Public Service Announcement
A capacity of 5000 is a waste of time and money. Think about it. This is one of the most important aspects of your business. Lose ability to communicate and you put your self at risk of losing business. Worse if a session does not go well and you need to call for help a dead battery could be a serious threat to your health or life. So make a wise purchase ........
Spend a little more and get highest capacity possible.
20,000 should be your minimum. That is the battery capacity. Also consider the output ability which is not directly related to capacity. In general as they size of battery increases and price goes up so do the other features but does not have to be that way.
Output rate. This impacts how fast it can deliver a charge. If a client is waiting for you that thing better charge your phone fast to get you back in the game. Lowest you will see is 1.0 amp. These are useless. Next step up in quality is 2.0 or 2.4 amp. Better but still not going to take advantage of newer phone quick charging capabilities. Next I have seen is 3.4 amp. I think I once saw a 5 amp but could not find it on this search so could be bad memory or an inflated claim on the one I did see.
Then look at the output ports. Standard USB or USB-C output. The more ports the better if you have more than one device. Say a tablet for surfing and responding to sites like this where you want a larger screen in addition to your phone and possibly a backup phone you keep hidden in case a client rips you off and takes your phone.
I hit Amazon and did some of the research for you.
https://www.amazon.com/30000mAh-Port...ery+pack&psc=1
30,000 mAh charger. Three 5V/3.4A output ports will charge your stuff in shortest amount of time giving power pretty much as fast as your device can take it. Though looks like it charges itself off a micro USB which means if the battery pack itself gets low may take long time to charge. It has a digital indicator to show exactly what percent power it still has left. Some units will only have a row of lights that show approximate power left. This is your business. If a unit has that keep walking to the next choice.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
This one has less capacity, 26,800. But it has quick charge 2.0 and 3.0 technology so if you have a newer phone capable of using these technologies your phone will charge at max speed. It has the digital display so you always know how much capacity you have left. But what I really like about this one is it has two input ports for charging. So if it is low you can plug in both inputs and decrease time to being fully recharged.
In addition to this you want to have a protective case that has a battery built in. Yes, this will make your phone a little larger but providers your clients are not seeing you because of how cute and petite your phone looks. And clients, that provider beyond the donation that accompanies it does not care what your phone looks like. Just go to Amazon and search. Put in your phone model followed by battery case and you will find most phones have a abundance of options.
For example galaxy S9 battery case yields...
https://www.amazon.com/s/ref=nb_sb_n...9+battery+case
Most cases are roughly 4700 mAh or higher. Consider that is enough to charge most phones fully from near empty at least once, maybe twice before needing plugged in to anything. Best of all if your phone gets low you just hit the button on the back and you are charging. No need to plug anything in. Here is one for the S9 that has 8000mAh.
https://www.amazon.com/Charging-Zero...9+battery+case
I have one for my phone that carries a 10,000 mAh capacity. I literally go a week between needing to plug in and never turn my phone off.