LiFePO4 or LFP batteries are much better in almost every way for 12VDC auxiliary or portable use and you should consider making the switch. Check out the new page here on the website. While battery chemistry is not directly on point with DMR, it is for hams. So take a look and consider the long term benefits: LiFePO4 vs SLA/AGM Batteries
Here’s a few, 20% the weight of the SLA and packs more power in the same physical size with up to 4,000 charge/discharge cycles, 10 fold more than SLA’s. If that is not enough to pique your curiosity, then please throwaway all your alkaline AA batteries and go back to carbon-zinc!