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charging 48v battery with 24volt input

Tecnodave said:
A DC generator produces DC directly

An Alternator produces AC which is then rectified to DC with diodes, Most common alternators are three phase AC at a variable frequency which is directly related to the r.p.m. of the Alternator.

An AC generator produces AC directly from the coils, the frequency of the AC is directly related to the shaft speed and the number of coils on the generator.... Common AC generators are 3600 r.p.m. or 1800 r.p.m. depending on the number of coils , 2 or 4 are most common

Honda Inverter generators are a hybird.....they are 3 phase alternator (AC) which is rectified to DC at about 80 volts which is then used to power the inverter to make the AC. So they are AC converted to DC then back to AC.

The advantage is frequency output is not directly coupled to the R.P.M. of the engine.....thus the inverter generators change speed to be more effecient which a AC generator cannot do as frequency is directly related to r.p.m.
the frequency of the alternator is directly related to the speed of the engine, the frequency of the inverter is derived from the logic in the alternator. They do not need to be the same.
Click to expand...
Thank you for that explanation. How does a DC generator produce DC directly?
 
Well, it does not produce DC directly, it does produce AC which is then mechanically rectified to DC through the brushes which reverse the connections every 1/2 rotation of the armature shaft. A DC generator does have multiple windings but only one winding is connected to the brushes at a time by the commutator bars.

Derpsy, my apologies, i dont mean to yell, sometimes it is very hard to get someone to focus on the important parts so i use caps to empathize the important points that people will read over and not understand. Electricity comes very easy to me, not so much to some people....
 
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Tecnodave said:
Well, it does not produce DC directly, it does produce AC which is then mechanically rectified to DC through the brushes which reverse the connections every 1/2 rotation of the armature shaft.
Click to expand...
And how is that output voltage tuned? Is the a/c voltage that's created already at the desired voltage?
 
Yes, it is the number of windings in each coil group and the rotational speed of the generator
 
Tecnodave said:
Yes, it is the number of windings in each coil group and the rotational speed of the generator
Click to expand...
so if given the rotational speed of the generator, could one contract the fabrication of an appropriate (not transformer) coil that will output the desired voltage? Will the change in voltage require a change of the conversion brushes?
 
Generators can be rewound for a different voltage by changing the guage of wire and the amount of wires (coils) in each group, not trivial, its a complete redesign...
 
There are electric motor shops that specialize in rewinding motors, its not an easily done process that end users are capable of. Yes for some voltage conversions the same brush/commutator is used. Some of the very early VoltsWagon conversions used an aircraft starter/generator which used different coils wound into WWII aircraft engine starter/generators.
 
Tecnodave said:
There are electric motor shops that specialize in rewinding motors, its not an easily done process that end users are capable of. Yes for some voltage conversions the same brush/commutator is used. Some of the very early VoltsWagon conversions used an aircraft starter/generator which used different coils wound into WWII aircraft engine starter/generators.
Click to expand...
Any idea what a shop like that might charge?
 
Its not cheap, probably more than a new generator suitable for the use intended, at least several hundreds if not more.
 
Id opt for selling the unit, buying a AC unit and then useing the link in my sig for DIY AC to DC charger based on server PSU. Then it doesnt matter what kind of generator you feed the chargers with.
 
At the output of the chopper it is square wave but this is smoothed into sine wave by the transformer along with its capacitors
 
DerpsyDoodler said:
the first ones listed are stepdown. Looks like the highest rated step-up 24-48 is $220 for 8.5a. That definitely does not seem cost effective.

Is there any way to replace a transformer on the generator and just have it generate 48v?
Click to expand...
Was thinking that might be a possabilty but the computer on the generator is 24v and does all the starting/ stopping/ timed charge, voltage adjustments, delay, and fuel pump prime and operation. starts with a single switch and was hoping to keep those perks
 
SO then who wants to buy a nice dewey 24v dc generator? 8 hrs of use, electric start. diesel single cylinder yanmar
 
The most simple way to do this is:
- Buy a 24 volt, 2 kW inverter
- Feed the inverter from the alternator (probably need a small 24 volt battery pack as well.)
- Feed the 120 vac from this inverter into a 48 volt charger

In spite of the slightly less than optimistic charge efficiency, this does work and it is done on conversion vans routinely.
 
DerpsyDoodler said:
What are the specs? i know diddly poop about dc generators.
Click to expand...
These Yanmar diesel generators are commonly used in the marine environment and as such are far more rugged than consumer generators, They are direct drive in that the generator has a female tapered shaft which directly couples to the tapered shaft on the engine. Not always but sometimes a prosperity taper is used which makes it hard to adapt engine to other uses. I have a few great honda engines from dead generators which do have a honda specific taper that i cannot find any pulley or coupling that will fit. Unfortunately honda generators do not outlast the honda engine.

Yanmar engines are the best of the best in small diesels......
 
Tecnodave said:
A DC generator produces DC directly

An Alternator produces AC which is then rectified to DC with diodes, Most common alternators are three phase AC at a variable frequency which is directly related to the r.p.m. of the Alternator.

An AC generator produces AC directly from the coils, the frequency of the AC is directly related to the shaft speed and the number of coils on the generator.... Common AC generators are 3600 r.p.m. or 1800 r.p.m. depending on the number of coils , 2 or 4 are most common

Honda Inverter generators are a hybird.....they are 3 phase alternator (AC) which is rectified to DC at about 80 volts which is then used to power the inverter to make the AC. So they are AC converted to DC then back to AC.

The advantage is frequency output is not directly coupled to the R.P.M. of the engine.....thus the inverter generators change speed to be more effecient which a AC generator cannot do as frequency is directly related to r.p.m.
the frequency of the alternator is directly related to the speed of the engine, the frequency of the inverter is derived from the logic in the alternator. They do not need to be the same.
Click to expand...
If I had two 24v dc generators of the same output could i wire them in series to get 48v to charge the batteries?
 
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