445 Battery Light On

[BBO]

The battery is 5-years old & I have been expecting to replace it, but...

Yesterday the battery light came on.
So with it running I checked the battery voltage, 14.37 vdc.

I shut it, off and the battery cranks the mower as normal; battery light still on when running.

With the mower off the battery voltage seems even high, at 12.90 vdc.

Can it be overcharging?

 

[Richard001]

BBO,

I don't think that the battery light on the dash is smart enough to know if the battery is being overcharged.

You said:

With the mower off the battery voltage seems even high, at 12.90 vdc.

There is always a little residual extra charge on a battery after it has been charged. Let it sit for and hour, then measure it again and let us know what you get then.

There was a guy who posted here recently that he felt his battery was being overcharged and he did find a problem with the connector at the regulator. Check the connector and the contacts. Scrape the contacts to make them shinny.

Here is the operation description of the charge circuit:


And here is the Schematic:


I have a PDF of the 445 service manual, but it's huge, 67MB.

Richard

 

[Garrett Wiggins]

It could also be a short in the wiring causeing it to back feed and cause the light to come on too right?

 

[BBO]

BBO,

I don't think that the battery light on the dash is smart enough to know if the battery is being overcharged.

You said:

There is always a little residual extra charge on a battery after it has been charged. Let it sit for and hour, then measure it again and let us know what you get then.

Richard

Well after sitting 2 days the battery voltage is still 12.37vdc and it still cranks fine.
And now (at least cold) the battery light is not on when running!

I will update this the next time I mow...

 

[Richard001]

Just for your info:

LEAD-ACID BATTERY INFO

A battery’s condition can be monitored by checking the electrolyte’s specific gravity with an inexpensive D-I-Y battery hydrometer to determine the percentage of sulphuric acid it contains.

A fully charged cell at 80 degrees F would show a specific gravity of 1.265. If all six cells are fully charged, an accurate digital voltmeter reading of battery voltage would show 12.68 volts.

Specific gravity for a 50 percent discharged cell would drop to 1.19 and battery voltage would fall to 12.24.

When specific gravity reaches 1.12, the cell is fully discharged and battery voltage falls to 11.89 volts, assuming the specific gravity is the same in all six cells.

Because specific gravity is affected by temperature, subtract .004 per 10 degree drop below 80 degrees F.


Richard

 

[BBO]

Just for your info:
LEAD-ACID BATTERY INFO
A battery’s condition can be monitored by checking the electrolyte’s specific gravity with an inexpensive D-I-Y battery hydrometer to determine the percentage of sulphuric acid it contains.
A fully charged cell at 80 degrees F would show a specific gravity of 1.265. If all six cells are fully charged, an accurate digital voltmeter reading of battery voltage would show 12.68 volts.
Specific gravity for a 50 percent discharged cell would drop to 1.19 and battery voltage would fall to 12.24.
When specific gravity reaches 1.12, the cell is fully discharged and battery voltage falls to 11.89 volts, assuming the specific gravity is the same in all six cells.
Because specific gravity is affected by temperature, subtract .004 per 10 degree drop below 80 degrees F.
Richard

I have read that you are supposed to add distilled water to a battery with low fluid level.
I have wondered why you do not add battery acid instead...

It's interesting when you buy a dry battery at a JD dealer, they fill it with acid...
Then they say you can charge it, but it's not totally necessary.
The battery will likely read over 12V and it will work without any time on a charger.
The same is true with a motorcycle battery.
With the acid, the cells start working.

And if you leave the light on in a car, killing the battery, just letting it sit for a time it may recharge itself enough to crank.

 

[BBO]

Update.
I had the battery tested. It is indeed good. (It's a 10 yr old Autozone battery!)
I now have a JD 3-year old battery on it and the symptom is the same.
It cranks fine and the light is not on when it's cold.
But with either battery after mowing about 1 hour the light comes on, and will not go off.
(Even after cranking it hot, the light comes right back on)
With the light on, it's still charging at about 14.4 vdc.

I plan to take the regulator off and look at all the wiring.
But I am wondering if the regulator is putting out too much voltage???

 

[Richard001]

Update.
I had the battery tested. It is indeed good. (It's a 10 yr old Autozone battery!)

Wow that is amazing. A lead/acid battery that lasted over ten years !

I now have a JD 3-year old battery on it and the symptom is the same.
It cranks fine and the light is not on when it's cold.
But with either battery after mowing about 1 hour the light comes on, and will not go off.
(Even after cranking it hot, the light comes right back on)
With the light on, it's still charging at about 14.4 vdc.

I plan to take the regulator off and look at all the wiring.
But I am wondering if the regulator is putting out too much voltage???

BBO - If you are measuring 14.4 V with engine at fast idle, that would be the correct voltage out of the regulator.

I suspect that, even though the output voltage is correct, that the voltage sensing part of the regulator is faulty. Have you removed the regulator connector and checked for good connection of the connector contacts?

Richard

 

[BBO]

Wow that is amazing. A lead/acid battery that lasted over ten years !
BBO - If you are measuring 14.4 V with engine at fast idle, that would be the correct voltage out of the regulator.

I suspect that, even though the output voltage is correct, that the voltage sensing part of the regulator is faulty. Have you removed the regulator connector and checked for good connection of the connector contacts? Richard

I took the VR connector off and cleaned it, but no visible signs at all that this is the problem.
No signs of corrosion or heat damage.
I will mow again later today to see what happens.

 

[Spanner]

And...

:wrench: