The two batteries for my mobility scooter arrived promptly and, although it was a bit difficult to learn how to put them in their casement, my husband managed to work it out, thankfully. I rang a man called Bill at Battery Trader who was exceptionally helpful to me. He quickly grasped my lack of knowledge and experience about voltage and charging and gave me some sound advice, which I wrote down, printed and gave to my husband, which was of great benefit. I still can't get my head round it, but thankfully my husband can, with Bill's help. We did need to buy a relatively cheap Voltage Multimeter, so we can keep a check on the batteries status, again advised by Bill but it is all, seemingly working now, so I can use my mobility scooter without feeling I am running out of power all the time. Any problems with batteries and 'jargon' - then speak to Bill!!! He is amazing.