So I bought an MPPT solar charger.
Given it's price, I'm highly sceptical and think it's probably just a DC-DC, but I thought I would give it a try anyway.
While I was modifying things, I went ahead and replaced all my 2.5mm 2pin JST connectors with 2mm HXT bullets
and 18AWG wire:
These provide a much better connection and the step up from 20awg to 18awg should ensure minimal wiring losses. I've still got a long run of 20awg down the length of the bike I need to replace, but it was a huge PITA to get in there so I won't bother doing that until I move ahead with my frame battery and have to redo all the wiring anyway.
I also removed one of the diodes I had installed. I was using one before the DC-DC and one after, but this just seemed to rob me of the minimal power the setup had available, so I've just left the diode on the battery side for now.
While I was at it, I trimmed off the extra white space from the sides of the panel...not exactly sure why, but I had my scissors in my hand with it right in front of me and I just started cutting.
I'd been thinking about doing it for a while, and am kind of glad I did as it makes the bike a bit less cumbersome. As you can see from the photo's below, I park it in my laundry next to a door, so not having the extra inch of solar panel each side actually makes it a good deal easier to park the bike and squeeze past it.
The MPPT has the added advantage of looking like it really could be my GPS tracking system.
I haven't got any stat's on whether or not it's improved the solar efficiency yet as the only day I've ridden it since making the changes was overcast and foggy all day. Now they're forecasting rain the rest of the week so I probably won't see if it's any better till next week.
It shouldn't be hard to beat the old setup though. In winter I was only seeing 0.4-0.9W charge typically while riding into the sun. If anyone has any other suggestions for improving the solar efficiency I'm all ears.