My mini Denso has never kept up with the fans. I sent it in and had it upgraded from 50 amp to 75amp. Then fabbed the large crank pulley for 3-1. At the same time a 2nd trigger wire was added. So now the feed wire to the batteries was 4 gauge from the alternator to the stater stud on the firewall. And 0 gauge from that stud to the battery. Still couldn't keep up. Then the regulator was swapped back to a one wire 16 volt. A new 6 gauge wire was run directly from the alternator to the battery. It'll put out about 18.2 with no fan around 2000rpm, 16.2 with one fan, 16.0 with both fans. These voltages have been measured up front and at the battery. At least it has constant 16.0 during the run. I'd swap it for a larger unit but have found none with the pulley centerline to the rear face of the alternator that weren't to big. The alternator sets right in front of the motor plate. I hate to cut a huge hole in the plate.
Doug

I have tried a ton of them over the years. I love the smaller ones, so easy to locate and clear everything, and None of them could keep my $hit charged.. So even the one wire standard 100amp unit do not work at idle with high output fans....And I did not just buy the cheap ones...I bought some really expensives ones with adjustable voltage outputs and everything.

Now I run these exclusively on my cars...
https://www.mechman.com/alternators...or-63-85-gm-polished-includes-2-pulleys/

Its the only alternator that charges my stuff at an idle with everything being electric....

It doesn't qualify as mini but for a "not that large" alternator the CS130 works awesome. My car with a 5" crank pulley at a 1250RPM idle can run, All exterior lighting(all factory crap) 18" 4000CFM electric fan, Electric Fuel Pump. electric fan on fuel cooler, EFI System, and normal car accesories like phone charger and crap. It can do that and hold 14.2-14.5 at idle if needed. It can also support the wipers but that is a situation I try to keep my car out of, but its done it lol.

My current one is 9 years old and I am just starting to question it, the last few times at the track my ride home has been at 13.5 volts, start it up cold the next morning and its back to normal 14.1-2. So Either the alternator is getting weak when its good and warm, or my continuous duty solenoid is starting to fail.

They are cheapish and available, I order mine for like an early 90s FWD cutlass when I go to the parts store but it is on several other GM vehicles. I run mine stock as a "three wire" setup that uses a charge light and a sense wire. The application I listed comes with a serpentine style pulley but the parts store counter guy swapped it out with V belt pulley for me.

I started to run this alternator because of an old member "Sloan" he had one that fit his trick aluminum bracket for a small block mopar with a meziere water pump. Bob Mazoline(spelling) made a run of those brackets and I snatched one up.

I had two group 24 12 V deep cycle marine batteries in my Cuda and I would charge them for around 48 hours with a self regulating 4 amp trickle charger to top the batteries off before going racing.
They would charge up to 13.8 to 14.3 on the charger and would settle down to 12.6 to 12.9 volts after sitting over night.
The 100 amp Powermaster alternator would charge, show on the voltmeter,14.5 V running and the batteries would stay above 12.5V at the local 1/8 mile races at the end of the day. I would take that same charger and charge them during the long ( usually from 45 minutes to 1 1/2 hrs. lunch break that track took
That car did not have big electric cooling high amp draw fans on it as it didn't have a conventional radiator, electric fuel pump, MSD 7AL2 ignition and big electric water pump with a small cooling fan on one of the oil coolers used as the radiator. Not a lot of amps used to run that car
The starters on our car are the biggest amp draw on the batteries usually
We normally don't drive them long enough at the races to recharge the batteries after every motor start

Badfish, you mentioned an electric fan on your fuel cooler.
what are you using for your fuel cooler ? any pictures ?
this item sets me on "mission creep" again.

One issue we had was with lead acid batteries. When you get low enough on the 60ft, those batteries don't last long anymore. We switched to those AGM red top batteries. I like them, but they do not have a lot of reserve, so a good charge system is a must. And then add to that a 14.5:1 engine to kick over, and you can see how going faster adds up...

the Cuda would 60 ft in the mid 1.22 to 1.26
Both batteries were mounted so the plates face to the front and back, not sideways to avoid the acid sloshing against the plates
One battery was bought in mid 2013 and the other one was bought two or three years later, both are still working good
I put the alternator on it before racing it due to not wanting to charge the batteries between rounds The analog volt meter never drop below 14.0 + volts with the motor running
The race MSD boxes are voltage sensitive, especially if the battery voltage get down near 12.25 V
This motor (I sold the car last month) had 14.9 to 15.3 to 1 compression ratio with a Power Master starter for the glide, it would turn the motor over several times before kicking out due to no snout centering bung in the stock type Powerglide case mounting the starter on the drivers side

Its not cooling fuel like you probably want to lol. Its a trans cooler with an electric fan plumbed into the return right before it dumps into the tank. Fuel temp is a thorn in the side of a lot of fuel injected combinations that return fuel from the rails. The cooler does help, I do not have before and after fuel temp information because I didn't log temp when I installed it. I have seen fuel temp as high as 130* in the return worst case, 120 is pretty normal after lots of driving(drag week). There is better ways to do a fuel system and I need to reboot my setup but for now this helps.

There is guys on these drag and drive events that have to pack the trunk full of ice around the fuel cell to keep temps down. I don't have to do that!

Totally agree on this....


And I think you got lucky on the batteries...My 60fts were in the 1.31-1.33 range...One battery I bought lasted only one weekend and mine was mounted so the plates would be least affected.

I am now trying out XS batteries...They add 10bs to the 34lb weight of a Red Top, but its got 1250CCA and a big reserve.

thank you.
i had an idea that's what you did, and if i ever experience hot fuel issues, i may try this.