73 1150 merc charging ?

[fordmugg]

My motor never charged the battery so my friends shop re did my stator and I just put a new rectifier in. So the batt reads 12.66 v with motor off, when I start it, it goes to 12.90 and if I rev it goes to 12.94... Is that about right for the charging system?

 

[fordmugg]

Re: 73 1150 merc charging ?

Bump

 

[Texasmark]

Re: 73 1150 merc charging ?

No! Normal charged voltage for me is 12.75v at rest, cool battery, not on a charger for at least 12 hrs to ensure that solution is at equilibrium. If you are going to push current into your battery to recharge it, you need a difference of potential and the more the higher the charging current. Most alternator circuits are voltage limited to 14.5v or thereabouts. The current delivered at this voltage depends upon the actual charge the battery has when charging commences and the amperage limit of the charger/regulator.

In short, you aren't doing a thing with the numbers you mentioned. At idle, a Merc alternator on an engine of that size will put out 13.5v roughly and by 1000 rpm's will be to 90% of full voltage. Giving the battery time to recharge, at that rpm the voltage will come on up.

So whatever you went in to have fixed, if it was being able to charge your battery, go get your money back or have them fix the problem.

My 2c,

Mark

 

[Chris1956]

Re: 73 1150 merc charging ?

Mark, That stator is only a few amps and is unregulated. You are expecting too much.

Fordmugg, If the voltage on the battery rises and their is no AC voltage at the battery, the charging system is working properly.

 

[fordmugg]

Re: 73 1150 merc charging ?

My friends shop that did the stator counted and copied the wire wraps even wire thickness to rewind it.. And it was done for free for me.. I also got a new rectifier but I can't get continuity from it doing the test .. Could a new rectifier be bad?

 

[Georgesalmon]

Re: 73 1150 merc charging ?

Could be bad rect. Those old mercs had unregulated output. Mine put out to much voltage (like 16). So I put in a rect/regulator to keep it down to 14vdc.

 

[Chris1956]

Re: 73 1150 merc charging ?

Ford, Did you check the rectifier with an analog meter? If so, each adjacent pair of terminals will have zero ohms with the meter leads on one way, and if you reverse the leads, the meter will show an open circuit. Digital meters may have a diode test setting.

 

[Texasmark]

Re: 73 1150 merc charging ?

Mark, That stator is only a few amps and is unregulated. You are expecting too much.

Fordmugg, If the voltage on the battery rises and their is no AC voltage at the battery, the charging system is working properly.

Look man, I know not the capacity of that charging circuit. What I am saying is the physics of the system that applies to all charging circuits, regardless of the vehicle. I have trickle chargers that follow the battery charge by a few volts. That is the way they are designed...low wattage, hence low charging current. This guy did not give us all the particulars. He gave us a couple of voltages and that's it. Nothing about battery condition, pre charge voltage or any of that. I'll just bow out of this,

Mark