Some of my low voltage solar lights along the side walk don't light any more. I have had them for one and a half years. Although the product instruction says that the battery lasts about 3 years, I wonder if change the battery would do the trick. I checked the voltage of the rechargeable battery that came with the lights. It's only 400 mAh. The rechargeable batteries I have found so far are all more than 2000 mAh. Is it safe to use those 2000 mAh for the low voltage lights, or I should keep looking for lower mAh? Thanks