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Charging System
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As I write this account, I do not have any suitable pictures to show - these will be taken and posted as soon as I get a chance.

My Morgan came with a 45 amp alternator and a 50 amp charger - and a dead house battery.  I wanted more power from my house batteries and a quicker way to charge them.   After looking around at all the systems that were available and reading a book entitled "Living on 12 Volts with Ample Power", I decided to use Ample Power products for my new charging system.  This decision was not for the faint of heart - it is a complicated and intricate system - but it works well and I have no complaints.  Well almost no complaints.  Ample Power does not sell their products to the public - you have to go through a distributor.  I found a distributor that I used - but cannot give him high marks.  I have "heard" that Jack Rabbit Marine knows his stuff, but have no first hand experience.

I have a wiring diagram of my charging system in a PDF file that may make it easier to follow my description.

I have seen it noted in a number of places that the typical "Off -1 -Both -2" battery switch on a sailboat (or power boat) is not a good thing.  This relies on you to remember to switch to a single battery when anchored so you can save the other battery for starting.  A better way is to have two banks of batteries - one for house use & one for just starting the engine.  This allows you to use all the power you want on lights, refrigeration, etc. without worrying if the engine will be able to start in the morning.  There can be a switch that will allow you to tie the house batteries to the engine battery should it go dead.  Another current thought is to keep as few connections to the batteries as possible.  To this end, a positive distribution point (PD on the schematic), and a negative distribution point (ND on the schematic) are used.  These are heavy bars of copper with numerous screw terminals available.  The screws will vary from a #8 to a 3/8".

First I want to define the Ample parts used before tying them all together.

High Output Alternator - The original Perkins 45 Amp alternator was replaced with a 125 Amp alternator.  These alternators do not include a voltage regulator and require that you purchase a separate regulator for it.  It works like a charm - my single complaint is that it is setup for a single belt - it needs two.  This unit is capable of eating through single belts faster than you want to imagine - so converting it to two belts is on the agenda!

Smart Alternator Regulator - as the name implies, this regulates the voltage coming form the alternator.  But as integrated part of the Ample Power system, it can be controlled from their Energy Monitor.  The SAR can be set to limit the current from the charging source.  The SAR follows the 3 stage charging cycle.

Power Supply - this is one half of the AC powered battery charger.  The power supply is capable of producing 15 to 55 amps depending on the model.  Several power supplies can be linked together to produce 12 volts at up to 255 Amps.

Smart Charge Manager - the SCM is the other half of the AC powered battery charger.  It controls the output of the power supply(s) according to the type batteries you have and the present charge of the batteries.  It also ties into the Energy Monitor.  The SCM follows the 3 stage charging cycle.

Isolator Eliminator - As mentioned above - the house batteries and the engine batteries should be separate.  So how do they all get charged?  One method is to place a diode between the house battery and the engine battery.  This works, but the voltage drop across the diode means the engine battery will never be fully charged.  The isolator eliminator replaces the diode without the unwanted voltage drop.  It senses the house batteries being charged and checks to see if the engine battery needs charging.  If so then it opens a circuit to charge the engine battery.

EMON - This is an energy monitor that can tell you the instantaneous state of your batteries, plus a history of your batteries with optional software.  It has an LCD display that can either scroll through a number of items, or just continually show one particular reading.  Typical items displayed are voltage on battery bank one, battery bank two, current amps being used or charged into battery bank one, AHrs used, AHrs remaining, time left at current battery consumption (bank one), and auxiliary charging amps (i.e. wind generator).  The optional software is installed on a PC and a serial port is used to read data from the EMON and track it's history. 

Genie 150 Generator - this is a 4hp diesel motor with a 150 amp 12 volt alternator that can be used as a 12 volt power source or as a charging source for the batteries.  Fuel consumption is about 1 pint per hour.  This unit has been great and terrible.  When it works it is great - but unfortunately it has not worked far more than it has.  My dealer has been of no use in trying to solve my problem.  I think I may have a fuel problem.  What happens is that the unit starts fine.  As with the engine alternator, the Genie also uses a Smart Alternator Regulator to control the voltage from the alternator.  The SAR has a 15 second delay between it seeing the alternator turning and when it actually starts the alternator producing current.  As soon as the alternator starts producing current the Genie bogs down and quits running.  I hope to trouble shoot this problem to an answer this fall when daytime temperatures will allow me to stay in the engine room for an extended period of time.  When it does run, inside the boat it sounds like a muffled lawn mower.  In the cockpit you can barely hear it.  I purchased the optional instrument panel that includes gauges for water temperature, oil pressure, and an hour meter. The control switch is incorporated into the panel.   I mounted the panel over the navigation station.

As of the summer of 2007 I finally got the Genie 150 running properly.  It turns out to have been a number of items - the return fuel line was crimped, the current limiting was not installed, and finally it turned out that the electron solenoid on the throttle was not engaging the engine to full power.  Since fixing these items I have had pleasant trouble free operation.

Overall Operation

The two 200 AHr 4D AGM batteries are wired in parallel.  The positive side of the batteries goes to the positive distribution point (PD).  A 400A fuse followed  by a shunt is between the negative side of the batteries and the negative distribution point (ND).  The only other direct connections to the house batteries are 4 thermistors (one each for the SAR, one for the SCM and one for the EMON), a direct sense wire for the EMON, and a pair of terminal blocks for SCM and SAR direct sense connections plus a few other miscellaneous items.  What might strike the casual observer as strange is that there is not "cut off switch" to these batteries.  Tied to the ND are all the grounds for the electrical systems - including the engine (not shown).  All items attached to the PD are fused.  Fuse size is based on the wire size and the wire size is base on the maximum current draw expected.  A hard lesson for me to learn is that fuses are not there to protect the equipment - rather fuses are there to protect the wire. 

Under shore power, the SCM runs the power supply to charge both banks of batteries and to provide 12 volts to the boat.  Other charging sources may be present (wind generator) but over charging is not permitted.  

There are a lot on interconnections between the two SAR's, the SCM and the EMON.  This allows the EMON to continually monitor the state of the batteries and to control the charging of them.  The SAR's and SCM have local LED's to indicate current state, but also provide connections for remote LED's for a more convenient positioning.  

The wind generator has a DPDT switch that allows the unit to provide charge, or to shut down the generator by shorting the output of the generator.  Being able to shutdown the wind generator is convenient when in a crowded dock - I guess the high pitch swishing sounds grates on some peoples nerves like the clanging of loose halyards does to me!

The EMON not only controls the charging of the batteries, it also displays to the user the current status of the system.  Voltage of the batteries is read from a wire connected directly to the positive terminal of bother battery banks.  Instantaneous current is measured for the house bank and the wind generator by a pair of shunts.  A shunt is a calibrated strip of metal that provides a small but constant voltage drop - the voltage across the shunt is a measure of the current passing through the shunt - i.e. 10mV/Amp.  Optional software (which I have but have never used) allows you to monitor the batteries through time to see how they are performing.  To me, the neatest thing that the EMON does is to allow you to check your batteries for actual AHr capacity.  As noted, I have 2 4D 200AHr AGM batteries for my house bank.  This would seem to indicate that I have 400 AHr available for use.  Doing the test that Ample Power recommends, the actual capacity is 379 AHr.  Considering that you should never drain the batteries more than 50%, I have about 180 AHr to use before needing to recharge.


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This page was last modified: 01/22/14
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