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Another Battery Charger Installation Question

I purchased a Xantrex TrueCharge 20+ for my boat. Since I only have two
batteries, I'm wondering about the advisabilty of using the third (unused)
charger output to run on-board 12 V 'stuff' while plugged into shore power.

What I visualize is a cable from the charger to a CB (CB1) switch, which then would
go to the primary DC breaker/disconnect (CB2)

charger ---CB1---CB2---DC Panel---Load
Batt---Bat SelSw-----^

Any pros/cons you see?

Regards,
Norm B

engsol wrote:

I purchased a Xantrex TrueCharge 20+ for my boat. Since I only have two
batteries, I'm wondering about the advisabilty of using the third (unused)
charger output to run on-board 12 V 'stuff' while plugged into shore power.

What I visualize is a cable from the charger to a CB (CB1) switch, which then would
go to the primary DC breaker/disconnect (CB2)

charger ---CB1---CB2---DC Panel---Load
Batt---Bat SelSw-----^

Any pros/cons you see?

I really wouldn't do that. I dont know how 'smart' the Xantrex is, If
it is smart, it may limit that output because it isn't 'seeing' a
battery on it. If its not so smart, the output voltage may go *way*
over 12V. Neither would be good for your 'stuff'. Also check if its
rating is averaged over all 3 outputs. If so there is no benifit in not
taking your feed from off one of the batteries.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.

On Fri, 13 May 2005 10:36:49 -0700, engsol
wrote:

I purchased a Xantrex TrueCharge 20+ for my boat. Since I only have two
batteries, I'm wondering about the advisabilty of using the third (unused)
charger output to run on-board 12 V 'stuff' while plugged into shore power.

What I visualize is a cable from the charger to a CB (CB1) switch, which then would
go to the primary DC breaker/disconnect (CB2)

charger ---CB1---CB2---DC Panel---Load
Batt---Bat SelSw-----^

Any pros/cons you see?

The charger can only put out 20 amps, which it will distribute among
the output terminals as needed - if you only have one output terminal
connected, it will get the full output of the charger.

Your extra switch to "make use" of the third output terminal is
unnecessary complexity. The charger will provide just as much power,
or will charge your batteries equally well, if you simply leave your
12 V "stuff" connected to the batteries, the same as if you were under
way or at anchor.

--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

"engsol" wrote in message
...
I purchased a Xantrex TrueCharge 20+ for my boat. Since I only have two
batteries, I'm wondering about the advisabilty of using the third (unused)
charger output to run on-board 12 V 'stuff' while plugged into shore
power.

What I visualize is a cable from the charger to a CB (CB1) switch, which
then would
go to the primary DC breaker/disconnect (CB2)

charger ---CB1---CB2---DC Panel---Load
Batt---Bat SelSw-----^

Any pros/cons you see?

Regards,
Norm B

I've got the same units and am not using the fixed 12v output. Don't see
any advantage to this over connecting stuff to the batteries through my
circuit breaker panel.

On Wed, 18 May 2005 20:37:38 GMT, "Gordon Wedman" wrote:

"engsol" wrote in message
.. .
I purchased a Xantrex TrueCharge 20+ for my boat. Since I only have two
batteries, I'm wondering about the advisabilty of using the third (unused)
charger output to run on-board 12 V 'stuff' while plugged into shore
power.

What I visualize is a cable from the charger to a CB (CB1) switch, which
then would
go to the primary DC breaker/disconnect (CB2)

charger ---CB1---CB2---DC Panel---Load
Batt---Bat SelSw-----^

Any pros/cons you see?

Regards,
Norm B

I've got the same units and am not using the fixed 12v output. Don't see
any advantage to this over connecting stuff to the batteries through my
circuit breaker panel.

After thinking it over, and based on comments to my post, I agree.
Not worth the trouble.
Question: What did you use for the disconnect between the charger
and the batteries? Fuse only? Circuit breaker?

"engsol" wrote in message
...
On Wed, 18 May 2005 20:37:38 GMT, "Gordon Wedman" wrote:

"engsol" wrote in message
. ..
I purchased a Xantrex TrueCharge 20+ for my boat. Since I only have two
batteries, I'm wondering about the advisabilty of using the third
(unused)
charger output to run on-board 12 V 'stuff' while plugged into shore
power.

What I visualize is a cable from the charger to a CB (CB1) switch, which
then would
go to the primary DC breaker/disconnect (CB2)

charger ---CB1---CB2---DC Panel---Load
Batt---Bat SelSw-----^

Any pros/cons you see?

Regards,
Norm B

I've got the same units and am not using the fixed 12v output. Don't see
any advantage to this over connecting stuff to the batteries through my
circuit breaker panel.

After thinking it over, and based on comments to my post, I agree.
Not worth the trouble.
Question: What did you use for the disconnect between the charger
and the batteries? Fuse only? Circuit breaker?

Wires go from the charger straight to the batteries, no fuse, breaker or
disconnect. I don't think the Xantrex manual mentioned using fuses but now
that you mention it I'm thinking this might be a good idea. If one of these
wires shorted out somehow you would get a lot of battery current flowing
through a small wire. Good way to start a fire.
Don't think you need any disconnect like a switch. I don't think Xantrex
says anything about not starting your engine while the charger is running
and I think I've done this with out ill effect. As a precaution it might be
good to shut off the charger while running the engine. Can't think of
another reason for having a disconnect?
As you probably know, the battery charger has an internal fuse for each
output. If you short an output you will blow the fuse and according to
Xantrex you must return the charger for servicing. If you open up the unit,
a bit tricky, you will see these are ordinary automotive flat fuses that
just plug in. Fixed mine in an hour.

On Fri, 20 May 2005 18:56:02 GMT, "Gordon Wedman"
wrote:

Wires go from the charger straight to the batteries, no fuse, breaker or
disconnect. I don't think the Xantrex manual mentioned using fuses but now
that you mention it I'm thinking this might be a good idea. If one of these
wires shorted out somehow you would get a lot of battery current flowing
through a small wire. Good way to start a fire.

The TrueCharge manual does recommend fuses at the battery end of the
positive wires - maximum 25 amps for the TrueCharge 20+.

Don't think you need any disconnect like a switch. I don't think Xantrex
says anything about not starting your engine while the charger is running
and I think I've done this with out ill effect. As a precaution it might be
good to shut off the charger while running the engine. Can't think of
another reason for having a disconnect?

No need for a switch. I often start my engine (a Lehman diesel) while
the charger is operating, and have had no problems.

--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

Another Battery Charger Installation Question