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Richwood · 03-18-2018, 03:46 PM

External battery packs are available either as sealed items that include the batteries or as a battery holder for 18650 batteries that you must add the batteries to. Generally for the add your own batteries versions you want to use unprotected 18650 batteries as most protected versions are too long to fit and the protection circuit is included in the pack electronics.

Any 18650 battery that claims a capacity greater than 3500 mAh should be avoided as the maker or seller is lying. Current state of the art is about 3600 mAh absolute max for 18650 batteries. All batteries sold by Mountain Electronics, Illumination Supply and Orbtronic are high quality. Many of those sold by ebay sellers and sold on Amazon the last I checked are not. I have seen 18650 cells claiming capacities up to 6000 mAh or more. No such thing unfortunately. A rule of thumb is if the battery name ends in "fire" it is a piece of junk from a unknown Chinese source. Buyer beware.

The same is true of ebay sellers USB battery packs, the ones with batteries sealed inside. I spotted one that claimed 50,000 mAh capacity in one spot and 500,000 mAh in another on the same listing. Based on listed physical size and price I suspect that it is about 10,000 mAh or less. If you look on Amazon watch the buyer ratings as many of the packs show high failure rates per buyers, a sign of cheap batteries or bad electronics. As is more and more true on Amazon, look and be careful. Let the buyer beware.

Many of the boxes sold without batteries are very inexpensive on ebay and I know nothing about them. I have two bought several years ago, labeled ENB which still work. The maker is now gone it looks like. Below is a link to one of the best add your own batteries versions based on reviews on Amazon. Note too that the removable battery versions also work well as pure battery chargers if you have a 18650 battery flashlight. As Lithium Ion batteries wear out or improve the unsealed units can have their batteries updated, impossible with the sealed units. IMO any of these are unlikely to damage an attached device as their batteries put out 4.35 volts maximum. The boxes contain a voltage boost circuit, that if it fails, is likely to cease boosting the voltage rather than fry the item being charged.

https://www.amazon.com/gp/product/B0...k_ql_qh_dp_hza

03-18-2018, 03:46 PM	#11
Richwood Astronomy Nut Posts: 519 Karma: 3700000 Join Date: Oct 2017 Location: Reno, NV Device: Kindle (All), Kobo (Multiple), Sony (most) and Nook Glowlight Plus	External battery packs are available either as sealed items that include the batteries or as a battery holder for 18650 batteries that you must add the batteries to. Generally for the add your own batteries versions you want to use unprotected 18650 batteries as most protected versions are too long to fit and the protection circuit is included in the pack electronics. Any 18650 battery that claims a capacity greater than 3500 mAh should be avoided as the maker or seller is lying. Current state of the art is about 3600 mAh absolute max for 18650 batteries. All batteries sold by Mountain Electronics, Illumination Supply and Orbtronic are high quality. Many of those sold by ebay sellers and sold on Amazon the last I checked are not. I have seen 18650 cells claiming capacities up to 6000 mAh or more. No such thing unfortunately. A rule of thumb is if the battery name ends in "fire" it is a piece of junk from a unknown Chinese source. Buyer beware. The same is true of ebay sellers USB battery packs, the ones with batteries sealed inside. I spotted one that claimed 50,000 mAh capacity in one spot and 500,000 mAh in another on the same listing. Based on listed physical size and price I suspect that it is about 10,000 mAh or less. If you look on Amazon watch the buyer ratings as many of the packs show high failure rates per buyers, a sign of cheap batteries or bad electronics. As is more and more true on Amazon, look and be careful. Let the buyer beware. Many of the boxes sold without batteries are very inexpensive on ebay and I know nothing about them. I have two bought several years ago, labeled ENB which still work. The maker is now gone it looks like. Below is a link to one of the best add your own batteries versions based on reviews on Amazon. Note too that the removable battery versions also work well as pure battery chargers if you have a 18650 battery flashlight. As Lithium Ion batteries wear out or improve the unsealed units can have their batteries updated, impossible with the sealed units. IMO any of these are unlikely to damage an attached device as their batteries put out 4.35 volts maximum. The boxes contain a voltage boost circuit, that if it fails, is likely to cease boosting the voltage rather than fry the item being charged. https://www.amazon.com/gp/product/B0...k_ql_qh_dp_hza Last edited by Richwood; 03-20-2018 at 02:20 PM.