Alternator Voltage Booster (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

This is a great little mod. I bought the "add a fuse" and a diode for less than $10. It increased my cold-start voltage from 14.1 V to 14.7V. Should suit my Northstar well.
 
This is a great little mod. I bought the "add a fuse" and a diode for less than $10. It increased my cold-start voltage from 14.1 V to 14.7V. Should suit my Northstar well.
Same. 14.2 to 14.7 volts and still have the fuse protection. Thanks folks, especially @AimCOtaco, for this little mod.
 
Last edited:
From 13.5V fully (warmed up) to 14.0V after the diode mod. Got mine from o’reilly’s -had to order it and wait and pick it up the next day.
9020BE64-3149-4122-B404-24533A9FDF3D.jpeg
 
This is a great little mod. I bought the "add a fuse" and a diode for less than $10. It increased my cold-start voltage from 14.1 V to 14.7V. Should suit my Northstar Deathstar well.
Fixed it for you. Gotta ensure those kyber crystal shards fuse correctly
 
I've been running that same diode for a few thousand miles now in my '03 LX... seems to be working well! I do get voltage readings every now and then on my Ultragauge of like 15.1 volts, but it's only for a brief moment. (I have an alert setup to let me know if voltage goes above 15, which is how I'm seeing the voltage briefly hit that high)
 
Is that Diode also a fuse? I'm glad it's working but I'd want to be sure that:

A. The Diode can handle unexpected loads (I used a 6-10A diode I think based on the 7.5A stock fuse).
B. The diode would pop and fail open if it hit loads that would pop the factory 7.5A fuse.

Not saying this Littelfuse diode isn't the greatest solution yet found, just stating my thoughts.
Running a big diode inline with the 7.5A fuse I'm confidant is both safe and robust.
 
Is that Diode also a fuse? I'm glad it's working but I'd want to be sure that:

A. The Diode can handle unexpected loads (I used a 6-10A diode I think based on the 7.5A stock fuse).
B. The diode would pop and fail open if it hit loads that would pop the factory 7.5A fuse.

Not saying this Littelfuse diode isn't the greatest solution yet found, just stating my thoughts.
Running a big diode inline with the 7.5A fuse I'm confidant is both safe and robust.
I agree.... it might not allow much more than 7.5A to come through. I don't have the right equipment to test, but would be great if someone who did would see how many amps the diode will take before it pops.

A company called TE connectivity makes a handy little fuse holder that should make it easy to daisy chain this diode and a fuse together for pretty cheap, but the metal connectors that go inside the fuse holder are on a 17 week lead time.... It would also require a mini fuse shaped device with pigtails to connect into the fuse panel.

2x mini fuse holder https://www.te.com/content/dam/te-c...ion/global/TS-ICT-2PNSFH_Mini_Fuse_Holder.pdf
mini fuse adapter with pig-tails: Amazon product ASIN B07CTRNYR1
I tried to find something with the pig tails on aliexpress, but no luck. Also had no luck finding the same type of product on a digikey type of site.
 
Is that Diode also a fuse?
Yes, by its nature a diode will fail OPEN like a fuse when carrying current above it's rating... usually. It will fail CLOSED with over voltage... usually. From the pic by @OEMGUY0720 the over current rating for the Littelfuse diode is 1A, which is more than ample for the sense line. The standard fuse rating of 7.5 does not reflect the current actually flowing through that wire, which under normal conditions is less than 10mA (<0.010 A). Instead, the 7.5 is just more of a standard value fuse and is ample to protect the wire from burning if somehow shorted to chassis ground.

If you want to test that this diode fails like a fuse, then buy an extra one and replace the fog light fuse (or some other switched circuit expected to pull >1A or >14 watts) with the diode. Switch on the lights and you might see a the lights come on very briefly. Flip the diode and look for brief light. At this point the diode is likely dead OPEN circuit.
 
It should be noted that this diode should not be used for a standard flooded battery if all systems are working properly. 13.6V from the alternator is optimal for charging with a tick lower for storage. Pumping a flooded continuously at >14v will cause too much gassing and damage the battery. >14v should only be present for equalization.
 
Any recommendation for what diode to use for this? I'm on Amazon shopping and the 6A diodes have different voltage ratings? Which one is best? And since I am asking questions, which diode voltage is best?

It would be great if someone has a reasoned answer for an electrical noob like myself
I just installed a home made voltage booster as my system was generally about 13.4 - 14.2 running and my optima's were not lasting as long as they do in another Toy' with higher voltage. Optima (AGM battery) recommends 14.0-14.8 or so which lead me to want to try this and see if my battery's last longer. I think the optimas were not reaching full charge with just 14.2 max from the alternator.
I used a circuit tap that is designed to add a fused circuit from a fuse panel without bypassing the original circuit fuse. I just chopped the output pin down enough that I could make the assembly narrow enough for the battery fuse block on the LC and used a basic 6A rectifier diode and a couple of solder joints. Configured this way the rectifier is in series with the ALT-S fuse. Here it is done and in (5a fuse for bench test only):
View attachment 1346811
View attachment 1346812

I had considered a wiring modification due to the tight space but this worked great and can be returned to stock in 1 minute if needed. Now I seem to be running between about 14.0 and 14.8 depending on operating conditions. This should keep things brighter and pulling lower current, the radios seem very happy as well. Optimistic that I'll get longer battery life but time will tell on that. Not a bad mod for $10 and a few minutes cutting and soldering.
 
I made and installed the booster @AimCOtaco outlined on page 2. I have dual AGM batteries charging off the alternator and wanted to supply them with the voltage they need to stay healthy. Prior to this I had been 'topping them off' monthly with an AGM charger/maintainer.

I coated the diode leads with liquid electrical tape after they were soldered to to add-a-fuse kit.
View attachment 2191332

It is a snug fit in the main fuse housing, but it fits.
View attachment 2191333

The Cruiser is now charging at 0.5 volt more than I was before: 13.5-14.1 vs 14.0-14.6.
Bump on where I can source this diode to maintain the 7.5A fuse
 
Bump on where I can source this diode to maintain the 7.5A fuse
If you’re here in North America you can get it from O’Reilly’s in-store or their online store. Check out my post above post #63 and #66.
 
If you’re here in North America you can get it from O’Reilly’s in-store or their online store. Check out my post above post #63 and #66.
Haha thanks, I am in America. I am just looking for the other option where I can keep the fuse as well. Has the solution from O'Reilly's been reliable for you?
 
Haha thanks, I am in America. I am just looking for the other option where I can keep the fuse as well. Has the solution from O'Reilly's been reliable for you?
A more expensive alternative, that requires some patience, in waiting for deferred gratification (read as they’re slow to ship):


I don’t know if it is any better than the domestic O’Reilly’s option, at 4.5-5x the price, but it does seem to work, and allegedly acts as a fuse too.

I guess the other option might be to use a 7.5a fuse in series with the diode.
 

Users who are viewing this thread

Back
Top Bottom