AGM BATTERY CHARGING - ALTERNATOR VOLTAGE BOOSTER

116,000 miles on my 2009 Sport purchased in November 2008. It could just have been its time... but then the boosted voltage could have helped it along a bit. Hard to know for sure...

 

I mean, over 100k miles and stressing it? Entirely possible this was a contributing factor.

 

After installing the HKB alt-s mod for my AGM battery my aftermarket stereo amp started occasionally shutting off momentarily and then starting back up. Wondering if that is just coincidental or if the increased voltage may be causing a power protect mode to initiate. Anyone else experienced anything similar?

 

Anyone know where to get the HKB fuse/diode combo? It appears they are out of stock and I like the idea of an all in one solution as compared to wiring another fuse into the diode.

 

Still have this diode? I'm thinking of upgrading to AGM and would want this when i decide to upgrade. I'm local. LMK, thanks.

 

You can only pick the fuse/diode combo from HKB as far as I know. I just got mine in the mail a week or two ago from them.

 

Do you have a link? The link earlier in this thread shows out of stock.

 

I ordered an adjustable one on Christmas while they were closed for holiday got it last week.

I'm sure they'll make a new batch soon.

 

Looks like they're out of stock. Sorry dude I might have snatched up the last one.

For those thinking of buying from HKB, be aware the shipment will take a few weeks to get to the USA from Australia.

 

man where’s the big red easy button! Simple and effective! Took me 5 minutes to complete and now my AGM + Lithium are charging happily at 14.8

 

Ford of all people stock an item that does the same thing considerably cheaper.

 

Do you have a link?

 

Here you go, probably cheaper at local Ford dealer.

$20 Diode Replacement for FORD YL8T14A604AA

https://www.amazon.com/Diode-Replacement-for-FORD-YL8T14A604AA/dp/B071RPLWY5

 

Add me to the list of people who have done this mod. Thanks for the great write-up.

Sadly though my voltage is going up as high as 14.95 which is too much. A bit odd considering my stock configuration tops out around 14.25-14.29v as measured using both a known good multimeter and a Bluetooth monitor (both are in agreement). It’s been cold lately but both of those measurements held consistent at 20 degrees and 50 degrees so doesn’t seem like a fluke. I’d say to everyone be sure to take measurements and don’t just assume you are getting an 0.5v boost with the diode.

Looks like I’ll have to go the HKB adjustable route. Ugh…

 

your voltage on startup and in park will usually if not always be higher. I hover around 14.1v to 14.4v when driving or at idle when the engine is warm.

 

Thanks, yes I understand. With this mod it's all about how much you want to tolerate the high voltage. In my brief tests it was too high (over 14.9) for my own personal comfort.

I need to run more tests & share pictures but that's gonna take some time to organize for sharing here. I have a gutter that just blew off my house so that just took over my top priority for a minute. I'll post back later once chores are done.

 

Just came across this thread, and maybe I have my head up my @ss (my wife constantly says I do), but my understanding about AGM versus flooded is that what an AGM battery needs is SLOWER and MORE CONTROLLED charging. Upping the voltage would do the opposite, along with the fact that cars/trucks built for standard flooded batteries don't have the logic (like me) to properly charge and maintain an AGM battery. Plus, without the logic circuits to control the process, it would easily lead to overcharging - which AGM batteries are much more sensitive to.

Just one of the many statements online:

These batteries like to be charged slow and low due to differences in internal resistance. Many AGM battery chargers have microprocessors that collect information from the battery and adjust the current and voltage accordingly. Some have different settings for charging flooded or AGM batteries. Overcharging can kill these batteries. Also, alternators are not chargers. Don’t rely on an alternator to do the work of a charger. If a battery is discharged to the point that it cannot start the vehicle, use a charger as soon as possible to make sure the battery gets fully charged.

 

Ive been watching this thread for years...

And for 4+ years ive had a duralast platinum AGM 27F in my truck (no booster installed).

And well, the sumbitch just wont die.

The truck will sit for weeks and then start right up, i only drive it a couple thousand miles a year.

So i continue to watch this thread... But i just cant seem to buy the aftermarket fuse lol

 

Well lots to unpack there but I will try to answer to best of my understanding...

Our 2nd gen Tacomas don't have much logic involved. Alternator is internally regulated to a certain voltage. AGM batteries just like Flooded Lead Acid (FLA) batteries that are designed for automotive use can be installed just the same and 100% can be charged by the alternator (that's the alternator's job, it does that for FLA batteries too). I don't know where the "slow and low" info is coming from but lots of people here don't have problems.

The entire reason for this thread is that AGM batteries need higher voltage output to fully charge. You won't get full potential out of an AGM unless it's charged at this higher voltage. the X2Power battery that myself and many others have specifies right on the battery itself to charge at a range of 14.4-14.8 volts which is higher than our alternator regulates for. This thread provides a cost-effective way to boost that voltage. It's a really clever way to do it and pretty darn safe, but it's a DIY solution and you need to double-check with the logic in your brain and a voltmeter to be sure you don't cook it.

Most definitely lots of people doing it without the booster. I'm running mine like that for now until I figure out what to do with more testing. Major reason to even do the booster is a) prevent sulfation and a premature battery death, and b) to get the most benefit out of the larger AGM amp hour capacity for things like using electronics for longer off grid on a single-battery configuration.

 

I have yet to see an AGM battery manufacturer recommend installing a diode or otherwise jacking up the alternator voltage. There is also a danger in overcharging an AGM. It’s not the same as putting an AGM on a charger designed for AGMs.