I already have a dedicated L-ion charger for top-up/maintenance charging (I believe the desulphation mode on regular charger/tenders is the issue here) .... but that's not the problem.
My concern is for normal, in use charging via the alternator and reg/rec (and potential problems with malfunction thereof leading to charging at a higher voltage than 15V).
Basically, does a modern, L-ion battery require a modern charging circuit to go with it, which contains some sort of (failsafe) voltage overload limiter, in case the reg/rec should fail.
And can such a facility be retrofitted somehow to an older system.
And yes, my electrics does stretch as far as understanding charge capacity, ie volts, amps, coulombs and time ... but not a lot further.
The main (only ?) reason that I'm concerned about voltage is that it says "caution - do not charge above 15V" on the battery casing.
With my limited electrical knowledge it seems entirely possible (and experience seems to confirm) that a charge circuit malfunction could lead to charging at over 15V, and this is what I would like to address.
Also ...
Ok, I could fit a mosfet reg/rec, which would probably be more reliable but crucially, I still don't think it would be entirely failsafe, but would merely reduce the odds of failure, ie not entirely guarding against it.
I could also fit a battery monitor, but this would merely be an alert and would rely on my noticing it and taking action to avoid catastrophe .. I want something that operates more like a fuse, ie it shuts the system down by itself as soon as there is a problem, requiring no action from me whatsoever.