81 Voltage Output (1 Viewer)

[lahauamike]

Hey all,
Looking for input on proper voltage, occasionally have a low battery the morning after night drives that doesn't have enough to crank. Alternator and voltage regulator seem to be working, battery is new. Any thoughts about the results in the picture? In addition to these, I measured the voltage with the motor turning 1500 rpm and the battery disconnected, got 16.7 V at the B+ lug at the alternator and the battery connection. Is there a battery issue or wiring issue between the alternator and battery? I expected to see 14+ on the battery since I'm getting it from the alternator but that's not the case.

 

[1911]

Check the condition of your cables and their connections, particularly the grounds.

 

[kerplunk]

Check the condition of your cables and their connections, particularly the grounds.

Pretty sure the voltage at all those spots should be the generally the same, all should be pretty directly connected. The reason they might be different is resistance in the cabling and connections (which could be the cabling directly between these points or the connection to the ground). And there should not be enough resistance to cause that difference in voltage.

Usually cleaning the battery terminals fixes this for me. The ground straps are also a common culprit.

 

[ToyotaMatt]

Do you have a oem toyota voltage regulator ?

or

a rock auto brand type ?

I have Run into bad or out of spec China ones more then once

if unsure

post photos of your current set up both regulator and your alternator

someone or me can easy iD what you have going
On here related

Just a possible and maybe likley source of your outlined symptoms in my option and personal shop experience

hope this helps

Matt