Originally Posted by lockieboi
Thanks for all the responses.
I quite fancy a project so I think I'm going to do this.
I've sourced a 7 amp hour Yuasa battery which should be sufficient.
I still have a few questions for all the experts in this field.
Firstly, what size fuses would be required or does it depend on the load?
The output from my OB looks as though there is a plug that should fit it? Ive attached a picture of the output.Attachment 96525
As a general rule...
You want the wire sized appropriately for the load (so it doesn't get hot, burn up, or have too much voltage loss)
The fuse protects the wire for taking more current than you've budgeted for.
My experience with some electronics is that they can be very finicky to poorly regulated or bad sine wave AC power. A phone draws about 15W max so your 7Ah battery will last for days without any charging at all. The problem with using more than the AA lithium battery pack suggested earlier is that its hard to get the charging cord from a larger battery to the phone and maintain waterproofness.