Battery Tender Junior float voltage??
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Racer
Joined: Mar 2016
Posts: 399
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Battery Tender Junior float voltage??
I have 3 of the BT Jr..iput my Fluke multimeter on to check float voltage--all 3 units read low from 13.06 up to about 13.12--all battery manufactures suggest 13.20 as being the lowest up to about 13.60 volts--my meter is fairly accurate--anyone else notice low float voltage?
Drifting
Joined: Sep 2004
Posts: 1,470
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I have 3 of the BT Jr..iput my Fluke multimeter on to check float voltage--all 3 units read low from 13.06 up to about 13.12--all battery manufactures suggest 13.20 as being the lowest up to about 13.60 volts--my meter is fairly accurate--anyone else notice low float voltage?
Melting Slicks
Joined: Jul 2010
Posts: 3,001
Likes: 243
From: Surprise, Az
I have 3 of the BT Jr..iput my Fluke multimeter on to check float voltage--all 3 units read low from 13.06 up to about 13.12--all battery manufactures suggest 13.20 as being the lowest up to about 13.60 volts--my meter is fairly accurate--anyone else notice low float voltage?
Pro
Joined: Sep 2009
Posts: 671
Likes: 10
From: Tulsa OK
I may not understand "float voltage" but my little Battery Tender, Jr. doesn't starting charging until the battery voltage drops down to 12.65v. I'm not sure at what voltage it goes into standby mode. Whenever I disconnect the charger and go for a drive the voltmeter shows 14.4v - 14.7v which makes me think the tender isn't maintaining the battery correctly. Any thoughts? 
OBD
OBD
Le Mans Master
Joined: Feb 2007
Posts: 8,514
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From: Currently somewhere in IL,IN,KY,TN,MO,AR,MS,AL, or FL
A fully charged lead acid battery runs 12.6 to 12.65 volts. How are you measuring the 13.06-13.20? If it is hooked to a battery (which a Battery Tender Jr. must be before it will produce any output voltage) then it is just supplying the current needed to run the car's computers in low power mode. The ~13.5 volt recommendation is for stationary batteries that are never discharged and recharged. That level will cause some liquid loss. The world is a compromise. Deltran compromises on trying to keep the battery as fully charged as possible without risking electrolysis of the water. I trust the Deltran engineers to know more about batteries that most people certainly including myself.
As far as 14+ volts when the car is running, GM doesn't care as much about how well they treat batteries. They are only interested in recharging the battery as fast as possible at the least cost. They can't spend a lot of money on fancy float circuits that the owner will never notice except in the price of the car.
As far as 14+ volts when the car is running, GM doesn't care as much about how well they treat batteries. They are only interested in recharging the battery as fast as possible at the least cost. They can't spend a lot of money on fancy float circuits that the owner will never notice except in the price of the car.
