Well after a couple of PM's with Lyen, and talking about my 84 volt pack...my requirements could not be met with these convertors...so I went down the local dump and came back with about a dozen small mains power supplies form things like LCD monitors, video cameras, portable speakers, printers etc etc.
all ranging from 100 to 240 volt input and various outputs, from 5 volt to 18 volt. Well sticking 84 volt DC in to them, and they pretty much all worked.. Often taking a few moments longer to power up than if feeding them with 240v AC. SO now I have a variety of small SMPSu's all usable with 84 volt in.
So my problem solved, all with PSU's from the dump
Mongoose MTB, Fox forks,26x2.3 tyres, 180mm disks. 20s 20Ah LiPo, Lyen 18 FET,5304 in 26 inch EX721. 9k miles 2years
Only Irish coffee provides in a glass all four essential food groups: alcohol, caffeine, sugar, and fat
“Rightful liberty is unobstructed action according to our will within limits drawn around us by the equal rights of others. I do not add 'within the limits of the law', because law is often but the tyrant's will, and always so when it violates the rights of the individual.”