Aux 12v battery BHAGM-AUX1-B
04-28-2024, 01:03 PM
#1
Senior Member
Thread Starter
Aux 12v battery BHAGM-AUX1-B
Hey guys, there are endless threads about main 12v battery on our trucks, but hardly ever anybody talks about the auxiliary 12v battery that is hiding under the rear bench.
They do work in parallel to provide stable power to onboard electronics during engine start, and in my opinion are overlooked. And getting a replacement is not trivial - seems like the only option is OEM part.
Here are my questions:
- how do you test health of that aux battery?
- does it make any sense to go for the hassle of getting dual aux battery setup - like on diesel version (2021)? will that help that the dreaded deep sleep?
- has anyone replaced that battery?
my truck turned 2 years with me, which means the original battery is at least 2.5-3 years old...
They do work in parallel to provide stable power to onboard electronics during engine start, and in my opinion are overlooked. And getting a replacement is not trivial - seems like the only option is OEM part.
Here are my questions:
- how do you test health of that aux battery?
- does it make any sense to go for the hassle of getting dual aux battery setup - like on diesel version (2021)? will that help that the dreaded deep sleep?
- has anyone replaced that battery?
my truck turned 2 years with me, which means the original battery is at least 2.5-3 years old...
04-28-2024, 04:32 PM
#2
Does the auxillary battery work with the Stop Start feature?
I just had to deal with one in my wifes 2017 Jeep Grand Cherokee. We were stuck in a long 3 hour traffic jam where we would literally pull up a car length and then sit for several minutes and repeat. This should be exactly what the ESS was designed for right? Wrong, by the end of it the battery was dead the lite on the dash was on and a message reading that the stop start was disabled and to see the dealer. At home I checked the voltage and the main battery that should be good for 3-5 was reading 12.5. The smaller ESS battery was at 11.8 volts. I took the small one to get a replacement at Autozone. I had put it on the trickle charge for about 45 minutes before heading out and it was up to voltage and holding. The guy tested it on his machine and said it was good and the cells looked good. I took it home put it back in and the JeeP started fine. I will test it again shortly.
Both batteries are closing in on 3 years now. We had to have them replaced after an electrical problem caused by rodents. I'm hoping that we are going to get more than 3 years out of these things. What happened to batteries lasting 10 years like they used to? At least with the JeeP I found out that I can buy the batteries over the counter. It still costs about $400 to replace them but that beats having to go to the Dealer and be charged double.
I just had to deal with one in my wifes 2017 Jeep Grand Cherokee. We were stuck in a long 3 hour traffic jam where we would literally pull up a car length and then sit for several minutes and repeat. This should be exactly what the ESS was designed for right? Wrong, by the end of it the battery was dead the lite on the dash was on and a message reading that the stop start was disabled and to see the dealer. At home I checked the voltage and the main battery that should be good for 3-5 was reading 12.5. The smaller ESS battery was at 11.8 volts. I took the small one to get a replacement at Autozone. I had put it on the trickle charge for about 45 minutes before heading out and it was up to voltage and holding. The guy tested it on his machine and said it was good and the cells looked good. I took it home put it back in and the JeeP started fine. I will test it again shortly.
Both batteries are closing in on 3 years now. We had to have them replaced after an electrical problem caused by rodents. I'm hoping that we are going to get more than 3 years out of these things. What happened to batteries lasting 10 years like they used to? At least with the JeeP I found out that I can buy the batteries over the counter. It still costs about $400 to replace them but that beats having to go to the Dealer and be charged double.
04-29-2024, 04:42 AM
#3
Replaced aux battery at 36000 miles
see my responses in red
Hey guys, there are endlesthreads about main 12v battery on our trucks, but hardly ever anybody talks about the auxiliary 12v battery that is hiding under the rear bench.
They do work in parallel to provide stable power to onboard electronics during engine start, and in my opinion are overlooked. And getting a replacement is not trivial - seems like the only option is OEM part.
Here are my questions:
- how do you test health of that aux battery? Mine failed and I received battery fault alarms in the dash.
- does it make any sense to go for the hassle of getting dual aux battery setup - like on diesel version (2021)? will that help that the dreaded deep sleep?
- has anyone replaced that battery? Yes replaced at 36000 miles in the 2021 Powerboost that I had. I traded that POS for a 2023 Lariat a few months ago.
my truck turned 2 years with me, which means the original battery is at least 2.5-3 years old...
They do work in parallel to provide stable power to onboard electronics during engine start, and in my opinion are overlooked. And getting a replacement is not trivial - seems like the only option is OEM part.
Here are my questions:
- how do you test health of that aux battery? Mine failed and I received battery fault alarms in the dash.
- does it make any sense to go for the hassle of getting dual aux battery setup - like on diesel version (2021)? will that help that the dreaded deep sleep?
- has anyone replaced that battery? Yes replaced at 36000 miles in the 2021 Powerboost that I had. I traded that POS for a 2023 Lariat a few months ago.
my truck turned 2 years with me, which means the original battery is at least 2.5-3 years old...
