Is a 70Ah Varta battery actually the right fit for a Nissan Patrol in Dubai?

Hi everyone, so I want to share something that genuinely surprised me when I started looking into replacing my car battery recently because I assumed this would be a simple straightforward process and it turned out to be considerably more involved than I expected, mostly because of how much variation there is in what different vehicles actually need versus what workshops tend to stock and recommend by default. I drive a Nissan Patrol and it's been my main vehicle here in Dubai for about four years, and last week after a family trip to the mall I came back to the car park and got absolutely nothing when I turned the key, just a weak clicking sound that every car owner dreads hearing in a hot underground parking lot on a Friday afternoon when you just want to get home. My brother in law helped me jump start it and I drove home but I knew from that point that the battery was finished and needed replacing before I got caught in a worse situation somewhere less convenient.
What I didn't expect when I started researching replacement options is how much debate there seems to be online about what battery capacity is actually appropriate for a large SUV like the Patrol, because some people say you need something significantly higher than standard while others argue that matching the original factory specification is always the right approach regardless of what aftermarket options are available. I came across a Dubai 70Ah Varta Car Battery Shop while searching for reliable options and found the information there helpful for understanding the relationship between battery capacity and the electrical demands of larger vehicles, particularly ones like the Patrol that run a lot of accessories simultaneously including powerful air conditioning, tow package electronics, and entertainment systems that all draw from the battery continuously even when the engine is just idling in traffic.
What I'm genuinely still confused about is whether going for a higher capacity than the factory spec provides any real world benefit for a vehicle like mine in this climate, or whether it actually creates problems because the alternator is calibrated to charge a specific battery size and fitting something outside that range affects how efficiently the charging cycle works over time. I asked two different workshops and got completely opposite answers which didn't help at all, one said always match the original spec and the other said going slightly higher is better for Dubai conditions specifically because of the thermal stress on batteries here. Has anyone here replaced the battery on a large SUV in Dubai and specifically researched whether the capacity affects long term alternator health, and did the workshop you used actually verify compatibility before fitting or just assume that any battery of roughly the right physical size would work without issue?

Match the factory spec unless your alternator is upgraded too, otherwise you're just adding stress without real benefit. Higher capacity doesn't help much if the charging system isn't designed to top it off properly.

I went through almost the same confusion with my Land Cruiser actually. Ended up calling Nissan service directly instead of relying on workshop opinions, and they confirmed sticking close to factory spec is generally safer unless you've added aftermarket electronics that draw more power. The "go higher for Dubai heat" advice sounds logical but isn't really how alternators are calibrated.

This happened to me too, that exact clicking sound in an underground parking lot, worst feeling ever. From what I understand the alternator is tuned to a specific charging range, so going noticeably higher than spec can actually mean it never fully charges the battery which defeats the purpose anyway. Slightly higher within reason is usually fine, but a big jump up isn't necessarily safer just because of the heat. Honestly the workshop disagreement you ran into is pretty common, most don't actually check alternator output before recommending a battery.

Had two workshops tell me opposite things too when I went through this. Ended up trusting the one who actually tested my alternator output first instead of just guessing.

With a Patrol specifically I'd be cautious about going too far above factory spec, since these already run a lot of accessories and the charging system is calibrated around that baseline. What helped me with my SUV was asking the workshop to actually test the alternator's output before fitting anything, rather than just eyeballing physical size like a lot of places do. The Dubai heat argument makes sense in theory but in practice it's more about how well the battery itself handles thermal stress, not necessarily about bumping the capacity higher. If a shop won't verify compatibility before installing, that's usually a sign to go elsewhere.