Off-highway is the correct word for that type of equipment.
48V questions...
- Thread starter JeffKeryk
- Start date
Off-highway is the correct word for that type of equipment.
If 48 volts became the standard there would be no problem with it all, only benefits of lighter cabling. Batteries would be be more expensive though. We have been here before, 6 volts was common in motorcycles and cars, we changed to a 12 volt standard for the same good reasons that 24 v or 48 volts would be beneficial, less voltage drop in cables and connections. Anyone who has run a 6 volt vehicle will know how much an improvement 12 volts was.
A move to 24 volts would be easier as many components are already available.
A move to 24 volts would be easier as many components are already available.
@barryh, do Brit cars still use a positive earth configuration?
I had to draw out a schematic some years ago to convince myself that jumper cables (when boosting a positive-earth car from a negative-ground car) still went positive to positive, and negative to negative.
Six volt starters were hot garbage. The technology at the time had them all direct-drive which guzzled power. I doubt they even rewired anything for 12 volts, probably just said well it's an intermittent load, if you don't grind on it for over 30 seconds it won't overheat. We also used generators back then; all the current had to flow through the brushes so that means double the amps, and double the wear.
30 years ago we went to gear reduction starters, they turn things over great. And of course there's better oil now too.
If we go to 48 volts there will be a lot of little things like power seat motors that will need redoing. Toyota could easily have done 48 with the Prius but chose 12. IDK why but they have a lot of tested, trusted, legacy 12V thingies and they WORK.
30 years ago we went to gear reduction starters, they turn things over great. And of course there's better oil now too.
If we go to 48 volts there will be a lot of little things like power seat motors that will need redoing. Toyota could easily have done 48 with the Prius but chose 12. IDK why but they have a lot of tested, trusted, legacy 12V thingies and they WORK.
Good lord no, not since the 60's when alternators replaced dynamos and negative earth became standard. I can just about remember car radios having a polarity switch on the back but I've never owned a positive earth car.
Been hearing about 48V systems for years now, about time to move forward... the small bits don't care, it's the power hogs that need "lots" of power that could benefit.
I do recall reading on EDN (I think) that years ago though GM had an internal specification of "thou shalt not design a harness with less than 22g wire" or something to that effect. Problems with pulling wire through whatever, or working with it. Makes me wonder if debug work might get harder.
48V, I suspect that might tingle if you have wet fingers. IIRC it's just below where regulatory standards change and thicker insulation, more user protection, more whatever has to be used.
Been a lot of inertia for 12V systems, but as pointed out, everything has more or less been reworked since the days of design once, use that part across every vehicle that an OEM makes (cig lighter, light bulb, power seat motor). I bet the worst bit now would be finding 48V batteries.
Actually... I wonder if 48V is the right number, why not 37V or 44V instead? why use "heavy" lead acid when lithium could be used instead? [Not that I'd want to pay for when those batteries wear out, just wondering, why an OEM wouldn't think about that. I'm still smarting over the undersized battery in my Honda.]
I do recall reading on EDN (I think) that years ago though GM had an internal specification of "thou shalt not design a harness with less than 22g wire" or something to that effect. Problems with pulling wire through whatever, or working with it. Makes me wonder if debug work might get harder.
48V, I suspect that might tingle if you have wet fingers. IIRC it's just below where regulatory standards change and thicker insulation, more user protection, more whatever has to be used.
Been a lot of inertia for 12V systems, but as pointed out, everything has more or less been reworked since the days of design once, use that part across every vehicle that an OEM makes (cig lighter, light bulb, power seat motor). I bet the worst bit now would be finding 48V batteries.
Actually... I wonder if 48V is the right number, why not 37V or 44V instead? why use "heavy" lead acid when lithium could be used instead? [Not that I'd want to pay for when those batteries wear out, just wondering, why an OEM wouldn't think about that. I'm still smarting over the undersized battery in my Honda.]
I've wondered about that 50 V threshold. A nominal 48 V system would actually run around 52.8 V, wouldn't it? (I'm extrapolating from nominal 12 V car batteries which are typically 13.2 V when charged.)
I guess if they dropped two cells (22 instead of 24) they could get under 50 V in real life.
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