Yes just watched that review, seems to prove out the claims.
Also read several reviews on boat forums regarding use. One review had some issues which seemed to relate to transport damage and then knock on effects, all other reviews are very positive.
It does seem though that although they can be taken down to 0V it is still recommended to keep them at approx. 50% or more to prolong life etc. Perhaps it is best overall to keep them charged as per an AGM, but with the added ability that if your stuck then you can use the whole battery without risk of destroying it, just maybe reducing life a little. i.e. plan as if it was an AGM, but with less worry about flattening it. Though then this beings the cost into question again!
Also seen this
20200320 Crystal® Battery Catalog (adobe.com)
from a manufacturer in Germany, the charging profile graphs are not something I know how to read (any battery people want to review?) but they are pretty adamant that charging them batteries correctly is needed, they offer their own charger to this.
Perhaps some further research on charging them properly / if DC-DC chargers will accept / charge them correctly.
Also, I am seriously struggling to find any for sale in the UK!
[/QUOT
Can provide these in the UK
