Vehicle batteries

[PWMDMD]

Talk to me about vehicle batteries. My 2020 Tundra battery went dead after 6 months. Since I also have 1000 watts of aftermarket audio gear in the truck I decided to update to a Northstar X2Power Premium AGM BCI Group 27F Car and Truck Battery. From my POV it has been flawless including in the dead of winter at -10F last winter.

My question is every now and then on the FB Tundra group someone claims the Tundra is incapable of fully charging these batteries without replacing a resistor somewhere. This got me interested so I tested the voltage of the battery. At 40F I get (edited) 14.25V while the truck is running and 12.5V with the truck off.

Any truth to this claim about the Tundra not being able to fully charge an AGM battery? I know total capacity goes down with temperature and so I think at 40F 12.5V is pretty good and represents a fully charged battery - correct?

 

[2010Civic]

Aren't most cars around 14V while running?

 

[PWMDMD]

Aren't most cars around 14V while running?

You are correct - I measured the voltage using a multimeter with the truck off but relied on the voltage reading through the stereo OBD-2 system and it is lower than when I measure voltage with the truck running at the battery terminals - it is 30F and 20 seconds after starting the truck cold I got 14.25V at the battery terminals.

 

[FZ1]

Talk to me about vehicle batteries. My 2020 Tundra battery went dead after 6 months. Since I also have 1000 watts of aftermarket audio gear in the truck I decided to update to a Northstar X2Power Premium AGM BCI Group 27F Car and Truck Battery. From my POV it has been flawless including in the dead of winter at -10F last winter.

My question is every now and then on the FB Tundra group someone claims the Tundra is incapable of fully charging these batteries without replacing a resistor somewhere. This got me interested so I tested the voltage of the battery. At 40F I get (edited) 14.25V while the truck is running and 12.5V with the truck off.

Any truth to this claim about the Tundra not being able to fully charge an AGM battery? I know total capacity goes down with temperature and so I think at 40F 12.5V is pretty good and represents a fully charged battery - correct?

All you need to know re batterys: Get the biggest battery, with the most cca and rc , that will fit your battery compartment. Agms typically last longer than conventional batterys.

 

[samven]

The bulk charge rate for an AGM could be 14v or 14.2 as the bulk phase is primarily concerned with current but the bulk phase only gets you to 80% or 90% charge. The Absorption phase (the last 10 or 20 %) is speced by the battery maker usually about 14.5v at 77F. As the battery gets colder the charge voltage should increase and as it gets hotter the voltage decreases. So at 40F they may spec 14.9v to reach a 100% charge but at 90F they may say 14.2v. I dont know what voltage you alternator puts out above idle or if it has a smart controller like some models that need to be programed with the battery size, age and capacity everytime you install a new one. But it is possible that your vehicle is never getting the battery back to 100% but only 85% or 90%. It wont do your battery any good but if you have enough reserve to operate at 80% you wont notice it except that you may be replacing them a year or 18 mos sooner than if they were charged correctly. Its not a bad idea if possible to put the battery on an external smart charger every once in a while to get it back up to 100% and help delay the degridation done by sitting constantly undercharged.

 

[PWMDMD]

Ok...I think I've got my head wrapped around this now. I forgot I have a trickle charger that does have a 12V AGM settling - when I hooked it up it showed less than 75% charge so clearly being undercharged. The guys on the Tundra forums have been using different ALT-S fuses for years with no problems - can use GM fuses but they need to be modified so I ordered one of these:

5A MK3 Mini blade (Electronic fuse version, Micro blade compatible) | HKB Electronics

The Alternator Voltage Booster was the first of its type on the market and is the only unit available that was has been purpose built for alternator voltage boosting.

www.hkbelect.com

which should boost me to where I need to be at 14.75V. The float charge for this battery is 13.5-13.8V and cycle service is 14.4-14.8V.

Thanks for the help!

 

[wrcsixeight]

I have cyced the snot out of a group 27 northstar, achieving ~1200 deep cycles over 6 years. The sheer amount of kwh passed through this battery before capacity declined to near uselessness, was impressive.

The trick with all lead acid batteries, is achieving the true full charge.
80% charged tp 100% charged takes no less than 3.5 hours, regardless of charging source used

This 3.5 hours assumes it is being held at 14.4 to 14.8v by the charging source.

This also assumes the battery is still healthy.

Less healthy and or lower voltage, and that 3.5 hours can double or triple, or.more.

There is no way around this.

99% charged is good. But half as good as achieving a true 100%, in terms of achieving maximum potential lifespan and capacity and retaining cranking amps.

Lower voltages allowed by vehicle do slow charging, and it only really matters when cycling the battery deeper. If the battery is full it matters little if vehicle voltage is low.

Any short term 1000 watt stereo use, engine off, will require no less than hours of driving to even get 99%+ charged, whether 14.2 or 14.8v is held by vehicle.

When deep cycled, odyssey and northstar require high amperage recharges from their most depleted states.

My group 27 held 13.06v rested, fully charged, at that 6 year mark.

Voltage is misleading in so many ways. And leads to misinformed statements as to state of charge.

Hold your northstar at 14.7v until amps taper to 0.4 or less, then float at 13.6 and amps will taper to 0.0x, and 24 hours later with no loads, voltage should still be well over 13

If not, cycle it deeply, then apply no less than 40 amps until 14.7 is achieved thenbhold 14.7vnintil amps taper to 0.4 or less.

This high amp recharge from a well depleted state is the tppl agm performamce restorative, as much as is possible.
Its excessive is used each and every deep cycle but after many deep cycles with only low and slow charge rates, or too long being less tham 100%, it works wonders.

 

[Kiwi_ME]

I think that's good advice and attaching a voltage logger such as a BM-2 makes it easy to keep an eye on things daily.

My EV charges the 12V battery at 14.65 V every 4 hours while parked and uses an Intelligent Battery Sensor to monitor 24/7 and advise the car if more or less is needed when it wakes up. It always keeps it fully charged while my ICE 12V depletes over several days because I don't drive it enough.

 

[Donald]

It looks to me that most newer charging systems in cars and AC plug-in chargers use the same setting for flooded cell as normal AGM. The spiral wound and other fancy AGM seem to take a different setting.

Most new cars have the alternator controlled by the ECM so it would seem to me it would not be too difficult to allow the ECM to be programmed to the exact battery you have installed. I know BMW does that but not many cars do.

Back in the day before alternators I know my Dad would fool with voltage regulator to get the generator to put out more current or higher voltage. I was pretty young (5) and did not know a lot about cars.

 

[y_p_w]

The charger's readings for charge level are more or less an approximation. It really can't know exactly what's in a battery I believe most readings are based on voltage. But yeah - if you're really worried about it, make sure that it's charged with an external charger periodically.

 

[SubLGT]

...when I measure voltage with the truck running at the battery terminals - it is 30F and 20 seconds after starting the truck cold I got 14.25V at the battery terminals.

That is too low. I haven't done the math for 30F, but at 35F an acceptable temperature compensated charge voltage for the Northstar is 14.96 -15.36 volts during the "absorption phase" (when charge current is decreasing and voltage is constant).

 

[SubLGT]

.....I think at 40F 12.5V is pretty good and represents a fully charged battery - correct?

That is closer to 75% state of charge. If you made the voltage measurement immediately after shutting off the truck, it will be artificially high due to surface charge. Wait 12 hours to get a more realistic voltage reading.

 

[PWMDMD]

That is closer to 75% state of charge. If you made the voltage measurement immediately after shutting off the truck, it will be artificially high due to surface charge. Wait 12 hours to get a more realistic voltage reading.

This was on a cold truck that sat overnight - the charger indicated the charge was just below 75%. This charging unit has a 12v AGM setting and tells you when bulk charging is complete and another indicator when it's "optimizing the charge" and finally when it is complete at 100%. I have a different ALT-S fuse coming that should bump the voltage up 0.5v to 14.75v and get me into the 14.4-14.8v required for the Northstar. I will also hook the automatic charger up once a month to make sure it's topped off. I also ordered the BM-2 to monitor in real-time.

Thanks again, everyone!

 

[PWMDMD]

I have cyced the snot out of a group 27 northstar, achieving ~1200 deep cycles over 6 years. The sheer amount of kwh passed through this battery before capacity declined to near uselessness, was impressive.

The trick with all lead acid batteries, is achieving the true full charge.
80% charged tp 100% charged takes no less than 3.5 hours, regardless of charging source used

This 3.5 hours assumes it is being held at 14.4 to 14.8v by the charging source.

This also assumes the battery is still healthy.

Less healthy and or lower voltage, and that 3.5 hours can double or triple, or.more.

There is no way around this.

99% charged is good. But half as good as achieving a true 100%, in terms of achieving maximum potential lifespan and capacity and retaining cranking amps.

Lower voltages allowed by vehicle do slow charging, and it only really matters when cycling the battery deeper. If the battery is full it matters little if vehicle voltage is low.

Any short term 1000 watt stereo use, engine off, will require no less than hours of driving to even get 99%+ charged, whether 14.2 or 14.8v is held by vehicle.

When deep cycled, odyssey and northstar require high amperage recharges from their most depleted states.

My group 27 held 13.06v rested, fully charged, at that 6 year mark.

Voltage is misleading in so many ways. And leads to misinformed statements as to state of charge.

Hold your northstar at 14.7v until amps taper to 0.4 or less, then float at 13.6 and amps will taper to 0.0x, and 24 hours later with no loads, voltage should still be well over 13

If not, cycle it deeply, then apply no less than 40 amps until 14.7 is achieved thenbhold 14.7vnintil amps taper to 0.4 or less.

This high amp recharge from a well depleted state is the tppl agm performamce restorative, as much as is possible.
Its excessive is used each and every deep cycle but after many deep cycles with only low and slow charge rates, or too long being less tham 100%, it works wonders.

So charged with a Noco Genuis10 and resting voltage is now 12.9v with BM-2. There is an option for a 12V repair setting for lead-acid batteries on the Noco. You have to disconnect the battery because it uses a higher voltage to fix sulfation and stratification - worth a try?

 

[meep]

There may be a fuse which can be replaced with a fused diode. I ran across this earlier this week on an amazon review for one of the x2power/northstar batteries. The diode introduces a voltage drop. It’s a GM tactic but supposedly at least some of the toyotas (4runner on this review) allow it to be done.

and yes, 14.6-8 was the proper bulk charge voltage for a similar battery I was ogling as well.

 

[PWMDMD]

There may be a fuse which can be replaced with a fused diode. I ran across this earlier this week on an amazon review for one of the x2power/northstar batteries. The diode introduces a voltage drop. It’s a GM tactic but supposedly at least some of the toyotas (4runner on this review) allow it to be done.

and yes, 14.6-8 was the proper bulk charge voltage for a similar battery I was ogling as well.

Already ordered

 

[samven]

So charged with a Noco Genuis10 and resting voltage is now 12.9v with BM-2. There is an option for a 12V repair setting for lead-acid batteries on the Noco. You have to disconnect the battery because it uses a higher voltage to fix sulfation and stratification - worth a try?

Dont use that mode on an AGM. In a traditional lead acid battery there is liquid acid next to the plates and if you hit them with too much voltage they will start to bubble, you can hear them when they are charging, but when you remove the charge the bubbles eventually make there way to the surface and the acid touches the plates. In a AGM there is a mat saturated in an acid paste against the plates, if they start to develop bubbles they get trapped and the acid cant get to the plate anymore so you loose that capacity and AGM cant get stratified, that only happens in the liquid acid because the acid can separate from the water and the heavier liquid goes to the bottom, boiling it mixes them together again. The paste saturated mat cant do this and boiling them depleats there capacity.

 

[wrcsixeight]

So charged with a Noco Genuis10 and resting voltage is now 12.9v with BM-2. There is an option for a 12V repair setting for lead-acid batteries on the Noco. You have to disconnect the battery because it uses a higher voltage to fix sulfation and stratification - worth a try?

Of all agm batteries, only Lifeline says 15.5v can be used to attempt to reverse sulfation from chronic undercharging. They explicitley state to initate 15.5v(for 8 hours!) Only after many many hours held ay 14.4v and amps taper to very little.or stop tapering.

Tppl agms are tickled to a premature.demise when deep cycled and only slowly recharged with a low amp charger.

My group 31 northstar has gobbled up 134 amps, easily, when well depleted. Its now due for a deep cycle and a high amp blast, despite being kept 99%+ since last deep cycle weeks ago.

Ive got.some free deka agms that have been my deep cycling batteries,.and they could use a break, and the Northstar, a workout.

 

[PWMDMD]

Dont use that mode on an AGM. In a traditional lead acid battery there is liquid acid next to the plates and if you hit them with too much voltage they will start to bubble, you can hear them when they are charging, but when you remove the charge the bubbles eventually make there way to the surface and the acid touches the plates. In a AGM there is a mat saturated in an acid paste against the plates, if they start to develop bubbles they get trapped and the acid cant get to the plate anymore so you loose that capacity and AGM cant get stratified, that only happens in the liquid acid because the acid can separate from the water and the heavier liquid goes to the bottom, boiling it mixes them together again. The paste saturated mat cant do this and boiling them depleats there capacity.

Hmmm…Noco says repair mode can be used on an AGM. My resting voltage is down to 12.72v this morning. Just leave as is?

https://no-co.zendesk.com/hc/en-us/articles/360052535494-Can-I-use-12V-Repair-Mode-on-AGM-batteries-

 

[samven]

12.7-12.8v is perfectly normal once the surface charge has bled off. I have heard that some of the spiral wound batteries have a slightly higher resting voltage. As far as the repair mode goes, I am not sure what they are doing but I do know that AGM manufactures warn against going beyond certain voltage levels and having a temp sensing charger can help prevent damage. Once bubbles start to form on the plate to mat surface there is no way to recover that capacity.