What's the R connection for on a Yanmar / Hitachi alternator?

[VicS]

Pushing this thread up the list again - hoping to get an answer from expert readers.

Jan

Tagging a new question to an old thread is not always the best way of generating new interest. People click on the title read a few posts realise its an old thread and move away to something new.

Some forums even forbid resurrecting old posts, except in certain circumstances, to the extent that if they are actively moderated the thread will be locked!


OTOH of course if you ask something that's previously been answered someone will soon tell you! >>> You cant win !

 

[misterg]

- I removed the diode splitter and have the alternator (B en E connections) charge the 180 Ah AGM house bank directly
- I have a Balmar Duo charge unit that funnels a charge to the (flooded wet-cell) cranking battery which remains in operation after 7+ years of service
- but the alternator is wired to the cranking battery via the standard wiring harness which means that R is sensing cranking battery voltage and not house bank voltage.

I'm having trouble visualising your set-up, but I think I can see that there could be a problem - I assume from the description that you have taken a connection directly from the alternator to the house bank, but are still feeding the ignition switch and indicator lamp (and by default the R terminal) from the cranking battery?

I don't see why you would need a relay - just move the ignition switch/warning lamp feed to the house bank? It's not very elegant though.

Might be worth contacting Balmar.

 

[Goudurix]

Hi Misterg,

My setup is one of the solutions proposed in Nigel Calder's (excellent) book, to get rid of the diode splitter and enable both dock charger and alternator to charge 2 battery banks of different technology and use:
- house bank, AGM 2x180Ah, servicing all equipment, electronics, fridge etc
- one 105 Ah cranking battery, wet flooded

How: both the Mastervolt dock charger and the alternator directly charge the house bank. The Balmar "Digital Duo Charge" (between house bank and cranking battery) funnels current to the cranking battery whenever the house bank voltage is over 13.0V (when it is charging). The Balmar Duo Charge is a smart device, can be programmed for battery type and voltages.
This works - the cranking battery is 7+ years and still happy

My doubts where about the alternator charging, and also the fact that my AGM died quite prematurely.
The alternator is (except for the B = charging current and E (negative ground) wired to the cranking battery, via the contact switch and engine panel. The contact switch is switching cranking battery + to a lot of functions, like oil warning lamp, cooling warning lamp, charge warning lamp, cranking relay,....and also to the alternator's internal regulator (sensing wire R and lamp charge signal L - see the electrical diagram in one of the above posts and higher up). So it is not simply a matter of running house bank + through the contact switch.

To enable to separate completely the sensing circuit R and charge lamp circuit L from the cranking battery, I decided to use the contact switch (cranking battery) to switch a simple relay (done last night...). The relay connects House bank + to the sensing circuit R and the charge lamp, only when I switch on the engine.

The alternator senses house bank voltage to regulate the charge of the house bank.

The Balmar Duo Charge takes care of toppng up the cranking battery.



I do not think that it was/is a problem to charge the separated house bank via the alternator, but to energize the alternator field winding via the cranking battery and sense wire R, but this means that the systems senses cranking battery voltage to regulate its charge and not the house bank voltage it is actually charging.

I cannot simply hook sense wire R to the house battery + because in that case, I would have house bank + and cranking battery + connected via the 50 Ohm resistor that is inside the darlington regulator. (that is the charge lamp circuit). Draining either of them into the other depending on voltage differential between the 2 banks. The drain itself would be a weak current, but I am more worrying about killing the regulator.

It works. A nice exercise but I also just replaced the dead AGM's by 2 100 Ah gel batteries and now I have to decide if I keep the stock alternator with its "dumb" regulator to charge the gel's....risk of either under- or overcharging.

Jan

 

[Haraka]

You’re probably all dead, or at least have sold your boats by now. But here goes . . .
The resistance R is not a sensor circuit - there isn’t one, it’s a pasdive Zener diode regulator. When potential is 14.4v each side of R, once up and running, there is no current flowing through R.

If the ignition lamp is 3watts (I read some where) it’s resistance is 48ohms. I read somewhere else R was measured as 43 (call it 48ohms too). So the combined resistance of these two in parallel is 24 ohms.

The coil (from yet a third source) is about 4ohms. So the voltage drop is 12 X 24/(24+4)=10.3v across lamp/R and only 1.7v across the coil. So barely enough to excite anything. Without R in parallel the voltage drop across lamp would be 11.1v, leaving a v meagre 0.9v for the coil to get excited about. So I think R’s sole purpose is to reduce the initial exciter circuit resistance to leave adequate volts to excite the coil.

Does anyone have a list of component values - R1, R2, R3, R4, Rn, ZD, Tr1(Darlington Pair), Tr2. I’m frustrated in nailing the circuit analysis.