Alternator rebuild shop in Denver?

Cruisertrash

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Awful quiet around here with CM going on!

Going to swap in a new alternator this weekend, then take my OEM unit to get rebuilt. That way I can have it spec’d for a little higher current load and either keep it as a spare, or swap it in and keep whatever Denso reman I find this weekend as the spare.

I’m having zero luck finding a local shop. Whatcha got?
 

powderpig

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An alternator for what vehicle?
D&D auto elec will rebuild Denso alternators and starters of gas and diesel. He is who I use not that Vanetta
is gone in Boulder. He is over in Wheatridge.
I do not have his address, but it will pop up in Google search.
I know that Denso does not rebuild a lot of older alternators and Starter any more. I really have not found a good rebuilt
alternator in any parts house I would recommend for these discontinued rebuilds from Denso.
 

Cruisertrash

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@powderpig

Thanks for the recommendation - I’ll look up D&D. This would be a stock alternator from an 83 60, definitely Denso. I found one on Napa that’s labeled Bosch and checks out with my truck, but under manufacturer it says “ND” ... maybe a rare Denso still floating out there?

Mine seems like it’s going wonky, plus I’d like to have a backup. I daily drive this truck so swapping in a parts store unit while I have the OEM unit fixed up is my path.
 

gr8fulabe

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Awful quiet around here with CM going on!

Going to swap in a new alternator this weekend, then take my OEM unit to get rebuilt. That way I can have it spec’d for a little higher current load and either keep it as a spare, or swap it in and keep whatever Denso reman I find this weekend as

I’m having zero luck finding a local shop. Whatcha got?

So how does this work exactly? For instance my hj47 is 12 volt. Can I tell them to redo it to put out more ??? Like can they make it put out 13.5amps or volts or whatever to support the higher charge needs of an agm battery? Or is it like moving from 40 watts or amps, to higher? Sort of like swapping g in a mean green alternator but in OEM form? Sorry, I don’t have the terminology down here. Electrical stuff is like 90% magic for me.

Thanks
Abe
 

cbelgard

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An alternator for what vehicle?
D&D auto elec will rebuild Denso alternators and starters of gas and diesel. He is who I use not that Vanetta
is gone in Boulder. He is over in Wheatridge.
I do not have his address, but it will pop up in Google search.
I know that Denso does not rebuild a lot of older alternators and Starter any more. I really have not found a good rebuilt
alternator in any parts house I would recommend for these discontinued rebuilds from Denso.
Sad to hear Vanetta is gone, I had my 8774 winch motor rebuilt there. It was a trip walking in there, a true throwback.
 

DaveInDenver

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So how does this work exactly? For instance my hj47 is 12 volt. Can I tell them to redo it to put out more ??? Like can they make it put out 13.5amps or volts or whatever to support the higher charge needs of an agm battery? Or is it like moving from 40 watts or amps, to higher? Sort of like swapping g in a mean green alternator but in OEM form? Sorry, I don’t have the terminology down here. Electrical stuff is like 90% magic for me.
They can rewind alternators to increase their output current. The voltage is controlled by your voltage regulator, which depending on the vehicle may be an external box or internal to the alternator.

There's logic to the way a vehicle charging system is built. There's voltage and temperature characteristics that dictate the ideal charging parameters for a battery of any type. For example most of the time the charging voltage is given as something like 13.6V at 25°C and will go higher or lower in voltage as you change temperature. It might be 14.0V at 0°C or 13.2V at 40°C (these are just examples, the battery manufacturer will specify them).

In that vein what you've heard about going from a flooded lead acid to an AGM is true in theory, they generally require a higher voltage to fully charge. However they also require their max voltage to be more carefully controlled to avoid over-charging. They are sealed so if you go too high and cause the electrolyte to boil and vent there's no way to put it back in so if this happens the loss in capacity is permanent while with a traditional flooded you can just add back in water.

So my point would be to tread carefully with trying to dial in charging with an alternator. The OEM picked the safest profile that won't be a problem for most any battery. They tend to fall into being able to do two of the steps, bulk charge (tons of current) and float (safe long term voltage), which does about 90% of an ideal charge. The third step of a minimally "ideal" profile is absorption is where the ideal voltage put on a battery to top it fully.

The best way IMO to deal with this, particularly with AGM that requires a pretty tight window optimally, is to use a charger at home regularly that's designed to work with your specific battery. If you want to do it on-board the best solution is a DC-DC charger that converts the crudely controlled alternator output to a well controlled multi-step profile.
 
Last edited:

gr8fulabe

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They can rewind alternators to increase their output current. The voltage is controlled by your voltage regulator, which depending on the vehicle may be an external box or internal to the alternator.

There's logic to the way a vehicle charging system is built. There's voltage and temperature characteristics that dictate the ideal charging parameters for a battery of any type. For example most of the time the charging voltage is given as something like 13.6V at 25°C and will go higher or lower in voltage as you change temperature. It might be 14.0V at 0°C or 13.2V at 40°C (these are just examples, the battery manufacturer will specify them).

In that vein what you've heard about going from a flooded lead acid to an AGM is true in theory, they generally require a higher voltage to fully charge. However they also require their max voltage to be more carefully controlled to avoid over-charging. They are sealed so if you go too high and cause the electrolyte to boil and vent there's no way to put it back in so if this happens the loss in capacity is permanent while with a traditional flooded you can just add back in water.

So my point would be to tread carefully with trying to dial in charging with an alternator. The OEM picked the safest profile that won't be a problem for most any battery. They tend to fall into being able to do two of the steps, bulk charge (tons of current) and float (safe long term voltage), which does about 90% of an ideal charge. The third step of a minimally "ideal" profile is absorption is where the ideal voltage put on a battery to top it fully.

The best way IMO to deal with this, particularly with AGM that requires a pretty tight window optimally, is to use a charger at home regularly that's designed to work with your specific battery. If you want to do it on-board the best solution is a DC-DC charger that converts the crudely controlled alternator output to a well controlled multi-step profile.

Thanks! Sounds like I’m best to leave well enough alone to me! I appreciate the insights!
 

Cruisertrash

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For what it’s worth D&D said they may or may not be able to spec my alternator for higher current. I’m primarily interested in having it rebuilt because it seems like it’s acting funny. Voltage dips randomly - on the highway, at idle, with lots of load, with very little load. Battle tests good, no parasitic drain, electrical has historically been rock solid in this vehicle. I recently replaced all the heavy gauge ground cables and the starter 12V cable. I cleaned up all the contact points before attaching the cables and I double checked that everything was tightened down.

Beyond that, I’d like to have a spare alternator anyway.
 

gr8fulabe

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So another question. If I had an OEM 24volt Diesel truck alternator & wanted it to be rebuilt into a 12 volt version, would they just need to know the specs of the 12 volt, or is there more to it?
 

powderpig

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Cruisertrash, Most cores are going to be the original ND case/guts and then rebuilt(bearings, brushes, regulator) by some of these aftermarket companies. There might be some knock offs that are new(from china), but for the most part, it is an original ND, but not reman'd by ND like they used to be. They might be using high quality parts for the rebuild or cheap parts. Yes, Bosch typically does a good job(at least for the original applications), but even they do not rebuild like ND does(at least in my experience).

Abe, best to ask the shop(D&D 303-423-6522) In theory, most shops can if they have the right tools. And then the the desire to do the tedious job of rewinding the rotor, dipping the assembly and baking the assembly. Then have the right size voltage regulator to fit the case(unless it is external VR).
Then wanting to warranty the product.
Doug has stains in his fingers from doing this job for a very long time. He is a master of the trade, and could do many things most people can not.
Doug has lots of cool old Generators, Alternators, starters 12V, 24V 6V stuff on the shelf he has rebuilt just waiting for the right customer to come thru the door. He may have what you want on the shelf already built.

Doug shop is a throw back to a long time ago, very similar to Vanetta. Vennetta has been gone about 3-4 years now. Boulder raised the
business property tax by 30% and many little mom and pops places closed up. He could not afford the rent any more. Shop had been there
since the mid 50's. He told me he might start up at his house, but never heard from him. He lives in Lyons area.
 

Cruisertrash

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@powderpig

too bad about old shops like the one in Boulder closing. I remember going to shops like that as a kid even in the 80s - for auto stuff or whatever else. For what it’s worth the guy on the phone at D&D was really knowledgeable.

Thanks for the info on the reman stuff. I figured the cases were the old original units and nobody made those but ND, but I was hoping it meant at least the reman parts came from ND. I’m probably going to pick one up today from whomever has it one stock. I’m headed to San Rafael this weekend and I’ll install the reman when I get back. At least I’ll have a spare with me if the original alt. shits the bed in the desert.
 

Cruisertrash

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@J1000 - see above. D&D Auto Electric in Wheat Ridge. I still haven’t done this so maybe we can get a 2 for 1 deal haha. I did talk to the guy on the phone and he said a rebuild is no problem - he said changing the alternator’s characteristics was iffy though.
 
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