I have been reading this thread about the wiring and the charging avidly, but I
have no training in electrical engineering and I am having difficulty figuring
out how all this comes together... is there a way someone could summarize this
in layman's (rank beginner) terms? I would like to know how the theory and the
real wiring/charging system come together on the boat, I guess on Edd's boat in
this instance, but, of course, I am looking to see how I can apply it in
understanding and upgrading the system on my boat as well..... I recognize that
the systems are going differ from boat to boat, but surely the principles must
be the same? Many thanks....
Richard
1985 C&C 37 CB; Ohio River, Mile 596;
Richard N. Bush
2950 Breckenridge Lane, Suite Nine
Louisville, Kentucky 40220-1462
502-584-7255
-----Original Message-----
From: Rick Brass via CnC-List <cnc-list@cnc-list.com>
To: 'Peter Fell' <prf...@gmail.com>; cnc-list <cnc-list@cnc-list.com>
Sent: Mon, Mar 30, 2015 8:38 am
Subject: Re: Stus-List New Wiring Diagram Draft (Edd Schillay)
In a 12 volt setup, 10.5v of differential between the fully charged/charging
bank (12.6 to 14.4v) and the depleted bank would probably mean that the
depleted bank has something wrong with it – maybe some shorted cells.
In a 24 volt setup with 12 cells, the fully charged/charging bank would be at
25.2 to 28v. The 10.5v differential would put the discharged battery at 1.5v
per cell – seriously discharged. The high voltage differential would normally
cause a high current flow, so I assume the Echo Charge is programmed to limit
the current because of the heat from high current.
If I recall correctly, the Blue Sea 12v ACR that I have on Imzadi is designed
to not open if either of the connected batteries is below something like 10.5
or 11 volts. That prevents current flowing from a good battery bank into a bad
one.
Rick Brass
Washington, NC
From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Peter Fell
via CnC-List
Sent: Monday, March 30, 2015 12:01 AM
To: cnc-list@cnc-list.com
Subject: Re: Stus-List New Wiring Diagram Draft (Edd Schillay)
The graph indicates it’s the other way round ... when the voltage difference is
high, the amperage output is low. I don’t understand why they would produce a
graph that goes out to a voltage differential of 10.5 volts!
I kinda get what they are saying .... but it’s almost like there’s a piece of
the puzzle missing in the manual.
Peter Fell
Sidney, BC
Cygnet
C&C 27 MkIII
From: Knowles Rich
Sent: Sunday, March 29, 2015 5:28 PM
To: Peter Fell ; cnc-list Cnc-List
Subject: Re: Stus-List New Wiring Diagram Draft (Edd Schillay)
Hmmm… When the voltage difference between a charging source and battery being
charged is high, the amperage flow is high as well, and vice versa.
The Operation Manual for the EchoCharge says:
"When the input voltage is 13.0/25.5 volts DC or higher, echo-charge
automatically switches ON. The LED glows a steady green. When the input voltage
is lower than 13.0/25.5 volts, the echo-charge automatically switches OFF, and
the LED blinks green. The output voltage of echo- charge is limited to
14.4/28.8 volts. When it reaches 14.4/28.8 volts, the charge current will
decrease, maintaining a float condition. The starter battery will be fully
charged without overcharging.
No load current drain on the house bank is less than 50 milli-amps.
If the input voltage is above 14.4 volts (or 28.8), output will be limited to a
maximum of 14.4/28.8 volts.
My interpretation is that when the output voltage of the echo-charge reaches
14.4 volts, it assumes the start battery is full and lowers the applied voltage
to float level, around 13.5. This reduces the charge current and keeps the
electrolyte in the battery where it belongs.
I suggest looking at this paper for more insight into the three stage charging
process.
http://xantrex.com/documents/Inverter-Chargers/Freedom-458/MS20070308_3-stage-whitepaper.pdf
In any event, I have had an Echo Charge unit on my boat since before 2000 and
have had the same start battery since then. The house batteries, two 400 series
Surrette batteries, finally reached end of service after 14 years. I have
installed echo charge units as part of rewiring the primary systems on many
boats over the years, and, other than a couple of units that died due to water
exposure, they all perform very well and the owners don’t have to do any
switching at all to maintain their battery systems.
Rich Knowles
Nanaimo, BC
INDIGO LF38
For sale in Halifax, NS.
On Mar 28, 2015, at 10:41, Peter Fell via CnC-List <cnc-list@cnc-list.com>
wrote:
It also says when the output voltage reaches 14.4 volts, it reduces the output
current to maintain a float condition. There’s also a curve in the owner’s
manual that relates difference in voltage between banks to output amperage.
When the voltage difference is low, the amperage is high and it decreases as
the voltage difference increases.
From: Josh Muckley via CnC-List
Sent: Saturday, March 28, 2015 10:26 AM
To: C&C List ; Rich Knowles
Subject: Re: Stus-List New Wiring Diagram Draft (Edd Schillay)
Rich,
Great explanation but don't the other combiners turn off once the starting
battery is greater than or equals to the house? As was pointed out to me the
echo-charge is simply a voltage follower with a limit of 14.4v. At least one
relay style combiner I've seem has an adjustable high voltage shutoff.
Josh
On Mar 28, 2015 10:51 AM, "Knowles Rich via CnC-List" <cnc-list@cnc-list.com>
wrote:
I didn’t realize I’d start such a lengthy discussion. Sorry for the late reply.
Work…
I like the EchoCharge unit for the following reasons:
When you combine batteries for charging using an automatically actuated
combiner, or by manual switching, all the batteries combined will receive the
same voltage at their terminals. While each battery will absorb different
amounts of amperage depending on their state of charge, a battery that is fully
charged will start losing electrolyte if it is continuously provided excessive
voltage when it is combined with a battery needing high voltage to efficiently
recharge it.
In a well designed system, the engine start battery should be reserved for just
that and nothing else. Although it will need to deliver high amperage to the
starter, it will do so for only a few seconds to start an engine in reasonable
condition, and that energy can be quickly replenished, usually within a few
minutes. An average size 27 or 24 fully charged battery in good condition
should be capable of starting a 30 hp diesel many times before requiring
recharging. Once recharged, the presence of excessive voltage as charging of
house batteries continues will cause the start battery to lose electrolyte. If
this process is repeated often or long enough, the start battery will
eventually lose enough fluid to be unable to start the engine. This situation
is exacerbated by the use of smart alternator controllers and multi step AC
chargers which cause higher charge voltages to be present than those produced
by internally regulated alternators and simple single voltage chargers.
Directing all charge capacity direct to the house battery, and using the
EchoCharge or a similar device to maintain a single purposed, isolated engine
start battery, ensures that the start battery only receives enough charge
voltage to recharge it to full capacity. Barring a failure, there will always
be reliable power to start the engine. Switching should be provided to enable
emergency use of the house battery to start the engine or the engine start
battery to provide house power.
I have also used EchoCharge units to provide charge power to windlass batteries
installed in the bow near the windlass. That saves a stack of money for
expensive heavy copper wires to feed the windlass from the main house battery.
If you install an EchoCharge, make sure it is in a dry, ventilated, relatively
cool location. It is not waterproof, the principal cause for failure I have
seen.
Multiple output AC chargers are OK to use but should be carefully chosen and
installed. If batteries are in parallel, only one charge leg should be
connected to that bank. If an automatic combiner is used, only one battery
charging source is required. For systems I design, I use a single output smart
charger to charge the house battery and rely on devices such as the EchoCharge
to distribute charge current as needed to start and other auxiliary batteries,
one device for each battery. That charger is connected to the same point in the
system as the alternator, as are any wind generators and solar panels on board.
As an aside, I’m intrigued by the discussion about installing ever larger
battery banks. Is this based on real calculated daily need, inefficient
charging systems or other factors? Average daily power consumption for our
boats including refrigeration, modern nav gear, sailing instruments, lighting
and entertainment should not exceed 150 A/hrs per 24 hour period and generally
will be much lower. A well maintained 450 A/hr house battery bank should be
plenty in my opinion. More than that is excessive weight that simply slows down
the boat and extends time between longer charges.
Controversy is welcomed!
Rich Knowles
Nanaimo, BC
INDIGO LF38
For sale in Halifax, NS.
Rich Knowles
Nanaimo, BC
INDIGO LF38
For sale in Halifax, NS.
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