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bob_deb · 25-12-2008, 04:21

MERRY CHRISTMAS EVERYONE !!!!!!!!

I will let you all know in a day or so what I find out.

thanks again - Bob

Sandero · 27-12-2008, 13:37

BTW Bob, The Link 20 should show WHICH battery bank is experience what level of charge or discharge. So which bank is showing the -4.6? If it is the hose bank then the source of the drain can ONLY be on that batt's wiring. If the starter, solenoid and so forth are on the start bank and the fault is on the house bank you can rule out the starter and solenoid.

bob_deb · 28-12-2008, 06:28

OK GUYS,
Here are my observations and assumptions,

The LINK shows -4.6 on start batt with batts connected or disconnected.
For the past 3 days I have been checking both banks with a multimeter,
checking the volts.
start house
12/25 batts disconnected and link connected 12.69 12.16
12/26 batts connected and link disconnected 12.69 12.16
12/27 batts connected and link connected 12.69 12.16

all the time, Link shows drain on start batt - (except when link is disc)
with no drop in volts over a total of a 4 day time period, I am thinking that
there really is no drain at all. From what I have read , and I may be wrong, with a -4.6 amp drain, a 125 amp battery should be shot in about 20 hours, showing volts to be low, or at least a big drop.
If anyone can verify this for me I would be gratefull.
thanks so much,
- Bob

svHyLyte · 28-12-2008, 07:48

Bob--

I went through a very similar experience some while ago that was discussed at length with the electrical wizzards here abouts (see http://www.cruisersforum.com/forums/...ysis-3664.html ).

Our difficulty proved to be the positive cable from our start battery to the switch, which had chaffed through on a ground strap from the fuel tank. This "short" caused the drain and also did great damage to our shaft and prop and was only discovered by accident by a yard worker doing some clean-up following the shaft replacement.

To the extent possible, it might be wise to check the integrity of the insulation on your cables.

FWIW...

svHyLyte

Sandero · 28-12-2008, 08:22

One last test.

Reverse the wiring on the Link. Make Batt 1 the start and Batt 2 the house or reverse from what you have been using. Remember to rewire all the small wires on the shunt ie switching them from one side to the other. Make sure you get them correct

If the -4.6 stays with the same battery as it was before the swap you have a bad monitor. If it moves to the "new battery" then the fault is OUTSIDE the monitor and in the wiring assiociated with the battery showing the -4.6.

Let's assume that this IS the case. Now you have to find what is actually causing the drain.

We've discussed removing all the loads from the offending battery circuit. If you've done that and all you have are the MAIN cables connected - the POS the selector switch or a POS buss and the NEG to a pos bus then you have some sort of short which is leaking to ground.

Now you have to look for a chafed wire any place where the pos wiring can come in contact with the neg or even ground - the engine block or any conductor which is path between neg and pos. Check the bilge pump.

This sounds like a lead to ground. Now you need to find it. But it should be in some of the primary wiring, IF YOU HAND DISCONNECTED all the other circuits.

Try and send a report!

bob_deb · 28-12-2008, 11:33

Hey defjef,

I reversed the batteries, changing all shunt wires (4) and switching wires on the batts. Origanlly the start was #1 and house was #2,
the start (#1) was showing the -4.6 , being switched,
the house is #1 and the start is now #2.
The #1 is still showing a -4.6 even after the switch.
Now I know it IS the link 20. Just to be safe, I checked all cables and everything looks good.
I believe the mystery is solved, now I just need to decide weather to buy a new link or , can I live with the false readings on the #1 batt, start batt.
thanks for all your help.
- Bob

RBEmerson · 28-12-2008, 12:29

Clean up the wiring associated with the shunt. The Link20, even as an ammeter, is really a voltmeter, measuring the voltage drop across the shunt (a very small voltage, BTW). Poor connections, particularly high resistance connections, on the ground side could cause an unusually large apparent draw (for a "no draw" situation). These poor connections will affect all parts of your boat's operation (no ground, no starter, for example).

Also, the shunt can be replaced (if it's corroded or otherwise damaged) without replacing the Link 20.

Do not rely on the present bogus numbers to be present forever. The Link 20 is wrong now and just subtracting 4.6A from its readings could cover over a real near-short or excess load later.

Sandero · 28-12-2008, 13:33

If all the wires were switched and the fault moved from one batt to the other my conclusion is that it is the Link. I suppose you could also reverse the batt leads to the link and see if the -4.6 stays with the same batt or moves. If it moves it could be at the shunt, but I am beginning to conclude the Link is at fault since you have A'B'ed everything and the tests point to a fault in the monitor.

I would contact the mfg tech support by phone and explain the problem and all the tests you have done and see if he confirms that it's the Link and what they suggest you do.

RBEmerson · 28-12-2008, 23:08

Here's a rather off the wall thought... just for giggles and grins, how about strapping the Link 20 into a car for short term testing? I wouldn't drive with the thing in place, of course, but it sure would answer a lot of questions in a hurry. Get a cheapo battery cable from Auto Zone, etc. for the break in the ground lead, to allow mounting the shunt, and take it from there.

bob_deb · 30-12-2008, 06:45

Hey Guys,

I'm starting to suspect the shunt may be bad, I know it is about 11 or 12 years old. I'm going to call the Link Tech Support, I hope shunts are cheap.
thanks
- Bob

RBEmerson · 30-12-2008, 07:32

It's a boat thing and boat things are never cheap, silly!

Sandero · 30-12-2008, 15:17

You can A-B the shunt too. Let's assume one side is OK and one is bad. If you reverse the link wires on the shunt and the problem moves to the other batt according to the Link then the shunt is the guilty guy. Now reverse the batt leads to the shunt (leaving the link wiring to the shunt) and if it remains on the same batt then you know it's the shunt.

Get it?

bob_deb · 30-12-2008, 16:14

I'm going to try this last suggestion, At this point, I'm almost certain it is the shunt. It makes sence. No matter how I change the wiring around , it appears that anything going through the right side of the shunt gives a false reading. the right side shows a -4.6 amp drain, constantly, but I never loose any volts from which ever batt is running through there.
I'll perform this last test, then can anyone tell me a good place to buy a shunt? Xantrex maybe ??
thanks
- Bob