New Third Party A1502 Battery to good to be true, what's going on?

[Frieg]

Hi,

earlier this year I bough a used 13 inch early 2015 MBP cheap which had a still working, but pretty used original battery (1400 cylcles, less than 60% remaining full charge capacity)

No problem, bought a third party battery (supposedly one of the higher quality ones) and changed the battery by myself. was way easier than I anticipated, took less than 30 mins.

So, now concerning the new battery...

I would expect some fluctuations of the full charge capacity value with use, but it just stays exactly.the.same!
Since I first fired up the Macbook with the new battery the capacity stays at 7176 mAh.
I did several SMC resets so far, some full cycles, but the value does not change.

imo what's going on here is physically impossible, minor fluctuations in capacity are to be expected. what could possibly keep this value fixed?

the battery age is a false value. the manufacturer reuses the circuits of original batteries and exchanges the cells with new ones.

oh and the battery is running perfect, it delivers the 8-9 hours of light use.

 

[Fishrrman]

How about a link to the replacement battery you bought...?

 

[Frieg]

Why does it matter? I won't advertise for the seller here and the shop site does not provide any interesting technical information. only that the battery is specced at 7000mAh.

 

[f54da]

I don't see what you're asking. You already know the battery is using a bms (likely not even the original TI one) providing fake info. The cells in your battery are probably b-grade at best. Estimated health only changes after checkpoints are hit (on the original ti algorithm), so your smc resets don't do anything.

So what exactly is your question. The fact that it's currently working doesn't contradict any of the above. You may have even gotten lucky and it'll last for more than 1 year. It's probably safe since I hope even the cheapo chinese bms implement basic ov/oc protections, but if you treasure your laptop like an heirloom I wouldn't risk it when there are chinese batteries that are at least more transparent about their supply chain.

 

[nickandre21]

Back in 2019 I got one Chinese replacement for my late 2013, couldn’t tell much from the original but the date on this was set to 2015.
The battery just like yours stayed stable for a long time. Then it would fluctuate when using it for light usage it would stay at a higher percent and heavy usage it would drop 5-6% in health. It gave a good 2 hours back up when under heavy loads.

I stopped looking at coconut battery and just used it. It’s now at 980 cycles however the health is erratic like I said before, light usage shows 83% health and heavy usage will make it go to 74% and coconut battery will show a check battery status.
However there has been no issues as of yet.

Give it a few more cycles and it may drop if that’s not the case use it as you would and just see if the back up time decreases or abrupt shut downs.
I’m not sure if this would be related but when the original battery was almost at the end of its health the fans would spin up quiet often and the mac would be laggy, when I swapped the battery for a new it was back to normal

 

[f54da]

On the 2013 at least, running without battery removed (or possibly when a faulty battery is detected?) will assert bd proc hot on the cpu and throttle to 800mhz or something.

 

[Frieg]

The question was „what’s going on“, the info that the battery may report a fake value on purpose (and that this is possible) is new to me and may answer my question I already guessed something like that but was unable to find one single report of similar symptoms so I assumed that it‘s not possible to alter the circuit of a battery in way that it reports a fixed value.

What does bms and ti stand for?

@nickandre21 did your battery also stay at the exact same initial full charge capacity value for a long time?

The battery is not a cheap one, it cost 120€ and the manufacturer assures that only high quality cells are used for his batteries. I will wait a few more cycles and contact the seller if nothing changes, will report back with how that went and what his explanation of this phenomenon is.

 

[f54da]

The BMS (battery management system) is what sits between the raw battery cells and the smc. It is the one that reports all data to the smc, handles balanced charging logic, has protections, etc. TI is texas instruments, they are a supplier of such BMS ICs. In the case of the 3rd party Chinese batteries they either reflash the firmware on the ICs, or just replace them entirely with something more amenable to reporting faked values. There's nothing inherently bad about using the non-original TI BMS, just that I'm skeptical they will spend the extra cents to implement all the same protections, configure the logic correctly, and so on. (Configuration meaning that even if you use exact same model TI BMS, you have to configure threshold parameters correctly).

>manufacturer assures that only high quality cells are used for his batteries.
Sure they all say that. Unless you verify their supply chain, you have no way of knowing. General principle when buying 3rd party li-ion batteries is to assume that nothing should be taken at its word.

I doubt you're going to get any explanation from manufacturer.

 

[nickandre21]

@nickandre21 did your battery also stay at the exact same initial full charge capacity value for a long time?

It did for a month or two if I recollect it was sitting above design capacity at 105% and then below 100%

I have seen some videos online where they do flash in a new mah onto the software even reset cycle counts.
However if the battery is working as advertised I.e giving you a good back up I would not worry much. That said if you feel like can always contact the seller and query them if they too feel it’s odd you can ask for a replacement

 

[jav6454]

Why does it matter? I won't advertise for the seller here and the shop site does not provide any interesting technical information. only that the battery is specced at 7000mAh.

Because normally I'd recommend you only buy 3rd party batteries from reputable sources like iFixit.

 

[f54da]

Lmao, ifixit sells the same mystery meat chinese batteries that others do, with double the markup.

 

[Frieg]

third party batteries are all hit or miss, no matter the source you buy them from. even ifixit is known for a risk of receiving a dud that races down to 60% capacity in less than 2 months. if you want to be absolutely sure to receive a battery of apple quality your ONLY option is to walk to apple or a certified repair shop and let them change the battery.

the seller answered that that symptom is not known to him so far and cannot really explain what's going on.
his argument was that in the same batch of the serial number of my battery (these are always randomly tested) always a different initial capacity value was read out. this would speak against the assumption that a fixed value was stored intentionally to mislead customers. he wrote as long as the battery runs down to 0 without the MacBook shutting off unexpected (without prior warnings) the full charge capacity value should be correct. but he suggested that I head to a German Mac community where his batteries are widely discussed and ask if others have similar symptoms. so he seems at least interested to gain more data on the phenomenon, but I am supposed to do the footwork

last cycle I let it run down until the MacBook shut off, there were the normal 10% and 5% warnings but a few jumps below 20%. 20→ 13→8 → 3 → off. the backup time was excellent and on par with what could be expected from a factory new MacBook 2015.

i will post in that community and will closely watch the battery. If it shows premature degradation the seller is known to exchange it for a new one.