custom clock battery holder for wallstreet

I have the same problem with a PB Titanium. The PRAM battery is dead, but a replacement is $50. I like the idea of using standard AAA batteries, but I'm not sure if the bulk would be worth the convenience of having such common batteries, as it isn't necessary to replace PRAM batteries all that often. I'm sure it's not too hard to find replacement battery cells and just replace the old ones, redoing all the connections as they were. I'm going to take a stab at that next week for the Titanium. I'll let you know how it goes.

If you want to try it too just take apart the clock battery and see if you can get some serial numbers or something to identify the cells, and then try mouser.com or digikey.com to find some replacement cells.

a standard AA or AAA isnt going to be the correct voltage. I don't remember the correct voltage for the WS pram battery, but, im fairly certain it isnt 1.5v (which is the voltage of AA, AAA, C and D batteries)

i know it wasn't 1.5. i thought it was 3.6 or somehting like that. that makes it painful to try to build one. something i planned a long time ago before the processor burned out was to put in an extension cable and set the clock battery under my hard drive. the drive in there is of a much lower profile than the original, and the battery fits with no trouble. there are only two issues with that: i need to get an expensive battery and i need to find the tiny little connector to make an extension cable to keep me from having to take the computer apart.

I made a post on TSF about this topic a while ago that you might find useful.
http://www.macshadows.com/forums/index.php?showtopic=7347

I don't think you should use cells other than the original VL-type rechargables. The 'Book expects those particular type of cells, any other invites disaster (a fubared PMU or similar.)

VL2330 cells are available, though not exactly cheaply. digikey lists them for US$7.38/each, or a package of 60 for $354, or a case of 600 for $2655. Buy lots and save big money! This sort of pricing does seem to invite shared purchases . . .

Heh, I suppose you could substitute VL2320s at $5.38 each, a slightly lower capacity but same charge spec (< 2.0mA.)

In the end I say better to leave it out than burn something up.

dan k

well, i suppose it looks like a new wallstreet clock battery under the hard drive then. i just need to figure out what kind of connector it is on the battery and board so i can fabricate an extension cable. at least that way, if the stupid thing ever dies again, i can just take the battery out from under the drive and disconnect it without complete disassembly.

Or just connect some wires directly to the board and run them to some other type of connector near the HD bay for the batteries. Actually, IIRC there should be enough room under the lobo to route wires if done properly.
I don't know, I may be remembering incorrectly.

yea that would be easy to do, but at least with an extension cable, the battery wouldn't have to be modified if it ever needed to be replaced again, and i could put it back to stock configuration any time. but that all depends on whether or not i can find the same size connector as in the wallstreet.

Dead battery pack + dead lobo + spare wires + your skills = easy to obtain extension cable.

already have the dead battery! time to get a new one and fab up the cable.

Same as watch batteries? Heh, surely you jest!

Well, no, they look similar but are very different. Critically, PowerBook PRAM batteries are rechargable where watch batteries are not.

OTOH, desktop Macs' PRAM batteries are not rechargable, so in theory you could use whatever you like there, assuming correct voltage.

dan k

No, you could not. If you used non rechargables in there, and if the mac tried to charge 'em, bad thing's would happen!

Thanks. But in theory at least, if I could find small enough rechargeable batteries with the same voltage and chemistry, they should work?

. . . Vanadium Pentoxide Lithium cells 2.3mm thick and 30mm in diameter ought to work dandy.

dan k

If you can find a suitably sized set of cells, with similar charge characteristics (read, chemistry), then ok. I think that dankephoto's idea is that the only appropriate chemistry is going to the the vanadium based OEM cells.

Here's one choice (as mentioned further up the thread), ranging in price from about $4.50 to $9.00 per cell:
http://www.panasonic.com/industrial/battery/oem/chem/lith/vana.htm
sourced from Digikey (look under VL series Panasonic coincells) The VL2330 runs about $7.40 a cell.

Panasonic seems to have good info on the charging characteristics. Here's the skinny on the VaO5-Li,on the off chance you were comparing to another type of battery:
http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_Lithium_VL.pdf

Just a cursory look says that for rechargeable coin cells, the vanadiums are about the only show in town. I don't really see any other chemistry, though I haven't looked very hard. Using the VL series (or something like it) with tabs already welded on looks like the ticket for rolling your own battery pack.

good luck!
mike

The old PB1xx series used a ML series (Manganese Lithium) cell, cost for a 45mAh 2020 cell is only US$2.68 at digikey. However, the charge current looks to be max 3.2v, where the VLs appear to accept 3.4v.

Might be worth a try though, what's the worst that could happen?

dan k

dankephoto wrote:

Might be worth a try though, what's the worst that could happen?

It is a Mac, so it might release the magic ooze.

- Your beloved mac may be consumed in a ball of flame
- which could then set your house on fire
- you could release the magic smoke, which is reeeeeealy hard to put back in
- you could hurt yourself or others
- you could over heat a battery whilst soldering the pack together, causing it to explode
- you could singe off your eyebrows
- you could accidentally kick the cord for your soldering iron, causing it to fall onto your bare leg, just above the kneecap, whilst wearing shorts

All in all, sounds like fun!

Heh. Sounds like an evening working at the tinkerin' bench. Minus maybe the burning down the house. It's not a productive evening if you don't pull the soldering iron over on your bare leg.

Looking at the ML series manganese lithium batteries as dankephoto mentioned-
The ML2020 is about as close as it's going to get at 45mA/h and 20mm diameter, compared to the VL2330 with 50 mA/h and 23mm diameter.

The ML2020 has a recommended charging current of 3.0 mA or less. The VL2330 has a recommended charging current of 2.0 mA or less. Those numbers work just fine for subbing a cheap ML series battery. The only issue that I see is that the charging voltages are different. The VL batteries charge at 3.4 volts/cell, and the ML at 2.8-3.2 volts. 3.4 volts will harm the battery. The spec sheet has several charging circuit examples using voltage dividers that could get around it. http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_Lithium_ML.pdf

For the $5 difference, I'd almost just consider using the more expensive cells, just to not have to worry about bodging up a workaround for the charging voltage...

mike

bloody hell, i didn't realize this was still getting replies. and no, i have no intention of killing myself in any various way while fixing my powerbook. sorry. i have other electronic devices i can blow up.

But that's $5 per cell, isn't it? Making ~$30 difference for the pack - each and every time it needs to be changed. And the idea here was to look for cheap alternatives to the ~$50 official solution, yeah?

Another thought: As per images here and here, the cells are connected in 2 series packs of 3 parallel, making 6V x 150mA/h. (Correct me if I'm wrong here)

As we're looking at alternative (ie more accessible) locations anyway, our size options are a bit more flexible. What about a pair of larger-capacity 3V cells?

BGMicro.com have the genuine correct cells for $1.07 each till the end of July - if you use the discount code BGJULY04 when you place the order. It's only 10% off if you're ordering after.

I just bought a dozen

i just recently got the new processor for the wallstreet, so this is finally at the top of my list of repairs again. i think i might just buy an original battery from ebay (anything has got to be better than my completely dead one). as i previously planned, i think i'll make an extension cable for it, assuming i can find the connectors or something similar at radio shack. the hard drive i have in the computer is plenty thin enough to slip the battery under it. that just seems easiest at this point, especially since it seems there are no other cell types that will make the correct voltage. maybe this is a case of the simplest idea being best....even if i have to pay a ton for a new battery.

That sorta beats the socks off of my quoted price.

Without re-reading the whole thread, how are you going to construct your stacks? I ask because I've got a similar task ahead, and am planning to build a tab welder (just bought a 0.5 F cap)

Good deal on those cells!

mike

Maybe (probably?) I'm an idiot but I just can't seem to find any VL2330 cells at BGMicro.com's website. A direct link maybe . . . ?

dan k

just made a model of the battery to see where i could shove it. i thought i was reading this thread when i was reading the thread about usb on the wallstreet (another thread, don't bother), and that for some reason forced me to consider heat under the hard drive. i suppose that wouldn't be an issue. anyway, i couldn't fit the model anywhere else under the keyboard. sounds like we're still going to have several different working solutions to the stock battery placement at the end of this.

As a leading digital product manufacturer, SVNCO ELECTRONIC TECHNOLOGY CO , LTD specializes in the R&D,manufacturing and distribution of portable audio digital products .Our product range covers MP3 players, MP4 players, Portable DVD, GPS, digital photo frame, Memory Cards.

Established in 2000 in Shenzhen, our company has more than 600 skilled & experienced workers and 30 R&D staff. There are advanced 10 SMT lines in our factory with 8,000 square meter facilities. The capacity of our factory is 10,000 pieces per day, and we have the capabilities to meet your outsourcing needs of these products.We have already set up a complete quality control system strictly conforming to ISO9000 standard and most of our products meet FCC, CE, SISVEL and RoHS standards. All our products pass through strict quality control and are 100% inspected to ensure the most satisfaction of our customers.

With creative designs and high quality, our products are popular in America, Europe, Southeast Asia and the Middle East, and many of them have been enjoying their success. We hope to cooperate with you and make mutual beneficial business between us.

SPAM SPAM SPAM mods?

Um, the first item on the Battery page? Ok, so it doesn't say VL2330 in the text, but it's visible in the image of the cell when you click through.

Oh. Actually, the cells pictured say CL2330. I can't find a datasheet anywhere for that part. A CLxxxx part almost certainly won't be the same chemistry as the VLxxxx part.

Well, for ~$1 each I suppose it's easily worth taking a shot. What could go wrong?

dan k

Well, they're the same voltage and capacity, so if there is any difference it would only be in a slightly different charge curve, I assume. Unless BG has them listed wrong, and they're not rechargables.