# Which power bank should I buy and PC Mag power bank reviews
## Original Post by [SimonJones](https://community.anker.com/u/SimonJones)
*June 5, 2020, 12:57am*
Hello All.
I’ve seen a few posts about power banks and thought it’s time I get one, but which one?
I have a samsung galaxy s20 which has a 4000mah battery.
I like the size and weight of the 10000mah power bank, but would this fully charge the battery twice?
I understand there is a certain amount of loss but how much loss?
I won’t ever need more than 2 full charges, but also what about loss over time like in storage or battery deterioration.
Any link or information would be awesome.
Here’s a PC Mag review including a lot of Anker power banks I found earlier.
<aside class="onebox whitelistedgeneric">
<header class="source">
<img src="https://d1bdmzehmfm4xb.cloudfront.net/original/3X/e/8/e8ac2c0f149edc711145cee5c896864f6f1e1ea8.png" class="site-icon" width="64" height="64">
<a href="https://uk.pcmag.com/smartphones/121055/the-best-portable-chargers-and-power-banks-for-2020" target="_blank" title="02:45PM - 05 May 2020" rel="nofollow noopener">PCMag UK – 5 May 20</a>
</header>
<article class="onebox-body">
<div class="aspect-image" style="--aspect-ratio:800/450;"><img src="https://d1bdmzehmfm4xb.cloudfront.net/original/3X/d/7/d7ec6bd91b60e1f35202181134fbc65c48738789.jpeg" class="thumbnail"></div>
<h3><a href="https://uk.pcmag.com/smartphones/121055/the-best-portable-chargers-and-power-banks-for-2020" target="_blank" rel="nofollow noopener">The Best Portable Chargers and Power Banks for 2020</a></h3>
<p>Is your phone, tablet, or laptop on its last legs before day's end? We have the best portable chargers and power banks to give you the biggest boost when you're out of juice.</p>
</article>
<div class="onebox-metadata"></div>
<div style="clear: both"></div>
</aside>
---
## Reply by [Insider](https://community.anker.com/u/Insider)
*June 5, 2020, 2:15am*
Hi [@SimonJones](https://community.anker.com/u/simonjones), you probably won’t quite get two full charges for your Galaxy S20 out of a 10000 mAh battery. The efficiency is generally 60-70%.
Here’s an article with some more information:
<aside class="quote quote-modified" data-post="1" data-topic="32280">
<div class="title">
<div class="quote-controls"></div>
<img alt="" width="20" height="20" src="/user_avatar/community.anker.com/ankerofficial/40/47840_2.png" class="avatar">
<a href="https://community.anker.com/t/getting-the-most-out-of-batteries-the-truth-vs-what-you-ve-been-told/32280">Getting the Most out of Batteries: The Truth VS What You’ve Been Told</a> <a class="badge-wrapper bar" href="/c/general-product-discussion"><span class="badge-category-bg" style="background-color: #AB9364;"></span><span style="" data-drop-close="true" class="badge-category clear-badge" title="Off-topic chat and general product discussion go here.">General & Product Discussion</span></a>
</div>
<blockquote>
<a class="lightbox" href="//forumus-uploads-production.s3-us-west-2.amazonaws.com/original/3X/3/6/36fc6ee1d48278d3a008d70a62f59ab9e1c252cf.jpg" title="How To Make Your Batteries Last.jpg" rel="nofollow noopener">[image]</a>
Phone batteries can be a bit of an enigma. They permeate our lives but what we know, or hear from others, about how to take care of them seems to be constantly changing. To make things more confusing, there’s a lot of conflicting info on battery care. Since batteries are somewhat our forte, it seems only fitting that Anker step in to answer some frequent questions and update some “common knowledge” about battery care.
Let’s get started!
Questions
1. What’s the average lifespan of a re…
</blockquote>
</aside>
If you’re still interested in a 10000 mAh battery, here are a couple options:
- **[PowerCore Slim 10000 PD](https://amzn.to/309us1n)**
- **[PowerCore+ 10000 with Built-In USB-C Cable](https://amzn.to/2MwPVJO)**
Hope this helps, and let me know if you have any further questions!
---
## Reply by [professor](https://community.anker.com/u/professor)
*June 5, 2020, 11:32am*
Expect about 1.7 phone recharges from a 10000mAh portable charger to a 4000mAh phone. You have a small loss in the portable charge about 6%-7%, a small loss in the cable about 0.5%-1% and a loss in the phone of about 20%. These stack up combined to about a 30% loss. As a quick rule of thumb use the 2/3rds rule.
10000 / 4000 = 2.5.
2/3rds of 2.5 = 1.67.
Try to use the shortest cable you can tolerate for the portable charger, it’s probably the only decision that matters as the portable chargers are similar efficiency.
If you store all devices around room temperature, expect the Anker Powercore to lose about 5%-10% capacity after 2 years but your phone to lose more, around 15%-20%. That’s because the phone gets hotter for longer and battery dies faster. So that 1.67x calculation would drop slowly over time. Not much you can do about that and yet use the phone regularly! That means you’ll likely use any Anker Powercore you buy now more often later in the phone’s life.
10000 is a good size, it solves worst-case situations very typically and probably your Powercore will outlive your phone…
---
## Reply by [SimonJones](https://community.anker.com/u/SimonJones)
*June 5, 2020, 11:30am*
I just took a look at the article, it's a great write-up.
Thanks [@Insider](https://community.anker.com/u/insider).
---
## Reply by [professor](https://community.anker.com/u/professor)
*June 5, 2020, 12:05pm*
Depends how you use and carry, if you’re ok with the idea of carrying a bigger power bank in a bag then 20 Ah is only a little bigger but noticeably heavier.
Personally if I’m just with pockets (jacket) I use a 6700mAh and a 6-inch cable; if I’m with a bag and phone, then I use a 10000mAh. If I’m with my tablet then usually carrying 20000mAh.
I have the 10000 PD Slim mentioned above, and recommend it. It's a good value all-rounder but try to pair it with an 18W PD charger to get it recharged in less than 4 hours.
---
## Reply by [SimonJones](https://community.anker.com/u/SimonJones)
*June 5, 2020, 11:32am*
Thanks again [@professor](https://community.anker.com/u/professor).
That's also awesome information. Seems like I could do with a 12000mAh but I could live with nearly 2 full charges in a 10000mAh.
---
## Reply by [paulstevenewing](https://community.anker.com/u/paulstevenewing)
*June 5, 2020, 3:18pm*
Also a consideration for you [@SimonJones](https://community.anker.com/u/simonjones) is the wireless Power Bank. If your phone and PowerCore will be together in your locker, your phone can sit on the wireless charge pad.
It’s 10000mAh, 5W wireless charger and 12W via USB - that’s 12W total, not each port.
It will certainly be a little larger, heavier, and a bit more expensive than the 10000mAh PD Slim, but if you’re not after fast charging it’s a solid option!
Take a look here,
<aside class="onebox whitelistedgeneric">
<header class="source">
<img src="https://www.anker.com/favicon.ico" class="site-icon" width="16" height="16">
<a href="https://www.anker.com/products/variant/the-hybrid-wireless-and-portable-charger/A1615011" target="_blank" rel="nofollow noopener">Anker</a>
</header>
<article class="onebox-body">
<div class="aspect-image" style="--aspect-ratio:320/272;"><img src="https://d1bdmzehmfm4xb.cloudfront.net/original/3X/7/d/7d92e676817e7031d5a6f0d268bc305ab564fd35.jpeg" class="thumbnail"></div>
<h3><a href="https://www.anker.com/products/variant/the-hybrid-wireless-and-portable-charger/A1615011" target="_blank" rel="nofollow noopener">The Hybrid Wireless and Portable Charger</a></h3>
<p>Anker Wireless Portable Charger, PowerCore 10,000mAh Power Bank with USB-C (Input Only), External Battery Pack Compatible with iPhone 11, Samsung, iPad 2020 Pro, AirPods, and More.</p>
</article>
<div class="onebox-metadata"></div>
<div style="clear: both"></div>
</aside>
---
## Reply by [SimonJones](https://community.anker.com/u/SimonJones)
*June 5, 2020, 3:53pm*
Awesome suggestion [@paulstevenewing](https://community.anker.com/u/paulstevenewing).
I like that wireless charger power bank option.
And in my locker it would work fine, and as it’s slow charging that would be ok, it can charge while in there.
If I need a quicker boost I can plug it in.
You guys know your stuff and are full of ideas.
You’ve given me lots to think about.
---
## Reply by [Shenoy](https://community.anker.com/u/Shenoy)
*June 5, 2020, 4:10pm*
I did a (almost…) similar fork of this… using the Powercore Essential 20000 PD with Anker PowerPort Wireless 5 Pad… (MicroUSB cable … this is the only shortest cable I could find).
Will be testing how it works for Charging iPhone today 😊
---
## Reply by [professor](https://community.anker.com/u/professor)
*June 5, 2020, 4:41pm*
Cool, well a 20Ah is only slightly more expensive than a 10Ah. You could just put a 20Ah in with a pad in your locker, and then every few days take the 20Ah home with you; recharges in 7 hours (overnight).
Leaving it on a pad will be a slow recharge but total touch effort would be minimum (take the 20Ah home every few days).
---
## Reply by [paulstevenewing](https://community.anker.com/u/paulstevenewing)
*June 5, 2020, 4:52pm*
Great minds think alike, I’ve done this recently.
I needed to do a recharge cycle on the PowerCore and charged my earbuds and phone wirelessly a few times. It drained it pretty quickly from what I recall.
---
## Reply by [Insider](https://community.anker.com/u/Insider)
*June 5, 2020, 5:07pm*
Has anyone tested the wireless efficiency compared to wired yet?
---
## Reply by [SimonJones](https://community.anker.com/u/SimonJones)
*June 5, 2020, 5:14pm*
I’m not an expert in these things but would guess wireless wouldn’t be so efficient?
Energy lost in heat?
---
## Reply by [Insider](https://community.anker.com/u/Insider)
*June 5, 2020, 5:16pm*
Exactly, so it probably wouldn’t be 60-70% efficient. Therefore, you’d get more out of a 10000 mAh wired than wireless.
---
## Reply by [SimonJones](https://community.anker.com/u/SimonJones)
*June 5, 2020, 5:17pm*
Ok yeah, that makes sense.
1.7 ish as [@professor](https://community.anker.com/u/professor) mentions I could handle, maybe even 1.5 charges, but no less.
---
## Reply by [professor](https://community.anker.com/u/professor)
*June 5, 2020, 5:21pm*
Someone should measure it.
It is jolly difficult to do it, you’d have to count how many phone recharges empty-full wired vs wireless, which would take 1-2 weeks.
You can’t measure it the same as wired of breakdown losses in Powercore vs losses in transmission vs losses in phone. You’d have to simply count full phone recharges. Wireless from those who have measured it is about 10%-20% less efficient, so 1.7 would become nearer to 1.3 to 1.5.
I can’t measure it myself yet. Someone with time and all the parts would have to.
---
## Reply by [Paul Ewing](https://community.anker.com/u/paulstevenewing)
*June 5, 2020, 5:21pm*
I guess it would be less efficient.
Sorry, I forgot you were looking to get up to full charges.
Be interesting to know how much loss there is as I’m very interested in this product.
---
## Reply by [SimonJones](https://community.anker.com/u/SimonJones)
*June 5, 2020, 6:24pm*
Hey guys, no problem.
The ideas and information here are amazing.
I’ve got lots to think about.
Thank you all so much.
---
## Reply by [Paul Ewing](https://community.anker.com/u/paulstevenewing)
*June 7, 2020, 9:16am*
Hey everyone.
Was reading the techie bit in this today and noticed this,
I was set on buying one of these but at that charging input speed I’m not so sure.
Now I do tend to charge my PowerCore overnight as my use of it is generally planned, but 8-9 hours to fully charge using the USBC non PD input is sheer madness!