Ni-Mh batteries in S4

Topics related to the Dataman S4
Guest
Posts: 723
Joined: 09 Nov 2011 17:16

Ni-Mh batteries in S4

Postby Guest » 14 Nov 2011 12:10

Hi,

Do I need to change any of the advanced parameters of the S4 for successful operation on NiMh batteries? The unit works fine, but it goes from "discharged" to "you need to jump through hoops to get me started" very quickly. Is it a case of altering the deep-discharge level?

Cheers,

Ant Moore

Dataman (Neil Parker)
Posts: 881
Joined: 10 Nov 2011 09:51

Re: Ni-Mh batteries in S4

Postby Dataman (Neil Parker) » 14 Nov 2011 12:11

Hi,

You can press FUNC SETUP on S4 and find "Deep Discharge" option which is normally set to 40. You can set it to different value using hex keys. There are some other charge options but I am afraid we havent really looked into this.

More to follow....

monolog99
Posts: 1
Joined: 08 Jul 2012 14:08

Re: Ni-Mh batteries in S4

Postby monolog99 » 31 Oct 2018 15:22

Stumbled across this post (7 years after the event!) - wondered if any more investigation or info came to light using NiMH batteries in an S4 as opposed to NiCads ?

Dataman (Neil Parker)
Posts: 881
Joined: 10 Nov 2011 09:51

Re: Ni-Mh batteries in S4

Postby Dataman (Neil Parker) » 06 Nov 2018 12:18

Hello monolog99,

We carried out extensive testing with NiMH cell packs but ultimately it proved unfeasible to modify the S4 firmware therefore, we still recommend using NiCad packcs with a capacity of no more than 800-850mAh.

S4 replacement battery pack: https://www.dataman.com/s3-s4-main-battery.html

Best regards,


Neil Parker
Dataman Programmers

Chromatix
Posts: 1
Joined: 24 Sep 2019 04:14

Re: Ni-Mh batteries in S4

Postby Chromatix » 24 Sep 2019 05:14

As part of restoring a second-hand S4 for my own hobbyist use, I'm building an adapter board to replace the original power jack and battery pack (which are both dead in my example). This board should comfortably fit in the battery compartment along with a 3x AAA holder. I'll need to cut a small window in the side of the case to access a new, more robust power jack mounted on the new board, and view some status LEDs beside it.

The adapter board incorporates two Cuk converters and a NiMH battery charger. One of the Cuk converters is a direct path from the new jack to the S4's battery terminals, supplying a steady 9.4V. The other one supplies 8.6V derived from the NiMH battery, and is thus idle when external power is present. The battery charger (a BQ2004) performs a safe two-hour fast-charge cycle, using the best practices of peak-voltage detection, thermal rise, and safety timeouts, via a simple buck converter and current-sensing resistor.

The watt-hour capacity of three AAA NiMH cells is maybe half that of a seven-cell NiCad AA pack, but since they can be obtained cheaply from any reputable supermarket, I expect this will greatly extend the useful lifetime of my unit. I suppose with a SMD version of the design, the board might be shrunk enough to fit a 3x AA holder, which would have a greater watt-hour capacity than the original pack.

The direct, properly stabilised path from supply to output is also likely to be kinder to the cells than the original design; based on the rather small capacitors fitted, I can only assume that the battery was used as a ballast when externally powered. For this reason, my design includes provisions to attach large capacitors to both the input and output, though they'll have to be stashed elsewhere in the unit's casing. There seems to be a suitable place in the vicinity of the contrast knob.

I'll post again when I'm further along with the project. I may even have some spare bare boards from whichever small-batch manufacturer I end up using.
Attachments
dataman-battery-1.jpg

mgarnett02
Posts: 1
Joined: 10 Jul 2021 01:46

Re: Ni-Mh batteries in S4

Postby mgarnett02 » 08 May 2022 08:45

Resurrecting an old post, but did you happen to complete this project?

Cheers

Mark


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