Hi again all,
Yes I'll post photos later this morning when I have my phone, just wanted to get my topic up & please note I am not on the boat today to immediately test any suggestions but back on board it tomorrow . I've just replaced my 43 year old Hitachi LR135-126 with this www.ebay.com.au/itm/112970369735?mkcid=16&mkevt=1&mkrid=705-154756-20017-0&ssspo=22on4tUnRUK&sssrc=4429486&ssuid=Rl3XIThiT--&var=&widget_ver=artemis&media=Copy. Yes, I know. Cheap Chinese generic alternator, I plan to upgrade this in the near future.
Also important is the fact that I have done away with the factory harness & B type panel. All wiring has been replaced with uprated wiring and the panel I have also custom wired. Oil pressure + water temp replaced with VDO. If more info is needed please don't hesitate to ask. I know the issue with LED vs filament, however I can still excite the alternator manually through an LED warning lamp circuit. More on that later.
On the back of that alternator, there is the B post (obvious one), there is also the T type Hitachi connector. The seller provided me with a diagram for the wiring in the T connector: S and L terminals. The L is wired to the charge lamp (which is LED) and works as it should: ON when alternator is NOT charging, OFF when alternator IS charging.
The S (sense I'm sure) is wired to the starter battery +ve. If this wire isn't connected to the +ve post the alternator output (once excited) is too high, 16v & up.
There is also an unmarked spade terminal on the back of the alternator. Here's the issue & I am hoping someone who is slightly more electrically inclined will be able to shed some light on why this is happening...... The alternator will not excite without the wire from the spade terminal being connected to the - ve side of a lamp (led) circuit! THEN, once the alternator is excited, that wire then changes to an AC output and will work with the tachometer,. Surely that wire should be just one or the other and not both?
I did wire it up to my 'voltage low' warning LED circuit (this lamp & circuit are spare, unused for testing at the moment) with a 5 pin relay so that once the alternator has been excited the relay will open the circuit however the relay switches too fast. The alternator needs a few seconds on the lamp circuit to energise but the lamp goes out within 0.5 seconds or less. Worth a shot. The other option I'm considering is an SSR with programmable delay etc but realistically I shouldn't need to, the spade terminal W or P) should just one output?
I have a Lifepo4 starter battery too. The set up is: alternator>Victron Argofet> Victron Orion-Tr Smart Isolated DC-DC charger>starter battery. I'm using the option Energizer terminal on the Argofet too but debating if this is causing issues? Otherwise, when the alternator is excited, all components & charges are working perfectly. Gauge panel works perfectly. Motor starts perfectly first go, cold or hot. (new starter installed by me) . 1AWG wire (new) from battery +ve to starter. 1AWG - ve to starter motor mounting bolt, circuit run for starter is 2 metres at most. New alternator belt, correctly tensioned.
Thanks in advance and hoping to fix this issue! I'm now at day 2 on this.
EDIT: Just realised I need to put up a alternator/starter circuit diagram which I will do shortly.
Mark.
I see you understand that a led light doesn't draw enough power to excite the field. Could you replace it with a filament just to prove its not the problem
Select to expand quotewoko said..
I see you understand that a led light doesn't draw enough power to excite the field. Could you replace it with a filament just to prove its not the problem
Hi Woko,
It's definitely on my list to test out even with the fact that the alternator does excite with just the LED warning lamp (which I never expected tbh).
I have also realised that I can do away with the Argofet energiser connection (I've just looked over the installation diagram again) due to my alternator not having a D+terminal.
I came to this thread thinking someone was excited about getting a new alternator... Like when you have a big night on ebay and you can't wait to get home from work to see if your new engine parts have come. 
Looks shiny but! Might order one myself now......
Select to expand quoteJonE said..
I came to this thread thinking someone was excited about getting a new alternator... Like when you have a big night on ebay and you can't wait to get home from work to see if your new engine parts have come.
Looks shiny but! Might order one myself now......
Haha 
now that you mention it the title could be mistaken for that! My click bait worked perfectly...
When alternator arrived: me excited
Now.?: Yells at alternator "just get bloody excited argh!" 
Looks good to see shiny new bits on the engine, the only downside is that they stand out against a mixture of factory silver paint, rust & various owners with silver spray paint! She's a tough little nugget tho!
Select to expand quoteMarionette said... Here's the issue & I am hoping someone who is slightly more electrically inclined will be able to shed some light on why this is happening......
The coils in the alternator have no electricity in them until the alternator generates electricity. The exciter is a small input from the battery for a few seconds until that small current induces a magnetic field which then generates electricity and feeds back a small part of that into the coil.
Freely available online are the "12 Volt doctor's practical handbook" and "The 12 Volt doctor's practical alternator handbook" both by Edgar J Beyn. Page 40-41 of that second book talks extensively about excitation in the field coils and the required/recommended resistance (he's saying between 50 and 150 Ohm).
Select to expand quoteFabulousPhill said..Marionette said... Here's the issue & I am hoping someone who is slightly more electrically inclined will be able to shed some light on why this is happening......
The coils in the alternator have no electricity in them until the alternator generates electricity. The exciter is a small input from the battery for a few seconds until that small current induces a magnetic field which then generates electricity and feeds back a small part of that into the coil.
Freely available online are the "12 Volt doctor's practical handbook" and "The 12 Volt doctor's practical alternator handbook" both by Edgar J Beyn. Page 40-41 of that second book talks extensively about excitation in the field coils and the required/recommended resistance (he's saying between 50 and 150 Ohm).
Hi Phil,
I'm OK with how the alternator excites & why it needs it I'm just not 100% sure why just one wire would be serving 2 purposes. I also think the internal regulator is busted as the output voltage is around 15-15.5V!
Re that book I people mention it alot however I've been unable to find a link to download it from that actually works. I have the latest edition of Nigel Calder's boat Bible but would like to add the 12V Doctor my collection as well.
Anyway today I'll be speaking with the electrical guru at Auto 8 so I'm hopeful that solves my issues. I'll post my results here just in case anyone else buys an Auto 8 alternator and has similar issues.
The cheap Chinese alternators are excellent quality. After you have wired it up to what the instructions indicate and you are sitting at the mooring with a battery selected, put your hand on the alternator to see if it's warm. Unless your engine is wired with a start switch and a starter button you may have power to the alternator when ever you have a battery selected. I have a switch in the "fields" wire to disconnect mine.
Select to expand quoteRamona said..
The cheap Chinese alternators are excellent quality. After you have wired it up to what the instructions indicate and you are sitting at the mooring with a battery selected, put your hand on the alternator to see if it's warm. Unless your engine is wired with a start switch and a starter button you may have power to the alternator when ever you have a battery selected. I have a switch in the "fields" wire to disconnect mine.
I have wired up alternators utilising an oil pressure switch (N/O) to connect the exciter coils. No need for manual switches in some cases.
Oil pressure comes up alternator connects,, Engine stops, oil pressure falls, alternator disconnects.
Alot of older plant equipment, tractors etc can be found wired like this. Must be pressure fed lube oil though.
Select to expand quoteRamona said..
The cheap Chinese alternators are excellent quality. After you have wired it up to what the instructions indicate and you are sitting at the mooring with a battery selected, put your hand on the alternator to see if it's warm. Unless your engine is wired with a start switch and a starter button you may have power to the alternator when ever you have a battery selected. I have a switch in the "fields" wire to disconnect mine.
I'm guessing you're being sarcastic about the Chinese alternators? All good lol, I'd have to take the view that it's a 'yes & no' type thing. It can be a lottery IMHO.
I am keeping the original Hitachi alternator & starter on board as spares, mainly that's what the changes were for. They were both still going very strong!
Cheers for the tip re alternator/battery power always on! I'll definitely do that. I previously did have a battery switch that I need to wire back in. That's next week, I hate working with 1AWG ha! For now however I just disconnect the battery terminals when I'm off the boat. No starter button (yet) just a 4 position ignition switch (Acc/Off/Ignition/Start)
Select to expand quotewoko said..
I see you understand that a led light doesn't draw enough power to excite the field. Could you replace it with a filament just to prove its not the problem
Woko, it worked (as expected).
Face-palm 
moment.
I decided to test if the L terminal in the T type connector would excite the alternator if I used a filament lamp. This was previously connected to the charge LED warning lamp & functioning. Without one on board I luckily decided to check the old Hella cabin lights. Had to remove the old housing of one & jury rig the globe but turned the key to acc & it lit up. Started the engine and BAM, alternator excitation.
Tachometer signal wire to P spade connection left in place, tachometer functions better now (with adjustments).
Alternator output 14v roughly, up to 15V, Orion-Tr Smart charging starter at 14.2V.
Thanks again for the help guys!
Select to expand quoteMarionette said..
Re that book I people mention it a lot however I've been unable to find
PM sent. They're in PDF format, 6mb and 10mB, plus 2 other books about trailer sailors/boat repair.
Select to expand quoteJolene said..Ramona said..
The cheap Chinese alternators are excellent quality. After you have wired it up to what the instructions indicate and you are sitting at the mooring with a battery selected, put your hand on the alternator to see if it's warm. Unless your engine is wired with a start switch and a starter button you may have power to the alternator when ever you have a battery selected. I have a switch in the "fields" wire to disconnect mine.
I have wired up alternators utilising an oil pressure switch (N/O) to connect the exciter coils. No need for manual switches in some cases.
Oil pressure comes up alternator connects,, Engine stops, oil pressure falls, alternator disconnects.
Alot of older plant equipment, tractors etc can be found wired like this. Must be pressure fed lube oil though.
That's an excellent idea. Thanks.
Select to expand quoteMarionette said..Ramona said..
The cheap Chinese alternators are excellent quality. After you have wired it up to what the instructions indicate and you are sitting at the mooring with a battery selected, put your hand on the alternator to see if it's warm. Unless your engine is wired with a start switch and a starter button you may have power to the alternator when ever you have a battery selected. I have a switch in the "fields" wire to disconnect mine.
I'm guessing you're being sarcastic about the Chinese alternators? All good lol, I'd have to take the view that it's a 'yes & no' type thing. It can be a lottery IMHO.
I am keeping the original Hitachi alternator & starter on board as spares, mainly that's what the changes were for. They were both still going very strong!
Cheers for the tip re alternator/battery power always on! I'll definitely do that. I previously did have a battery switch that I need to wire back in. That's next week, I hate working with 1AWG ha! For now however I just disconnect the battery terminals when I'm off the boat. No starter button (yet) just a 4 position ignition switch (Acc/Off/Ignition/Start)
I'm serious about the quality. I have a Chinese starter motor and alternator on my Kubota and they are pretty much what you would expect from a country that has the largest electric car manufacturing by an enormous amount.
Select to expand quoteMarionette said..woko said..
I see you understand that a led light doesn't draw enough power to excite the field. Could you replace it with a filament just to prove its not the problem
Woko, it worked (as expected).
Face-palm moment.
I decided to test if the L terminal in the T type connector would excite the alternator if I used a filament lamp. This was previously connected to the charge LED warning lamp & functioning. Without one on board I luckily decided to check the old Hella cabin lights. Had to remove the old housing of one & jury rig the globe but turned the key to acc & it lit up. Started the engine and BAM, alternator excitation.
Tachometer signal wire to P spade connection left in place, tachometer functions better now (with adjustments).
Alternator output 14v roughly, up to 15V, Orion-Tr Smart charging starter at 14.2V.
Thanks again for the help guys!
Gotta love a winner Cheers
Select to expand quoteRamona said..Marionette said..Ramona said..
The cheap Chinese alternators are excellent quality. After you have wired it up to what the instructions indicate and you are sitting at the mooring with a battery selected, put your hand on the alternator to see if it's warm. Unless your engine is wired with a start switch and a starter button you may have power to the alternator when ever you have a battery selected. I have a switch in the "fields" wire to disconnect mine.
I'm guessing you're being sarcastic about the Chinese alternators? All good lol, I'd have to take the view that it's a 'yes & no' type thing. It can be a lottery IMHO.
I am keeping the original Hitachi alternator & starter on board as spares, mainly that's what the changes were for. They were both still going very strong!
Cheers for the tip re alternator/battery power always on! I'll definitely do that. I previously did have a battery switch that I need to wire back in. That's next week, I hate working with 1AWG ha! For now however I just disconnect the battery terminals when I'm off the boat. No starter button (yet) just a 4 position ignition switch (Acc/Off/Ignition/Start)
I'm serious about the quality. I have a Chinese starter motor and alternator on my Kubota and they are pretty much what you would expect from a country that has the largest electric car manufacturing by an enormous amount.
Good to know, I feel a bit better now. I was expecting to be roasted on here as soon as I said Chinese alternator haha,! Don't get me wrong, I do alot of my buying for the boat on Aliexpress but one still needs to be wary.
Select to expand quotewoko said..Marionette said..woko said..
I see you understand that a led light doesn't draw enough power to excite the field. Could you replace it with a filament just to prove its not the problem
Woko, it worked (as expected).
Face-palm moment.
I decided to test if the L terminal in the T type connector would excite the alternator if I used a filament lamp. This was previously connected to the charge LED warning lamp & functioning. Without one on board I luckily decided to check the old Hella cabin lights. Had to remove the old housing of one & jury rig the globe but turned the key to acc & it lit up. Started the engine and BAM, alternator excitation.
Tachometer signal wire to P spade connection left in place, tachometer functions better now (with adjustments).
Alternator output 14v roughly, up to 15V, Orion-Tr Smart charging starter at 14.2V.
Thanks again for the help guys!
Gotta love a winner Cheers
Select to expand quoteFabulousPhill said..Marionette said..
Re that book I people mention it a lot however I've been unable to find
PM sent. They're in PDF format, 6mb and 10mB, plus 2 other books about trailer sailors/boat repair.
Thank you Phil! Very much appreciated, have emailed you now.
