IIc external Prairie Pack

10 replies [Last post]
vapor's picture
Offline
Joined: Jan 26 2010
Posts: 31

I have a Prairie Pack I am trying to get up and running on one of my IIc systems. I was wondering if anyone out there has any manuals, specs or other information to help me get this thing up and, specifically, in finding the correct battery replacement (25 year old battery is obviously dead now).

Any help or advice is greatly appreciated.

Thanks,

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Offline
Joined: Dec 19 2003
Posts: 832
Please share. . . pictures and data

Vapor,
I realize you came here looking for help, but it would be nice for the rest of us if you could take a couple of pictures of the pack, share the part/model#, maybe the serial # (just for trivia).

Have you opened it up yet? I suspect that you might find a NiCad battery bundle, wired in series. If so, the batteries might be labeled as to their individual ratings, and might be analogous (the same size) as standard consumer batteries. These should be replaced with rechargeable batteries, as they should all be rated for 1.2 volts. If you do all of this, you should also replace any capacitors, as they too have a limited life/use span.

Mutant Pie

vapor's picture
Offline
Joined: Jan 26 2010
Posts: 31
I would be more than happy to

I would be more than happy to post some pictures. I have a replacement battery but I'm not sure it is going to work. It is actually two 6 volt (UPS-like) batteries in series.

I'm still playing with it but should be able to get some pictures up soon.

vapor's picture
Offline
Joined: Jan 26 2010
Posts: 31
IIc Prairie Pack Slide Show
Offline
Joined: Dec 19 2003
Posts: 832
Yikes! It's big.

Thanks for linking the pictures. Wow! What a heavy beast, eh? That's portable computing in the early 1980's for you. Still it's way better than those ComPaq monsters. They were as big as a suitcase and three times as heavy.

Anyway those types of 6v batteries should be easy to replace at Batteries+, or another like retail distributor. They probably even have the same exact size, as they looked like standard ones to me. Due to the age of this thing, once you get the old batteries off, and before you connect the new ones in place, you should probably clean all of the connectors with anhydrous alcohol and a clean old tooth brush to remove micro corrosion. The corrosion makes the connectors have more resistance, and that can shorten the battery life, etc. . .

If you really want the batteries and the other circuitry to last longer, get one of those power conditioners that people buy to plug their high end electronics into, and use it as an intermediary between the wall outlet and your Prarie Pack.

Offline
Joined: Dec 19 2003
Posts: 16
Re: IIc external Prairie Pack

Did you solve your problem?

I also have the Prairie Pack System (including the C-Vue LCD Display adapter).

As I recall the batteries are easily replaceable sealed lead-acid batteries, costing about $30 to replace, similar to these:

All Electronics link - click here

If you still need information, I will pull mine out of storage and get more specific information

speedyG's picture
Offline
Joined: Nov 16 2011
Posts: 2375
Re: IIc external Prairie Pack

this kind of batteries are common in electric wheelchairs and the two most common infos are usually printed somewhere at the batteries themselves in the common specs as : XX Volt / XX Ah where Ah specifies the amount of Amperes they are able to deliver in 1 hour. Related to that capacity is the strength of the related charger ( regular /10th or /12th part of the entire capacity ( for example 10 Ah => Charger 1 Ampere ) It would be a good idea to use a modern charger that is capable to recognize the true voltage at the end of the clips/plug because the modern chargers then switch from heavy loading cycle to standby charging mode ( in above example the load wil turn down to 150 mA ) if the voltage at the plug indicates the batteries to be loaded to the limit - and that prevents the batteries from overload or overheat and therefor extends lifecycles of batteries.

With some more specific data you might even instead use NiMg Batteries instead and save a lot of weight and size ( usually a NiMG battery only has half the weight as NiCD at same capacity ) - they are commonly used in electric bicycles ( but you have to be aware that they are used in bicycles in different types of voltage from 12 Volt up to 48 Volt and you might only use the 11,1 Volt Typ ( commonly speced as 12 Volttyp ).... but they are really expensive...

the very most high-tech version would be to make an own batterypack by yourself with the modern LiPo batteries - but this requires special knowledge to the the construction of the charger because LiPo batteries require a balancing process while charging to prevent them from starting to burn during the charge-cycles but the advantage is 3 to 4 time more capacity at same weight... for example 12 volt lead / 12 Ah => 6 kgs <=> 12 Volt 36 Ah LiPo with 5,9 kgs at smaller size ... resulting in the usable time 2 hours with lead and 6-7 hours with LiPo !
There is plenty stuff in the internet availiable related to this topic and most of it is within pages related to electric RC-Models ....

__________________

In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....

gsmcten's picture
Offline
Joined: Oct 4 2005
Posts: 2609
Re: IIc external Prairie Pack

Vapor and LAX,

You two are very lucky.
I have actually only seen one "Prairie Pack" for the IIc since 1995.
One of my friends bought one when they first materialized. I didn't think it was a neccesity for me as I would be working in an office type environment all the time.
Doh! A Homer Moment. lol
Oh the unwizedness of youth. Smile

__________________

Steven (gsmcten)

"Apple ][.....It's ALIVE!!!!!"

MarkO's picture
Offline
Joined: Dec 10 2011
Posts: 666
Re: IIc external Prairie Pack

I had a Prairie Pack back in the 1980's with my //c and the Apple LCD monitor... I sold the whole thing to buy my first IBM AT clone in 1987...

Sealed Lead Acid batteries are what mine had too... About 25 Pounds, the Pack, the //c the LCD and the Matching Prairie Case...

Offline
Joined: May 27 2009
Posts: 922
Re: IIc external Prairie Pack

It is important to match the charging circuit to the battery's chemistry. If these are indeed sealed lead-acid batteries, then I suggest you use nothing but lead-acid batteries.

Do not switch to NiMH, NiCd or even worse Li-ION or Li-Po. If you do that and continue to to use the existing charging circuitry, you're looking at a fire hazard straight away.

Also be aware, that sealed lead-acid batteries can usually deep discharge without harmful effects - especially if the battery is engineered to do so. And I suspect the original ones in the prairie pack are. Same thing goes for NiCd cells. They can handle

On the other hand, NiMH and Li-ION and Li-Po need not only a specific charging curve and circuit, but they also must be monitored for discharging. Take them down too far, even one time, and they're dead. You will need a circuit to monitor the discharge rate as well.

All the new modern battery chemistries will generally outperform the original one, but they require a whole different way of managing them.

http://www.buchmann.ca/faq.asp

__________________

On a clear disk you can seek forever..

speedyG's picture
Offline
Joined: Nov 16 2011
Posts: 2375
Re: IIc external Prairie Pack

speedyG wrote:

the very most high-tech version would be to make an own batterypack by yourself with the modern LiPo batteries - but this requires special knowledge to the the construction of the charger because LiPo batteries require a balancing process while charging to prevent them from starting to burn during the charge-cycles .

I allready explained this in the post above......

__________________

In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....