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Re: Can 14.4 V be too much of a good thing for 12 V battery?

Thu Jan 18, 2018 12:14 am

-brighter headlamps during inclement weather. Incandescent bulb output is strongly influenced by voltage, and the LEAFs habitual under-volting is behind many of the "terrible high-beam" complaints with the incan bulbs, I believe.

I had the same thought, but can detect no increase in headlight brightness when the wipers are on.
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Re: Can 14.4 V be too much of a good thing for 12 V battery?

Thu Jan 18, 2018 6:28 am

BuckMkII wrote:I noticed when frequent rain began in the fall that LeafSpy showed the DC/DC converter maintains 14.4 V for as long as the wipers are on, and that my attempts to recharge the 12 V battery manually with an external charger every-other weekend resulted in the charge rate immediately dropping to near zero, indicating (if I'm not mistaken) that the battery was already fully charged.

So, great! When we had an unusually long period of no rain in December, I made a point of running the wipers on the lowest intermittent setting on about a third of my trips, just to keep the 12 V battery topped up. Now I'm just wondering: if it rains all the time, is there any risk of overcharging the 12 V battery by keeping the voltage high all the time?

You probably have not noticed that working voltage of ANY car is in the 13.5-14.5 volt neighborhood while the car is in use...

Anytime the car is running, the alternator is charging the battery at this voltage to cover for all of the accessories, a/c, heat that use up power. That way the 12v battery does not discharge.

Just because the system voltage is "higher" when the car is running, does not mean that the 12v battery is being over charged. Every 12v battery charger has a voltage in the 14 volt range..

Don't worry about it.... All this is normal. The time to worry is if the "running" system voltage while running starts going down to 12v volts or lower.... That means the car is not charging the battery.

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Re: Can 14.4 V be too much of a good thing for 12 V battery?

Thu Jan 18, 2018 7:01 am

smkettner wrote:Higher voltage is ok when a bit chilly out so no harm when raining.

I notice this as well (14.4+V when colder)...and no, it doesn't hurt a thing. Even my LiFePO4 battery can accept that at the high-end of the range.
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