Yep, the Maha comes with a cable for a 12V DC power source, which is very handy for cars and many solar chargers.

But the La Crosse is probably a better solar charger in general because you can set the current down to 200mA/battery if necessary. (The BC-900 is much more sophisticated than the Maha, but you're unlikely to be using most of its fancy features in an emergency.)

However, if I lost power, I would likely first charge this or a larger capacity SLA and then use it to power my rechargers.

The Maha also goes down to 200mA. I have one.

The cost to run rechargables is so low I don't think the savings from solar are significant. The benefit is not relying on the grid, which matters in extended power cuts or when away from civilisation.

I use Eneloops rather than Li-Ion except where equipment comes with its own Li-Ion (phone, camera etc).

I have a Maha too. Actually, the slow charge current for AAs is 300mA, not 200. But the difference is minor and shouldn't have any impact.

I only use solar during power outages, camping, Field Day (a ham radio thing), or just to check out everything works w/o electricity.

Otherwise, I recharge via AC, as it just costs a couple of cents per battery to recharge.

For a solar or bob charger look at something simple like the maha c401fs. the small size works well in my bob as well.

Then I have the c9000 for those once a year or so maintenance cycles.

Maybe we are talking about different products? I have the MH-C9000. It doesn't have a "slow charge" as such; rather, it lets you pick the charge current. As the specification on the linked page says, the lowest charge current is 200mA.

It's a good charger, but physically bulky if you plan to carry it around backpacking, and the user interface is a bit cumbersome too. It has no permanent memory, and if you want anything other than the factory defaults you have to re-enter them every time for every battery. It doesn't even use the settings for the first battery as the defaults for the second.