ARMYCHIEF

ARMYCHIEF

I have a 2004 Fiesta Vee 250. The alternator isn't charging the batteries. The alternator output is OK, but voltage at the batteries doesn't increase. The batteries charge from the on board AC charger. Is there an in-line fuse somewhere? Any other suggestions?

212rowboat

where are you getting your reading from for the alternator?  

are you MPI or carb'd? 

LaRea

The battery isolator is basically a traffic cop that controls who charges the batteries.  I've never heard of one failing, but you could start there and look for damage or loose connections.  Anybody know where they hide the battery isolator on a 250?

ARMYCHIEF

This is a MPI engine. I read 14.5 volts on the alternator POS & NEG posts. Traced the ALT POS wire to a (CYC) block? (don't know what this is) 14.5 volt in 13.7 volt out. Wire goes from there to battery switch. The battery voltages will not rise above 12.6 volts even at 1500 RPM.

NavyCTRC

bypass the switch and see what you get...or just replace it.  My bet is the switch is bad.

alger34

I have an 07 fv 250. Had the same issue and in my case it was the isolator. Cheap and easy fix. I believe the isolator was fried when someone turned the battery switch with the motor running. Check for continuity across isolator to double check.

212rowboat

the CYC is your PCM and which is required on a MPI engine, and the reason I asked that question.  The alternator has a regulator built in, but the PCM is what decides the batteries need- they won't get a full shot (14.5vdc) unless they're really low.. the 13.7vdc is a voltage intended to maintain charge (12.6vdc will actually allow it to drain- 13.7 is the maintenance/resting charge)... 

the good news is your batteries are healthy at 12.6....

yup.... isolator.... 

ARMYCHIEF

Thanks, and I'll repeat your question. Does anyone know where the battery isolator is on a 250 Rinker?

Handymans342

Near the battery charger?

ARMYCHIEF

Thanks,
I'll look there.

alger34

It is on the bulkhead in the engine compartment between the aft cabin and engine. 

ARMYCHIEF

Thanks, I'll test it this weekend