how to modify a car alternator for 48v charging
- Thread starter mikeb
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gnubie
Solar Wizard
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Is it possible? Yes. Yes you can pull it apart change the configuration of the windings and rectifier, add a current monitor / limiter, change the voltage regulator, perhaps add some capacitors and "its easily done".
On the other hand, it may be more practical to use a DC-DC converter. If you can provide more details of exactly what you are attempting someone may be able to give you more guidance.
On the other hand, it may be more practical to use a DC-DC converter. If you can provide more details of exactly what you are attempting someone may be able to give you more guidance.
Master Dalor
Self made Master
Hello. You could use a dc to dc boost converter. Of course, if you go from 12v to 48v , it is 4 times more, so you must divide your amps by 4. If it was 12V 100 Amps, At 48V, 25Amps. with the dc to dc 80% efficiency 25Amps x 0.8 = 20 Amps. Also, the alternator needs a 12V battery to excite the electromagnet of his regulator.
i would add a second alternator to an existing houseboat motor so that when its running it charges the regular 12 v system with the original and the new alternator also charges 48 v large li-ion power wall battery for a 48vdc inverter so i would not have to have a 110v generator at all.
Master Dalor
Self made Master
I just found that: https://www.electriccarpartscompany...or-Regulator-for-12V-24V-48V-Charging-Systems
There are certainly other brands, I don't know what it's worth.
I saw a video from victron where they burn alternators when charging directly lithium battery, with the alternator running at idle speed, there is not enough airflow to cool it.
Does a boat engine run at idle speed? Or does it always run at the same speed?
Anyways, the alternator must be cooled, maybe it could be disengaged when the engine runs slow with some kind of clutch, or in the link I provided, you will find that they resolved that problem.
I hope you get some ideas, happy if it helps you.
There are certainly other brands, I don't know what it's worth.
I saw a video from victron where they burn alternators when charging directly lithium battery, with the alternator running at idle speed, there is not enough airflow to cool it.
Does a boat engine run at idle speed? Or does it always run at the same speed?
Anyways, the alternator must be cooled, maybe it could be disengaged when the engine runs slow with some kind of clutch, or in the link I provided, you will find that they resolved that problem.
I hope you get some ideas, happy if it helps you.
Master Dalor
Self made Master
Sure I used round number for easy calculation, and pointing the fact that the amps are divided, but I can also calculate 57.6V divided by 14,4V, man, it's also 4 times, how can that be? hehehe :D
Master Dalor
Self made Master
just a crazy idea, you could use 4 12V alternators powering 4 12V batteries in series, but each one must be isolated from the ground and from each others.
On YouTube Julian Illet tries that with 18650 cells and usb single cell chargers, among many other interesting ideas, also small dc to dc converters.
On YouTube Julian Illet tries that with 18650 cells and usb single cell chargers, among many other interesting ideas, also small dc to dc converters.
Master Dalor
Self made Master
Good morning. Maybe it's better to isolate also the 48v alternator from the ground (the engine mount is ground)
efficientPV
Solar Addict
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Just on a theoretical basis. Alternators are three phase. If you wired those three phases into two 24V to 120V transformers, that would get you close to the right voltage and it would be isolated.
Master Dalor
Self made Master
Hello efficient pv.
Depending on the rpm, the alternator stator produces different variable voltage and frequency, the regulator energising the rotor winding modifies the magnetic field of the rotor. The magnetic field becomes weaker with higher rpm to keep stable voltage output.
To use the 3 phases, the regulator must be removed, and the rotor must be powered by external source, so with changing rpm, the stator outlet voltage frequency and amps will vary accordingly.
So I don't know how much volts you expect to see with the 24V 120V transformers and how you would wire them on the 3 phases? Can you explain?
Delco-Remy 36si or 55si series 24v alternators. These are continuous duty marine-diesel alternators. Clones of the 100Amp 36si can be found for about $300. Then you can get a 24v to 48v booster. If I remember correctly, 3000rpm on the alternator would give you about 75Amps @ 28v.
Hedges
I See Electromagnetic Fields!
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Why just not implement a regulator for 48V?
No way the winding insulation gets anywhere near breakdown.
The diodes might. See if you can look up data sheet. Or test one with a curve tracer or similar non-destructive method.
Worst case, just isolate the diodes and pull the wires out to 6 diodes externally.
They need better heatsinking, anyway. The negative ones to case are fine, but the positive are on too small of a plate. (use forced air, too)
No way the winding insulation gets anywhere near breakdown.
The diodes might. See if you can look up data sheet. Or test one with a curve tracer or similar non-destructive method.
Worst case, just isolate the diodes and pull the wires out to 6 diodes externally.
They need better heatsinking, anyway. The negative ones to case are fine, but the positive are on too small of a plate. (use forced air, too)
Hedges
I See Electromagnetic Fields!
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- Mar 28, 2020
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I think that for certain. "Enamel" or polyester insulation has breakdown voltage of around 1000V per mil. The magnet wires I've used had operating voltage ratings of around 600V. You just don't get anything under 100V without extremely thin layers (such as IC processes, not wire insulation).
Overheating will cause breakdown, so does mechanical damage (at which point moisture can allow conduction.) The only place I saw problems were multi-kV transformers where winding techniques determined whether ends of the winding that were several kV apart could be physically adjacent, and the 40 awg wire had been manually handled, probably stretched to the point of damaging insulation.
Here's the 24v alternator that I plan to use for my portable charging system.
And here are some specs for the Delco-Remy version.
www.delcoremy.com
Hope this helps and God bless!
Kugel
New USA BUILT 24V 100A Alternator for Cummins Marine replaces 4078701 19011203 | eBay
Find many great new & used options and get the best deals for New USA BUILT 24V 100A Alternator for Cummins Marine replaces 4078701 19011203 at the best online prices at eBay! Free shipping for many products!
www.ebay.com
And here are some specs for the Delco-Remy version.
8600398 36SI New Alternator | Product Details | Delco Remy
www.delcoremy.com
Hope this helps and God bless!
Kugel
Aaron_85
New Member
i had a shower thought for an easy, yet probably not very efficient (but who cares lol) method to achieve charging from a vehicles engine.
if you're running an all in one inverter with a 240v/220v charger like the MPP solar range, use an appropriately sized to your alternator output 12v inverter on it. limit AC charging on all-in-one accordingly to not smoke your cars alternator.
No doubt round trip efficiency sucks, but the engines running anyways. This way you don't need dual alternators/voltage systems for your vehicles electrical, and if the "hotel" power system is far away from the engine at the other end of your RV/trailer, higher voltage means less current, smaller cables and less vdrop.
if you're running an all in one inverter with a 240v/220v charger like the MPP solar range, use an appropriately sized to your alternator output 12v inverter on it. limit AC charging on all-in-one accordingly to not smoke your cars alternator.
No doubt round trip efficiency sucks, but the engines running anyways. This way you don't need dual alternators/voltage systems for your vehicles electrical, and if the "hotel" power system is far away from the engine at the other end of your RV/trailer, higher voltage means less current, smaller cables and less vdrop.
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