Not sure what you mean by over-expecting from automotive gas engines, but an automotive diesel engine's turn at around 600-800rpm when idle, and should be putting out around 4-5hp at least at that speed, and that as well at a superb fuel consumption, so I still find that an "automotive diesel engine conversion" a very attractive technical proposition, but again, no verdict could be made until after testing.
Thanks for your input.[ Parent ]
You did say it was remote. For a large system like you are describing get the diesel genset and the fuel delivery to with it and you will better off than most people in the city, if you enjoy it , but it will cost you quite a bit per kwh of diesel compared to the grid.[ Parent ]
The most efficient way is with a directly connected generator and this generator would need to be compatible with battery charging requirements. I couldn't see you finding such a thing commercially suitable for use at 48v.
"The alternator's output is stepped down using an iron-core AC Transformer, then run through a rectifier to output DC current to charge batteries."
That answers your own question, that is not direct connection, you have included a battery charger even if simple and home built. Once you go the battery charger route then your original question goes out the window. The new issue is what is the most efficient battery charger.
Beyond this the issue comes down to so many factors that I can't be bothered to wade through it. The high tech battery chargers are primarily designed for mains use and their main purpose is to look after the batteries. On mains they take what is needed to do it.
Running these things from generators alters the equation where you are looking at fuel economy load etc and in most cases they are expensive and far from ideal but they do give ideal charging characteristics.
Your transformer and rectifier if using a suitable transformer will be as good as the expensive high tech things but will not be as good as a direct 3 phase alternator rectified and set up for battery charging directly at 48v.
Single phase is dreadful for battery charging.
You will have so much advice that you will be no wiser in the end.
Flux[ Parent ]
Great explanation!
The reason for the inefficient iron core generator, mainly not to mess up with a readily available 220V single phase generator, by simply running a wire from it's output socket to a 1:4 or 1:3 transformer, so that when the resulting single phase AC passes through the rectifier, it gets within a reasonably efficient charging frame.
Yes, single phase & iron core transformer, both add to inefficiencies. So, what about directly connecting the high A/C line (220VAC) into the battery pack (after rectification)? Wouldn't that be comparatively efficient?
I know that a 3-phase PMA turning within the 50-60VDC Voltage frame is the most efficient way to go, but that would need some re-engineering work to an off-the-shelf generator.
It is preferable to either go for no retrofitting at all, or designing a completely custom-designed & built engine/generator.
To comply with the second route, any comments on the automotive diesel engine's retrofitting with the right PMA running at idle speed or just above idling speed! Wouldn't that be most efficient from both aspects i.e. the fuel consumption as well as battery charging? Also easier maintenance, widely available parts, cheaper, etc.....
Thanks. [ Parent ]
