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shaggy Articulating
Joined: 08 Feb 2007 Odometer: 560 Location: Manchester, UK
1961 Mercedes-Benz Unimog 404 Doka
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Posted: Sat May 26, 2007 10:22 am Post subject: Best 24V alternator for 404?
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Howdy,
We're going 24V ('cos the 12V starter is a bag of sh**e) and I need juice. We have a stock genny, but probably won't fit it because it's huge and only about 600 Watts.
Anyone got a top tip on which vehicle/truck to get an alternator off? Would like about 100 amps, but that's flexible.
cheers,
jim
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The Original Tom Guest
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Terranosaurus Articulating
Joined: 26 Apr 2007 Odometer: 949 Location: Bishop Auckland County Durham
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Posted: Sat May 26, 2007 6:04 pm Post subject:
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Do you jut want 24v starting? Or do you need anything else 24v/
If only starting you can do it using 12v alternator and the second battery purely in the starter circuit, depending how complicate you want to make things this can either be uncharged and allowed to slowly drain with each start up then put on charge when you get back home or with the relevant relays and an extra solenoid it can be made to charge from the normal alternator. A lot easier than going to the grief of converting everything else.
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:) Mud Obsessed
Joined: 06 Feb 2006 Odometer: 4337 Location: Norfolk
1995 Land Rover Defender
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Posted: Sat May 26, 2007 6:47 pm Post subject:
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sptb wrote: | ...If only starting you can do it using 12v alternator and the second battery purely in the starter circuit, depending how complicate you want to make things this can either be uncharged and allowed to slowly drain with each start up then put on charge when you get back home or with the relevant relays and an extra solenoid it can be made to charge from the normal alternator. A lot easier than going to the grief of converting everything else. |
It's not so easy to reliably swap from parallel to series connection "with the relevant relays and an extra solenoid", as you need to break and make two separate connections in the right order to avoid short circuiting one of the batteries. Also the contacts have to be rated to carry full starter current.
I suggest that a better option is to leave the batteries permanently connected in series to provide 24V and charge the lower one with a 12V alternator as per the normal connection. Then use a DC-to-DC converter to charge the upper battery from the lower one (only switch the DC-DC on when the alternator is charging).
I make this suggestion becasue of sptb's comments, but it would be better if you could fully specify your objectives and limits.
--
Tim.
__________________________________ -- Timothy Birt -- |
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Terranosaurus Articulating
Joined: 26 Apr 2007 Odometer: 949 Location: Bishop Auckland County Durham
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Posted: Sat May 26, 2007 6:52 pm Post subject:
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No it's not absolutely straightforward, which is why I said the relevant... but its not too difficult either people have been doing it with rally cars for 30 years quite successfully. Hot BD's are a pig to start.
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:) Mud Obsessed
Joined: 06 Feb 2006 Odometer: 4337 Location: Norfolk
1995 Land Rover Defender
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Posted: Sat May 26, 2007 7:25 pm Post subject:
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Yes, I agree it can be done; in fact I have used a set of Albright contractors to do a similar job, importantly they had interlock micro-switches so I could ensure they sequenced correctly.
I didn't want Jim to think a couple of 100A change-over relays would be suitable as a DiY series/parallel battery converter, becasue that won't work reliably.
--
Tim.
__________________________________ -- Timothy Birt -- |
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shaggy Articulating
Joined: 08 Feb 2007 Odometer: 560 Location: Manchester, UK
1961 Mercedes-Benz Unimog 404 Doka
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Posted: Sat May 26, 2007 8:23 pm Post subject:
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Apart from the starter. we have a 24V magnetic clutch hydraulic pump, and want a 24V winch, compressor and petronix electric ignition. Full 24V for us.
If you're stood in front of the bonnet looking backwards, it is on the left of the engine, turning clockwise.
catch you soon,
jim
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:) Mud Obsessed
Joined: 06 Feb 2006 Odometer: 4337 Location: Norfolk
1995 Land Rover Defender
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Posted: Sun May 27, 2007 5:39 am Post subject:
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Direction of rotation for an alternator is irrelevant, it will work out-of-the-box either way.
Direction of rotation for a dynamo is important, but can be easily be corrected by reversing the field winding connections (inside the dynamo) if it is going the wrong way.
There may not be much difference between a 12V and 24V alternator other than the regulator which is often a changeable item. As long as it generates enough voltage at low rpm to cut-in it might be an easy option to get a 24V regulator and fit it to a 12V alternator. Changing the pulley for a smaller one will increase the speed of the alternator and help generate more volts at lower engine RPM.
A long time ago (15+ years) I built my own regulator for a Lucas 17ACR alternator with a trimmer so the voltage could be adjusted (not to 24V though). Depending on how adventurous you are with the sparky bits I could possibly find the circuit I used and you could modify it as required.
--
Tim.
__________________________________ -- Timothy Birt -- |
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shaggy Articulating
Joined: 08 Feb 2007 Odometer: 560 Location: Manchester, UK
1961 Mercedes-Benz Unimog 404 Doka
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Posted: Sun May 27, 2007 9:30 am Post subject:
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There's bit that we're adventurous with - but not the alternator! 404's are incredibly reliable things, and I want to find a nice bosch or similar that takes the minimum of munging.
I ask because someone once mentioned a particular truck alternator that was a nice fit, of course, I can't remember which one!
I'm chief hammerer and grinder, derek does anything requiring subtlety and patience. The wiring loom is custom, from the ground up and made for 100amps- it wasn't done by me and all worked, first time!
jim
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moggs Just got MTs
Joined: 23 Nov 2005 Odometer: 227 Location: kendal cumbria
2007 Mercedes-Benz s404.1
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Posted: Sat Jun 23, 2007 5:59 pm Post subject: alternator
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leyland roadrunner. thats wats on mine, easy fit to.
mines a motor maneli version
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moggs Just got MTs
Joined: 23 Nov 2005 Odometer: 227 Location: kendal cumbria
2007 Mercedes-Benz s404.1
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Posted: Sat Jun 23, 2007 6:03 pm Post subject:
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oh sorry and its 24 volt 100 amp, fitted easy enough, just couple of wires, piece of cake jim. why faff about with split systems and relays.
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shaggy Articulating
Joined: 08 Feb 2007 Odometer: 560 Location: Manchester, UK
1961 Mercedes-Benz Unimog 404 Doka
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Posted: Sun Jun 24, 2007 1:33 pm Post subject:
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Cheers dude,
That's what I was looking for! We're not going split, although we'll probably end up with a 12v battery as well (someone bought me a 24 -> 12V converter).
jim
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shaggy Articulating
Joined: 08 Feb 2007 Odometer: 560 Location: Manchester, UK
1961 Mercedes-Benz Unimog 404 Doka
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Posted: Fri Dec 21, 2007 5:13 pm Post subject:
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Finally, I actually bought an alternator!
I could only find roadrunner ones at 50 amps. I ended up buying new from Lancashire Rotating Electrics in Leyland, lovely people worth a mention.
It a 100 amp Perkins job, very properly made, and it should even fit.
(with wrong pulley on)
jim
__________________________________ Bright Orange Unimog 404 DoKa
www.foodfight.org.uk/mog |
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