We’ve hinted at bits and pieces of this along the way, but I wanted to
write up a more formal review of the changes we made this week while we
had the engine out to replace the fuel tank.
Our original battery system was 2 banks of 4 and 2 6Volt batteries that
were combined to make two banks of 220Amp Hours and 440 Amp Hours each.
This was proving to be a bit limiting. I also suspect our batteries are
waning and we’ll replace likely replace them further down the road.
However, for now what we’ve done is create on large house bank combining
all of these batteries into one 660 Amp Hour bank and we added a second
12V dedicated starting battery.
The new positive post of the new battery is wired directly to the
starter and the negative joins the common negative bus in the house bank
battery trays (i.e., they are wired together).
We already had a Blue Sea Automatic Charge Relay
which combines both banks whenever it sees an adequate input charging current
on either bank. For us this means that when the alternator is charging the
starting battery it will combine and also charge the House, or when the solar
and\or AC Shore Power Charger is charging it the House it will also top-up the
starting battery. This second possibility is called a dual sensing ACR
and is somewhat less known about, read the Blue Sea Page on ACRs for more on that.
The battery changes should give us adequate power to not have to run
engine for charging as frequently. However our alternator was only
65Amps and it had an internal single-stage regulator.
We upgraded our alternator to a 100amp Leece-Neville 8MR2401UA which was
a physical drop-in replacement (same size, bolt pattern etc.) as our
smaller 65Amp Leece-Neville. This was the maximum size we can run our
engine with a single 1/2” belt.
We also replaced the internal regulator on the new alternator with a
three-stage or smart regulator.This regulator senses the voltage of the
battery, temperature of the battery and the alternator and adjust the
output of the alternator to provide the best charging current given the
state of the batteries and the environment conditions.
The process seemed like it was going to be:
- remove the old alternator form the engine
- remove the internal regulator from the new alternator and install
the conversion kit to allow the alternator to be controlled by the
external regulator. There are excellent step-by-step instructions on
- Bolt the new regulator onto the engine
- Wire the external regulator to the alternator, Ignition (or a pump
driven solenoid which turns the regulator on and off) and its
sensors to the battery bank (temperature and voltage) and alternator
- Mount the external regulator
Seems pretty straight-forward and in fact all of that took a few hours.
This is where easy goes crazy…. I was doing this over the weekend and
all of the pre-tests Balmar says you should run using your voltmeter
were not working properly. I spent at least a day tracing wires all over
the engine compartment, under the cockpit floor and the lazarette to
ensure I was wiring the thing correctly. But despite seeming to be wired
correctly, in the end it wasn’t working right and the problem had to do
with how much the new alternator and the old alternator differed from
each other. The old alternator was case-grounded which means it was
grounded through the way it was bolted to the engine. The new alternator
was externally grounded which means you need to run a wire from the
negative (-) post on the alternator back to the negative (-) on the
batteries (our your common ground).
It took about an hour on the phone with Rich from Balmar and his patient
troubleshooting guidance (and an emailed picture of my wiring) for him
to come to the conclusion about my ground problem with the alternator.
We borrowed a jumper cable from the always helpful Kyle Cox at Tarheel
Aluminum Fabrication (he made our tank) and we tested our theory… BINGO!
Everything was working yaay!!! Phone support, let me restate that.
Knowledgeable, technical, skilled phone support is awesome thank you
Now our alternator and regulator are working properly!