Fast Charging VS Slow Charging Phone

Discussion in 'General Hardware' started by Hulk, Nov 21, 2018.

  1. Hulk

    Hulk [H]ardness Supreme

    Nov 4, 2005
    I just got a Motorola Z3 Play phone and it came with a fast charger. It charges the phone really quickly, like 90% in 50 minutes or something like that. But what I know about charging electric bike and RC car batteries is that the slower you charge them the longer they will last. I was wondering if the same thing applies to phone batteries? I'm wondering if I should let the phone charge slowly especially overnight. I kept my last phone (Moto G 1st gen) for 6 years before upgrading to this one so I'm not one of those people that upgrades every year or two. I'd like this phone to last me at least 5 years.
  2. auntjemima

    auntjemima [H]ardness Supreme

    Mar 1, 2014
    I know what you mean by slow charger. You are referring to a standard charger offered with a cell phone versus the fast charger, or higher output.

    My understanding is the fast charger will kill batteries faster. Heat is one of the biggest factors.
    Last edited: Nov 21, 2018
  3. E4g1e

    E4g1e [H]ardness Supreme

    May 21, 2002
    Sorry about that. I got carried away. If that's what you meant, then there are some cell phone included chargers that are already super-fast. And there are a few people who switch to a slower or much slower (much lower output) charger. Unfortunately, one can actually go too low on the replacement charger, in this case: The output becomes too low for the phone to operate when plugged in. An example is that a given cell phone requires 10 watts (2.0A @ 5V) to properly charge or operate the phone. Unfortunately, a lot of people cheap out by buying a 2.5W (500mA @ 5V) charger - and that will cause problems with most current cell phones.
    auntjemima likes this.
  4. kora04

    kora04 n00b

    Dec 22, 2012
    Depends on you. I want the fast charging because it's fast & the phone will not outlive the battery with me. I want the newest flagship and don't plan on keeping a phone too long.
  5. Tiberian

    Tiberian DILLIGAFuck

    Feb 12, 2012
    The general rule with Li-Ion batteries which are the most commonly used type in modern devices is that heat is bad for them, whether it's heat caused by the device itself becoming warm during use, or by external heat aka used in a hot environment, but most especially the heat buildup in the cells of the battery itself during a charging session. Qualcomm Quick Charge 1.0 and 2.0 both basically provided as much current as they were allowed by the spec to the cells and that created heat during the charging process. Quick Charge 3.0 took a different approach and lowered the current being provided but raised the voltage which dramatically reduced the amount of heat generated internally in the cells and it's actually not bad now.

    For years I refused to use Quick Charging even on devices that supported 1.0 and 2.0. I have a Motorola "TURBO" charger which is Quick Charge 2.0 compliant and if I use that charger with my LG V20 (which supports an offshoot of Quick Charge technology known as Power Delivery) the battery does get quite warm depending on how much charging has to take place; if it's under 40% when I first attach the charger it will definitely warm up to about the 80% point then it cools down as the current requirement drops in that last 20%.

    I recently got a Samsung fast charger that was originally supplied with the Note 9 and gave it a shot with my V20 and it uses Power Delivery to provide Quick Charge 3.0-like charging speeds (the V20 technically is Quick Charge 3.0 compliant because of the Snapdragon 820 SoC but LG decided not to support QC3.0 for some stupid dumbass reason). During the charging process with the Samsung charger the battery temp barely rises at all even from a very low charging point (under 20%) so it's a vast difference and now because of this I don't mind using Quick Charging even if it's Power Delivery to get it done.

    Personal recommendation: never use quick charging unless you really truly do need to get a useful charge and do it quickly as in you have limited time to plug in and get the most charge you can. Other than that, and if you don't have a device that is either QC 3.0 compatible or supports Power Delivery with an appropriate charger I'd say use a traditional one, say a 2A charger (they all provide 5VDC but they vary in terms of how much current aka amperage) and a decent USB cable - I say decent USB cable there because the majority of them are just crap, really. Spend a few bucks and get a good USB cable whether it's microUSB or USB-C, doesn't matter, just don't get the bargain basement $.99 for a 3 foot cable kind of crap. Monoprice makes excellent USB cables of all kinds, some with 26 gauge wiring to ensure you're going to get all the current the charger can provide efficiently.

    I haven't really noticed that much of a boost in terms of charging times personally: if I use a plain old vanilla non-QC compatible 5V 2A charger with my V20 the battery can go from 15% to 85% in about 1 hour and 10 to 15 minutes. I use an app called AccuBattery that alerts me when it's at 85% and I unplug, this increases the lifespan of the battery as measured in months and years, not on a per charge basis, there's real science behind this 80-85% point and it's a proven thing to help battery lifespan.

    If I use the Samsung fast charger from the same 15% to 85% it takes roughly 55 minutes to an hour solid so, it's not really saving me a big huge chunk of time. It doesn't really charge it up to 50% all that fast either, roughly 1% a minute is what I've noted.

    tl;dr Newer quick charging tech like QC 3.0 or Power Delivery (and QC 4.0 now too) works better and charges faster while reducing the heat that older QC tech caused which means it's more efficient and less damaging to the battery. If you don't have a QC 3.0/PD device, use traditional non-QC capable chargers and only use QC chargers (if your device supports it) occasionally when you really need a quick charge, literally, but don't use the quick charger every single time you charge the device, use the vanilla one(s) for that purpose aka day to day charging.