Thanks for the feedback:

I should perhaps have pointed out that I don't understand the maths of how all of this works - so any comments pointing how much extra grunt I would get compared to a single Yellow Top would be useful. I could always just put two Yellow Tops in parallel if my (older model) National Luna system allows that??

silver G,
They look good, but I'd prefer not to place 100% of my trust in one battery - having two that can be started off if the one goes belly up seems to make sense.
Would two of these fit under a 110 passenger seat?

RogerM
Slightly confused on this whole subject, so apologies for the dumb question - but AGM is a type of battery rather than a brand/model? If so, are there any particular brands models that are highly rated and what advanatges would a AGM have over the optima's?

ivanll
Why? Cost? better performance etc?

nickdisjunkt
"Getting intelligent charging devices that enable you to charge you batteries beyon dthe 70% limit that is practically reachable with a standard alternator or solar regulator, will increase the usable battery capacity and make deep discharges less common."

I think the National Luna system I have is quite good - though I struggle to use my 17" laptop for more than 3 hours (heavy processing, large screen etc doesn't help).

Any more thoughts on this...?

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Kiwi, 7 years around Africa. Overlanding channel:https://www.youtube.com/c/roamingyak