# Im getting 10.03 volts when I try to start my riding mower at the battery,I get the same reading at the starter.Is that too much volt drop? ?

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• Anonymous
2 months ago

What is the mower doing?  If it is not starting, replace the battery.

• M.
Lv 7
2 months ago

Is it cranking slowly?

"Voltage drop" in conductors is related to resistance.

Your wires seem to be doing a good job.

"Voltage drop" of the battery is related to the capacity of the battery and the electrical load.

As a battery ages and is abused and the temperature drops, the battery capacity drops.

As a starter ages and wears out, it may become an increased load to the battery.

So you need to figure out whichbis your problem.

Usually it's the battery, but sometimes it's the starter.

Having an amperage measurement would point at the culprit, the battery or the starter.

The battery could use a charge and see whether that helps.

How OLD is the battery?

• 2 months ago

That's too low.  Now, either the battery is defective (despite being new),  it isn't being charged properly or there's a wiring/switch issue.  It is often the latter on mowers since the wiring, connections and switches tend to live in damp conditions and corrosion can set in.

I'm assuming you do have the right battery?

• 2 months ago

A fully charged 12 volt battery should read at east 12.6 volts with a digital volt meter. Any less and it is not fully charged. A reading of 12 volts means it is only 25% charged. A drop to 10.3 volts is slightly more than normal but not out of the question. if the mower starts then you have no problem. If it doesn't then look for a loose or corroded connection or a cable that is bad. If you see swelling in a cable it is defective.

• KY-Clay
Lv 7
2 months agoReport

It will read the same on a analog meter but it is hard to see the difference between 12.6 and 12 volts. On a digital meter it is easy. I did not mean 10 V. A fully charged battery will read 12.6 V, 12.4 at 75%, 12.2 at 50%, and 12 V at 25%.

• Snezzy
Lv 7
2 months ago

Check the voltage between the battery terminal and the battery connector as you try to crank. (Helps to have two people.) Do this for both the positive and for the negative. As you are certainly aware, there should be almost no voltage drop across those connections, but if there is dirt, corrosion, or bolts that won't tighten properly, then you'll see instantly what's wrong, as your meter shows 2.6 volts between the post and the connector.

• 2 months ago

There will be some voltage drop but I don't know if 2.6volts (12.6 - 10.0) is too much. It does sound like a bit much though. Put your meter on the lowest voltage setting and measure the drop between the battery terminal and the battery cable that connects to the terminal. Do this for both the positive and negative sides. There should be zero volts drop.

If this is all OK, then the starter motor is drawing too much current. This could be because there is a short in a section of the winding in the starter or more likely the starter is having to work too hard to turn over the engine.

The more current that the starter draws the more voltage drop there will be. If all of the connections are good then the voltage drop is occurring inside the battery (normal). As the battery ages it's internal resistance goes up and more voltage is dropped for the same current flow. So assuming your new battery is good then the voltage drop is caused by the starter drawing current. A certain amount of drop is normal as all batteries have some internal resistance. So if the new battery is known to be good and all of the connections, including the ground connection of the battery and also the starter, are good, then:

1). The voltage drop is normal and the engine turns over normal.

2). The engine is harder to turn thus causing the starter to draw more current and in turn         dropping more voltage inside the battery.

3). The starter has a problem, like a short in the winding or bad bearing, etc.

• elhigh
Lv 7
2 months ago

That does seem like a lot. Look for a damaged cable or a loose connection. Don't forget ground connections!

• 2 months ago

Riding mower batteries are notorieously short lived. And often need a new one in the spring.

• SaltySnaks2 months agoReport

It’s a brand new battery from Costco