Battery monitor inaccurate.....

[NYSail]

hello all,
Hoping to get a bit of input on readouts I am getting on my Xantrex LinkLite battery monitor. To start I had to replace the in-line fuse holders (2) on the linklite due to heavy corrosion so had to splice in two new wires and a connector to battery. Used same size wires and fuses. I have a house bank of 2 lifeline 4d agm batteries that may be nearing the end as the p/o said they were 5/6 years old 2 years ago. So I am watching consumption and just can’t figure out how I am eating 200ah quicker than I did previously..... nothing has changed in the way we function. I left my slip on Sunday with batteries fully charge (week plugged in). No wind so we motored 7 hours. This is with my balmar 150 amp alt and external regulator. I adjusted the regulator as per mainsail to match charging of the lifelines (volts and time for bulk and absorb) and according to code read-outs all is functioning as Should be. However during trip I watched as my amp hours used continues to climb..... volts into battery according to monitor were correct matching regulator read-out and double checked at battery with meter. During trip we used autopilot chart plotter, wind, speed, stereo and freezer refrigerator.

Could the batteries just be at the end and slowly not taking a charge. Or could the monitor be acting up?

Just as an add..... my 2 weeks to block island right after I installed alternator but before the wire changes to the monitor all was typical.

Thanks!
Greg

 

[NYSail]

And: on hook since Sunday night...... motored yesterday from fishers island to watch hill which is about 1.5 hr trip and meter is showing 12.4 volts/ 177 ah used / 59.7%

 

[Gunni]

The simple answer is that your battery no longer has the assumed Ah capacity programmed into the meter. You can adjust the meter battery capacity setting using Function F01

 

[NYSail]

It’s set for 440ah....... which reflects the house bank

 

[dlochner]

It’s set for 440ah....... which reflects the house bank

Over time and charge cycles the actual capacity of a battery declines. This is likely the problem. AGMs need to be fully charged at a rapid rate to slow the decline. Amp hour counters need to be adjusted periodically to compensate for this decline. The Balmar Smart Gauge, which uses battery voltage does not need recalibrating.

Here's an article on the subject from MaineSail: https://marinehowto.com/programming-a-battery-monitor/

 

[Maine Sail]

When you fire up the alt or any other charge source can you see the amperage going into the bank??

Regardless of correct shunt wiring or not there is virtually no possibility your 5-6 + year old bank is still 440Ah. This makes any calculation being made for SOC incorrect.

Spend some time digesting the article linked to above by Dlochner.. It may take a couple of reads through for it to catch.....

You could also have a shunt wiring issue too so be sure to read the sister article to the linked article..

Installing an Ah Counter (LINK)

 

[NYSail]

When you fire up the alt or any other charge source can you see the amperage going into the bank??

Regardless of correct shunt wiring or not there is virtually no possibility your 5-6 + year old bank is still 440Ah. This makes any calculation being made for SOC incorrect.

Spend some time digesting the article linked to above by Dlochner.. It may take a couple of reads through for it to catch.....

You could also have a shunt wiring issue too so be sure to read the sister article to the linked article..

Installing an Ah Counter (LINK)

So I started generator and charging looked good. 20amps plus/minus. However I just turned on engine to compare and



Looks like something is not right.........

 

[dlochner]

Looks like something is not right.........

Yep, time to call the battery mortician.

You may want to read this from the Practical Sailor blog: https://www.practical-sailor.com/blog/Dont-Kill-That-New-AGM-Battery-11662-1.html

 

[NYSail]

So let me ask.... and again pardon my electrical ignorance. Every weekend I discharge to above 50% then plug in for 5 days at dock so I am fully charging bank. With generator and with shore power I get a 20+ amp reading on monitor however appear to get negative readings when charging via alternator....... alt is reading correct volts on monitor, regulator as well as at battery.

Greg

 

[NYSail]

And i don’t disagree that the batteries may be done based on a 7+ age 5+ of which I don’t know about.

Greg

 

[dlochner]

It is conceivable that you have 2 or more separate issues that have occurred simultaneously.

Every weekend I discharge to above 50% then plug in for 5 days at dock so I am fully charging bank.

Given the age of the batteries the 50% SOC that you have reached, may be considerably lower because of the factors cited in the article on MS's site. It is possible that you might be discharging to 20 or 30%.

With generator and with shore power I get a 20+ amp reading on monitor

What is the maximum output of the charger? Can it put out more than 20 amps? When the charger is on, it will effectively power all of the electric devices, so if the radio, lights, and whatever are on and draw 10 amps and the battery will accept 10 amps of charging current, the charger will put out 20 amps. The charger will make up for any current draw that the battery can't meet.

however appear to get negative readings when charging via alternator....... alt is reading correct amps on monitor, regulator as well as at battery.

Assuming the Link gauge is more or less correct, then the current draw is ~10 amps greater than the alternator can supply. Sources of this draw can be electronics, lights, USB charging ports, electric fuel pumps, etc. etc. It could also be the case that the alternator is not producing any electricity due to blown diodes or some other fault. If you have a stock internally regulated alternator, it may not be set up to properly charge the AGMs and is not producing sufficient current to both charge the batteries and meet the electrical demand. Or the whole system could be wired incorrectly yielding erroneous readings on the gauge.

If I was a betting man, I'd bet some beer and an afternoon sail that the main problem is aging/dying batteries, followed by inadequate charging of the batteries, either the AC charger is too small or the external regulator is set incorrectly.

 

[Maine Sail]

If you are not seeing amps-in from the alt, the neg alt wire, perhaps others too, are bypassing the shunt. Again read both articles very carefully...

 

[NYSail]

If you are not seeing amps-in from the alt, the neg alt wire, perhaps others too, are bypassing the shunt. Again read both articles very carefully...

Just want to again say Thanks to all......
Yes Maine I had the alt neg attached prior to shunt... learning I am! The batteries are in their last leg though and hope to get through season with these. Was hoping to maybe switch to 6volt if I can fit them in space.

Again THANKS!

Greg

 

[Maine Sail]

Just want to again say Thanks to all......
Yes Maine I had the alt neg attached prior to shunt... learning I am! The batteries are in their last leg though and hope to get through season with these. Was hoping to maybe switch to 6volt if I can fit them in space.

Again THANKS!

Greg

It's not just the alt. No neg wires, including the start battery neg, can be on the house bank side of the shunt. There is only one negative wire allowed to "jump the shunt" and that is a Balmar Smart Gauge because the Ah counter does not even have the resolution to measure its load and because the Smartgauge needs to be on the physical battery post for optimum accuracy..

 

[dlochner]

So regulator temp and neg should also not be on battery side??

Temp sensor is OK because it does not draw any current. The regulator negative should be upstream from the shunt.

 

[NYSail]

Temp sensor is OK because it does not draw any current. The regulator negative should be upstream from the shunt.

Got it...... will move to buss after shunt.....

Thanks!