Best aftermarket alternator, and how big?

Wellfooled49

Wellfooled49
Apr 12, 2022
4
0
1
PNW
Currently running a 125Amp alternator in my stock 2013 3500HD (don't get me started on why such a lame a** alternator). Want to replace with larger alternator to help increase amps going to my DC to DC charger in my 5th wheel. I find 250-300Amp alternators on the webs, but would appreciate any input you guys have on what you suggest. What brand do you recommend, and what size? Also, does your recommendation mean a smaller belt?
 

2004LB7

Well-known member
Dec 15, 2010
6,282
1,683
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Norcal
dual alternator for the win

I think these are all the part numbers to add a 2nd alternator

Alternator # 204278
Bracket # 356246
Bolts 3Ea # 518637
Spacer # 624586
Cable Aux Gen # 943124
 

Wellfooled49

Wellfooled49
Apr 12, 2022
4
0
1
PNW
I think these are all the part numbers to add a 2nd alternator

Alternator # 204278
Bracket # 356246
Bolts 3Ea # 518637
Spacer # 624586
Cable Aux Gen # 943124
Didn't really want to go the the expense of adding a 2nd alternator, but appreciate you taking your time to look these up. If I do go that way, I'll certainly use the info you provided.
 

gmduramax

Shits broke
Jun 12, 2008
4,042
224
63
Nor cal
The alternator off of a L5P is like 280 amps and I think if you get one from an ambulance package they’re more like 350