To make sure the device can withstand voltages normally encountered with charging a lead acid battery you should search for one specified to work in a car. For example, search using the following key words: 6-24V to 5V 3A CAR USB Charger Module DC Buck Step down Converter Module You can find one for 99 cents including free shipping from China - (I have not tried it) 73 Ken KE2N -----Original Message----- From: Bob Pyke [mailto:k6ecm1@gmail.com] Sent: Monday, July 10, 2017 1:12 PM To: Users of Asterisk app_rpt <app_rpt-users@lists.allstarlink.org> Subject: Re: [App_rpt-users] USB Battery Bank that supports 'Pass Through Charging' and acts as a UPS for Allstar Nodes running on a Pi I've looked at these 13 v devices and always wonder it they will handle the 15 CDC of an auto charging system like all our radios. Some 12 vdc evils will only work properly if the have 12 vdc not 13.8 vdc for example. The information on these devices is lacking. Any insight into to this issue? Just too bad the rest of the electronics world does not have a ham background. Sigh! Thanks, Bob k6ecm 73 Sent from my iPhone