Ideas why laptop charger stays stuck at 'not charging' or 'zero charge rate'? - Page 1
Forum section: electronics / beginners

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: July 16, 2025, 05:41:44 am
content: I added a buckboost to make the charge voltage go from ~13V of the leisure battery to 19v.It will charge sometimes and other times not.I thought maybe due to fluctuations in the environment perhaps the boost dipped below 19V. I checked this and it was still around 19V but I raised it to around 21V to be sure and yet the problem persists. What I mean is I raised it to 21V and it worked for a while but then went back to not charging so it wasn't that that rate was overcharge voltage and thus causing the issue.I looked online and found a thread that even someone who plugs it into normal wallplug experienced the same thing so I am guessing it might not be to do with the idiosyncratic setup of using a buckboost.It is currently on 91% and zero charge rate. Even though it can stay at this status for a whole day it seems to very gradually be declining hence why it is at 91% as day by day there is a tiny deficit which is not being replenished. Sometimes it will suddenly work again and charge to full but I have no idea what causes this to happen.As long as it just decided to do that now and then while the rest staying at an even keel I suppose it is ok.No telling when it will decide to start charging again though and it would be nice to figure out why it happens.EDIT: Hmm, I just tried unplugging and plugging back in again and hey presto it is charging. The solution on the thread I read the other day of aforementioned person with the same issue but with wallplug mentioned they waited for the laptop to boot before plugging in and then it worked. I remember I did try that after their recommendation and it did work that time but then back to the previous issue.Now it worked again so I wonder if the battery has to 'warm up' before it will take a charge? :shrug:

author: JustMeHere
author_rank: Frequent Contributor
timestamp: July 16, 2025, 05:49:47 am
content: Most laptops do not fully charge the battery anymore. You will need to look at your bios settings. The laptop I'm using right has the battery at 74%. Mine is set to keep the battery between 70% and 80%. I can put it into "high mobility" mode and it will charge the battery to 100%.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: July 16, 2025, 05:56:13 am
content: Quote from: JustMeHere on July 16, 2025, 05:49:47 amOh right. That is reassuring to know then that it might not be a malfunction at all. I don't mind that. The only concern was that it could have drained to 0% and still not charged but if it is just doing some cycling thing or whatever, no problem.I only leave it plugged in to the power supply anyway. I tried to leave it unplugged the other day and it just decided to switch off after about half an hour using the battery even though I had checked the charge remaining only a few minutes before and was reading over 1 hour left.It is not a spring chicken btw. I think circa 2013.

author: jwet
author_rank: Frequent Contributor
timestamp: July 16, 2025, 03:24:15 pm
content: Chargers also probe the battery before they start charging- this is call "preconditioning". They want to make sure that the battery is in good shape before they put real current to. There are generally a few tests. They measure battery temp, if its high, they delay charging til it cools down. They measure open circuit voltage, if a battery is over discharged, less than about 2.4V/cell for lithium, they won't initiate fast charging- they may initiate a slow charge and see if they can get the cell up to 2.4 or so. There may be other things that chargers do during preconditioning.This can be frustrating. I have some Ryobi power tools and they are very finnicky about declaring batteries unchargeable and just flashing a red light on the charger. I've taken these packs apart and often find one weak cell that can be brought back up with an hour on a bench supply at a low rate to get it up to 3v- be careful, there is a hard limit at 4.2 that you shouldn't get too near without some precision. You'll see a lot of frustrated carpenters and tradesmen on Youtube that have found ways around these rejected batteries- some of the methods work some of the time. If you have a battery that hasn't got 500 cycles on and you can open it without destroying it, take a look at the individual cells. I have problems with these Ryobi's because I leave them up at a cabin and they sit for a few months at a time, on return, they've self discharged below the chargers magic number and get rejected. I actually think the packs get lonely up there...;-}. A hard over discharge of a battery is fatal but well designed products shouldn't allow this. This soft over discharge of sitting doesn't seem to be fatal but can require some manual intervention.Good luck.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: July 16, 2025, 04:23:17 pm
content: Quote from: jwet on July 16, 2025, 03:24:15 pmCheers.Why do you have them in a cabin for a few months? Is it some type of remote setup?

author: BeBuLamar
author_rank: Super Contributor
timestamp: July 16, 2025, 04:36:36 pm
content: Today most laptop charger is only the power supply the laptop itself control the charging. The laptop would stop charging when it determines enough charge.

author: radiolistener
author_rank: Super Contributor
timestamp: July 16, 2025, 04:55:01 pm
content: Charging circuits in laptops are not simple, they often use a microcontroller with sophisticated algorithms. If the controller detects that the laptop has been plugged in for a long time, it may intentionally keep the battery charge below 100% (usually at 80-90%) to reduce battery aging. This is because batteries degrade faster when constantly kept at full charge, so this behavior is designed to extend battery lifespan rather than being a fault.If you want to fully charge the battery, simply unplug the laptop for a few minutes to signal the controller that you intend to use it on battery power. Then reconnect the charger and wait for the battery to reach full charge.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: July 16, 2025, 05:13:47 pm
content: Quote from: radiolistener on July 16, 2025, 04:55:01 pmWould this still apply even if the laptop is from 2013, as stated?I don't care about it as long as it is normal operation which it seems from replies it could well be.

author: radiolistener
author_rank: Super Contributor
timestamp: July 16, 2025, 05:18:02 pm
content: As far as I remember, I first encountered this feature on my laptop from HP around 2013. So yes, it's quite possible that your device already uses similar battery management logic.

author: jwet
author_rank: Frequent Contributor
timestamp: July 16, 2025, 05:39:57 pm
content: Why do you have them in a cabin for a few months? Is it some type of remote setup?Its on the water about 4 hours north of me in Coastal VA. Its in a quiet cove off the Chesapeake bay- Crab country. My inlaws retired to the area from Washington, DC. The lot next door went up for sale and I bought it. Its on the water with a nice pier and a small house that I build with a friend- something I allways wanted to do. My friend was a retired custom home builder and helping to build a little cabin sounded like fun. Its nice an relaxing. Giant deck, 1 bedroom, nice bath, small kitchen, living room area and of course an electronics lab that I share with the stacked washer and dryer. The lab has just enough test equipment to be do some things (Rigol Scope, Chinese ARB Generator and a few power supplies- and a 3d printer). I also have a second class set of tools up there so I don't have to haul them back and forth- Ryobi bonus pack, drill, jigsaw, little circular saw. We go up for about a month in the summer and then on and off for holidays, etc. I've talked to Ryobi and they're verified that their batteries do get lonely when left too long.Take care

author: tooki
author_rank: Super Contributor
timestamp: July 16, 2025, 05:59:44 pm
content: Quote from: BeBuLamar on July 16, 2025, 04:36:36 pmNot most, but all. And most likely for all laptops ever made, since all laptops need the ability to be mains-powered. (Does anyone know if there has ever been a laptop that only used battery packs that could only be charged in an external charger, the way power tools work?)

author: BeBuLamar
author_rank: Super Contributor
timestamp: July 16, 2025, 06:33:49 pm
content: Some of the older laptops that used NiCad or NiMH the charger controls the charging rate although the laptop continuously draws power from the battery.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: July 16, 2025, 09:18:29 pm
content: Quote from: tooki on July 16, 2025, 05:59:44 pmStill trolling.One out of the three laptops on my desk always charges to 100%.Once again, you're wrong.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: July 17, 2025, 06:41:30 am
content: Quote from: jwet on July 16, 2025, 05:39:57 pmSounds like a nice getaway.I also have thought about constructing my own structures however there aren't the raw materials on site at least for wood and that costs a lot to buy not only for untreated trunks but also haulage.I have been thinking of making out of clay like historical british buildings as there is an abundance of that!

author: tooki
author_rank: Super Contributor
timestamp: July 17, 2025, 03:01:32 pm
content: Quote from: JustMeHere on July 16, 2025, 09:18:29 pmI am absolutely correct: I said nothing about charge levels. (Besides, 100% is a charge level the laptop can choose to charge to.) The entire post I responded to is BeBuLamar saying that “most” laptop “chargers” are just power supplies. I say that I suspect it’s actually all. That’s it. No more, no less.I don’t think you understood what BeBuLamar was saying.So fuck off with your “trolling” claims. You don’t even understand what the term means. Just because you disagree with something I say doesn’t mean I’m trolling.

author: tooki
author_rank: Super Contributor
timestamp: July 17, 2025, 03:07:10 pm
content: Quote from: BeBuLamar on July 16, 2025, 06:33:49 pmWhat do you mean exactly by this? Can you elaborate?Many modern laptops require a battery to function because peak current draw exceeds what the power supply can deliver, even if the average current is no problem.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: July 17, 2025, 03:08:10 pm
content: Quote from: tooki on July 17, 2025, 03:01:32 pmLol at least I am not the only one that gets hate on this forum. It seems the place is just generally quite toxic.I agree that I tire of people overusing 'troll' for anything they personally find not to their taste. It has become like the 'incel' insult. People just want to throw it at anyone they want to take a shot at.

author: Halcyon
author_rank: Unknown
timestamp: July 18, 2025, 05:59:45 am
content: Quote from: electroniclearner820327 on July 17, 2025, 03:08:10 pmNope, it's actually quite tame for an internet forum, I wouldn't have it any other way. People just need to learn to get along with each other, or if they can't, leave each other alone and stop bickering like school girls.

author: amyk
author_rank: Super Contributor
timestamp: July 18, 2025, 06:47:17 am
content: Grab a few laptop schematics, study their power circuitry, and the datasheets for the related control ICs.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: July 18, 2025, 08:10:55 am
content: Quote from: Halcyon on July 18, 2025, 05:59:45 amYes I wrote before that I like how this place seems to take a lighter touch to moderation than places like reddit for instance which I ran from and have now blocked on my adblocker from even showing in the search results. Feel a weight lifted off now I have done that.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 22, 2025, 01:55:16 pm
content: @electroniclearner8 ...maybe adblock eevblog too ? when you answer like this ... meh

author: Haenk
author_rank: Super Contributor
timestamp: July 22, 2025, 02:12:22 pm
content: Quote from: jwet on July 16, 2025, 03:24:15 pmFor Google records: I experienced the same with an 4.0Ah Einhell pack, just about 2 weeks ago. Had the block in the shed and last used autumn of 2024 - attached to the tool, but with a physical switch (so no drain, just natural leakage). Pack refused to get recharged. 4 screws later, I was able to measure the individual blocks (4x3 AFAIR) - sure enough, one was rather low. With my bench PSU, set to 3.5V and at first limited to 100mA, later to 1A, I charged up all blocks individually. When all were at the same level, I put the thing back on the charger, and it was happy to quick charge it to "full".Good to know: The Einhell packs don't seem to destruct themselves when below BMS-happy voltage.