X2Power Premium AGM BCI Group 27F Car and Truck Battery G-27F not holding charge

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I purchased an X2Power Premium AGM BCI Group 27F Car and Truck Battery G-27F in March of 2021 from Batteries Plus. The battery is in the Tundra with an after-market S-ALT diode that allows the charging system to charge the battery at 14.8v and I routinely see 14.7 and 14.8v at startup.

The first thing I did when the battery was new was top the battery off with a charger capable of charging an AGM. It did its thing saying it was fully charged and my BT charge monitoring confirmed it. I've done this several times because although it would show 100% charge immediately at the end of the charging even by the next morning it was at 90%.

A few months ago I started to see 90%, then 80%, then 70% capacity after sitting overnight. This morning it's cold and it's currently 46% and 12.26v. The truck still cranks right over. The cranking voltage is 10.40v and the average charging voltage at idle is 14.50v and the average charging voltage at high RPM is 14.58v.

The truck is driven every day at least 16 miles and most days more than that with a couple +1hour highway trips per month. I'm guessing this less than 2-year-old battery is dying?
 

PWMDMD

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Will the battery pass a load test?
Not sure other than to say it's producing 10.40v during crank which is just above the 10.00v cutoff for the normal range on my BT monitoring app which is setup for an AGM battery.
 

JHZR2

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Disconnect the battery, charge it, let it sit disconnected for 2-3 days. Does it still lose significant capacity? If the answer is yes, the battery may have an internal short. If the answer is no, you have high parasitic current in the Tundra.
 

PWMDMD

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14.8v at what temperature? Are you sure the temperature compensation was right?


if you used some custom setup and it overcharged the battery, it will lose capacity.

That said, that level,of loss after charge tells me you may have a parasitic load. What is the draw on your vehicle when shut off, locked, closed, and fully asleep?
I'm using a NOCO Genius 10 and I just tried charging it on the AGM setting. It initially showed red and battery low, it gave it two very brief rounds of voltage up to about 15v, and then it went green indicated it was fully charged at 12.75v and it went into trickle mode.

Very confusing...
IMG_4546.png
 

PWMDMD

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Disconnect the battery, charge it, let it sit disconnected for 2-3 days. Does it still lose significant capacity? If the answer is yes, the battery may have an internal short. If the answer is no, you have high parasitic current in the Tundra.
See above...my NOCO Genius 10 won't even charge it above 12.75v.
 

PWMDMD

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I disconnected the battery and threw it on the AGM repair setting which is currently cycling it quickly between 14.25 and 14.70v.
IMG_4547.png
 

PWMDMD

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Not sure if this is helpful but these are the voltage readings for the past 7 days.
IMG_4548.png
 
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...This morning it's cold and it's currently 46% and 12.26v. The truck still cranks right over. The cranking voltage is 10.40v and the average charging voltage at idle is 14.50v and the average charging voltage at high RPM is 14.58v.
14.58V is a bit low for a cold X2Power/Northstar battery. If the battery temperature is 35F, the recommended temperature compensated charging voltage is 14.96V - 15.36V
 

PWMDMD

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14.58V is a bit low for a cold X2Power/Northstar battery. If the battery temperature is 35F, the recommended temperature compensated charging voltage is 14.96V - 15.36V
I've never seen the Tundra charge go above 14.8v even with the after-market diode and even then that's right at startup. If begins to trickly down to 14.5ish after a few mins.

It says on the battery the service charge is 14.4-14.8v and the float charge is 13.5-13.8v at 25C.
 
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I've never seen the Tundra charge go above 14.8v even with the after-market diode and even then that's right at startup. If begins to trickly down to 14.5ish after a few mins.

It says on the battery the service charge is 14.4-14.8v and the float charge is 13.5-13.8v at 25C.
I have never seen my Subaru charging voltage exceed 14.95V, even on a very cold morning.

From the Northstar manual that JHZR2 linked: (edited for clarity)
If the battery temperature increases above +25°C (+77°F), a thermal compensation of -4 mV/cell/°C to reduce charge voltage is recommended. Conversely, if the temperature decreases below 25°C, the charge voltage should be increased by 4 mV/cell/°C.
 

PWMDMD

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I just finished the "AGM Repair" sequence and the battery is at 12.64v or 83%. This of course includes surface charge and so I'm interested in where it will be tomorrow morning. If 12.64v is the best charge I can get does this confirm something is in fact wrong with this battery?
 
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it’s not just voltage reading you need to know. You must know the actual amperage is being put into the battery.

Thin Plate Pure Lead batteries can accept up to 40 percent of their amp hour rating. Which in a case like a group 27 battery could be up to potentially as high as 40 amps or more for a period of time at the beginning of charging a TPPL battery.

TPPL batteries do much, much better with a initial high amperage charge then tapering after that. To where acceptance of charge is only 0.5 amp per 100 amp hours at 14.7 Volts.


No smart charger will really be capable of achieving a true 100 percent charge with hardly any battery. Much less a TPPL battery.
 
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