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Hello fishhawk,
yes, i looked for an AGM.

I did measure the Voltage on the posts too and i also get the same 15'ish results. After what kind of time am i expected to see "usual" Voltages ? I would like to check if the Volt charger treats the (then new) AGM well enough.

Greetings and thank you again for your shared knowledge.

Nils
T
 

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I did measure the Voltage on the posts too and i also get the same 15'ish results. After what kind of time am i expected to see "usual" Voltages ? I would like to check if the Volt charger treats the (then new) AGM well enough.
I'm not an expert on the battery charging profile, I just know it's different. See this post:
http://gm-volt.com/forum/showthread.php?92913-can-you-put-another-type-of-12-volt-battery-in-volt&p=1248209#post1248209

Here's some more information:
http://gm-volt.com/forum/showthread.php?10171-What-chemistry-is-the-Volt-s-12-volt-battery

HTH.
 

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Hi Fishhawk,
oops, thats a misunderstanding, i was aware that i have to swap for the same type of battery, which i will do (VRLA/AGM).
But earlier in this thread it was established that the starting charge Voltage is 15,1 Volts which is sure-death for all kind of Lead batteries.
I measured the same Voltage...
But it seems that the Voltage goes down after a few minutes and i wonder after how many minutes this was observed so i can start to compare.
Because if it is NOT going down quite early then the Volt is a battery-killer...

Greetings,

Nils
 

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Many older cars have self contained voltage regulators that were temperature compensated. On a very cold start, yes they would charge in the low 15's and taper down. On a hot day with temps under the hood reaching over 200 degrees the charge rate was in the mid 13's. The voltage on a lighter plug is usually lower than the battery due to losses from smaller wire. Most bulbs in vehicles are rated for 15V even though we think of them as 12V. AGM batteries are usually never constantly charged over 14.8V. As long as the rate of charge falls in a few minutes to that range, the system is working as planned.
 

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I have an accessory plug voltmeter plugged into the port inside the dash compartment. At first (week or so ago) the car was running at 13.8v or so. Then it started showing 15.1v last couple days and seemed to be staying there. Then, after reading this post, I checked at the battery with a digital VOM. Initial reading on start ramped up to 15.1, then began to drop. After a couple minutes, it was at 14.1 or so. I have seen it running as low as 13.0 and as high as 15.1. My Leaf tends to run mostly at 12.9, with the occasional foray into 14.4 for awhile, usually in colder weather. Our Camry Hybrid seems to run in high 14's as I recall. So I dunno. But many, myself included, feel the Leaf keeps its battery undercharged. I see no evidence of excessive gassing on the Volt's battery. It's a 2013 with 22k on the clock.
 

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I have an accessory plug voltmeter plugged into the port inside the dash compartment. At first (week or so ago) the car was running at 13.8v or so. Then it started showing 15.1v last couple days and seemed to be staying there. Then, after reading this post, I checked at the battery with a digital VOM. Initial reading on start ramped up to 15.1, then began to drop. After a couple minutes, it was at 14.1 or so. I have seen it running as low as 13.0 and as high as 15.1. My Leaf tends to run mostly at 12.9, with the occasional foray into 14.4 for awhile, usually in colder weather. Our Camry Hybrid seems to run in high 14's as I recall. So I dunno. But many, myself included, feel the Leaf keeps its battery undercharged. I see no evidence of excessive gassing on the Volt's battery. It's a 2013 with 22k on the clock.
You cant tell much about the condition/performance of the AGM battery (or the charging system for that matter) with just a voltmeter
Dealers use an expensive capacitance based test tool called the Midtronics GR8 at the very least you would need an old school carbon-pile load tester

All of what you have described in terms of voltage would be considered 100% normal for the Volt's BCM controlled 12V charging system as is dependant on a myriad of variables such as temperature, load demand, and basic joule counting

WOT
 

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I see the same using a power port volt meter . --- all normal

the other data point is what you see after shutting off the Volt during the 10 mins before the power ports shut down.
If that number gets too low then we worry.

I have not see that go below 11.9 and around 12.2 + average.
 
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