CMOS battery replacement

I am trying to get an old Toshiba Satellite 1805 up and running for a friend. The only hardware issue that I have encountered is a bad cmos battery. The Toshiba part number is GDM710000003 and the battery model number (the entire part is just two wires and a plug coming off of a battery) is US1620N. I can't find the original part from Toshiba's parts distributor and the cheapest one I can find online is $35. Can anyone say with certainty that if I buy a new Li-i rechargeable battery that is the same voltage and with approximately the same mAh, I can solder the wires to the battery? I can buy such a battery for $10. Thanks.

 

I'd guess that as long as the voltage is the same and the battery will fit into the laptop that it would work. But that's only a guess. I did find a US1620N that sounds like what you need for less than $15 online but it's apparently out of stock currently. There's a link you can click to ask to be notified via email when they have more in stock. But I know nothing about the vendor/seller. You can check them out yourself here:

http://www.pchub.com/uph/laptop/48-...-Item-Toshiba--Battery---Cmos-Resume-RTC.html

Also suggest you use a search engine to check out the vendor to get some idea of their reputation if you're thinking of waiting to see if they do actually some more stock in.

Good luck!

 

WOWOWOOW DO NOT PAY 15$ OR ORDER ONE!!!

You can buy cr2032 lithium batteries at the dollar store!

 

Yeah, but does a CR2032 (which is the standard CMOS battery, I think, in most desktops) have the the same voltage as the US1620N for an old Toshiba laptop? If not, he may fry his CMOS chip or, at best have wasted a dollar and some more time.

Maybe that US1620 is just a CR2032 in an insulated jacket, but I can't say. Do you know for certain op2rules? And even if it is, he'll still have to solder the leads to the battery properly and then insulate the battery before slipping it into the case (clearly the laptop doesn't have a standard CR2032 socket).

If he can do that and IF the voltage is the same maybe that will work.

 

You will need a 3Volt re-chargeable tagged coin cell like this one, this is only an example and you can probably get them cheaper if you shop around.

Make sure the new one will physically fit and don't use a non tagged one as soldering directly to a battery can damage it. Your original battery's capacity is 17mAh but don't worry about that to much this is not critical just make sure that the new one will fit and is 3volts re-chargeable with tags and you should have no problems. The old one has a piece of heat shrink tubing around it, if you don't have any just use PVC electrical insulation tape.
Also polarity is important don't connect the battery backwards as it wont like it.

 

Thanks from me also voodoo3rd. Glad to get some good info about types of CMOS batteries. Hadn't thought about problems/damage to a battery caused by attempting to solder leads to it either.

 

A CR2032 would explode if I put it in this laptop.

Soldering is not an issue for me. I keep my iron hot.

Can you say this with absolute certainty? Or let's just pretend we are on "Who Wants to be a Millionaire" and I'm phoning a friend. You are the friend and I'll ask you how certain you are. Please state how certain you are of the above case in a descriptive format (very sure, somewhat sure, etc.) and a numerical format (%). I'll post a picture of my nipple if you do.

 

That's an understatement, for sure.

The US1620N cell is a lithium cell. Lithium batteries are known to be quite nasty if the charging current isn't properly managed. Explosion and fire are quite possible.

 

Hi Phred,

The guys are right on this. A hint: If the new battery is the same type and roughly the same size it should be about the same capacity. Very little capacity is needed with CMOS. Also I haven't seen a rechargeable battery in any Computer in maybe 15-20 years.

Good Luck, Jim

 

Thanks mate. It's a Toshiba Satellite 1805. I found a comparable battery for $6.99us shipped from China (I hope I get some lead in there with it). I'm going to solder it to the adapter and run it for a while hoping I don't get a Lithium ion infused laptop.

 

Phredrick is right -- a CR2032 might well explode if it was used in place of the US1620N cell. op2rules does not rule this time.

Both are lithium cells. But the CR2032 is not rechargeable; the US1620N is. The CR2032 cell is likely to behave very badly if it exposed to a charge current. It should only be installed in circuitry that has protection against charging currents across the cell.

See footnotes (a) and (b) on UL's datasheet here.

 

"Soldering is not an issue for me. I keep my iron hot."
Keep it up

"...mat (%). I'll post a picture of my nipple if you do."

If your female, The mAh capacity rating refers to the storage capacity available from a battery. A battery with a capacity rating of 17mAh(milliamp hour) could(in an ideal world) deliver a current of 17 milliamps for one hour. So if your CMOS drinks lets say 17 micro amps and your battery is 17 mAh it will last for 1000 hours, 17 ÷ 0.017 = 1000
Higher milliamp-hour ratings for the same battery type will mean longer run times but will take longer to charge.

If your male I don't wish to see your bits :eek :-D

 

Hi All,

CMOS only draws current and very little at that, while changeing state. Batteries in that service last about as long in service as they would sitting on the shelf. About 5 to 8 years if I remember correctly. It is correct that a non-rechargeable batt should not be used in place of a rechargeable one. I used to put a Diode in series in that case so the batt would not charge. That was way back before CMOS BIOS. Current draw was relatively heavy at that time and the replacement was usually 3 AAA alkalines for a 3.6 volt nicad pack.

Good Luck to All, Jim