Spin SP315-51 Shuts down when picked up and moved.

cfs_spin_user · June 2022

I have a Spin SP315-51 that shuts down when picked up and moved when powered by the battery. It usually recovers after I press the power button for a few seconds. The last time it did not. It would only power up with the AC adapter plugged in. It shows that the battery is connected but 0% charge. Before I unplugged the AC power and moved it, it was showing it was fully charged (100%). I tried many combinations of pressing the battery reset switch and power buttons for over 1 minute without success. I disconnected and reconnected the battery connector without effect. I found a video of an Aspire user reporting the same problem

https://youtu.be/ArFfRXkWn3U?t=1388.  He traced the problem to a case open detect switch. I cannot find anything that could be such a switch inside the Spin 3. I understand, based on that video, pin 3 of the battery connector needs to be connected to ground in order for the battery pack to connect the battery to the connector. I do not measure any voltage at the battery pack power pins with the battery removed. I did not try connecting pin 3 to gnd to confirm that this is how this battery pack worked in case it is different from what the Aspire owner found.

Where is the case open detect switch on this Spin 3? I cannot find it. Is it under the motherboard? Is there another cause for this problem. My experience when batteries fail their voltage drops but does not go to zero or they loose capacity. Replacing the battery will not fix the issue if it is a faulty open case detect switch.

I installed the latest drivers I found on the Acer download page without effect. I did not update the bios for fear of the flaky power. Running Windows 10.

Thank you.

cfs_spin_user · July 2022

This is a known but NOT well documented fault with the batteries in many Acer laptops. ‘This type of fault tends to happen when the device stays connected to AC power all the time, when the device is shutdown using the power button, or when the device runs out of battery too often.’ In my case, I use this laptop as a desktop replacement and leave it plugged into the AC adapter almost all the time. I do not like disconnecting the plug into the laptop because it is one of the smaller ones and this puts wear on that connector and it is hard to find replacements.

I would argue this is a design flaw. The battery monitor inside the pack detects an over or under voltage condition and turns off the FETs that connect the battery output to the connector.

I monitored the battery voltage on my laptop using the BatterInfoView utility for a few hours today. I disconnected the AC power and turned on the laptop this morning. BatteryInfoView showed the voltage at 16.4, 7 watt discharge and it dropped to 95% charge almost immediately after disconnecting the AC adapter. When I plugged it back in, after an hour the voltage ramped up to 17.0V and 0 milliwatts discharge. This is a 4 cell pack and max voltage should be 16.8V. After several hours of the laptop running and plugged into the AC adapter the battery voltage slowly dropped to 16.89 volts.

What you are supposed to do with lithium ion batteries is charge them at 1C (constant current) until the voltage gets to max. You then charge the battery at constant voltage mode until the charge current drops to 1 to 10 mA. You then disconnect the battery from the charge circuit. If you do not disconnect the battery from the charger you can overcharge the battery damaging it and, worse case, cause a fire. It would appear that Acer laptops are hot rodding the top off a little to speed things up. The margins may be very tight so that this occasionally trips the fault detection inside the battery CPU disconnecting the battery from the connector. In my case the overvoltage likely tripped. It likely took a few days for the battery to self discharge and drop below the fault trip point thus explaining why it had no voltage at the connector and later started working. In addition, there is likely more to this than that being that the monitoring program is fairly involved.

The other fault modes are harder to explain without diving deep into the boot loader and shutdown code on the processor or the code in the CPU in the battery pack. Atmel has a nice application note for their reference design for a Smart Battery. You can find it here:

http://ww1.microchip.com/downloads/en/Appnotes/doc2599.pdf

The Smart Battery Data Specification can be found here:

http://www.sbs-forum.org/specs/sbdat110.pdf

Both contain a summary table of commands over the SMBus. Battery Mode and BatteryStatus are two of the few write commands that could be used by the BIOS or the OS to disable or enable the battery. I do not see a command that could be called “reset”.

The Atmel application note mentions that their code contains a boot loader for updating the code in the CPU battery monitor via the SMBus.

Commodore_1995# · June 2022

It is usually located near the ram memory. Can you send a clear picture of your motherboard?

cfs_spin_user · June 2022

I wish it was there but I do not see it. If it is there it is under the motherboard or done some other way that does not involve a switch. Is there a utility that can check its state other than the battery showing up with 0% charge and not charging?

Image: https://us.v-cdn.net/6029997/uploads/editor/07/trv15q7f3ytj.jpg

Image: https://us.v-cdn.net/6029997/uploads/editor/bi/ldnz2uwqx0g2.jpg

Image: https://us.v-cdn.net/6029997/uploads/editor/0s/3w4eat8qfd9r.jpg

billsey · June 2022

The SP315-51 models do not have a case open detect switch.

cfs_spin_user · June 2022

Checked against another working battery. These batteries when unplugged disconnect the battery pack from the connector. Pin 3 appears to be pulled to ground at the connector on the motherboard (measured with a ohm meter). Now after taking the unit apart yet again the battery started working again. Shows up as over 90% charged. I love intermittent failures.

Commodore_1995# · June 2022

Have you checked the bios version?

Image: https://us.v-cdn.net/6029997/uploads/editor/3d/qecgjc5gil67.png

cfs_spin_user · June 2022

It has version v1.08, the latest version for this model according to Acer's support page. So far you are zero for 2 with your suggestions.

It is likely an intermittent issue with the control module inside the battery pack. Especially with pin 3 on the MB grounded which appears used on other Acer models to be part of a open case detection circuit. I do not see how the bios could be part of the problem. Current information suggests pin 3 is not controlled by the processor so what would the bios do. I do not have the inclination to dismantle the battery pack like the more determined gentleman in the video, and reversed engineer the battery pack to nail this down. I was hoping that I could find someone from Acer on this forum that actually has the schematics for this laptop as well as knowledge of this type of failure and could confirm that these battery packs use pin 3 to disconnect the batteries as part of a multi issue protection circuit. If the module is detecting something inside the battery pack and disabling it that would explain the failure and suggest buying a replacement battery. Based on what I measured and observed this is likely, being that pin 3 is grounded on the MB.

It would be helpful if you provided more information for why the bios could be the problem before suggesting a solution that could BRICK an otherwise working laptop. As you should know, updating a bios on a laptop with intermittent power issues is risky. If the update does not complete before a power loss you can completely disable the laptop without possible recovery. The beauty of updating a bios on a laptop is it should greatly lower the risk because it is inherently "battery backed up". On a desktop this is not the case. On a laptop with power issues you are really pushing your luck.

billsey · June 2022

Yeah, this is a community support board, so no Acer Engineers to answer questions, only other users like us. The SP315-51 models do have a battery reset switch, which when used properly should do a reset to the internal settings on the battery module. You need to shut down and disconnect power, then press and hold the reset for at least 15 seconds and 30 is better. Then wait long enough to finish a cup of coffee before reconnecting power, then wait again until the battery charge indicator shows a full battery. When you then power up the internals of the battery will be reset to known good parameters.

cfs_spin_user · June 2022

Really, then people like Acer-Ingrid, Acer-Joe and other members of the Acer-Crew are just PR types? Do not need an engineer, just a good tech. Based on what you said this forum is just the blind leading the blind. Are their any Linux developers here? They do a lot of reverse engineering of these products.

Apparently I was unable to make clear that I had done all kinds of machinations of the battery reset, power-on, waiting, disconnecting the battery, the AC adapter etc in my original post and those that followed. Reading comprehension is tuff on us all. It appears much of what I wrote that I thought demonstrated that I did all of these BASIC troubleshooting attempts was not clear.

Still DO NOT have a real answers and the suggestions have a car mechanic whimsy to them. The guy in the video seemed more determined. These battery packs have circuitry. There are many chips out there for this, some with very informative datasheets. I did not got to the trouble to narrow down the problem at that level. All things point to the battery being the problem being that pin 3 is grounded at the MB. The other Acer models appear to use this for an open case disable function. The pack on its own appears to use it to disconnect battery power from the connector when the pack is removed. There is a SPI type interface, but it seems used to interrogate the battery pack and not control it. Your comment seems to suggest otherwise. Something keeps track of the battery history based on the battery report. Is that in the battery packs or in the OS? Other documentation states the battery reset switch just disconnects the battery from the laptop that mimics a battery removal. You then need to "train" the OS to establish a battery history. However, the utility BatteryInfoView, makes me wonder if there is some history stored in the battery pack.

Please provide resources that provide more information.
Thank you.

billsey · July 2022

The Acer employees you mention are moderator for the forums. They likely fit somewhere in the hierarchy under support, but not as technical types. I believe battery stats are held both by the battery and by the OS, hence the need occasionally to calibrate the OS or reset the battery. Google seems to be better at handling the OS side than Microsoft, but that wasn't the case for quite some time. I haven't seen technical details of what actually happens inside the battery, but experience shows that the reset, when done properly, does seem to get it's stats under control even when really corrupted. Experience also shows that just pressing the reset button doesn't do a full reset but does do a forced power off of the laptop.

Commodore_1995# · July 2022

I have a question: when you disconnect the battery and turn on the computer using only the power supplied by the power adapter, does the computer turn off when moved? If there is a power cut button, it is likely on the other side of the motherboard.

cfs_spin_user · July 2022

This is a known but NOT well documented fault with the batteries in many Acer laptops. ‘This type of fault tends to happen when the device stays connected to AC power all the time, when the device is shutdown using the power button, or when the device runs out of battery too often.’ In my case, I use this laptop as a desktop replacement and leave it plugged into the AC adapter almost all the time. I do not like disconnecting the plug into the laptop because it is one of the smaller ones and this puts wear on that connector and it is hard to find replacements.

I would argue this is a design flaw. The battery monitor inside the pack detects an over or under voltage condition and turns off the FETs that connect the battery output to the connector.

I monitored the battery voltage on my laptop using the BatterInfoView utility for a few hours today. I disconnected the AC power and turned on the laptop this morning. BatteryInfoView showed the voltage at 16.4, 7 watt discharge and it dropped to 95% charge almost immediately after disconnecting the AC adapter. When I plugged it back in, after an hour the voltage ramped up to 17.0V and 0 milliwatts discharge. This is a 4 cell pack and max voltage should be 16.8V. After several hours of the laptop running and plugged into the AC adapter the battery voltage slowly dropped to 16.89 volts.

What you are supposed to do with lithium ion batteries is charge them at 1C (constant current) until the voltage gets to max. You then charge the battery at constant voltage mode until the charge current drops to 1 to 10 mA. You then disconnect the battery from the charge circuit. If you do not disconnect the battery from the charger you can overcharge the battery damaging it and, worse case, cause a fire. It would appear that Acer laptops are hot rodding the top off a little to speed things up. The margins may be very tight so that this occasionally trips the fault detection inside the battery CPU disconnecting the battery from the connector. In my case the overvoltage likely tripped. It likely took a few days for the battery to self discharge and drop below the fault trip point thus explaining why it had no voltage at the connector and later started working. In addition, there is likely more to this than that being that the monitoring program is fairly involved.

The other fault modes are harder to explain without diving deep into the boot loader and shutdown code on the processor or the code in the CPU in the battery pack. Atmel has a nice application note for their reference design for a Smart Battery. You can find it here:

http://ww1.microchip.com/downloads/en/Appnotes/doc2599.pdf

The Smart Battery Data Specification can be found here:

http://www.sbs-forum.org/specs/sbdat110.pdf

Both contain a summary table of commands over the SMBus. Battery Mode and BatteryStatus are two of the few write commands that could be used by the BIOS or the OS to disable or enable the battery. I do not see a command that could be called “reset”.

The Atmel application note mentions that their code contains a boot loader for updating the code in the CPU battery monitor via the SMBus.