Charger Voltage Too High

W

willbur

Joined
Jun 6, 2013
Messages
1,636
Location
sw ohio
Greetings All-
Got a NOCO Genius 5 charger charging/maintaing a good battery. Solid green light indicating fully charged battery on for last four days (maintain mode). Checked voltage- 16.6. Yikes! NOCO tech support says this is fine. Can't be. Tried another car with an almost new AGM and same thing. Worried I may damage electronics.
Ideas/opinions welcome
 
willbur said:
Thank you-so car is fine, but is the NOCO charger fine?
Click to expand...
I've never took voltage off mine but if I had to guess it went into equalize mode or something akin to that. There is a wealth of info in this thread.

Battery Charger Testing Results

Like a number of us on here, I have a number of battery chargers. I keep a bunch because I have a number of cars that dont get year-round use, and I also have some for maintenance. Because there is now an Automotive Electrical subforum, and because there are a lot of good questions...
bobistheoilguy.com
 
willbur said:
Greetings All-
Got a NOCO Genius 5 charger charging/maintaing a good battery. Solid green light indicating fully charged battery on for last four days (maintain mode). Checked voltage- 16.6. Yikes! NOCO tech support says this is fine. Can't be. Tried another car with an almost new AGM and same thing. Worried I may damage electronics.
Ideas/opinions welcome
Click to expand...
Did you check the voltage with the charger still attached?
Your alternator will usually put out 13.8-14.4V and a fully charged car battery should read 12.7-13.2 (depending on manufacturer)
 
wpod said:
Do the volts reduce as the battery charges?
Click to expand...
No- go up as it accepts charge. Internal battery resistance increases as battery charges up. I never saw a voltage beyound about 15.5 before observing the 16.6. I forgot to mention, after seeing the 16.6 at the battery posts with the charger atached; I put on a NOCO Genius 1 and saw 12.88v at the posts with it attached- normal maintenance level.
 
willbur said:
No- go up as it accepts charge. Internal battery resistance increases as battery charges up. I never saw a voltage beyound about 15.5 before observing the 16.6. I forgot to mention, after seeing the 16.6, iI put on a NOCO Genius 1 and saw 12.88v- normal maintenance level
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16.6V on a fully charged lead acid battery of any type is just going to make it gas. No big deal on a flooded battery where you can add more water, but it can eventually kill an AGM.
 
According to the Genius manual, "repair mode" is 16.5V + 5A and has to be initiated manually.

Using 12V Repair. [From Standby Press and Hold 3 Seconds With Clamps Connected to the Battery]
12V Repair is an advanced battery recovery mode for repairing and storing, old, idle, damaged, strati ed or sulfated batteries...................

CAUTION. USE THIS MODE WITH CARE. THIS MODE IS FOR 12-VOLT LEAD-ACID BATTERIES ONLY. THIS MODE USES A HIGH CHARGING VOLTAGE AND MAY CAUSE SOME WATER LOSS IN WET (FLOODED) CELL BATTERIES. BE ADVISED, SOME BATTERIES AND ELECTRONICS MAY BE SENSITIVE TO HIGH CHARGING VOLTAGES. TO MINIMIZE RISKS TO ELECTRONICS, DISCONNECT THE BATTERY BEFORE USING THIS MODE.
Click to expand...

Some of the OptiMate chargers will go up to 22V (at 0.4A) in repair mode (16V if the battery is connected to vehicle electronics)
 
It shouldn’t be that high. If it’s in repair mode, the voltage will cycle up and down and not stay there. In general, the noco is a very conservative charger - and tends to shy from aggressive charging. for me it’s rather undesirable because of that. Car electronics exposed to those kinds of voltages could become risky at some point.

on the other hand, how the volt meter is functioning can also produce weird results. If its reading peak ripples or noise or has an internal fault… which my old Klein would do with no warning, you could get a poor reading. Verify the meter to be certain?
 
For comparison, CTEK specifies 15.8V max. with the MXS 5.0, in the initial desulphation mode in every program, which I've seen last only very briefly, and during the final reconditionng mode on the programs that employ it, with a 2h or 6h duration.
 
I don't trust noco, 16.6v is too high for a lead battery based on what I have read over the years; unless noco has discovered a new technique.
CTEK is the one to use as reference
 
meep said:
It shouldn’t be that high. If it’s in repair mode, the voltage will cycle up and down and not stay there. In general, the noco is a very conservative charger - and tends to shy from aggressive charging. for me it’s rather undesirable because of that. Car electronics exposed to those kinds of voltages could become risky at some point.

on the other hand, how the volt meter is functioning can also produce weird results. If its reading peak ripples or noise or has an internal fault… which my old Klein would do with no warning, you could get a poor reading. Verify the meter to be certain?
Click to expand...
Got four multimeters. All agree. Thought of that LOL
 
bonjo said:
I don't trust noco, 16.6v is too high for a lead battery based on what I have read over the years; unless noco has discovered a new technique.
CTEK is the one to use as reference
Click to expand...
I’ve never seen this including taking data with data acquisition meters.

This looks like a repair mode.

I’ve literally left these on for months with no issues.

I suspect a repair mode was initiated.
 
JHZR2 said:
I’ve never seen this including taking data with data acquisition meters.

This looks like a repair mode.

I’ve literally left these on for months with no issues.

I suspect a repair mode was initiated.
Click to expand...
Repair Mode? First thing I thought. It was not initiated by me- especially because it happend on TWO batteries. Batteries were connected for multiple days and totally left alone. To initiate repair mode requires two deliberate actions: press standby and then hold down for 3 seconds. Not something done inadvertently. Perhaps the charger malfunctioned? I'm sending it back for warranty evaluation by NOCO, but whatever they say or do, I'm getting a CTEK.

:rolleyes:NOCO tells me this is "normal" charging (twice), and the way its chargers work.
 
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LvR said:
Nope ............ it goes down - probably approaching around 3mOhm when fully charged
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Thank you-
I disagree with you. Sources? I called EastPenn/DEKA, widely regarded as a top brand manufacteur, and asked tech support about this. They told me internal resistance increases as a battery charges up. Thats why the observed charging vdc increases with SOC according to Ohms Law. Charging current decreases due to internal battery resistance increase and observed charging voltage goes up at the meter.
 
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