want to bother with lithium primary batteries or rechargeable batteries and their associated holders so I opted to use supercapacitors. Specifically, I use the Panasonic EEC-F5R5U105 supercap with a capacitance of 1F and a max voltage rating of 5.5V.

Charging is easy: I simply run 5V power through a diode and a resistor sized to prevent exceeding the diode's current limit and the capacitor charges in about 20-30 minutes. The diode prevents the supercap from discharging through the resistor when the power fails.

I use a 1N4148 small signal diode rather than a 1N400x-series diode because the 1N4148 has a smaller reverse leakage current. A 240 ohm resistor keeps the peak current to 20mA (the diode can handle up to 200mA forward current) and the capacitor is charged up in about 20 minutes after power-on. Adjust the values for your specific needs.
Once charged, it maintains the Oncore's RAM for several weeks with no power.

On Mon, Apr 25, 2016 at 12:25 PM, Azelio Boriani azelio.boriani@gmail.com wrote:

--
Pete Stephenson

time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

I used a non-recharable coin battery and after maybe 5 years it's
still working.  The coin battery will last as long as whatever its
shelf life is.  It is only used if power fails and then only to hold
the data in the volatile memory.

On Mon, Apr 25, 2016 at 3:25 AM, Azelio Boriani
azelio.boriani@gmail.com wrote:

--

Chris Albertson
Redondo Beach, California