From recommendations on a CR-V forum I follow, I just bought a Deltran Battery Tender Junior. It is more than a trickle charger; it monitors battery condition and charges only as needed.
Now that we have an HR-V, the CR-V often goes unused, and needed a charge to start recently. We got the tender to keep it topped up.
Disconnected batteries will self-discharge, so a tender would be better than just disconnecting it.
The term 'Trickle Charger' implies that a constant current will be applied to the battery. This simple, antiquated type of charger could over-charge your battery, and shorten its life.
The 'Battery Tender' mentioned in the last post is common these days, and costs a bit more. A more accurate name for these devices is 'Battery Maintainer'. As mentioned it monitors battery condition and charges only as needed. You cannot use it on a fully-discharged ("flat") battery, however.
Here is one of the top brands (included with some high-end weekend supercars, from the factories):
I have a CRV in the States and a HRV in Brazil. I use a Deltran Battery Tender Junior for the CRV which has worked great up to 3 months and I suspect would be fine on longer stays. I have no power receptacle in Brazil, so I disconnect the negative side of the battery. This has worked fine on 3 month periods, but now I'm away for 6 months and we'll see how much juice is left when I return. Temperature where I store the HRV is steady 80F.