so the battery doesn't come with the bafang kit so could end up costing 800 euro for a conversion feck that.
It depends which kit you buy and who you buy it from, Anto. With the front wheel motor kit from Ecosmobile, you get the battery in the kit for 400 pounds and change, so the entire installation costs including delivery costs well under 500 Euro.
It's just happenstance that I bought my Bafang centre motor kit from people who sell the motor and controller electronics and wiring as one kit, and the battery separate. I found them the cheapest in total, and their control electronics weren't crippled, and I judged after speaking to them on the phone that they were technically competent, which couldn't be said for some of the clowns viewing ebikes as an opportunity to make a quick buck.
But if you look around on the net, you'll find a centre motor kit that comes complete with a battery. Whether it will be cheaper in total than the people I referred you to, is another matter. A good place to start is
https://www.pedelecs.co.uk/forum/ -- but don't start running after every short-lived enthusiasm of the people there; that's a sure way to spend your money and get something short-lived in return; in addition, some of the people there are UK sellers of certain brands and go off at half-cock at every unproven new-new-new piece of soon-to-be-yesterday's-news. Stick to the two Bafang motors I've identified for you (the 8FUN QSWXK kit Ecosmobile sells on EBay or direct and the BBS1 Bafang 8FUN motor Eclipsebikes sell and for which they also supply suitable plug and play batteries for good prices), which are the common motors among other members of this forum for the good reason that they all have their brains in gear and a tight hand on their wallets.
Note that I trashed my QSWXK kit after 3500km. But I'd been expecting something like that: I just never ride on the flat, and the hills of West Cork killed it; I thought I had good value out of it as an initial experiment to discover whether I liked the experience or should give up cycling altogether. The motor could in theory be rebuilt with steel gears instead of the nylon gears I melted, but the motor itself is the cheapest part of the kit, and the control electronics also melted down, so I didn't bother, just went to the BB motor. The BB motor is a stronger item, which is why it costs more. Mine has already outlived the QSWXK and is going strong. If you read roundabout on the forum here, you will discover that some other ebike owners and I discussed the matter and came to the conclusion that an ebike motor is a consumable item: you can't expect it to last as long as the bike, and you really must look after the battery carefully.
However, if you want to buy a 36V 250W Bafang centre motor kit without a battery, I'll be happy to give you my old kit's battery, which was in good nick when I put it away. It's 9Ah, which should give you a reasonable range. It fits in the water-bottle space on the downtube; it has its own quick release rack with a lock and can be charged on or off the bike. Let me know if you're interested -- and before you actually spend money on the rest of the kit! -- and I'll take it out and put a meter on it to check precisely what sort of nick it is in. You'll need someone competent in electrics to join the wires from the battery cradle to the wires from the motor, but I'll send you the colour codes; I did it myself.
