200 Amp high output alternator and cabling

J

Jeff Blake

Well-known member
May 6, 2016
429
16
Pacific Beach, San Diego
Disco 2

Stock alt is 130 amp.
RR amp (direct fit) is 150 amp.

I found this reman Bosch alt that claims 200 amp.

http://www.ebay.com/itm/282364564386?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

The sellers eBay feedback is impeccable, but doing some searches around the net raises some questions, but can't find anything very concrete. Sounds too good to be true... 200A for $175.

Anyway, I bought it last night. When I get a winch soon, I should be able to test its output with a DC clamp meter.

On to cabling:

Has anyone run the alternator cable directly to the battery? I don't think it would work, but would be nice. Failing that, I'd like to upgrade to beefier cables for alt->fuse box and fuse box -> battery, but I can't find those 90 degree elbow lugs anywhere. Any tips?
 
bendts

bendts

Well-known member
Jan 27, 2015
277
18
Farmland
When my alt went bad in my 01 D2, i found something on the web about Bosch having a Lifetime warranty - so I called Bosh and told them what i had and that it died - they did a warranty exchange at the nearest shop that handled Bosh. This was 6 years ago while in Denver.

I swear that my Alt is 160 amp's - maybe wrong on that.

Worth a try.
 
jymmiejamz

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
bendts said:
When my alt went bad in my 01 D2, i found something on the web about Bosch having a Lifetime warranty - so I called Bosh and told them what i had and that it died - they did a warranty exchange at the nearest shop that handled Bosh. This was 6 years ago while in Denver.

I swear that my Alt is 160 amp's - maybe wrong on that.

Worth a try.
Click to expand...

You might have the P38 alternator which is the same as a DII but 150A.
 
best4x4

best4x4

Well-known member
Mar 1, 2015
595
72
Beaumont, TX
I've bought Ebay Alternators before from a few different sources. Zero issues with any of them.

The cable going to the alternator is much thicker than most Jeep's I ever messed with when I was installing a larger AMP alternator. If it's not a gauge 2 wire it's pretty darn close.
 
best4x4

best4x4

Well-known member
Mar 1, 2015
595
72
Beaumont, TX
Yep it is stock, then rebuilt with higher AMP hardware. When I had an 05 Rubicon I found out a Durango alternator was 160amp vs a 130amp in my Rubicon. Cheap & simple upgrade, and online or rebuilt locally it could go up well past 200AMP and MUCH cheaper vs a Mean Green Alternator.
 
rovercanus

rovercanus

Well-known member
Apr 24, 2004
9,651
246
Unless you are wiring your winch directly to the alternator, the load will be pulled from the battery and the alternator will supply the battery.
What are you trying to accomplish with a higher current alternator?
 
J

Jeff Blake

Well-known member
May 6, 2016
429
16
Pacific Beach, San Diego
Hmm you might be right, so in that case the alternator cable would only read whatever the max amps that the battery can absorb, correct?
So at idle, the alt is showing around 10-15 amps, are those amps going into the battery and then powering the truck, or direct to the truck? I would think the current follows the path of least resistance, so it flows direct to the truck (headlights, etc)? So in that case, the winch may pull some amps from the battery (up to what the battery can absorb) and pull the rest from the alt?

My current alternator may be on its way out. Alt was putting out no volts the other day, but it started working again after restarting the truck. I have always wanted a 150amp alternator anyway, so this mishap justified to myself to go looking for one, but then I found this 200 amp option. I have a dual odyssey, fridge, onboard air (soon), winch (soon), lots of lights, and who knows what other electronic ideas I'll come up with. More amps the better!
 
squirt

squirt

Well-known member
Nov 13, 2008
824
13
Los Angeles
Jeff Blake said:
Any tips for testing an alternator output with basic equipment?

The only thing I can think of is creating a 200 amp load and using a DC clamp meter on the alternator cable - so tie up against a tree and run a winch? Anyway to do it without a winch?

This device is cool - https://www.powerprobe.com/hook-page/
but it only does 100amp
Click to expand...


Bring it to Autozone/O'Reilly/whatever and have them test the charging system with a resistive tester?

We used to do it in my high school auto shop.
 
rovercanus

rovercanus

Well-known member
Apr 24, 2004
9,651
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A higher capacity alternator doesn't necessarily put out high current, it just has the ability to do so if the load is there. If the load isn't there it will supply current to whatever the draw is, in other words, if you don't have anything that is wired to one of the fuse boxes now drawing high current, a higher capacity alternator want do much good.
Winches are wired to the battery because they draw high currents that would over power an alternator.
I have a superwinch EP9i which draws the following. As you can see, it draws much more current than a typical alternator could supply but a battery can.
 
J

Jeff Blake

Well-known member
May 6, 2016
429
16
Pacific Beach, San Diego
rovercanus said:
A higher capacity alternator doesn't necessarily put out high current, it just has the ability to do so if the load is there. If the load isn't there it will supply current to whatever the draw is, in other words, if you don't have anything that is wired to one of the fuse boxes now drawing high current, a higher capacity alternator want do much good.
Winches are wired to the battery because they draw high currents that would over power an alternator.
I have a superwinch EP9i which draws the following. As you can see, it draws much more current than a typical alternator could supply but a battery can.
Click to expand...

Yeah I totally understand that, what I am unclear on is if the winch is pulling 300a from the battery, would the alternator also push out its max amps (200a) or will it only push out whatever the battery is capable of absorbing (probably like 25-50amps)? Or would the winch pull like 150 from the battery, and 150 from the alternator at the same time?
 
p m

p m

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Apr 19, 2004
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La Jolla, CA
www.3rj.org
Jeff Blake said:
Yeah I totally understand that, what I am unclear on is if the winch is pulling 300a from the battery, would the alternator also push out its max amps (200a) or will it only push out whatever the battery is capable of absorbing (probably like 25-50amps)? Or would the winch pull like 150 from the battery, and 150 from the alternator at the same time?
Click to expand...
It is hard to tell how much the alternator will push when the winch is in near-stall - but likely close to its max current output.
 
p m

p m

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Apr 19, 2004
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ok boys, you got me thinking for a while.

To get the same alternator to produce 40% more current, you need slightly more than a new diode pack.
The stator winding should be able to support higher current; the existing one _may_ live through some short bursts of high output, but if you draw that much on a duty cycle higher than normal, you'll have a meltdown.

So... for the winding wire to support 40% more current, it has to have 40% more cross-section (or about 20% larger diameter).
Since the volume in which the winding resides is fixed, 40% larger cross-section in a winding wire means you'll have about 40% fewer turns in it.
40% fewer turns in it means you need to spin the rotor 40% faster to achieve the same output; it also may mean (and likely does mean) that your alternator's output at idle is going to be 40% less compared to the factory.

The final answer - yeah or nay - depends on your gearing, driving habits, and distances. If your daily commute is less than an hour, very likely the battery will be progressively undercharged.
 
J

Jeff Blake

Well-known member
May 6, 2016
429
16
Pacific Beach, San Diego
p m said:
ok boys, you got me thinking for a while.

To get the same alternator to produce 40% more current, you need slightly more than a new diode pack.
The stator winding should be able to support higher current; the existing one _may_ live through some short bursts of high output, but if you draw that much on a duty cycle higher than normal, you'll have a meltdown.

So... for the winding wire to support 40% more current, it has to have 40% more cross-section (or about 20% larger diameter).
Since the volume in which the winding resides is fixed, 40% larger cross-section in a winding wire means you'll have about 40% fewer turns in it.
40% fewer turns in it means you need to spin the rotor 40% faster to achieve the same output; it also may mean (and likely does mean) that your alternator's output at idle is going to be 40% less compared to the factory.

The final answer - yeah or nay - depends on your gearing, driving habits, and distances. If your daily commute is less than an hour, very likely the battery will be progressively undercharged.
Click to expand...

Hmmm. Interesting info, thanks. I have solar, and a dual odyssey 68a setup, so that helps..
Sounds like I should get the alt tested at an auto store (at ~650 rpm, and high rpm) to see how it performs before I install it. I will also drop a message to the seller and ask what modifications were made to go from 130 to 200

Funny, I'm actually moving to Pacific beach at the end of the month - if you have any shop recommendations let me know!
 
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