Who has upgraded their alternator to higher Amp model?

[fkloster]

Please share your story.

[Bigd9]

When the alternator went bad on my last coach, I had it rebuilt. The owner of the small shop that did the work asked me if I wanted him to increase the output. I said sure. Never noticed any difference! I think it went from 110 amps to 130 amps.

[YooperVer]

I put a large frame 100 A alternator in my sailboat to charge house batteries (950 AH bank). Needed to go with dual belts and reinforce the mounts. Serpentine belt would have been better, but an expensive modification on my engine. Got a good amount of dusting off of belts and belts don't last forever.

Note that you will see high amp ratings on some light truck alternators these days, but they are not really designed to put those amps out for the long periods of time to charge a large battery bank and are really only capable of those outputs for short time periods. For continuous duty alternators are derated quite a bit (my 100A is same frame size as 160 A units). A 100 A alternator will demand over 2 horsepower from the belt drive and puts out a lot of heat (alternators are like 60% efficient I think). Of course you can get much higher rated alternators, but really need to be careful in application (crankshaft side loading, belt capacity, heat rejection, proper regulation, heavy gauge cabling etc). It is not just a simple swap of alternator for large size in most cases.

[JNSNWT]

I’m curious as to why you would want to upgrade to a higher amperage model.

Are you wanting to charge the batteries faster while driving down the road or are you wanting to run additional accessories while driving?

Or am I missing something (which happens quite often).

[Sam.B]

You wouldn't notice a difference unless you were using more electricity than it was producing at 100 amps. It will just recharge the battery quicker. Not enough difference to worry about side load on the bearings.

[fkloster]

Originally Posted by JNSNWT

I’m curious as to why you would want to upgrade to a higher amperage model.

Are you wanting to charge the batteries faster while driving down the road or are you wanting to run additional accessories while driving?

Or am I missing something (which happens quite often).

My situation. 28 year old coach with 160 amp factory alternator... (80 amp @ idle)

After i replaced my battery sets last year (twin Caterpillar 8D 1500 CCA starter batts and 4X 27m AGM 800 CCA deep cycle house batteries)... i noticed driving at night in poor weather, with dash heater fan wide open.... roof mounted defrost fans on high... wipers... all exterior lights... wife making blended drinks ect ect... and brand shiny new MAGNA 2,800 watt inverter inverting away... i noticed that slowly but surely... my volts would slowly just creep down to sub 12 volts.... as old girl just couldn't keep up with our non sense @ night. Did alot of research... found a company in CA that builds 270 amp 28Si 12 volt alternators that bolt right in (120 amp @ idle). after completion, i found a big difference while @ night and electric stuff is ripping.

[twinboat]

You could have a boat load of batteries or 1 little one.

If you draw more amps then the alternator puts out, you will see a drop in volts.

I upgraded to a 150 amp alternator and added an external, 3 stage voltage regulator, on my boat. It ran on dual V belts and at high charging rates, with 800 AH of batteries, it was tough on the belts.

The 3 stage regulator had a temperature monitor that would cut back output if the alternator got to hot. It also had a belt saver routine, that slowly ramps up the output.

To realise the higher outputs of these alternators, you need to upgrade the output and ground wire from it to the battery. I was using 2 gauge and it cranked out 150 amps until it got hot. Then it would regulate up and down as it cooled, until the battery bank was at 75% or more. That's when it would cut back to absorbsion mode. Not bad for a small frame alternator.

[fkloster]

Originally Posted by twinboat

You could have a boat load of batteries or 1 little one.

If you draw more amps then the alternator puts out, you will see a drop in volts.

I upgraded to a 150 amp alternator and added an external, 3 stage voltage regulator, on my boat. It ran on dual V belts and at high charging rates, with 800 AH of batteries, it was tough on the belts.

The 3 stage regulator had a temperature monitor that would cut back output if the alternator got to hot. It also had a belt saver routine, that slowly ramps up the output.

To realise the higher outputs of these alternators, you need to upgrade the output and ground wire from it to the battery. I was using 2 gauge and it cranked out 150 amps until it got hot. Then it would regulate up and down as it cooled, until the battery bank was at 75% or more. That's when it would cut back to absorbsion mode. Not bad for a small frame alternator.

So, is that normal for a functioning 160 amp alternator not keeping up in a 40 foot coach with all the bells and whistles running? I did not upgrade my existing cabling to the inverter & Batts... but the guage looks big. The part is internally regulated. Hers is a link to the site...:

https://www.qualitypowerauto.com/

LOL one thing is for sure... 270 amp part can now keep up with wife's hair dryers, curling irons, ice makers... ect. Not sure if maybe back in 1990 people didn't get after it like they do these days!

[AnotherMike]

Originally Posted by fkloster

Did alot of research... found a company in CA that builds 270 amp 28Si 12 volt alternators that bolt right in (120 amp @ idle).

Thank you for the pointer. I'll probably be contacting them.

[fkloster]

Originally Posted by AnotherMike

Thank you for the pointer. I'll probably be contacting them.

yep it was like $500 shipped. I thought a great value based on the amps. I really do like sometimes not waking up the big gen and just inverting off of engine power @ night... its a nice alternative @ times...

[twinboat]

Originally Posted by fkloster

So, is that normal for a functioning 160 amp alternator not keeping up in a 40 foot coach with all the bells and whistles running? I did not upgrade my existing cabling to the inverter & Batts... but the guage looks big. The part is internally regulated. Hers is a link to the site...:

https://www.qualitypowerauto.com/

LOL one thing is for sure... 270 amp part can now keep up with wife's hair dryers, curling irons, ice makers... ect. Not sure if maybe back in 1990 people didn't get after it like they do these days!

A hair dryer will typically draw 12 or so amps, maybe more. That's at 120 volts.

Take that 12 amps and multiple it by 10, when you usung 12 volt power and now your drawing 120 amps plus 15% for conversion inefficiencies.

Add that 135 amps and any other 120 volt items amps, X 10, plus all of the 12 volt items that the chassis and house need to run and you are way over the alternators capacity.

I was talking about the wires on the back of the alternator that go to the battery, not the inverter cables.

I would find a wire gauge calculator to figure out how large an alternator cable you need, otherwise you could overload the wire it came with.

[lwmcguire]

Originally Posted by twinboat

A hair dryer will typically draw 12 or so amps, maybe more. That's at 120 volts.

Take that 12 amps and multiple it by 10, when you usung 12 volt power and now your drawing 120 amps plus 15% for conversion inefficiencies.

Add that 135 amps and any other 120 volt items amps, X 10, plus all of the 12 volt items that the chassis and house need to run and you are way over the alternators capacity.

I was talking about the wires on the back of the alternator that go to the battery, not the inverter cables.

I would find a wire gauge calculator to figure out how large an alternator cable you need, otherwise you could overload the wire it came with.

Twinboat nailed it

If your load is that high going down the road, start the generator

[RickNC]

Worked on upgrading the alternator in my 1995 Winnebago today. The original alternator is rated at 105 amps of which about 75 are available at idle. Problem has been on hot summer days sitting in traffic with A/C on Max, Engine cooling fan, Engine management and the inverter running the refrigerator The alternator hasn't been up to the task. I opted to replace the oem Delco CS130 with a larger case CS144 200 amp from Hurst. The mounting holes are 5/8 farther apart than the old alternator so I had to cut the existing adjustment slot out and machine in a new slot. The back brace on the alternator had to be stepped and lengthened to accommodate the 3/8" deeper body of the new alternator. While the paint dried on the modified brackets, I partially disassembled the new alternator and "reclocked" it so the back brace would fit. New alternator and modded brackets went back in without an issue. Started the engine and everything is working correctly. The only thing I have left to do is install a 6 gauge wire from the alternator to the battery to piggyback the 6 gauge wire that is part of the factory harness.

[fkloster]

Originally Posted by RickNC

Worked on upgrading the alternator in my 1995 Winnebago today. The original alternator is rated at 105 amps of which about 75 are available at idle. Problem has been on hot summer days sitting in traffic with A/C on Max, Engine cooling fan, Engine management and the inverter running the refrigerator The alternator hasn't been up to the task. I opted to replace the oem Delco CS130 with a larger case CS144 200 amp from Hurst. The mounting holes are 5/8 farther apart than the old alternator so I had to cut the existing adjustment slot out and machine in a new slot. The back brace on the alternator had to be stepped and lengthened to accommodate the 3/8" deeper body of the new alternator. While the paint dried on the modified brackets, I partially disassembled the new alternator and "reclocked" it so the back brace would fit. New alternator and modded brackets went back in without an issue. Started the engine and everything is working correctly. The only thing I have left to do is install a 6 gauge wire from the alternator to the battery to piggyback the 6 gauge wire that is part of the factory harness.

Nice install Rick! I'm impressed with your mod. I was very fortunate and did enough homework on the original footprint to know that mine would bolt right in. I'm also glad to know that if i ever do want to upgrade gauge of wire... I can just piggy back an additional wire to the batts. Thank you!