Voltage test

[al m]

I installed a new Dynamo on my b6100 on the weekend.tonight I did a voltage test at the battery posts.before start up,12.4 v.Start tractor,rev engine,13.4 v
My instincts are telling me all is well
Searching this board gives results for amperage
Can anyone confirm my belief the electrical system is working correctly?

 

[100 td]

Increase in voltage says the dynamo and rectifier/regulator are working to some extent, and could be totally fine. Hopefully with some time the terminal voltage will increase a bit higher as the battery charges.

 

[85Hokie]

I installed a new Dynamo on my b6100 on the weekend.tonight I did a voltage test at the battery posts.before start up,12.4 v.Start tractor,rev engine,13.4 v
My instincts are telling me all is well
Searching this board gives results for amperage
Can anyone confirm my belief the electrical system is working correctly?

13.4 is about perfect - too much higher can cause problems, lower is not getting enough.

Should have a smidge more than 12.4 before turning the key however. 12.6 would be 100% charged

 

[100 td]

13.8~14.1 volts when cold would be better for a cyclic starter battery, as components heat up the voltage will generally fall a bit. The output of dynamos is generally low so until your battery's storage capacity has been replenished from it's previous state you may not see the higher terminal voltages.

 

[al m]

I am seeing this ,along with my initial positive thoughts,that the changing system is fixed and operating as it should
Thanks guys

 

[Tooljunkie]

Actually a good like new battery is 13.2 volts. 2.2 per cell when new off the factory line.
Rule of thumb in automotive field is 14.2 to 14.6 volts.
Minimum should be 1 volt over battery voltage. I would say with a dynamo you are right on the mark.

 

[85Hokie]

Actually a good like new battery is 13.2 volts. 2.2 per cell when new off the factory line.
Rule of thumb in automotive field is 14.2 to 14.6 volts.
Minimum should be 1 volt over battery voltage. I would say with a dynamo you are right on the mark.

TJ,

For a typical LEAD-ACID battery, you will never find a "fresh" battery at 13 volts! It might have started there, but will never "finish" there

Here is the chart for "typical" fresh batteries :

State of Charge
Specific Gravity Voltage
12V
100% 1.265 12.7
75% 1.225 12.4
50% 1.190 12.2
25% 1.155 12.0
Discharged 1.120 11.9

now this is a wet cell (flooded) battery...most common on the market.

A hydrometer will tell the specific charge if a VOM is not available.

Now when you charge it - it will climb up to the voltage close to the charging voltage (and yes that rule of thumb is true +1 V) - but will settle back down to the 100% charged voltage.

Excellent reading on state of charge and charging of L/A batteries.

https://pssurvival.com/PS/Batteries/Lead_Acid/Lead-Acid_Battery_State_Of_Charge_Vs_Voltage_1993.pdf