Cannot answer your second query , but the first one is easier... While battery chargers generate a voltage of 42v at about 4 amps and are about 80% efficient , so will be drawing around 200 watts . In theory a 250 watt jobbie from halfords should do the business. However a lot of the cheaper invertors do not like driving into an inductive load... Which the charger is and may not actually start, so a bigger unit rated at 500 or 750 watt is safer. You would also be better to start the invertors off load and then plug in the charger after a few seconds. Once the invertors is up to speed and voltage.I have done this with the slightly smaller 29v charger for a lower powered bike without problem from a 250 watt invertors.
It would, though that depends on the protections if any that the Yamaha uses. It would take a full 8 hours to charge the battery...
The charger for li ion packs works in two modes .. for the early part of the charge it restricts the current into the pack by throttling back in its output voltage. This is because the conversation chemistry will only proceed at a certain rate.. if more voltage is applied, the process is inefficient and the excess energy just succeeds in heating the battery pack... Not good!. That phase is called constant current. When the battery has nearly charged, the charger reverts to constant voltage of say the 42v , and maybe after a time then switches off entirely. Any charge balancing , or more properly voltage balancing , will be done within the battery pack itself. ... Otherwise the charger would have some 12 cables rather than the two or three they currently have. Very sophisticated systems like the Bosch and others, have communications protocols so they can inform the charger, or other diagnostic kit, on the state of play of each Bank of cells.
No need for an inverter and better not to use one in fact. You don't say the voltage of your battery? You want a CC (constant current) CV (constant voltage) boost converter.
A full explanation regarding this "statement" backed with technical evidence would be appreciated, bearing in mind there are different types of invertors and qualities that differ vastly in cost. Everything in my house that is rechargeable is done so via an inverter, and has been for the past few decades. Should I stop now ?
Absolutely. Ring a power company and ask them to connect you up to the mains.
Which, because of my location is not a viable financial possibility. As I have studied and upgraded my system over the years as technical advances have arisen, I perhaps thought that after reading your reply, that I had missed something, and that a new member had some new informative and valuable information to share, rather than return with an off hand flippant and non conclusive reply.
I thought I did have the most efficient method until I read your post stating "better not to use one" which, to simplify matters, is the reason I asked you why ?
Oh I see, you haven't actually tested anything. You're just getting this stuff from a book, internet, or more likely a forum I bet, but since you like your references and have them what are they because I'd like to read them too?
I have been building and installing alternative power supplies for the best part of 40 years as a successful business. I have worked hand in hand with "the industry" in improving, promoting and simplifying designs and applications for end users. I have learned through life's experience, that I don't always get it right, and I can learn further information from two year old to a one hundred year old and beyond. Part of my interest includes the use rechargeable forms of transport for use in remote locations where off grid supplies are the only source. When someone brigs up a question to the viability of using such a supply, I'm interested. You obviously have no idea the amount of time effort and money I've sunk into my "interests", in the same way I have no idea of who you are, and unlike you, I make no assumptions. For all I know, you could be one of the development engineers I am in daily contact with.
