Different ground readings on batteries

[Maraian]

I was testing to see if I had a good ground and I got two different readings on the two batteries. One battery gave me 0.3 ohm. The other battery 6 ohm. Is this normal?

 

[GA_Boater]

I guess you are measuring between the ground post and a ground buss.

The 6 ohm reading is not good. Check all the connections.

 

[bruceb58]

Using meter measuring ohms is actually a poor way to check grounds since even 0.1 ohm isn't good. Measure the voltage drop between two points with a load to see how much voltage drop develops.

 

[Maraian]

I guess you are measuring between the ground post and a ground buss.

The 6 ohm reading is not good. Check all the connections.

I was checking between the back of the engine block, there is a bolt with many ground wires connected and the negative battery post. I have two batteries. One battery measured .3ohms, the other battery 6 ohms.

 

[bruceb58]

If there is anything drawing current while you are making that measurement, your ohms you measured will be WAY off.

If you really want to make an ohms measurement, remove the positive leads of both batteries and repeat your measurements on the ground cables. Like I said before, ohms is not a good way to measure this. Even your 0.3 ohms is bad but not likely accurate either.

If you really had 0.3 ohms, a 20 amp load would drop 6V across your cable! No way that is likely happening.