I'd like to start a thread about startup problems by power regulation and RTC or CMOS batteries. MyToshiba's (T1000LE, T1200 and T1600) and Laser LT321 have their original power adapter. Primary batteres are dead, but laptops worked fine on mains- until recently. Messages like: RESUME BATTERY LOW or CMOS BATTERY LOW started to appear. Loading those batteries seemed impossible, even by removing the main battery. And after a while, the computers don't even startup- the red "battery" LED flashes in sole response. It is obvious that the BIOS needs power to startup. Which battery must be replaced? Internet mentions RTC battery, CMOS battery, Resume battery and Auxillary Battery. They're small (2,4V to 6V, about 30-90mAh) but the original batteries seem only available in the USA or Canada and are quite expensive (20-40 dollar). Is it possible to construct such batteries by using a series of small cellphone NiCd batteries? And: Can I use charged AA batteries with same voltage (but a lot of mAh) shortly, as a test to solve the problem?
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Laptop RTC battery syndrome
- Thread starter Tichwin
- Start date
Terry Yager
Veteran Member
Yes. Sometimes. (I've rigged-up a lot of different internal batteries in various laptops). Give it your best shot with the cheapest cells you can find.
--T
--T
Dwight Elvey
Veteran Member
Hi
Most laptops have a soldered in battery someplace. It is usually
3 NiCad cells and, space allowing, can be replaced with portable
phone batteries ( not cell phone ).
If you can't find some NiCads small enough, look for someplace
else in the case that you could put it. You can then just run
wires to the location.
I actually recommend remote mounting like this.
One can then put the battery into a small baggie to help protect
against leaks.
You have to disasseble the case to get at these batteries. Each
laptop has it's own tricks on how to open them up.
Good Luck
Dwight
Most laptops have a soldered in battery someplace. It is usually
3 NiCad cells and, space allowing, can be replaced with portable
phone batteries ( not cell phone ).
If you can't find some NiCads small enough, look for someplace
else in the case that you could put it. You can then just run
wires to the location.
I actually recommend remote mounting like this.
One can then put the battery into a small baggie to help protect
against leaks.
You have to disasseble the case to get at these batteries. Each
laptop has it's own tricks on how to open them up.
Good Luck
Dwight
O.k. Terry and Dwight, thanks for your reply. Those NiCd cells are quite easy to purchase so I'll give it a try. Opening up laptops is relatively easy, much easier than I thought.
What I still want to know is how these small batteries load and how much time it takes to activate them. I concentrate on the essential CMOS RTC.
I've read on the net that the CMOS battery is loaded via the main battery through a trickle process. On Compuserve, a collegue got the advice to charge his Toshiba T1200 with NiCd main battery in place almost overnight with the original adapter- not to load his old main battery but to load his RTC CMOS! I tried this but it failed: after about 3 hours, the continuous red LED indicating battery charge changed to alternating red/green flashing. The adapter got pretty hot, also, so I stopped charging the T1200.
I tried to charge the CMOS RTC without main battery, at first 30 minutes, than 60 minutes. No go, still red light flashing. How much time would I need to load a new CMOS battery, and how (with or without the main battery)?
What I still want to know is how these small batteries load and how much time it takes to activate them. I concentrate on the essential CMOS RTC.
I've read on the net that the CMOS battery is loaded via the main battery through a trickle process. On Compuserve, a collegue got the advice to charge his Toshiba T1200 with NiCd main battery in place almost overnight with the original adapter- not to load his old main battery but to load his RTC CMOS! I tried this but it failed: after about 3 hours, the continuous red LED indicating battery charge changed to alternating red/green flashing. The adapter got pretty hot, also, so I stopped charging the T1200.
I tried to charge the CMOS RTC without main battery, at first 30 minutes, than 60 minutes. No go, still red light flashing. How much time would I need to load a new CMOS battery, and how (with or without the main battery)?
Dwight Elvey
Veteran Member
Hi
The fact that your charger got hot indicates that the battery has at least one shorted
cell.
I't may be that it requires the main battery to be connected to charge.
You should be able to charge the cells using an external source. Like I said,
the NiCad is usually 3 cells or a 4.5v battery. You should be fine charging
at a rate of 5 to 10ma. You can setup from some supply with a dropping
resistor. You should only need to remove one lead of the battery.
You just need to make sure that you keep the current low for charging.
I find it strange that you'd need the main battery to charge but that may
be true. Typically the charge rate used is really low in these laptops so just
charging for a couple hours may not be enough. Unlike a desk top, they'd
normally only need a trickle charge to hold, unlike your typical desk top
that would need to take advantage of a possible shorter on time.
Try leaving the laptop ON for at least 24 hours and then try a reboot.
Dwight
The fact that your charger got hot indicates that the battery has at least one shorted
cell.
I't may be that it requires the main battery to be connected to charge.
You should be able to charge the cells using an external source. Like I said,
the NiCad is usually 3 cells or a 4.5v battery. You should be fine charging
at a rate of 5 to 10ma. You can setup from some supply with a dropping
resistor. You should only need to remove one lead of the battery.
You just need to make sure that you keep the current low for charging.
I find it strange that you'd need the main battery to charge but that may
be true. Typically the charge rate used is really low in these laptops so just
charging for a couple hours may not be enough. Unlike a desk top, they'd
normally only need a trickle charge to hold, unlike your typical desk top
that would need to take advantage of a possible shorter on time.
Try leaving the laptop ON for at least 24 hours and then try a reboot.
Dwight
Thank you Dwight. I will try a 24 hour charge on the Toshiba T1600 with some safety precautions. Also, I prefer using the existing charging circuit of the laptop. I've been advised to measure the working temperature of this circuit regularly because the largest condensators might be destroyed by excessive heat during extended chargup sessions.
What surprises me is, that my Toshiba 386 computers (Toshiba T1850 and T1850C)do not have these CMOS problems at all. I did'nt use these laptops for over a year. I decided keeping on using the neat 1850 and dismount the 1850C completely for study purpoises.
After a year, the main battery and rtc-cmos were completely "empty" and the BIOS did'nt find the harddisk. I took only 10 minutes charging with the original adapter and 1 reboot to bring the computer into action. After 3 hours, the main battery indicator LED changes to yellow and yes, the 1850 can work about 15 minutes without it's adapter. Amazing if you take the age of the main NiCd into consideration: 15 years! Before dismounting the 1850C I noticed that it's main battery is dead but within 5 minutes, the RTC-CMOS can be charged. It looks like the 386 power charging circuit is different!
What surprises me is, that my Toshiba 386 computers (Toshiba T1850 and T1850C)do not have these CMOS problems at all. I did'nt use these laptops for over a year. I decided keeping on using the neat 1850 and dismount the 1850C completely for study purpoises.
After a year, the main battery and rtc-cmos were completely "empty" and the BIOS did'nt find the harddisk. I took only 10 minutes charging with the original adapter and 1 reboot to bring the computer into action. After 3 hours, the main battery indicator LED changes to yellow and yes, the 1850 can work about 15 minutes without it's adapter. Amazing if you take the age of the main NiCd into consideration: 15 years! Before dismounting the 1850C I noticed that it's main battery is dead but within 5 minutes, the RTC-CMOS can be charged. It looks like the 386 power charging circuit is different!
Epson HX-20 battery
Epson HX-20 battery
Now this one's for you Terry (Yager).
I just bought a HX-20 that hadn't been used for a long time. It has the original EPSON AC-adapter but I wasn't sure about the internal battery. I proceeded to charge the battery for 4 hours. It worked: I disconnected the adapter, put on the computer and it started. So far, so good.
Then, I wanted to continue loading towards 8 hours. I shut the computer off, reconnected the adapter and waited another 4 hours.
This time, disconnecting the adapter and switching on the computer did nothing. The computer works only when I reconnect the adapter. But the operational manual warns to never to use the computer while batteries are being charged i.e. with the adapter connected to AC.
What has happened? Have I overloaded the battery? And by doing this maybe I unloaded the battery without knowing? What must I do now? Wait for a few weeks to let the battery unload completely or just replug the adapter en load the battery for (8) hours?
Epson HX-20 battery
Now this one's for you Terry (Yager).
I just bought a HX-20 that hadn't been used for a long time. It has the original EPSON AC-adapter but I wasn't sure about the internal battery. I proceeded to charge the battery for 4 hours. It worked: I disconnected the adapter, put on the computer and it started. So far, so good.
Then, I wanted to continue loading towards 8 hours. I shut the computer off, reconnected the adapter and waited another 4 hours.
This time, disconnecting the adapter and switching on the computer did nothing. The computer works only when I reconnect the adapter. But the operational manual warns to never to use the computer while batteries are being charged i.e. with the adapter connected to AC.
What has happened? Have I overloaded the battery? And by doing this maybe I unloaded the battery without knowing? What must I do now? Wait for a few weeks to let the battery unload completely or just replug the adapter en load the battery for (8) hours?
Terry Yager
Veteran Member
Normally, I'd recomend 'zapping' the NiCad pack. You appear to have a little experience with batteries, so if you want to try this technique, just remember, YMMV. I usually zap my HX-20 packs by connecting them momentarily to the 12-volt battery in my car. I have resurected several shorted HX-20 packs by this method. PM me if you want more details. BTW, the recomended charge time for the HX-20 is eight hours. Too little and the battery won't charge completely, leading to (eventually) 'memory effect', and too much could burn-out the NiCads early from over-charging. (And yes, NiCads have been known to take a 'reverse charge', when they have been allowed to discharge completely). Google should turn up more info...
--T
--T
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