The NorthStar AGM Battery + Voltage Booster Upgrade

Green Jeans · Dec 29, 2019

Was truck camping last night and listened to my 2013 run a purge cycle for what seemed like 20 minutes.

crashnburn80 · Dec 29, 2019

Sold My Subaru said: ↑

Was truck camping last night and listened to my 2013 run a purge cycle for what seemed like 20 minutes.
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Suuuper annoying when camping or working on the truck. I swear it knows too and runs an extra long cycle at those times.

SR-71A · Dec 30, 2019

crashnburn80[OP] said: ↑

The factory supercharger uses a water to air intercooler, which uses an electronic pump to cycle the coolant. The pump is tied into an emissions circuit that also runs a purge cycle when the truck is off, so the supercharger pump also runs for short intervals seemingly at random when the truck is off.
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Ahh cool. Did not know that. Seems odd though to cycle coolant when the truck is off.. Long-term storage of trucks with superchargers must be more of an issue than it normally would be too..

crashnburn80 · Dec 30, 2019

SR-71A said: ↑

Ahh cool. Did not know that. Seems odd though to cycle coolant when the truck is off.. Long-term storage of trucks with superchargers must be more of an issue than it normally would be too..
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If you didn’t disconnect the battery then yes.

buyobuyo · Dec 30, 2019

SR-71A said: ↑

Ahh cool. Did not know that. Seems odd though to cycle coolant when the truck is off.. Long-term storage of trucks with superchargers must be more of an issue than it normally would be too..
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Cycling the coolant pump is a byproduct of being tied into the emissions circuit. It's runs well after the truck has cooled down. It would be beneficial if it ran for awhile right after the truck shuts down, but you would need an electric fan as well to draw air through the intercooler heat exchanger.

Norton · Dec 30, 2019

SR-71A said: ↑

Seems odd though to cycle coolant when the truck is off.. Long-term storage of trucks with superchargers must be more of an issue than it normally would be too..
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It's definitely odd, and best summed-up by @12TRDTacoma...

12TRDTacoma said: ↑

The intercooler pump was a total half baked afterthought that executed properly should have a relay attached to the ign wire of the ignition which is wired in such a way where that relay is only engaged to run the pump while the engine is running.
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skierd · Jan 4, 2020

If anyone is considering getting a new battery, BatteriesPlus is currently doing 20% off car batteries with online purchases instead of the normal 10, plus a $30 rebate on the X2 AGM battery.

elricfate · Jan 4, 2020

I'm running a stock lead acid right now however I ordered the 1a diode from digikey ( two of them in fact ) and installed it. OBD is reporting charging voltage of 14.7. That will do for now since it won't harm the stock battery while I look for deals on an AGM.

crashnburn80 · Jan 4, 2020

elricfate said: ↑

I'm running a stock lead acid right now however I ordered the 1a diode from digikey ( two of them in fact ) and installed it. OBD is reporting charging voltage of 14.7. That will do for now since it won't harm the stock battery while I look for deals on an AGM.
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That will over charge a lead acid battery and lead to rapid failure. A lead acid battery should charge at a peak of about 14.1-14.2v. The voltage booster mod should not be run on lead acid batteries.

skierd · Jan 4, 2020

What’s a good charger for AGM batteries with a small footprint, something that could be left on the truck all the time? From roughly October to April I plug my truck in every night anyway, and could easily do it every week in summer.

Norton · Jan 4, 2020

skierd said: ↑

What’s a good charger for AGM batteries with a small footprint, something that could be left on the truck all the time? From roughly October to April I plug my truck in every night anyway, and could easily do it every week in summer.
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Norton said: ↑

FWIW, I've run a CTEK MULTI US 7002 universal charger for years. Very versatile - a fully-automatic 8-step charging curve; desulphation function; low ripple; and dedicated AGM, Supply & Recondition modes, make it suitable for just about any 12V lead-acid battery (e.g., Wet, MF, AGM, GEL and Ca). Designed for safety, it's protected from reverse-polarity connections and is short-circuit proof. Highly recommended.
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skierd · Jan 4, 2020

Hmm this might be the ticket for where I live:

https://smartercharger.com/collections/vehicle/products/ctek-nus-4-3-polar

elricfate · Jan 5, 2020

crashnburn80[OP] said: ↑

That will over charge a lead acid battery and lead to rapid failure. A lead acid battery should charge at a peak of about 14.1-14.2v. The voltage booster mod should not be run on lead acid batteries.
Click to expand...

Weird. Everything I've read online says 14.7 is a safe voltage for regular cells, anything above will cause the electrolyte to boil over or other issues. But I already took it out of the fuse hole any way, so it doesn't matter.

Mobtown Offroad · Jan 5, 2020

crashnburn80[OP] initial post: ↑

The NorthStar AGM Battery + Voltage Booster Upgrade

This thread covers upgrading to the best AGM battery available and modifying the voltage regulator via plug and play fuse to charge the battery at increased voltage, as required by spec on an AGM. Side benefits include brighter halogen headlights and higher flowing fuel pumps for supercharged applications.

Best AGM Battery
3 big heavy weight names constantly come up in the high performance AGM battery space, Opima, Odyssey and NorthStar. There are other brands out there that make AGMs as well, but this thread will focus on the top 3 names in the industry.

What is an AGM battery and why does it matter?
AGM stands for Absorbed Glass Matt. These batteries are maintenance free, they are sealed (non spillable), they have a higher power density than a flooded lead acid battery, they are typically more reliable with a longer life span. AGMs can charge much faster and have the ability to deep cycle. An AGM is superior in every way to a standard lead acid battery.

Understanding battery sizes
The 2nd Gen Tacomas came with battery size 24F for non-tow package trucks and 27F for tow package (TRD) trucks. The 3rd Gen Tacomas only received the smaller 24F batteries. It is possible to mount a larger 27F in a 24F tray, these were interchangeable on the 2nd Gen. It is also possible to mount a larger group 31 battery in place of either, though group 31s are large and heavy, it is recommended to get a group 31 battery cage from an aftermarket vendor.

The best way to evaluate what you are getting is looking at the data.

Battery Data

Battery Data Notes:
*Stock specs are based on value replacement Toyota TrueStart batteries. OEM battery specs are unpublished. 18mo warranty is replacement warranty, they pro-rate in tiers after than for 42 mo. The TrueStart Batteries are likely much higher performance and quality than the OEM included with the vehicle.
*NorthStar offers a 4 year warranty, buying BatteriesPlus X2 labeled NorthStars is cheaper and extends the warranty to 5 years.
*NorthStar claims 900 charge/discharge cycles in publications, but if you look at the data details that is 50% change rate, the other brands use 80% charge rate. NorthStar 80% change rate spec is 400.
*Odessey batteries do extreme vibration testing and pass but do not provide a multiplier value like Optima and NorthStar.

Looking at the specs, it is pretty clear NorthStar is the superior product. The NorthStar 27F has over 2x the reserve capacity of the OEM 24F and almost 2x the CCA, while also beating out every performance spec of the larger group 31 Optima. And if you have a 2nd Gen the 27F is factory size. If you have a 3rd Gen, fitting a 27F should be no problem.

If you are looking to go big with a Group 31 battery, Odessey and NorthStar are much more equally paired. However, in every spec where there is a difference NorthStar comes out ahead. Note that even the 27F is significantly heavier than stock, and group 31 batteries are even heavier. Tray and support cracking has been reported with heavy batteries and off road use, something to consider.

Looking at every measured metric, NorthStar AGMs are the best battery on the market.

Some Optima background
Optima was made in the USA. In the early 2000s Optima was purchased and the new parent company cut cost and moved production to Mexico. There was some overlap in the mid/late 2000s where both the US factory and the Mexican one were producing batteries. In 2008 I think the parent company closed USA production and shifted all production to Mexico. The Mexican made batteries that are said to not be of the quality the Optima brand was built on. While the USA plant closed in 2008, there was still stock of the USA made batteries that likely lingered around for a little while before eventually all being sold and replaced with Mexican made ones.

I had a yellow top that I purchased in 2005 for winching on my Wrangler Rubicon. That battery was a trooper and did great on long hard winch pulls in well below freezing temperatures. I kept it for 8 years across several vehicles before eventually selling it with a vehicle. I would no longer buy an Optima and instead run a USA made NorthStar AGM.

Selecting a battery size
27F vs Group 31. The NorthStar 27F is 20lbs over stock for a 2nd Gen while offering substantial gains across all spec'd metrics. Going to an even larger Group 31 NorthStar does offer more power, but I would only consider doing so if one really needed the additional reserve capacity. The additional added weight at 76lbs on the front battery tray is a lot and certainly doesn't help the Taco lean. With the deep reserve capacity, one might consider a single Group 31 NorthStar as an easier alternative to a dual battery setup. For my use I chose a 27F NorthStar.

Charging Voltage
AGM batteries require a higher charge voltage than lead acid. Since the Tacoma is calibrated to charge lead acid, that means the charge voltage is insufficient. Lead acid may charge at 14.0v-14.4v. I measured my 4.0 2015 Tacoma hot charge at 13.91v idle, and 14.02v rev.

Right on the NorthStar AGM battery, cycle service charge 14.4v-14.8v.

Very clear the 14.02v charge voltage is insufficient, meaning the AGM battery must be maintained on a plug in wall charger for proper AGM health or the alternator voltage must be boosted. If the charge voltage is not sufficient, battery sulfation will occur and reduce the performance and life of your AGM battery.

Voltage Boosters
These devices work by effectively tricking the alternator voltage regulator into seeing less voltage than it is actually producing thereby causing it to compensate to produce more. So in a simple example if you want to increase the voltage by 0.5v, you cause an artificial 0.5v loss on what the voltage regulator detects and it compensates by raising the voltage an additional 0.5v giving you a net gain.

The Alt-S Circuit <-Needed for this mod
The Alt-S circuit is the circuit used by the voltage regulator to monitor voltage at the battery and adjust accordingly. You can read more on the Toyota Alt-S circuit here. This simple mod is only works in vehicles where the Alt-S circuit exists for the voltage regulator to control the voltage. In some newer vehicles like the 2016+ Tacomas, the voltage is regulated by the ECU, meaning no voltage regulator Alt-S circuit to spoof.

HKB Electronics Voltage Boosters
There are a lot of methods to do this mod. I am not interested in hack solutions, I wanted something safe, proven and polished. If this mod goes wrong there are a lot of expensive electronics at risk. HKB Electronics out of Australia offers specifically designed plug and play voltage booster kits for the Tacoma for this exact purpose. Australia has some of the best 4WD companies on the market due to their environment, it is not surprising it is an Australian company to offer this product.

HKB Electronics offers two different products for the Tacoma, a 'fixed' 0.5v booster or an adjustable booster 0.2v-1.0v in increments of 0.2v. Unsure which to get, the obvious answer was clearly buy them both so I can test them and tell you guys which is better.

The AGM specs 14.4v-14.8v cycle service charge (aka alternator charge). Meaning that is the operating voltage target window that we want to adjust the alternator charge voltage to. Based on stock measurements it looks like 0.5v increase minimum.

HKB Adjustable voltage booster

To install, you simply replace the fuse in the 7.5A 'Alt-S' location (shown in upper left) with the modified voltage booster in your under hood fuse box. Basic plug and play.

Adjustable voltage booster shown mounted and set to +0.8v. (0.6v recommended)

Here is a photo of the 0.5v booster installed.

Testing
I originally measured the voltage with a multi-meter off the battery. The results I got were somewhat misleading. The problem was the data provided by a multi-meter is a fixed point in time, and charge voltage fluctuates over time. I needed to determine the peak charge voltage baseline so I can then make the required adjustment to set it to 14.6-14.8v, but I cannot accurately tell where the peak is with the multi-meter. I really needed to track the voltage over time so I knew the highs and lows of the data to determine the voltage setting more accurately.

So I logged my stock alternator charge voltage settings over time.

I checked the voltage monitor for accuracy with my multi-meter, it specs to be within 0.03v. I confirmed it meets spec, it reads 0.03v low. In the big picture that is a very small delta but good to know.

I then set my booster up to +0.6v and logged more data.

Over several days the peak voltage recorded was 14.69v, and being 0.3v low, that means peak voltage is 14.72v, up from 14.09 recorded (14.12 actual). I then sent this data off to NorthStar, and they agreed the settings look optimized and no further adjustments were necessary.

Based on my 2015 Tacoma 4.0 130A alternator, the HKD Electronics booster set to +0.6v provides measured maximum performance benefit without overcharging the battery. The 0.5v booster would also do well at 0.1v less, meaning ~14.6v which would also just make it into the optimal 14.6-14.8v charging range specified by NorthStar.

While these settings worked on my truck, you should test to confirm what works on yours to avoid overcharging. If using a multi-meter, it is best to test your truck on cold start after sitting for an extended time such as overnight, as the voltage output will be highest then.

If you are interested in knowing more on charging systems, this is a good overview of how voltage regulators, alternators and batteries work together in the charging system.

Battery Data Logging
I really wanted to log voltage data over time to better help me track and tune my battery and charging performance. After hunting for some products to accomplish this, I found this

$29 Battery Monitor BM2 BM3 Bluetooth 4.0 Wireless Battery Tester 12V Automotive Battery Load Tester,Automotive Charging and Cranking System Monitor Digital Battery Analyzer for Android & iOS

bluetooth battery monitor.

For only ~$32 this provided far better insights to my charging system performance than my $100+ multi-meter, because it gave me the running history over time. This is what I used to share the charging voltage plots earlier in the thread. Note that for best performance, you want to install this on-top of the battery. My picture above is somewhat temporary positioning for testing. If you install alongside the battery the low power bluetooth signal will not be able to broadcast through the lead battery, causing very directionalized range performance. The power draw for the monitor is 1mA, so you don't need to worry about it draining your battery. It also stores up to 30 days of data on board and then will sync it when you are back in range so you don't have any gaps in your data logs.

Battery alarms
Bonus features for those that run camping gear off their batteries at night, or just like more data, it has multiple adjustable power alarms so can have it notify your mobile device at a power percentage level. You can also monitor your battery charge in real time if you are curious on the charge status. It will also notify your mobile device of any abnormal start conditions.

Battery Tie Downs
The Northstar batteries do not fit the OEM tie down well, it is a very tight fit. The top of the battery is too wide causing the tie down to need to go underneath the battery handle as shown in earlier photos. There are aftermarket tie downs that resolve this issue, here are a few:

@Coupe sells adjustable battery tie downs on TW.
Rogue Off Road battery tie down
Off Grid Engineering battery tie down

Headlight Boosting
Halogens increase exponentially to the power of 3.4 with voltage increase, meaning the voltage booster upgrade is substantially beneficial to halogen output. Running some basic math:

Calculated: (14.65v/14.02v)^3.4=1.16 aka a 16% increase over pre-boost voltage.

Measuring actual lux
14.0v = 2014 lux
14.7v = 2335 lux
15.9% measured increase over pre-boosted stock.

0.1 increase difference in theoretical vs calculated is impressive to say the least.

Where to buy:
HKB Electronics of Australia
Adjustable voltage booster
Fixed 0.5v voltage booster

BatteriesPlus
X2 Power NorthStar Batteries (10% off buy online and pickup in store)
24F NorthStar
27F NorthStar
31 NorthStar
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Beautiful write up. I was having issues with my Northstar and this just cleared it all up.

Mike O · Jan 5, 2020

Fingers crossed for a 3rd gen solution......

SR-71A · Jan 6, 2020

Don't think I've ever seen as many repeat questions in one thread as there are in here haha

ihatemytruck · Jan 8, 2020

SR-71A said: ↑

Don't think I've ever seen as many repeat questions in one thread as there are in here haha
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That's TW for you

ramonortiz55 · Jan 8, 2020

Mobtown Offroad said: ↑

Beautiful write up. I was having issues with my Northstar and this just cleared it all up.
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So is it fixed?

Mobtown Offroad · Jan 8, 2020

ramonortiz55 said: ↑

So is it fixed?
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Bad battery. Northstar shipped me a replacement today under warranty. I’m going to install the voltage booster and also I have a NOCO charger. I wired in the quick disconnect so I can leave it plugged in since I only drive it a couple times a month.

Norton · Jan 8, 2020

Mobtown Offroad said: ↑

Bad battery. Northstar shipped me a replacement today under warranty. I’m going to install the voltage booster and also I have a NOCO charger. I wired in the quick disconnect so I can leave it plugged in since I only drive it a couple times a month.
Click to expand...

Nice. I also went with quick disconnects for mine. CTEK offers a number of options, including Comfort Indicator Eyelets that provide a visual depiction of battery status.

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The NorthStar AGM Battery + Voltage Booster Upgrade

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