https://www.tayna.co.uk/leisure-batteries/exide/et650/ I am considering these to replace my dud banners that failed after 2 years. Bit of confusion on Ah and WH as 650wh equates to 650/12= 54Ah. But they claim 100Ah at C20 rate I think. Any experts there to offer advice on these batteries or would you recommend different choice. Limited to 190mm height.