Backup battery problems

[G4EML]

The radio had a small internal battery which maintains the memory when turned off. If this battery has failed then it will behave as you have described.

[M7PKY]

I have since today also the problem that all settings are lost after switching on again.
Do you have an idea how to solve the problem?

Having seen two people comment on this, I thought I might throw something into the ring as well for the developers.

I have heard that the stock firmware changed the RTC from using the RTC internal battery to using the main radio battery when the radio is switched on. It then switches back to the RTC battery when it is switched off. I am not able to provide a source for this information, and I am also not able to test because I failed to take a backup of the flash before overwriting the stock codeplug, but someone who did should be able to evaluate if this is the case by loading on the stock firmware, turning the radio on and pulling the main battery. If the time is not correctly retained, or not retained at all, it will confirm this information is correct.

Is it possible something the stock firmware does for RTC battery management is not being done in this firmware, causing the battery to drain and not recharge (if it can even be recharged, not sure?)

[VK3KYY]

I have since today also the problem that all settings are lost after switching on again.
Do you have an idea how to solve the problem?

Having seen two people comment on this, I thought I might throw something into the ring as well for the developers.

I have heard that the stock firmware changed the RTC from using the RTC internal battery to using the main radio battery when the radio is switched on. It then switches back to the RTC battery when it is switched off. I am not able to provide a source for this information, and I am also not able to test because I failed to take a backup of the flash before overwriting the stock codeplug, but someone who did should be able to evaluate if this is the case by loading on the stock firmware, turning the radio on and pulling the main battery. If the time is not correctly retained, or not retained at all, it will confirm this information is correct.

Is it possible something the stock firmware does for RTC battery management is not being done in this firmware, causing the battery to drain and not recharge (if it can even be recharged, not sure?)

The RTC battery can't be charged, its a standard watch battery.
Edit. See Colin's post below. It appears to not be a standard battery and it can be charged.

According to STM, who make the CPU, the RTC is powered by Vdd when the CPU is running, there is no special configuration required.

See https://community.st.com/s/question/0D5 ... nd-battery

[M7PKY]

I have since today also the problem that all settings are lost after switching on again.
Do you have an idea how to solve the problem?

Having seen two people comment on this, I thought I might throw something into the ring as well for the developers.

I have heard that the stock firmware changed the RTC from using the RTC internal battery to using the main radio battery when the radio is switched on. It then switches back to the RTC battery when it is switched off. I am not able to provide a source for this information, and I am also not able to test because I failed to take a backup of the flash before overwriting the stock codeplug, but someone who did should be able to evaluate if this is the case by loading on the stock firmware, turning the radio on and pulling the main battery. If the time is not correctly retained, or not retained at all, it will confirm this information is correct.

Is it possible something the stock firmware does for RTC battery management is not being done in this firmware, causing the battery to drain and not recharge (if it can even be recharged, not sure?)

The RTC battery can't be charged, its a standard watch battery.

According to STM, who make the CPU, the RTC is powered by Vdd when the CPU is running, there is no special configuration required.

See https://community.st.com/s/question/0D5 ... nd-battery

Makes sense that it would be, sure, but you know how weird these radios can be wired. Wouldn't be shocked if it was wired weirdly. Would you mind humoring me and testing using the battery pull method on stock fw I described? I would do it for you, but as I said, no flash backup, sorry!

[VK3KYY]

Having seen two people comment on this, I thought I might throw something into the ring as well for the developers.

I have heard that the stock firmware changed the RTC from using the RTC internal battery to using the main radio battery when the radio is switched on. It then switches back to the RTC battery when it is switched off. I am not able to provide a source for this information, and I am also not able to test because I failed to take a backup of the flash before overwriting the stock codeplug, but someone who did should be able to evaluate if this is the case by loading on the stock firmware, turning the radio on and pulling the main battery. If the time is not correctly retained, or not retained at all, it will confirm this information is correct.

Is it possible something the stock firmware does for RTC battery management is not being done in this firmware, causing the battery to drain and not recharge (if it can even be recharged, not sure?)

The RTC battery can't be charged, its a standard watch battery.

According to STM, who make the CPU, the RTC is powered by Vdd when the CPU is running, there is no special configuration required.

See https://community.st.com/s/question/0D5 ... nd-battery

Makes sense that it would be, sure, but you know how weird these radios can be wired. Wouldn't be shocked if it was wired weirdly. Would you mind humoring me and testing using the battery pull method on stock fw I described? I would do it for you, but as I said, no flash backup, sorry!

You can reload the official firmware and test this even without the backup of your Flash memory.

I think the only thing you need to do is change one of the configuation files in the official CPS to allow you to upload your official codeplug again, otherwise you won't be able to use the radio because the keypad is locked.

See the bottom of the installation post

viewtopic.php?f=19&t=2380&p=19678&hilit ... 3D0#p19678

In settings.ini, Change

password=0 to password=password

[G4EML]

We don't have a schematic of the MDUV380 but we do have schematics for the MD380 and the MD9600 and it is very likely that the MDUV380 is the same.

Both of these have the same circuitry for the RTC battery and it turns out that it is in fact rechargable and has a 1K charging resistor from the 3.3V rail. I had always assumed it was non rechargable but checking the datasheet for the battery part number confirms that it is a rechargable type.

The RTC battery is however only recharged while the radio is turned on. So there will be a relationship between the number of hours the radio is turned on and the number of hours the RTC will continue running when the radio is turned off.

It may be that the people who are seeing the symptoms of a flat RTC battery have got into the state where the battery has a low charge. Using the radio for a short while and then turning it off will probably not put much charge into the RTC battery.

Maybe the way to fix this would be to leave the radio powered on for as long as possible, or even leave it turned on in the charger overnight.

I can also confirm that the problem is not unique to the open firmware. My MD9600 used to have the same problem when running it's factory firmware.

Colin G4EML

[VK3KYY]

We don't have a schematic of the MDUV380 but we do have schematics for the MD380 and the MD9600 and it is very likely that the MDUV380 is the same.

Both of these have the same circuitry for the RTC battery and it turns out that it is in fact rechargable and has a 1K charging resistor from the 3.3V rail. I had always assumed it was non rechargable but checking the datasheet for the battery part number confirms that it is a rechargable type.

The RTC battery is however only recharged while the radio is turned on. So there will be a relationship between the number of hours the radio is turned on and the number of hours the RTC will continue running when the radio is turned off.

It may be that the people who are seeing the symptoms of a flat RTC battery have got into the state where the battery has a low charge. Using the radio for a short while and then turning it off will probably not put much charge into the RTC battery.

Maybe the way to fix this would be to leave the radio powered on for as long as possible, or even leave it turned on in the charger overnight.

I can also confirm that the problem is not unique to the open firmware. My MD9600 used to have the same problem when running it's factory firmware.

Colin G4EML

Hi Colin

Thanks for investigating this.

I wasn't aware that those normal looking watch batteries could be recharged.

[G4EML]

Neither did I until I found the part number.

It is a MS412F-FL26E cell and the datasheet can be downloaded from Mouser.

The capacity is 1 mAh !

Colin.

[M7PKY]

The RTC battery can't be charged, its a standard watch battery.

According to STM, who make the CPU, the RTC is powered by Vdd when the CPU is running, there is no special configuration required.

See https://community.st.com/s/question/0D5 ... nd-battery

Makes sense that it would be, sure, but you know how weird these radios can be wired. Wouldn't be shocked if it was wired weirdly. Would you mind humoring me and testing using the battery pull method on stock fw I described? I would do it for you, but as I said, no flash backup, sorry!

You can reload the official firmware and test this even without the backup of your Flash memory.

I think the only thing you need to do is change one of the configuation files in the official CPS to allow you to upload your official codeplug again, otherwise you won't be able to use the radio because the keypad is locked.

See the bottom of the installation post

viewtopic.php?f=19&t=2380&p=19678&hilit ... 3D0#p19678

In settings.ini, Change

password=0 to password=password

Thanks for the pointers. I loaded the stock firmware back on. It was one very messed up, unhappy radio until I reuploaded the codeplug, but I can confirm that this is indeed NOT the case. The clock correctly retains the time on battery pull.

[VK3KYY]

Thanks for the pointers. I loaded the stock firmware back on. It was one very messed up, unhappy radio until I reuploaded the codeplug, but I can confirm that this is indeed NOT the case. The clock correctly retains the time on battery pull.

Do you mean the hardware RTC is not running when the radio is not turned on, or not running when you pull out the battery ?

If its the latter then, this suggests the RTC battery has a connection to the battery directly, rather than the regulated 3.3V rail; which is only powered then the radio is turned on, because the regulators take currently which would flatten the battery if they were constantly on.