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I just thought I’d mention something I have found now on two 424’s recently.
The DC +12 volt cable the runs from the common terminal of the battery switch to the DC Panel is woefully inadequate. It may have been OK 30 years ago but as we had more and more devices connected to the DC panel, the voltage drop gets worse and worse.
This time is presented itself as a large voltage drop on one side the buss as the compressor for the refrigeration unit started up.
As we did not have a larger cable on hand, we run 2nd cable (#8) along with the original wire. It seemed to help the problem.
Hope it helps someone…
Alan
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What size was your battery cable before you added the additional 8AWG wire?
For comparison sakes, my cable is all 2/0.
-p
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s/v Deep Playa | Pearson 424 Hull #152 | http://www.DeepPlaya.com |
@DeepPlaya |
W7PEAOn Tue, Jan 3, 2012 at 6:08 PM, Alan wrote:
I just thought I’d mention something I have found now on two 424’s
recently.
The DC +12 volt cable the runs from the common terminal of the battery
switch to the DC Panel is woefully inadequate. It may have been OK 30
years ago but as we had more and more devices connected to the DC panel,
the voltage drop gets worse and worse.
This time is presented itself as a large voltage drop on one side the buss
as the compressor for the refrigeration unit started up.
As we did not have a larger cable on hand, we run 2nd cable (#8) along
with the original wire. It seemed to help the problem.
Hope it helps someone…
Alan
UNABATED_______________________________________________
maillist mailing listhttp://server12.websitehostserver.net/mailman/listinfo/maillist_pearson424.org
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Owners no more...
Thanks Dawn and Patrick! -
I believe that splitting the load over two smaller cables is not allowed
in ABYC, for what it’s worth.On 1/3/2012 6:08 PM, Alan wrote:
I just thought I’d mention something I have found now on two 424’s recently.
The DC +12 volt cable the runs from the common terminal of the battery switch to the DC Panel is woefully inadequate. It may have been OK 30 years ago but as we had more and more devices connected to the DC panel, the voltage drop gets worse and worse.
This time is presented itself as a large voltage drop on one side the buss as the compressor for the refrigeration unit started up.
As we did not have a larger cable on hand, we run 2nd cable (#8) along with the original wire. It seemed to help the problem.
Hope it helps someone…
Alan
UNABATED_______________________________________________
maillist mailing listhttp://server12.websitehostserver.net/mailman/listinfo/maillist_pearson424.org
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Pete,
“I believe that splitting the load over two smaller cables is not allowed
in ABYC, for what it’s worth.”For what it’s worth… we’re out in the boonies and the closest #6 cable is over a 100 miles away…. and we can’t get the compressor running cause there is only 11.5 volts… so we doubled up the cables… for the time being. Have not been plugged in 2 and 1/2 months.
I am sure the ABYC people won’t mind.
My point was to make people aware that the original cable that most of us still have is too small for present day loads and needs to be replaced with a larger cable.
alan— On Tue, 1/3/12, Pete Dubler wrote:
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It was not a battery cable. The original wire is white and goes from the common terminal of the battery switch under the nav station to one side of the DC ammeter on the panel. Hard to tell, may be a 10…. we didn’t have anything else except a hunk of #8. When we get to someplace that has cable available we’ll replace both of them with a #6.
For me – on my boat, I replaced the cable with a #6, but ran the refer and the SSB off a bus directly off the battery bank… fuses of course, but those two loads are not taken from the DC panel.
Alan— On Tue, 1/3/12, Peaboy Walters wrote:
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And a fine point it is.
On 1/3/2012 8:11 PM, Alan wrote:
Quote:Pete,
“I believe that splitting the load over two smaller cables is not allowed
in ABYC, for what it’s worth.”For what it’s worth… we’re out in the boonies and the closest #6 cable is over a 100 miles away…. and we can’t get the compressor running cause there is only 11.5 volts… so we doubled up the cables… for the time being. Have not been plugged in 2 and 1/2 months.
I am sure the ABYC people won’t mind.
My point was to make people aware that the original cable that most of us still have is too small for present day loads and needs to be replaced with a larger cable.
alan— On Tue, 1/3/12, Pete Dubler wrote:
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Try this link. Don’t forget to double the cable length because you have two wires, plus and minus. If you assume a 10′ length from the battery selector switch to the breaker panel, this computes that the voltage drop at 25A will be about .3v for 8-AWG wire. This should be OK at that load. If you have high starting current for your compressor, you can use a bigger cable or put a large electrolytic capacitor behind your panel. Something like 50,000uf might work depending on the compressor. You might find something like this at a dump inside an old piece of junk electronics. The cap would get wired to the + and – bus-bars on your panel. Observe the polarity marking on the cap when wiring it up. The cap should be rated for at least 20v.
http://www.stealth316.com/2-wire-resistance.htm
I have the original 8AWG cables to the panel. The only large load I have is the elecra-san treatment system. Its about 60A when running. My panel voltage drops down to below 11v sometimes when running it, but everything works.
Regards
Rich
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You are correct the supply feed is undersized and has no circuit protect at the source. This is to protect the conductor, not the panel.
There’s no main DC breaker on the panel (not on mine anyway).
I’m replacing my two battery switches with a Blue Seas 8690 switch.
It keeps the start and house independent but on a single switch (still offers combine). It has a 100 amp breaker for the DC panel feed and a 24 hour bus for your bilge pump and stereo.I’m tying my house batteries together to form a single bank, running them to a large bus bar and getting rid of the mess of wires that are terminated at the back of the switch. Adding terminal fuse blocks at the battery output. Moving the shunt and any other connections in the stbd cockpit locker into the hanging locker.
Later when I move the house batteries into a spot in the cabin I’ll tie into the DC system at the bus. Thinking Trojan 105’s in that spot under and just aft of the salon table.
Chuck
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