Nicad voltage and charge time

[Guest]

I have recently acquired an S4 which appears to have had very little use (if any). The serial number is around 15000.

I have performed the "30 second reset" trick which worked OK and the S4 has powered up and started to charge.

As the nicads have probably not been charged for years, I guess I will need to cycle them a few times to get the capacity up. As expected, the initial charge only lasted a few minutes. I used the right arrow trick to restart the charge which lasted around 45 minutes.

The displayed voltage is now around 9.2v and this has fallen to 9.0v after about 1 hour - I pressed ENTER after 25 minutes when I got the timeout bleeps. I have a few questions:

- How long should it normally take to recharge the nicads?
- How long should the nicad pack power the S4?
- Is there a significant current load difference between just have the S4 powered up and displaying the voltage and temperature and actually writing an eeprom? Old nicads can usually cope with low current loads but not high current loads.
- Is it possible to display the lithium battery voltage? Does a low voltage lithium battery result in the library not loading?
- How old is my S4 with a serial number of 15000?

Many thanks

g8tzl2004

[Dataman (Neil Parker)]

Hello g8tzl2004,

Thank you for your post. I am glad to hear that you have managed to get your Softy4 up and running again.

You can find some additional information about the Softy4 on our website here and the different device libraries can be found here.

I have answered your questions below:

- How long should it normally take to recharge the nicads?
When the charger is ON, 650ma a.c flows into the S4 and this will recharge the battery in about
an hour. A reasonable working capacity will be restored in much less time.

- How long should the nicad pack power the S4?
The battery is capable of the following typical performance when fully charged:

• Standby 10ua - about 12 weeks retention of program, data and configuration. After that the Lithium cell takes over.
• Viewing 30ma - 20 hours of editing (25% less via RS232)
• Burning 180ma - 3 hours programming - the actual number of PROMS varies widely from about 100 oldest-type to 1000 latest-type
• Emulating 100ma - 6 hours emulating (depends on amount of access that the target system makes and the load it places on the data lines).

Of course real world situations are a combination of these activities.

- Is there a significant current load difference between just have the S4 powered up and displaying the voltage and temperature and actually writing an eeprom? Old nicads can usually cope with low current loads but not high current loads.
Please see above.

- Is it possible to display the lithium battery voltage? Does a low voltage lithium battery result in the library not loading?
No, and no, basically. But it should be providing greater then 3v whilst in circuit otherwise it is not really doing its job and should be replaced.

- How old is my S4 with a serial number of 15000?
A Softy4 with a serial number in that range would have been sold prior to 1995!

I hope this helps.


Best regards,

Neil Parker
Dataman Programmers

[Guest]

Many thanks Neil,

I'm surprized the Nicads still charge after 17 years!!! - must be good quality!! However, capacity is down as, after a few cycles, charge time is only about 20 minutes...but its still OK.

I have a couple more questions:

- Is it OK to leave the PSU/charger connected to act as a power "backup" when burning an eeprom?

- Is nicad charge termination just based on a rise in battery temperature or does it use the delta V method with a temperature backup? If charge termination is just based on temperature, I presume I would have no problems charging higher capacity NiMH's if I ever replaced the nicads?

- I presume the lithium battery is completely dead so there is no nicad backup - is it OK to just leave it like that? I presume I could just use the reset trick if the nicads go flat?

- I will make a serial eeprom adapter to program a 24c16. I've read up what I need to do...just wondered if there are any issues I might encounter?

Many thanks.

g8tzl2004