Acer Swift 7 (SF714-51T) full charge battery capacity keeps decreasing with every charge cycle

Hi there,

First time posting, so forgive me if there's some obvious solution which I haven't tried yet.

So, a bit of context, I purchased a second-hand Acer Swift 7 laptop (SF714-51T), expecting there to be some degradation in the battery's full charge capacity which I had then calculated to be at 60%, much lower than expected. Now I could've returned the item for a full refund, but I had been looking for one of these units for a while and finally found one at an affordable price. The store I purchased it from provides a 12 month warranty, with an option to request repair, however the store's manager kept giving me the run-around and kept refusing to do this, even though it was explicitly stated in their warranty policy.

Anyways as I really wanted to keep the laptop and hate contributing to e-waste, I managed to get a partial refund just in case I needed a new battery.

First I tried software troubleshooting, starting with a manual battery calibration (Charging to 100%, discharging to 0% and charging to 100% again), I'd repeated this about 20-25 times, however the full charge capacity kept jumping round all over the place between 60% and 5% of design capacity. I'd confirmed this with numerous battery reports generated by windows. I still kept getting unexpected shutdowns, incorrect battery estimates, etc.

Then, I reinstalled battery drivers numerous time, still no success in achieving a steady battery estimate nor a full charge capacity reading. Then I reset the operating system within windows, deleting all files. I had done this 3/4 times. Afterwards I'd completed a fresh clean installation of windows using windows media creation tool and booting from a USB drive, deleting all partitions when the option had allowed for it so the SSD would also be completely freed up. I still kept getting the same issue with full charge battery capacity going all over the place.

After doing all the software troubleshooting steps I could think of and search for, I then used a different high-quality charger but the problem remain unchanged. I purchased a new genuine battery (AP17A7J), which was pretty costly at £99.50. I replaced the battery and did a couple more charge cycles however, although it started at near the full design capacity, the full charge capacity started dropping with each charge, by around 300mWh each time which is around 2.5% of design capacity.

I'm at the stage where I can't think of anything else other than some unobservable issue with a power-controlling component on the motherboard, which I've tried to inspect to the best of my ability but I can't see any damaged component.

I know I'd kick myself if I don't try and at least exhaust all my options, where the final one is to ask the acer community, What should I do? Especially if the answer is a really simple and inexpensive one. Please help.

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AnhEZ28

@Mikarch do you still have problem with unexpected shutdown with the new battery?

Mikarch

Hi there @AnhEZ28

No unexpected shutdown with the new battery yet, however with the the full charge capacity decreasing with each full charge, it seems like it's heading in that direction. Also just did another full charge and the capacity at 100% has reduced by another 250mWh.

Mikarch

Here's a copy of the latest battery report.

Battery report 3.pdf

StevenGen

Mikarch said:

Here's a copy of the latest battery report.

If you purchased a none OEM battery and this laptop is working on it now and the “capacity keeps decreasing” then this is normal with none OEM batteries that are sold today! Btw, the 15" sibling of the Swift SF514-51T has the OEM "Battery PANASONIC AP16L Polymer 2S1P PANASONIC 2 Cell 4670mAh Main COMMON w/ LEM+ship mode" Acer part #: KT.00205.008 see if you can get a Panasonic battery for the SF714-51T within their range?

With replacement batteries it’s always a lottery of the quality that you get as they are cheap copies from China (some with very low quality and that is irrespective of the price you paid and even the ones that are quoted as OEM) as Acer do not have OEM batteries for this laptop that they fitted when this laptop was released! These batteries (as I’ve experienced ove rthe years with old laptop and I’ve bought many) always have charging problems and/or indications within the battery charging capacities that are shown in the Win-10 battery task bar icon and battery reports e.g. they either show 60% charge when they are fully charged and refuse to charge and so on, hence you need to run the laptop on battery power a few times and completely drain the charge until the windows warning of low battery comes on, don't worry about battery reports as they mean nothing.

You have done all the right battery calibrations that a consumer can do. I wouldn’t worry about the “battery capacity keeps decreasing” that you are so worried about as replacement batteries are not an OEM quality like Acer fitted (which for the SF714-51T are not made anymore) also check the DC in cable both at the side plug and the mobo plug ends (see caption) as its connection and deterioration state could have allot to do with how your battery is being charged, also inspect your charger, as old chargers do deteriorate and affect charging.

SF415-51T OEM Acer listed battery

DC IN CABLE

Mikarch

Hi @StevenGen

Thanks for the reply, I'll check out if Panasonic have an equivalent battery for the SF714-51T in their range. As for the replacement battery, I actually called up Acer who referred me to their official parts store 'Justacer' and this is where I purchased the part from. The new battery was manufactured at the same site as the old battery, which I believe is contracted to Simplo Technologies and their factory in Taiwan working on behalf of Acer (From my research this is where all the original AP17A7J batteries came from). It is an OEM battery as Acer have assured me, its possible they gave me a substandard battery, but I can't believe it would show the kind of degradation that is noticeable over only a few days.

With regards to the charger, I have replaced this a little while back with a new, high quality charger with smart output protections.

I'll check out the DC IN cable when I next open up the laptop. If it was deteriorated, what would I be looking for? Also are there any other cables or components I should check when I open up the laptop?

Mikarch

One more thing, there is a slight crackling/static/almost whining noise coming from towards the back of the laptop near where the connection point for the battery is, I didn't think anything of it, maybe just chalking it down to the noise the current makes as the laptop is in operation, or possibly the sound the sound of the SSD. Its quiet and really you can only hear it if you press your ear towards that section. Though it might be an indicator of what's going on with the battery, if anyone has answers?