Hitachi to Prestolight Alternator upgrade + Adverc

[xeitosaphil]

Anybody done this upgrade?
Having been onto Adverc Technical, they seem to be struggling a bit to come up with an answer to my question

They say they haven’t come across this scenario before – (seems a little strange to me)

The question if someone has- the tee plug in the original Hitachi/Mitsibushi alternator has two wires that come out of it .One is R/B - Red/Black- which is the coolant warning light power feed to the lamp from the Original alternator, and one L/B - Blue /Black which is the ignition warning light power feed to the lamp.

Question is, the L/B - Blue /Black which is the ignition warning light power feed to the lamp is no problem – it fits to the D+ terminal on the Prestolight alternator - a must for the alternator to work. The problem is where to fit the existing R/B - Red/Black- which is the coolant warning light power feed to the lamp which is left over from the Tee plug?
I did wonder, and also suggested to them I might just connect it to the D+ terminal as with the other L/B cable as long as it didn’t have any detrimental effects which could invalidate my warrantee. Having asked for confirmation in writing just to be safe, they couldn’t decide if it was a good idea or not as the voltage produced by the D+ terminal could output 14v+ and they seemed to be unsure as to the effect on wiring, diodes and lamps in the circuits.
It would appear from the wiring Diagram for the Yanmar 2GM20 late model Small Instrument panel – no tacho, that the wire in question is a 12v ignition supplied power feed, but the problem I have is I have no available space on the terminal stud for another ring connector supply. I already have all the original rings and additional Tiny Tach, Engine Hours gauge, and an increased wire size ring terminal for the upgraded Starter Solenoid circuit feed.
I am reluctant to use a scotch type splice connector for such an important power feed on one of the existing cables and wondered if the forum have any experience of this upgrade and could suggest where to take the feed from?

As always grateful for any replies - Philip

 

[xeitosaphil]

Why is it when uploading attached thumbnails they are not big enough to see? is it because I use the basic up loader facility?

 

[VicS]

No problem with size ( your pics that is) Right click, open in new tab, go to new tab and click on image ... plenty big enough!

Cooking lunch so will look later

 

[pvb]

I did wonder, and also suggested to them I might just connect it to the D+ terminal as with the other L/B cable as long as it didn’t have any detrimental effects which could invalidate my warrantee. Having asked for confirmation in writing just to be safe, they couldn’t decide if it was a good idea or not as the voltage produced by the D+ terminal could output 14v+ and they seemed to be unsure as to the effect on wiring, diodes and lamps in the circuits.

Yes, you could put it on the D+ terminal. It won't harm anything. Battery voltage will be 14+ anyway during charging, so voltage isn't an issue. However, I'm not sure why it should be designed to be supplied from the alternator though.

 

[VicS]

At first quick look

I dont know why the R/B to the coolant warning light comes from the alternator.

I think it can be connected to the positive (R/B) supply to the other warning lights from the keyswitch instead

Need to dig out some more wiring diagrams ... which will do later if no other suggestions/help forthcoming.

It will alwys be live if taken from the D+ terminal. If taken from the other R/B wiring it will be controlled by the key switch


That's one of the diags from the Yanmar manual isn't it?

 

[VicS]

Actually thinking that the diagram might be slightly wrong ........ I think it ought to show a connection with the other R/B wire... where it shows it as just crossing.


The connection to the alternator is not a supply from it but an excitation supply to it which is required in addition to the ignition warning light connection for the Hitachi alternator.
Thats the connection to the R terminal in this diagram of an Hitachi alternator

I suggest to investigate the posibility that there is a supply on the R/B wire when the key switch is ON

If so insulate the wire, check that the waning light works if you short the sensor (W/L) wire to earth when the key is on.


Got to go ... shopping to do!

 

[xeitosaphil]

At first quick look

I dont know why the R/B to the coolant warning light comes from the alternator.

I think it can be connected to the positive (R/B) supply to the other warning lights from the keyswitch instead

Need to dig out some more wiring diagrams ... which will do later if no other suggestions/help forthcoming.

It will alwys be live if taken from the D+ terminal. If taken from the other R/B wiring it will be controlled by the key switch


That's one of the diags from the Yanmar manual isn't it?

Yes Vic you are absolutely right – wiring diagram is from the online German Yanmar Workshop Engine Manual Site http://www.motoren.ath.cx/

It is common practice on the Yanmar 2GM 20 wiring loom as per wiring from Tee plug on alternator - not sure what the alternatives are on other engines.

Yes, you could put it on the D+ terminal. It won't harm anything. Battery voltage will be 14+ anyway during charging, so voltage isn't an issue. However, I'm not sure why it should be designed to be supplied from the alternator though.

Is it anything to do with the fact the power feeds to the engine charge and oil pressure senders are closed when ignition is first turned on and linked to the buzzer, but the coolant warning light is only linked to the buzzer and closed when the temperature rises and closes the sender switch? Or am I talking nonsense?

 

[VicS]

Is it anything to do with the fact the power feeds to the engine charge and oil pressure senders are closed when ignition is first turned on and linked to the buzzer, but the coolant warning light is only linked to the buzzer and closed when the temperature rises and closes the sender switch? Or am I talking nonsense?

I think its an error in the diagram!


If I am right and you connect to the D+ as pvb suggests you will I think find the other warning lights will be on and the buzzer sounding even when the key switch is off because there will be a constant feed to the circuits from the battery via D+.

Try it!

 

[xeitosaphil]

Actually thinking that the diagram might be slightly wrong ........ I think it ought to show a connection with the other R/B wire... where it shows it as just crossing.


The connection to the alternator is not a supply from it but an excitation supply to it which is required in addition to the ignition warning light connection for the Hitachi alternator.
Thats the connection to the R terminal in this diagram of an Hitachi alternator

I suggest to investigate the posibility that there is a supply on the R/B wire when the key switch is ON

If so insulate the wire, check that the waning light works if you short the sensor (W/L) wire to earth when the key is on.


Got to go ... shopping to do!

Thanks Vic , will try your first option first, re checking to see if there is a 12v supply to the R/B at the back of alternator Tee plug and shorting sender wire to earth.

I think its an error in the diagram!


If I am right and you connect to the D+ as pvb suggests you will I think find all the warning lights will be on and the buzzer sounding even when the key switc is off because there will be a constant feed to the circuits from the battery via D+.

Try it!

Will try this option 2nd just to make sure, will be at the boat tommorrow so will let you know how I get on - Thank you both for your input and the options.

 

[pvb]

I think its an error in the diagram!

Great!