https://www.amazon.com/Perfine-BL-44E1F-Li-Polymer-Replacement-Removable/dp/B07MNQ9BGY/ref=sr_1_1?keywords=lg+v20+4100mah&m=A2QZ8SV8TD2939&qid=1556257968&s=merchant-items&sr=1-1#customerReviews

You can also shorten that to this link (so only leave the part before "/ref=")

• https://www.amazon.com/Perfine-BL-44E1F-Li-Polymer-Replacement-Removable/dp/B07MNQ9BGY

Rather than from the Amazon US, I have bought three from Amazon Spain - first impressions of the 1st one here.

They don't seem to be available on Amazon Canada and UK. In Spain, Germany, France and Italy they come from the same seller in Germany (with slight differences in prices and special promotional discounts):

• https://www.amazon.es/V20-H910-H990N-US996-F800L/dp/B07M8M4RT6/ (Spain)

• https://www.amazon.de/H910-H990N-US996-F800L-wiederaufladbare/dp/B07M8M4RT6/ (Germany)

• https://www.amazon.fr/H910-H990N-US996-F800L-wiederaufladbare/dp/B07M8M4RT6/ (France)

• https://www.amazon.it/V20-H910-H990N-US996-F800L/dp/B07M8M4RT6/ (Italy)

but the Perfine seems like a good option too.

I am quite happy so far. I have not actually seen the full 4100 mAh indicated by AccuBattery, but I am quite happy with the 3800+ mAh and 3900+ mAh capacities that I have seen with my first two items (P4101 and P4102 - IDs assigned by me, to keep them apart)

• Testing P4101 gave me 3800+ mAh after 3 days of discharging to 0% and charging up to 100%

• I have been using P4102 for 2 weeks more how I normally use a battery - so less discharging to 0% and charging to 100%. I have also e.g. charged it while using it for navigation. AccuBattery is indicating 3900+ mAh after 14 days of use

Next for me is testing item #3, so P4103.