In solar powered vaccine storage systems high quality wet cell batteries have the potential of lasting longer than sealed batteries. However, they periodically need the addition of distilled water. Distilled water can be hard to obtain in remote areas.
Sun Frost has developed a method using waste heat from the condenser or compressor to distill small quantities of water needed to make up for water loss in batteries.
If there is sufficient interest and support we could develop the concept into a commercial product.
If interested please contact Sun Frost.