Link Battery Monitor Installation

[Snotter]

I managed to snag an old Link 10 monitor off of ebay. I hooked it up this weekend and was pleased to see it work; however, I was surprised to see a negative current draw with my charger running. This got me wondering if the Link 10 can sense the charger's output if the negative wire from the charger goes to a battery post. Does anyone know if I should move the charger's negative wire to the system ground side of the shunt?

 

[Stu Jackson]

The three things we can't help with on the internet are sounds, smells and wiring! Without a wiring diagram, that is!!! But you knew that from our last conversation: http://forums.catalina.sailboatowners.com/showthread.php?t=114137&page=2

That diagram didn't show the connected grounds.

If you've wired it correctly, you should see positive charging. Perhaps you were mistaking the number of incoming amps with draw. I have a Link 2000, same concepts, but I'm not that familiar with the Link 10 display.

You also have to read this: http://c34.org/bbs/index.php/topic,4922.0.html

 

[Rich Stidger]

Yes, the negative side of the charger should attach to the load side of the shunt. The charger current must flow thru the shunt for the Link 10 (or any of the Links) to show the charging current.

Additionally, if the Link 10 cannot "see" the charging current, it has no way to keep track of the state of charge of the battery.

Double check the wiring diagram that came with your Link 10 and I think you will see the wiring error.

 

[Snotter]

Thanks, Stu, for the good link. Rich, thanks for the advice. My Link 10's wiring diagram didn't show a charger (at least one I didn't see). That my monitor is'nt registering the charger seems to be indicative of a rogue circuit. I suspect that the many loads that are wired directly to my battery posts all represent rogue circuits. You gotta love previous owners. (I suspect that the next owner of my boat will be saying the same thing.)

 

[Stu Jackson]

KISS. Have your charger go to your PDP, the same place your alternator output goes, which is to your house bank #2 (+). Then it should work if you've wired the combined negatives to the shunt, and then from the other side of the shunt to the ground.

Don't leave it for the next guy, you ight as well enjoy all the fruits of your labors, plus your new Link.

 

[Rich Stidger]

Actually my Link 20 (which is just a dual-battery version of your Link 10) doesn't show a charger or the alternator connection either. however it states that all loads must connect to the 12V system ground side and that NO other wires except the shunt are to be connected to the battery negative.

See the wiring from my Link 20 attached.

Now I know that there is lots of controversy about alternator connections directly to the battery, and lots of owners like to have the bilge pump directly connected to the battery so that it can't be inadvertently disconnected.

If you connect your Link 10 exclusively and directly to the battery as shown and then connect all A-B switches, bilge pumps, chargers, alternators, etc. to the load side of the shunt, you can then follow the best practice that you believe in and still have a Link system that wil accurately measure and report on your battery system.

Now at this point you may not wish to rewire your batteries and eliminate all of the direct battery connections. Just be aware of what connections are not "seen" by the Link and understand those consequences.

 

[Snotter]

Rich and Stu, thanks for the advice. Stu, I hope to be sending you an updated wiring diagram shortly after more of my stuff comes. Rich, I wish I had held out for the Link 20. I am going to try to accomodate the shortcomings of the link 10 by setting up the monitor for 540 ah, which corresponds to all 3 of my banks in parallel. When on the hook, I will probably switch in the starter battery to the house bank (my nose is always to the grind stone I can never get away for more than a couple of nights).

I was pipe-dreaming last night about getting a digital volt meter that can interface with a laptop via the USB. It wouldn't be hard to write software to monitor separate banks. The shunts would probably be affordable. The digital meter probably wouldn't be. I wonder if there are any silicon chips out there that are affordable from which hardware could be built easily. I believe there is money to be made in the future boat-monitoring hardware/software/networking industry.

 

[Rich Stidger]

Actually in my case the dual channel Link 20 was a waste. I originally had two house banks, each one being a pair of golf cart batteries. I used the Link for years to monitor each bank separately, but I always kept my A-B switch set to BOTH creating one larger house bank.

I always mentally added the AH discharge states of both batteries together to get one number that represented the two defined house banks that I was using as one.

Then in a lucid moment, I decided to move one single wire to enable the first Link 20 channel to monitor all four of my golf cart batteries. Now I have just one number to look at and no mental addition to perform. Duh.

I ended up using the second channel to monitor the output of my wind generator. This provided new data that I previously didn't have but find useful.

So IMHO the bottom line is that having a Link 10 to monitor a single house bank made up of several batteries is all you really need. Anything else is simply over complex. And I think that monitoring the starting battery is really a waste if it is truely used as a starting battery only.

 

[Stu Jackson]

There you go again!

Let's get back to KISS for you. I agree with Rich in concept about not needing the separate Link features for a reserve bank if it is used as such, or even as a start bank, since hardly anything is used to start our small diesel engines.

A single Link would suffice for most sailors to monitor just the house bank.

However, since you do have the Link 20, why not use it? I bought a Link 2000 in 1998 well before I knew much about the more sophisticated electrical systems like the ones we have, and am glad I did because it allows me a simple way to check the reserve bank with the Link. Otherwise I'd have to go to "all the trouble" :neutral: of pulling out my dvm and checking it (OK, let's NOT get into a dvm & voltage argument here, not the point of this discussion).

You have a not unusual system with two house banks and a separate reserve bank.

So combine the grounds from the two house banks onto one lug of the shunt, and the reserve to the other. Pretty simple. Then you, like Rich, don't have to "do the math."

Shunts: These things drive people crazy. The documentation of "battery side" and load side" and "shunt side" in the instructions literally sucks. To simplify it, think of a shunt as a simple flow meter: whatever you want to measure HAS to go THROUGH the shunt and then to ground. So, for a dual shunt, one side of the shunt does the house bank, the other side does the reserve bank. "Incoming" is "from" the individual banks. "Outgoing" is from the shunt "to" the engine ground. There are only four connections. You should disregard for a moment the complications that appear on the instruction manual wiring diagrams for all the smaller wires. Just concentrate on the four wires: incoming from banks, outgoing to engine ground.

 

[Rich Stidger]

However, since you do have the Link 20, why not use it?

Oops, Stu. I think our friend has a Link 10, not a 20. I was just pointing out to him in my last post that a single channel Link 10 is probably perfectly satisfactory, and that my dual channel Link 20 was not really being used effectively for many years. Therefore he shouldn't feel badly that he didn't get a Link 20.

 

[Stu Jackson]

OOPS, back

Rich, you're right. However, if he forgets about the reserve bank part, then what I suggested for ganging the house banks he has still works.

 

[Snotter]

This thread is providing some great food for thought. When wiring up the Link 10, I did lead all the wires from the neg posts of the 3 banks to the Link. I climbed into my bunk that night fearful that the Link Nazis were going to keel haul me in the night for blatantly disregarding their manual which states to use a single wire. I originally included the starter battery in the total capacity that I input into the Link 10. After reading the posts here, however, I think I will subtract out the battery.