Parasitic battery draw with HKB Voltage Booster Fuse

**Update** After receiving some solid expert advise from HKB and @Dm93 the voltage drop method for measuring amperage draw does not work with any circuit with a diode. Therefore, my HKB Boost Fuse is working as it should.

Hello world, I have been chasing down a parasitic draw issue for quite some time and I have finally found the culprit. I have an Odyssey AGM battery so I installed a HKB voltage "boost" fuse to increase the alternator voltage to properly charge my battery. Upon performing a voltage drop test my alternator circuit is drawing .3 amps with the HKB "boost" fuse installed. And with a regular fuse the amp draw is 0. Has anyone had an issue with parasitic battery drain with a "boost" fuse installed? Maybe the HKB fuse is defective?

https://www.hkbelect.com/product/24...nic-fuse-version-micro-blade-compatible-2010/

 

Is this the actual voltage booster/fuse?

 

That is a picture from HKB's website. Mine is identical to the picture.

 

I had one installed for a couple years and never noticed a draw causing problems. The truck would sit for a week or more at a time and never had a dead battery afterwards.

 

I used a chevy fuse with x2 agm battery .I have not had any issues ..there's a ford one you can use ..but pretty sure it will make your rig break down cuz it's ford....lol

 

My battery will go dead in 2-3 weeks if sitting. I am kind of wondering if there is a current flow direction for the booster fuse and if I have it installed backwards.

 

What is your alternator output at idle?

 

Yes you can try that ...I forget witch direction ..easy to find on YouTube . To verify ... I did this "upgrade " only 6 months ago ...so not as long as you ...

 

Ford fuse with an Odyssey G65 AGM. No problems. Not even the breaking down because "it's a Ford" comment.

 

It's 100% impossible that device increases voltage with its 2 leads/terminals.

 

And you would be 100% wrong.

 

Depends on state of battery voltage. The voltage ranges from 13.8-14.5 volts. Usually just after startup it will hover in the mid 14's for voltage. I have a volt meter in the cab so I can observe the change in voltage over time.

 

the booster will add to the current through the sense circuit, as it is required to forward bias the diode. The key part here is your voltage regulator is “off” with the ignition off so if the sense wire has current going through it with the truck off you’re VR in the alternator has issues.

 

Do you think the voltage regulator would act differently with the booster fuse vs. a regular fuse? With a regular fuse installed there is 0 amp draw.

 

i don’t know how sensitive the meter you’re using the measure. But likely there is a very small amp draw through the circuit you aren’t seeing. The regulator shouldn’t operate any differently to my knowledge.

 

You wont do any harm flipping the booster to make sure it is in correctly. I remember the instructions stating so. I put mine in wrong the first time. Check your voltage reading and leave the booster in the position giving you the higher of the two voltage readings. I have a voltage meter in the power port 24/7 and I have not noticed any significant voltage drop when parked, but I don't usually park more than a week.

 

In the cab is just a volt meter which reads down to the 10th's. For the parasitic draw I used the volt drop (down to the 1,000th) technique using a multimeter then cross referencing the volt drop on a chart for fuse type and amperage to determine the amp draw.

 

if it is installed backwards it will block the sensed voltage to the alternator and it will fail to full on. I would not recommend leaving it at full voltage which is typically 15-16 volts.

 

i would double check using an in line ammeter capable of measuring to 1mA.

does the draw come back after reinstalling the booster with the truck off?

 

Thats not what happened to me. When I first put it in, there was no voltage boost. When I flipped it, the voltage boosted to 14 volts.