Charging issue??

[DatsunKaua'i]

New voltage regulator, new battery, alternator is showing 13.8v off the positive post on alt but battery is only at 12v. Also the charging light is on in cab on dash board but if I rev up engine the charge light will go out but once back down to idle charge lamp comes back on. 

[datzenmike]

 Why was the regulator changed????? Did you keep the old one???

 

 Measure across the battery terminals with it running and not running, what do you get?

 

Loosen one of the battery terminals and BRIEFLY disconnect it from the battery with the engine running. Does the engine keep running?

[DatsunKaua'i]

14 hours ago, datzenmike said:

 Why was the regulator changed????? Did you keep the old one???

 

 Measure across the battery terminals with it running and not running, what do you get?

 

Loosen one of the battery terminals and BRIEFLY disconnect it from the battery with the engine running. Does the engine keep running?

I threw old regulator out it was completely corroded. Battery is 11.8 not running running I get 12.3

[john510]

11.8 volts is a dead battery.

[datzenmike]

11.8 is slightly discharged. I drove my not charging 710 at night with the lights on (very dim) at just under 10 volts, no radio because the transistors needed more than 10 volts to work and turn signals stopped flashing.

 

The alternator is charging slightly if reading 12.3 when running but not near enough to push a charge into the battery. You want about 2 volts more than a fully charged 12volt battery which is about 12.6 at 60F. A usual charging alternator reads over 14 volts.

 

I would guess that when it started not charging you just replaced the regulator? and when that didn't work you replaced the battery?  Gets expensive throwing parts at it. Take the alternator to a store that will spin them up and check the output for you. They are solid state and the only mechanical moving parts to wear out are the brushes. You used to be able to get a brush kit for $5 but no one does their own work on their cars now a days so I think that pretty much stopped being an option. It's possible a diode might burn out but usually the brushes the wear down too short to make good contact..

[DatsunKaua'i]

1 hour ago, datzenmike said:

11.8 is slightly discharged. I drove my not charging 710 at night with the lights on (very dim) at just under 10 volts, no radio because the transistors needed more than 10 volts to work and turn signals stopped flashing.

 

The alternator is charging slightly if reading 12.3 when running but not near enough to push a charge into the battery. You want about 2 volts more than a fully charged 12volt battery which is about 12.6 at 60F. A usual charging alternator reads over 14 volts.

 

I would guess that when it started not charging you just replaced the regulator? and when that didn't work you replaced the battery?  Gets expensive throwing parts at it. Take the alternator to a store that will spin them up and check the output for you. They are solid state and the only mechanical moving parts to wear out are the brushes. You used to be able to get a brush kit for $5 but no one does their own work on their cars now a days so I think that pretty much stopped being an option. It's possible a diode might burn out but usually the brushes the wear down too short to make good contact..

 

 

Ok will get the alt tested. Yea sucks keeping in throwing money at this thing

[datzenmike]

Try to avoid throwing parts away. Sometimes the old part is still good and you can keep it as a spare. I've pulled brushes from an old alternator to keep another going.

[bottomwatcher]

12.2v is a discharged battery. 12.4v is 50% 12.6v is a full battery at rest. Charging voltage automotive is 13.8v 

Charging voltage truck or marine is 14.1 or 14.4. Standard lead acid battery.

[banzai510(hainz)]

if alternator is putting out 13.8 volts I says its good.  14 would be better with everything off but I say its OK right now. as some regulators might regulate lower some  higher other days.

 

I notice the USA made Mechanical volt regs are the worst. Napa used to sell them and others under the Echlin brand.

 

CLEAN the connections at the battery terminal. In Hawaii lots of corrosion  do + side and minus side battery. Better yet get new cables every 6 years of so.  The 1pc molded ones are best. Not the 3 pc kind

 

I use a Innova plug in battery /alternatot monitor that plugs in the cig lighter(if it works)  this moneitors that battery better than the idiot light as those as not as reliable sometimes. Unless total failure. with this you can tell if not charging and head home while still on full charge on battery

http://innova.com/en-US/Product/Detail/3721

 

Go home and eat Opihi Brahda!

Edited September 26, 2019 by banzai510(hainz)

[Eric]

2 hours ago, datzenmike said:

Try to avoid throwing parts away. Sometimes the old part is still good and you can keep it as a spare. I've pulled brushes from an old alternator to keep another going.

 

I always try to keep old parts as well but not everybody has the luxury of space and workshop.

and how long do you suppose to keep them? I have 4 Datsun, i just cannot keep all the old parts anymore. I know, it's a luxury problem..

[thisismatt]

When you get the alt tested, make sure you ask them what voltage it's putting out.  If their dumb test can't tell you, take it somewhere else.  The numbnuts at Vatozone will tell you "it's good" but it might only be putting out 12-13v and that is not enough voltage to charge & maintain your battery.

[DatsunKaua'i]

On 9/25/2019 at 7:04 PM, thisismatt said:

When you get the alt tested, make sure you ask them what voltage it's putting out.  If their dumb test can't tell you, take it somewhere else.  The numbnuts at Vatozone will tell you "it's good" but it might only be putting out 12-13v and that is not enough voltage to charge & maintain your battery.

Ok will do thx so much

[DatsunKaua'i]

On 9/25/2019 at 5:27 PM, banzai510(hainz) said:

if alternator is putting out 13.8 volts I says its good.  14 would be better with everything off but I say its OK right now. as some regulators might regulate lower some  higher other days.

 

I notice the USA made Mechanical volt regs are the worst. Napa used to sell them and others under the Echlin brand.

 

CLEAN the connections at the battery terminal. In Hawaii lots of corrosion  do + side and minus side battery. Better yet get new cables every 6 years of so.  The 1pc molded ones are best. Not the 3 pc kind

 

I use a Innova plug in battery /alternatot monitor that plugs in the cig lighter(if it works)  this moneitors that battery better than the idiot light as those as not as reliable sometimes. Unless total failure. with this you can tell if not charging and head home while still on full charge on battery

http://innova.com/en-US/Product/Detail/3721

 

Go home and eat Opihi Brahda!

 

 

Hahahahhaha mahalo nui Palala. I'll do this

[banzai510(hainz)]

update us if fixed.

13.8 is charging 

[DatsunKaua'i]

K so I put in new alt old one was bad put it on and sparked like hell when I connected wires to the back of alt. Black one I could attach white/red would spark

[datzenmike]

Black goes to a ground lug on the alternator case. The White/Red stripe goes to the insulated terminal.