LINK 2000 - CAN "LOWBAT" MESSAGE BE WRONG?

[Savanna]

Hi Forum Members,

I have been very impressed with the depth of knowledge some of you have regarding electrical systems, and I wonder if one of you might be able to shed light on my problem with a Link 2000 controller unit please.

Currently my Link 2000 is flashing a "LOWBAT" message at me, but there is no sign whatsoever that my batteries are low, and I continue to use them as normal. The controller looks after only one battery bank (6 x 6V Sonneheim batteries connected in series and parallel to provide a 12V supply rated at 600 Ahrs), which is charged either by 2 x 75 Amp alternators, or using shore power and a Link battery charger/inverter.

The battery bank is nominated as "Bank 1" for monitoring and control purposes. I have read the manual (which doesn't help much), and checked the settings for Bank 1 which all seem good to me. As a "what if scenario" I checked the settings for Bank 2, and increased the Ahr setting from the factory setting of 200 Ahrs to 600 Ahrs, and this stopped the "LOWBAT" flashing at me, but only for a few days.

Any ideas on how I might understand what is happening, and how to fix it, would be much appreciated.

[Badsanta]

do you know your battery bank Ahr capacity and the resting voltage?

[Opie91]

The "LOW BATT" message comes on when 50% of the declared capacity of either battery has been reached. The system uses two factors to figure out when to turn on the "LOW BATT" warning. The 50% number (called the discharge floor) as well as the battery capacity of each bank.

The Link 2000 cares about amps mostly. It counts them to let you know how much power remains/consumed. If the battery capacity is not set right, the unit will get confused since 50% of a 200ah and 50% of a 400ah bank is a big difference. The discharge floor is what percent of discharge the system uses to turn on the "LOW BATT" warning. I believe you can set it between 5-100% of the rated capacity of the bank.

Here are some examples of how the two numbers work together:

Example 1:

200ah bank. 50% discharge floor.

200ah * 50% = 100ah (when you consume 100 ah the low batt warning will illuminate)


Example 2:

200ah bank. 20% discharge floor.

200ah * 20% = 40ah (when you consume 40 ah the low batt warning will illuminate. This show why setting the floor is important.)


Example 3:

400ah bank. 50% discharge floor.

400ah * 50%=200ah (now the warning will go illuminate after you consume 200ah)


Attached below is the Link 2000 manual. Read, understand and do the set up procedure. Once everything is done put a full charge on all batteries and then sync the system.

Take the time to understand the system and set it up, if you do not the information you get from it may be incorrect.

Good luck.

[Badsanta]

Yes, what opi said

[Savanna]

Hi Badsanta and Opie91,

Many thanks for your prompt responses. I will read the manual again and check the settings when I go to the boat tomorrow, and let you know what progress I make.

[LJH]

Savanna,

Just after we bought this boat and I was unfamiliar with our Link2000 we had similar symptoms when the field wire to my alternator broke. As Opie91 mentioned above you have probably hit the discharge floor. As it seems to be a surprise to you, it may be because the batteries have not charged properly, or not as much as you had expected.

[Savanna]

Hi All,

Had a very interesting afternoon, manual in hand, learning about my Link 2000. Have managed to get the "LOBAT" message to stop flashing at me, but I don't understand why. Any explanations would be much appreciated.

As noted in my OP, the Link 2000 on my boat controls only one battery bank, which has a capacity of 600 Ahrs, and the Bat Capacity for BAT1 has been set accordingly. I started by checking each of my 6 x 6V batteries with a multimeter, and all read 6.47 to 6.50 V, which is OK.

I then checked the settings (F01 to F15) - all were set at their defaults, so changed F11 from "Off" to "On" (thus Bat 2 will not be used for control), and changed F13 (the Discharge Floor) to 75%.

Then at rest (nothing switched on), the Link 2000 indicated the following for BAT1 : V=12.95, A (draw)=0, Ah=-0.3, Time=CCC. On switching on my fridge and freezer these changed to V=12.85, A=-13.5, Ah=-0.6 (and dropping), Time=33.6 (with discharge floor set at 75%). It appears so far so good, but "LOBAT" message was still flashing at me.

Then, although there is no BAT2 battery bank, I checked all the F settings for BAT2. These were all at the default settings, so I left them alone (F13, the Discharge Floor is set at 100%). I then set the battery capacity at 600 Ahrs (even though no BAT2 battery bank exists).

At rest, the Link 2000 showed V=12.90, A=0, Ah=-483.6, Time = CCC. When I switched on my fridge and freezer these changed to V=12.80, A=0.2, Ah=-483.6, Time - CCC. Clearly the Ah reading at minus 483.6 is an anomaly, as there is no BAT2 to be discharged to this level.

At this point I switched on my shore powered battery charger (a Link 25), and the charging cycled through charge, accept, and float over a period of about 2 hours. After charging the BAT1 Ah showed as +36.60, and the BAT2 Ah showed as -488.2.

At this point I increased the battery capacity for BAT2 to 1000 Ahrs, and this stopped the "LOBAT" message from flashing.

Do I have a ghost battery bank??? Having now attained a much improved understanding of my Link 2000, I would be really keen to understand what is happening here.

[LJH]

Savanna,

The Ah and A on the Bat 2 side of your link depend on how your negative shunt wired. If you have a current passing through it then the link will count the Ah. You had 4.6Ah pass through the B side of the shunt. This does not affect the operation of the Link2000, but it will continue to climb. Once you reach 100% of your programmed Bat 2 capacity the LO BAT will come on again. If you follow the procedure to manually reset the amp hours to zero for Bat 2 periodically you should clear up the issue.

[Badsanta]

Aside from your link system I would do some battery testing. When I got my boat the servey found low voltage. I was able to get several batteries replaced. Day trips were fine but I had continuing low battery. I finely pulled all my batteries and charged them sepritly till full. After 48hours of resting all voltage remained the same at 12.8 volts. I then used a load tester on the batteries looked like a 12 volt toster. All tested fine but one. The voltage was fine but under a load one was compleatly flat. Replaced that one and everything was fine for 8 years. What I am tri g to say is there is more than voltage involved. Just because you have proper voltage a bad cell will put a constant drain on your system. You have to test each battery alone and not connected to anything. my local battery shop will charge and test each for free. Best of luck.

[Savanna]

Hi LJH,

Many thanks for that useful information which will allow me to manage the issue. My Link 2000 Manual includes a wiring diagram which shows a twisted pair of wires coming off the LHS of the shunt labelled BAT1, and a second twisted pair of wires coming off the RHS of the shunt labelled BAT2. I'd be interested to know whether you think that disconnecting the right hand twisted pair would solve the problem in a more permanent way?

Hi Badsanta,

Many thanks for that additional piece of good advice. The batteries I have are quite old, and a load test would seem to be a very sensible thing to do.

[LJH]

Savanah,

I think it would work, but my manual recommends moving the wires to the other side of the shunt so that the Bat 2 mirrors the Bat 1. Connecct the green (B1SHG) and brown (B2SHG) wires together and the orange (B1SHB) and yellow (B2SHB) wires together. (page 38 in my manual)

[Savanna]

Hi LJH,

Thanks for that - I must have been getting tired eyes when I got to the end of the manual - that's exactly what I'll do. Many thanks again for your willingness to help, and your excellent advice.

[LJH]

My pleasure, hope everything works out for you.

[nhschneider]

I, too, have a Link 2000 and have found that it can deliver erroneous information. When it does, I remove all power to it and upon reconnection, the problem will sometimes disappear. Xantrax, who bought Heart Interface many years ago, no longer supports the product. Mine still works to engage or disengage invert or charge but its information on battery condition is no longer reliable.

Fair winds and calm seas.

[jimking100]

I too have a link2000 and the same problem which I worked on for about a year. As previously stated, there is no support from Xantrex. Last year, I hired a "certified marine electrician" who worked on the system for a couple hours ($180) and he basically reported the Link 2000 had failed. Cannot replace so now I just monitor a separate volt meter to make sure all my systems are charging properly and the batteries are staying charged. I will be interested to hear if you have any better results.