Once again I considered Garmin dedicated devices and supposed IP68 Android phones. They all seemed too costly and even then not ideal solutions. What I wanted was a practical battery life on the iPhone. So swap the battery!
On eBay the batteries are £16 from what look to be fair suppliers. Anyone offering a capacity twice the original couldn't be genuine as budget phone batteries haven't improved that much. Replacebase fitted the bill and the battery arrived in a day or do.
A key advantage of the 1st edition of the iPhone SE is that it can be opened with a small screwdriver and a plastic pry. No glue is involved, hence not water resistant! I followed a YouTube video and found the job fairly straightforward. The hardest point was softening an adhesive strip under the old battery which hadn't done the quick detach trick. At this point it might be fair to point out that I am dextrous and have a good stock of tools. If that description doesn't fit you, then perhaps best to use a phone repair shop...
A few weeks after the swap I'm pleased to report that it was well worth doing. The SE isn't known to have great stamina so I didn't expect miracles, but the working life has improved considerably. It's hard to quote an objective figure as power consumption depends on the duration of screen illumination, probably daylight intensity and if photos were taken.
How the old battery showed 91% and was so poor in use is a mystery to me, although there's lots online to suggest that the figure can be faked.
