Silva S15 backup battery

[Quester]

Like many others I have a Silva S15 DSC VHF with a defunct memory backup battery. Symptoms: loses squelch, volume, MMSI number and date/time settings. The battery is a Panasonic CR2016 soldered to the PCB.

The CR battery designation means a primary battery not a re-chargable but when I check voltage whilst it's still soldered to the PCB it starts at a discharged 0.1 V and rises steadily over a period of time (currently 1.36 V after the VHF switched on for a couple of hours) so is obviously being charged.

Does this mean that, not only is it a duff battery, but that a blocking diode is failing to stop a spurious charge getting to the battery or that Silva did not design the circuit correctly?

Forum member Oilyrag says he's replaced his with a Maxell ML2016 T6 which is a 25 mAh re-chargable but 25 mAh seems very low for long term (power off) backup.

Can anyone throw any knowlegable light on this conundrum?

 

[savageseadog]

I have this piece of sh*t radio and will be replacing the battery.
Re. the "charging". no piece of electronics is completely open circuit, a diode will allow a small reverse current of a few micro amps for example which will be enough to "charge" the battery. Your meter will only draw a few micro amps so the battery will appear to recover. I doubt that the battery is connected via a diode but probably through an chip which will do much the same.

 

[Quester]

So you would replace the battery with another CR2016 as the charge that is apparently seeping through would not be enough to properly charge a rechargable ML2016. Am I right?

 

[savageseadog]

So you would replace the battery with another CR2016 as the charge that is apparently seeping through would not be enough to properly charge a rechargable ML2016. Am I right?

Yes. Use the CR2016, it will last longer, a rechargeable will probably never properly charge and will be less likely to leak noxious goo onto the circuit boards. It was useful to know the battery type BTW.

 

[SHUG]

Had the same problem but could not source a replacement battery , not even from Silva.
I mean the battery with the terminals spot welded to the case. The solution was fix wires to a standard CR**** battery with conducting epoxy and then solder them into place with the battery glued in a corner of the case. Sorted.... but for how long?

 

[Quester]

Now that sounds like a plan and a cheaper option as the non-tabbed CR016 batteries are very cheap and available. Could also get a higher mAh version perhaps to avoid the next premature failure.

 

[CET1]

Normally with thios type of arrangement we would install wires on pcb conneted to separate battery holder makes for future replacement or try CPC.farnel for tagged battery.