Boiled battery - voltage too high?

[easterr]

Hi All,

My one month old Bosch battery is leaking acid from the vent holes. Truck is a 2006 Denali. I discovered this bc of a windshield washer fluid leak and thought maybe I damaged a hose while replacing the battery. I went to Pep Boys to exchange the battery and was told this is caused by the alternator overcharging.

The mechanic tested the voltage and it hit 15.01 once and then fluctuated in the high 14s. I also tested when I got him and got a high of 14.93. He said it is likely the voltage regulator in the alternator, but 06 has an external regulator. On a recent 400 mile trip, the voltage gauge appeared to read normally, (fluctuating between 13-14.5) but it could have been 15 volts and not 14.5., hard to say with the voltage gauge. I also got a CEL and code for general misfire, which I've read can happen if the voltage is too high. I cleared it and haven't received the CEL again.

What I have searched for and cannot find a definitive answers is if this voltage is too high, and, if so, is it alternator or voltage regulator. How can I test to determine?

Thanks very much in advance, not sure if there is a problem on the one hand (defective battery) and then what to replace if there is.

 

[SnowDrifter]

~15v is normal charge voltage for these rigs. It's fine.

FWIW a shorted / bad cell in a battery will cause the others to overcharge

 

[Doubeleive]

sounds more like a funky battery to me, a battery charger could maybe cause that to happen I would be hesitant to blame it on a oem alternator that's probably only putting out 110-140amps. the voltage isn't really what matters it's the amps.

 

[BG1988]

Hi All,

My one month old Bosch battery is leaking acid from the vent holes. Truck is a 2006 Denali. I discovered this bc of a windshield washer fluid leak and thought maybe I damaged a hose while replacing the battery. I went to Pep Boys to exchange the battery and was told this is caused by the alternator overcharging.

The mechanic tested the voltage and it hit 15.01 once and then fluctuated in the high 14s. I also tested when I got him and got a high of 14.93. He said it is likely the voltage regulator in the alternator, but 06 has an external regulator. On a recent 400 mile trip, the voltage gauge appeared to read normally, (fluctuating between 13-14.5) but it could have been 15 volts and not 14.5., hard to say with the voltage gauge. I also got a CEL and code for general misfire, which I've read can happen if the voltage is too high. I cleared it and haven't received the CEL again.

What I have searched for and cannot find a definitive answers is if this voltage is too high, and, if so, is it alternator or voltage regulator. How can I test to determine?

Thanks very much in advance, not sure if there is a problem on the one hand (defective battery) and then what to replace if there is.

No wrong the hybrid are pumping out 15volts almost all the time without issue .. those use a High voltage DC to DC converter 185AMP output on demand ...2.4KW to 2.7KW

if you are that worried there is 14 and 16 volt automotive batteries on the market. they cost about 250-300$ though..

I like how GM says it's delicate like a flower... yet the Cadillac version has like twice the electrical stuff as the tahoe hybrid.. all the goodies available..




the battery you had was weak buy one from autozone they can handle the 15VDC no problem duralast gold group 48 DLG model

 

[SnowDrifter]

No wrong the hybrid are pumping out 15volts almost all the time without issue .. those use a High voltage DC to DC converter 185AMP output on demand ...

if you are that worried there is 14 and 16 volt automotive batteries on the market. they cost about 250-300$ though..

Yeah you can get 14/16v. Generally they're for special applications though. Need a special charging system for them. The things are NOT drop in. Especially not 16v being that they charge in the 18 to 19v range. 14v can sometimes be worked in with the stock electronics as they charge in the 16.5v range

 

[easterr]

Thank you for the responses, very much appreciated. I have continued looking around and found some info that may be known, but thought could be helpful for future searches.

The 05+ trucks have a Regulated Voltage Control system, which is a fuel-saving measure and reduces the alternator output based on need, which is why the volt meter has always fluctuated so much (always curious why). Info below:

https://rangetechnology.zendesk.com/hc/en-us/articles/205922836-Voltage-Gauge-fluctuations

Assuming I read this correctly, the charging system's normal duty cycle is between 11.5 -15.5 volts. Description of the charging system below in first link and second link contains a good explanation of the higher voltage aspect.

https://www.performancetrucks.net/f...mance-21/05-e-fans-voltage-drop-259676/page2/

https://www.pirate4x4.com/forum/gen...5-3-chevy-silverado-charging-14-75-volts.html

I guess I am going back to pep boys to argue the volts are normal and did not affect the battery. Unfortunately, the acid also destroyed the battery tray and likely caused the windshield washer reservoir to leak, which is how I discovered the battery issue.

Thanks all very much again

 

[easterr]

Update: battery continued to boil and Denali charged at 15.2v. Alternator began to whine, so replaced with an Bosch that was sold as OEM on Amazon. Seemed fine and drove it last night for 30 mins and volts were mid-14s. Today began charging at 15.2 and battery leaked.

Please does anyone have suggestions? Could the alternator be overcharging because the battery was ruined from initial overcharge? This is the second battery, the first that leaked was tested and was dead so was replaced. Denali starts and drives fine. Resting voltage of battery is in the 12s (while truck is off but connected to terminals).

Thanks in advance. Thought the alternator would have solved this.

 

[Doubeleive]

Update: battery continued to boil and Denali charged at 15.2v. Alternator began to whine, so replaced with an Bosch that was sold as OEM on Amazon. Seemed fine and drove it last night for 30 mins and volts were mid-14s. Today began charging at 15.2 and battery leaked.

Please does anyone have suggestions? Could the alternator be overcharging because the battery was ruined from initial overcharge? This is the second battery, the first that leaked was tested and was dead so was replaced. Denali starts and drives fine. Resting voltage of battery is in the 12s (while truck is off but connected to terminals).

Thanks in advance. Thought the alternator would have solved this.

so....your still using the bad battery????? doesn't sound like you replaced it and have continued to use it, batteries do not fix themselves

 

[easterr]

so....your still using the bad battery????? doesn't sound like you replaced it and have continued to use it, batteries do not fix themselves

Thanks. This is a new battery - the second, however, it also leaked from 15.2volts before I replaced the alternator. After new alternator, it all seemed fine last night and then this morning while idling only, volts were 15.2 and it leaked. Thanks again

 

[Doubeleive]

Thanks. This is a new battery - the second, however, it also leaked from 15.2volts before I replaced the alternator. After new alternator, it all seemed fine last night and then this morning while idling only, volts were 15.2 and it leaked. Thanks again

I wouldn't continue to use this leaking battery, a battery should not leak unless something is wrong with it internally or the mixture is wrong, do yourself a favor a get a AGM they can be had from rockauto for $160, no core, autozone sells them for like $185 with a core