Alternator not charging auxiliary batteries

[SternWake]

A while back an acquaintance diagnosed his friend's vehicle as needing a new starter, as it did not start.

He removed the alternator and took it to the auto parts store to get a new 'starter'.

I'm surprised he admitted it.

It was the ignition switch that was causing the no start, IIRC

 

[ginga]

Hmm, I swapped that wire this morning and drove for two and a half hours and my batteries are just getting lower. The only thing drawing power is a fridge.

 

[SternWake]

Are your house batteries grounded to frame/engine/alternator mounting bolt?

Is your solenoid actually closing with ignition on/ engine running?

house battery Voltage at battery terminals when engine is running should begin in the low 13's and climb upwards, hopefully into 14's.

Check your fuse, when you had it hooked to starter motor, the starter could have drawn enough current from house bank to blow fuse/trip breaker.

 

[ginga]

Are your house batteries grounded to frame/engine/alternator mounting bolt?

Is your solenoid actually closing with ignition on/ engine running?

house battery Voltage at battery terminals  when engine is running should begin in the low 13's and climb upwards, hopefully into 14's.

Check your fuse, when you had it hooked to starter motor, the starter could have drawn enough current from house bank to blow fuse/trip breaker.

On my house battery negative terminal I see a ground that goes to the frame a second ground that goes down and is grounded at the starter.  And one more ground that snakes into conduits to where I can't see but I'm sure that that's a ground from something else. 

 The solenoid is closing and opening because when I turn the car on or to accessory and flip the switch I can hear the solenoid click.

I checked the fuse and it's all good.  

To measure the house battery voltage I will need a minute to wire up that ammeter to it

 

[SternWake]

Please recheck your wording above as to house battery and startng battery.


You should have a digital multimeter, even the free to 7$ one at harbor fright is good enough for diagnostics regarding voltage.

 

[galladanb]

Awesome! So glad you figured it out!

I'll bet your batteries will be charging up now!

I had to step away for a few hours, as I picked up a hitch with hardware for cheap!
Had to go, lol!!!

 

[ginga]

Please recheck your wording above as to house battery and startng battery.


You should have a digital multimeter, even the free to 7$ one at harbor fright is good enough for diagnostics regarding voltage.

It should all be working now.  I don't think my ground for the auxiliaries was good enough.  It's still not great but the meter is reading a sharp increase in voltage when the car is turned on and I flip the switch to bridge the connections.  I'll drive again tomorrow and check with the hydrometer.

 

[SternWake]

 but the meter is reading a sharp increase in voltage when the car is turned on and I flip the switch to bridge the connections. 

I take it your ammeter does not read loads AND charging sources, only loads?
A sharp increase in voltage with the engine on definitily means charging is occurring.  An Ammeter would show how much.
YOur house battery frame ground likely goes from battery to frame to firewall to engine battery ground and then engine battery back to engine block.
The firewall to engine battery ground is often just 12AWG, and All your house battery charging current is being limited by this undersized wiring.
Easiset solution is to add another ground cable from engine( alternator mounting bolt) to nearby frame. 
If all your house battery charging current from alternator is flowing through the 12AWG firewall to engine battery ground, this ground might develop issues soon and perhaps cause some driveability issues or other electrical weirdness.

 

[dr_nelson]

A while back an acquaintance diagnosed his friend's vehicle as needing a new starter, as it did not start.

He removed the alternator and took it to the auto parts store to get a new 'starter'.

I'm surprised he admitted it.

Hilarious, I had to laugh so hard my laptop almost fell down from my lap!

 

[dr_nelson]

Hey ginga, I just wanted to thank you for all your posts about hooking up the alternator to charge the house battery. Your diagram is very helpful, because this is coming soon for me, too, and because I really don't know jack about electrical stuff. I don't even have a multimeter.
Really appreciate it and I hope you get your issue figured out, soon. This forum is just awesome.

 

[ginga]

Hey ginga, I just wanted to thank you for all your posts about hooking up the alternator to charge the house battery. Your diagram is very helpful, because this is coming soon for me, too, and because I really don't know jack about electrical stuff. I don't even have a multimeter.
Really appreciate it and I hope you get your issue figured out, soon. This forum is just awesome.

  Well I'm glad that my diagrams aren't too messy to read.  I'm very happy that you've found them helpful.  I don't really know jack about electrical stuff either so I feel I'm in the same learning boat as you.  Also I very much agree about this forum.  The people here are fantastic and have been very patient and informative with me.  Sternwake has given me loads of good information on all of my electrical work.  He's been amazing and I wonder if you might find some good info from him and others in some of my previous threads.  I bet you could learn a lot just by sifting through his posts.  

I'm probably gonna get another hands in lesson with my car soon as my starter seems to be acting up.  From what I'm reading I linebacker it doesn't seem like it'll be that difficult, but I'll need to make double sure first beforehand.  

Good luck to you in your battery wiring!  And yes my issues seems to have been mostly resolved, thank you!