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I think I need a new alternator!

svein

svein

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Location
Norway
Just did my summer vacation - 800km on veg oil with no trouble!

I am however worried about my alternator. I think it needs an upgrade. Changed my belt and charged it for three days, but I still saw low voltages(13,9 avg.) and flickering headlights. I could also see the lift pump pulsing more irregularly, when my vegtherm was engaged, so I seems it’s about voltage drops.

I have added quite some load to the system, my vegtherm veg oil heater draws about 25a, and I have 20a of aux lighting, so I think an upgrade is in order to keep the batteries happy.

I’ve been reading all the posts available at the moment and it seems like an ad244 is the right upgrade for my 99 suburban. Which alt would you recommend? Is it enough with 130a, or should I try to go for a 200a option to have headroom?

Cheers
 
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I have all ready upgraded all the battery cables with the ptsolution kit, so I have a 4awg wire to the alt. Do you think that would be enough, or would I need to upgrade further? In that case, it might be sufficient to settle for one of the 145a units that´s available..
 
I´m beginning to think that maybe the most feasible option might be to go for a stock ad244 with 145a. That´s an 40a upgrade from my stock alt, so it should theoretically cover my added 40a? On the other hand, it would be good to have headroom at idle speed as well. I could get a 145a version from rock auto quite cheap, or to a crazy expensive price at a Norwegian shop...haha
 
A bone stock 145 amp ad244 can do 220-240 amps when cold, but output quickly falls off as it heats up. It looks like they're selling stock replacements and giving you the cold output instead of the 100C output that GM rates them at
 
Very few people need more than a ad244 will put out. Powermaster makes nice stuff, but most people don't need more than a $110 ad244 from rockauto. I have the 130 amp ad244 on my Suburban and it holds 14+ volts at idle with both airs on, headlights(all 6 on), and with my travel trailer plugged in. A stock 145 amp ad244 is known to put out 85-90 amps at idle and hit 145 amps at 1500-1800 rpm's.
 
The other day I put an amp clamp meter on the positive from the alt to the battery while the truck was idling on veg oil. I measured roughly 70a with the high beams and my aux lights on as well as the vegtherm heater. Knowing that the sum of aux lighting and vegtherm makes 45a, it´s not much letft of those 70a for the rest of the truck. On the other hand - what else would actually draw power?

Recently I´ve been thinking that maybe my biggest problem could be a slipping belt. I have a 102" belt on currently. The belt tensioner is at the very end of its mark. I changed the belt, and that moved the belt tensioner about a cm into the range. Later when I got home from my holidays I changed the belt tensioner as well with a new one from rock auto. That belt tensioner went straight to the max tension position even with the new(500ish km) belt. I´ve been thinking maybe I should try a 101,5" belt or a 101" belt?

Theoretically, upgrading from my 105a alt to an 145a alt should be enough for my added 45ish a load. However I´m still dreaming of a LED bar on the roof, and Id rather have headroom than be at the limit - when that said, it is a significant difference between a stock ad244 from rock auto and a power master alternator, so I´m weighing pros and cons and money. Luckily, I´m off to Germany for work for the rest of the month, so yet again I have too much time to plan upgrades for my truck when I get home.. :D
 
Rock auto is simply like a network of parts houses. They can get High quality or junk. Make sure what you are ordering.

Powermaster is a brand that makes the very best. They always perform well and don’t cost much or sometimes anything more to have power levels at what ever rpm you want. They absolutely outlast anything else. You can call and speak to an engineer that will determine what is the very best way to set it up.

Having an alternator put out what is needed instead of blasting power too fast is a serious battery killer. To low of charge does the same. At work we deal with battery banks that cost more than any new pickup. Keeping the batteries in the prime of their charge is key to long term cost return.
 
There's plenty of horror stories involving powermaster. Nobodies stuff is perfect, and it seems the bigger a company gets, the more negative's get through. Mean green is another big company with good feedback. For the AD244, alternatorparts seems to be a well respected authority on them. Rockauto is simply a retailer of others parts, you get what you pay for, buy a cheapy, they send you a cheapy, and vice versa. It would be nice if there was an easy way to control them, but the late model GM alternators made by Bosch have excellent output and can be had for cheap. But they require the GM control system(or if ypu're handy a few have used arduino's) to make them charge at anything other than 13.8 volts. I believe you can get one of the 220 amp Bosch alternators for about $150 from Rockauto.
 
If you want a quality no nonsense true hot rated alternator then go with an Amptech. They are hand wound, large heatsink units, I have been using these on various marine builds for the last 20 or so years with no complaints. I have used their large case 300 amp units in a daily high current application and they simply put out and stand the test of time.

Their L unit is what you want to go with, it is externally regulated which is crucial for hot rated perfomance IMHO no internal reg means bigger diodes and heatsinks. Their stealth regulator is bullet proof but only a single step unit so will hold your batts at say 14.4V. If you want to go three step charge then the Balmar MC614 plays nice and is reliable. The stealth should work out fine for you though. This will cost but as far as alternators go there is no such thing as a cheap hot rated option.

Also note the rule of thumb for alts is 2/3 output for longevity. So if you want 140A go with a 200A or so.

Cheers
Nobby
 
I knew finding the right alternator would be opening Pandora’s box, haha! :)

Thank you again everyone for good advices and recommendations. I believe in overhead when it comes to electricity (and everything else in life, haha), so I’m really thinking I should go for a 200a-ish alternator.

Well worth to check around, though - an 200a will cost me about 500usd shipped to Norway. The local parts store wanted the same just for a 140a...

In planning to order new injectors and a fluiddampr soon, so I’m gonna check if maybe I could get an alt sent with the same shipment. Hey, if I order enough I might even be able to get a little discount on an order somewhere.
 
Friday it finally happened!
I ended up installing a 230A Tuff Stuff 8237D Alternator from Quadstar tuning. Its an AD244 alternator.

It was a one to one swap for my 1999 6.5. Old one out. New one in. Add a ground connection. Done.
From having varying voltage with my old alternator from 12-13, I am now rock steady at 14,5V even with my veg heater and auxiliary lighting in use. I even seem to read higher fuel pressures in average.

So happy!!
2019-09-13 13.48.09.jpg
 
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