[utopia]

If I'm seeing that right, the mounting clip looks surprisingly like one of the cable cleats that I used for the heavy gauge electrical wiring to my shed.
Nowt wrong with that though.

I'm toying with fitting one of these myself, but ...
What I would really like is a device which has the added feature of cutting the charging circuit in the event of a system failure which would otherwise lead to overcharging of the battery (ie above the 15v limit recommended for my lithium battery).
But in lieu of that, the monitor device might well be a useful part-solution.
In that respect, although the smaller unit is neater, the bigger one should be more obvious and would therefore be more noticeable, giving more chance to respond quickly.

edit .. and the excess charge obviously has to go somewhere once its cut from the battery.
Notice, I'm not a natural electrician.

I can't help wondering if it would be possible to arrange for a relay to switch between the charge monitoring and the battery condition functions.
Furthermore that this relay could operate in conjunction with say, the neutral switch such that, under most conditions (ie when in a gear) the unit would monitor the charging circuit but would switch to indicating battery condition when in neutral.
That's probably asking for too much (and would be a messier installation) but I mention it just in case any electrical wizards can take it further.