Which Battery Monitor ?

[Hyprdrv]

Would you prefer to see what a total bank is or individual battery state? My boat is electric drive. Knowing what the state of the individual batteries are in a 12 pack is vital. I've installed a system called PakTrakr and 15 minutes after installing it discovered one battery was in bad shape along with 2 that were slightly undercharged or unbalanced. If I went by the Link10 I would have never known it. The charger would have continued to try and charge the bad battery and possibly overcharged the rest. BMS are relatively new but the information needs to be something you can use.

Steve in Solomons MD

[Patrick_DeepPlaya]

Originally Posted by Hyprdrv

Would you prefer to see what a total bank is or individual battery state? My boat is electric drive. Knowing what the state of the individual batteries are in a 12 pack is vital. I've installed a system called PakTrakr and 15 minutes after installing it discovered one battery was in bad shape along with 2 that were slightly undercharged or unbalanced. If I went by the Link10 I would have never known it. The charger would have continued to try and charge the bad battery and possibly overcharged the rest. BMS are relatively new but the information needs to be something you can use.

Steve in Solomons MD

PakTrakr Multi Battery Monitor Battery Pack Monitor

That looks really cool, and to be honest it'show I thought these devices should have worked any way. I'm hopeful the more technical minds will weigh-in on the pros\cons.

-p

[Patrick_DeepPlaya]

I contacted PakTrakr and they say you need two a remote for each battery bank. I'm not sure how many banks per display you can have. I'll point them to this thread.

-p

[Stefan128]

In some cases a very simple Ah counter seems to be useful - the one like this RV & Marine Battery Monitor I met a few guys that loved this Ah counting philosophy.

[Hyprdrv]

Patrick,
Max number of batteries on a remote is 6. The problem is how far away is your second bank from the first if you have less. Since my 12 propulsion batteries are all together my 2 remotes were mounted side by side. The issue was the location of the display which was 30 feet away. PakTrakr fabricated the connecting wires to my required length and problem solved. The also spread the box (conformal?sp) so it was somewhat water proof and I'll mount inside a water proof box at the helm. I'm also adding a second larger monitor (not from PakTrakr) at the Nav Station for easy reading. You can add as many batteries as you want, just add remotes in a daisy chain and you don't need exactly the number 6 either. The monitor will recognize how many you have and display them. If you have more than 1 pack they probably can extend the wires for you to chain them together. Great guys to work with and will work with you.

Steve in Solomons MD

[Stu Jackson]

Jay,

You may be interested in this thread: Link-series Charging Algorithms -- The "Gotcha" Factor!

Stu

Originally Posted by JayH

I've noticed that the SOC on my Victron BMV tends to lose capacity noticeably after about a week. I can tell from the batteries' acceptance rate that they are closer to full than the BMV indicates.

The unit is designed to automatically "sync" itself back to 100% periodically when it sees float voltage and low current. Unfortunately, my solar installation creates this scenario when it is trying to charge but house loads are pulling the current down, so I have the sync disabled.

Because of this, and since I rarely plug into the dock anymore, I have to do the sync manually from time-to-time.

The cause of the SOC getting out of sync may be because of incorrect settings for either the Peukert Exponent, or Charge Efficiency Factor, both of which the BMV allows you to set.

[Jeff Millar]

Amplepower has a good one also.

[Extemporaneous]

Just sharing....
I have read many times that a lead acid battery is dead when it reaches 10.5 Volts. I assumed that was measured at rest. I've just read that it is actually when it reaches 10.5 Volt with a 20 hour rated load applied.

Perhaps most knew that but I certainly had it screwed-up, so I thought I'd mention it........ for those using a volt meter to monitor their batteries.

Cheers,
Extemp.

[4wsilver]

Originally Posted by Extemporaneous

Just sharing....
I have read many times that a lead acid battery is dead when it reaches 10.5 Volts. I assumed that was measured at rest. I've just read that it is actually when it reaches 10.5 Volt with a 20 hour rated load applied.

Perhaps most knew that but I certainly had it screwed-up, so I thought I'd mention it........ for those using a volt meter to monitor their batteries.

Cheers,
Extemp.

This is an important point and worth mentioning. Some of the early responders to this thread obviously did not know it, one kept ranting about only measuring voltage after resting battery 4 hours. Charts are available for comparing battery voltage for: AT REST, 20 HOUR (discharge) RATE, and many other conditions. The 20 HOUR RATE is the most accurate indicator of charge. I will also note that you can calculate the 20 Hour Rate by simply dividing the battery amp hour rating by 20 to get amps.

I read this to get an idea of an inexpensive battery monitor for several different applications. It is clear that one size does not fit all. I currently have Xantrex pure sine inverter-charger in one unit and I will say that I will avoid Xantrex not based on poor performance or unreliable operation, but the customer service is not good. I was given inaccurate answers about their product and only because I had already studied it myself, was I able to use it. I will note that the temperature function will not work on LIFEPO4 units. That is the only accurate information that customer service gave me.

I am currently looking at the BMV and Paktrakr units. Each had advantages and are inexpensive enough. One fits one application and the other fits a different application better.

Ironically I am reading this forum after watching news of the meltdowns of the Nuclear plants in Japan last night and remembering the problems we had with the regulatory agencies in Japan and US regarding battery banks and monitoring at Nuclear plants. Neither of these countries would allow state of the art battery monitoring (used in most manufacturing plants for DC banks) for the DC battery bank which backs up the backup Diesel generators to pump water. They also didn't allow an increase in the battery banks to allow a 24 hour backup rather than the 1 hour in the original design. I wrote several procedures for changes that were never allowed. The other thought is that the operators should have initiated a full scram at the first sign of the earthquake. It is obvious that they did not.

[Mark Johnson]

We have had excellent results with our "Link 10", for over 15 years now. To use the v reading alone is shear folly. It is NOT an accurate assessment of a batteries state of charge. If one wants another, less complicated solution than monitors... it's using a hydrometer to test the "wet" batteries specific gravity. It is not likely that anyone would do this several times a day.

Once batteries have been installed in your boat, the FIRST electronic "gadget" to install, is a good monitor.

Mark

[Hyprdrv]

"I will also note that you can calculate the 20 Hour Rate by simply dividing the battery amp hour rating by 20 to get amps."

Could you explain what the "AMPS" is indicating better for me? Is this just indicating the amp draw per hour over a 20 hour time period? I'm not sure I understand the correlation. Dead is dead no matter how you get to 10.5v even if the battery is just sitting there right?

Steve in Solomons MD

[Hyprdrv]

Mark,
I had the Link 10 when I bought my boat. The issue I had was not knowing the state of the individual batteries, in my case 12 propulsion bank AGM's. The Link 10 only shows the state of the entire bank. This can be misleading since an overcharging or undercharging can occur if you have a bad battery in the string. Most chargers look at the pack as a whole not on an individual battery bases so that once one battery reaches it's charge parameter it switches to the next perameter without looking at the weekest state of charge in the string. This could lead to undercharging the bank as a whole if the peramiters are wide enough. To solve this issue I'm also installing a balancing system that will shuffle power between batteries to "balance" them. A Hydrometer isn't going to work in my case.

Steve in Solomons MD

[PamlicoTraveler]

I recommend the Link 2000 and other Xantrex products EXCEPT to say they offered me no customer service or support. We had to replace ours after a power surge and their customer service was the worst.

[Mark Johnson]

Originally Posted by Hyprdrv

Mark,
I had the Link 10 when I bought my boat. The issue I had was not knowing the state of the individual batteries, in my case 12 propulsion bank AGM's. The Link 10 only shows the state of the entire bank. This can be misleading since an overcharging or undercharging can occur if you have a bad battery in the string. Most chargers look at the pack as a whole not on an individual battery bases so that once one battery reaches it's charge parameter it switches to the next perameter without looking at the weekest state of charge in the string. This could lead to undercharging the bank as a whole if the peramiters are wide enough. To solve this issue I'm also installing a balancing system that will shuffle power between batteries to "balance" them. A Hydrometer isn't going to work in my case.

Steve in Solomons MD

This is true. Monitors only measure the state of charge of the bank as a whole. It is a given that if you have a bank of batteries in parallel, every battery, as well as every cell of every battery, must be within normal parameters. Otherwise, you are both getting an inaccurate perception of what to expect from the current state of charge, but you will quickly ruin the other batteries in the bank. I would just monitor the bank as one, and if it is ever underperforming in ANY way, test the capacity of each battery individually. If there is a bad one, remove it right away.

To test a batteries capacity, disconnect it from the others... Then start with a full charge, and put a 20a load on it until it reaches 10.5v, measured with a high quality digital multimeter. Next, do the math. A 100a/h battery should theoretically deliver 20a for 5 hours, etc. Seldom do even new batteries match their rating, but within 90% is considered OK.
With a smaller bank, a monitor can alert you to go looking for a problem, but the above test is how you find it. IF you had "wet" batteries, a specific gravity test of each cell, (after charging), will tell you that you have a bad cell right away.

In your case, with THAT many batteries in your bank, a single cell or perhaps single battery having a problem, may well not be evident right away, because it is such a small % of the bank. You will have to test once in a while, or perhaps there is a more creative solution? Hmmm...

Mark

[Mark Johnson]

Originally Posted by PamlicoTraveler

I recommend the Link 2000 and other Xantrex products EXCEPT to say they offered me no customer service or support. We had to replace ours after a power surge and their customer service was the worst.

When we got our "Link 10" years ago, it came with a small thick white book that claimed to have ALL of the answers... They had a contact phone number, and said that they "would be glad to help" in the set up process, but if after answering your question, they could show that the answer had been in our "white Book", we would be charged $100.00 SERIOUSLY! We read the book for hours, until we found the answer...
Many companies, unfortunately have this attitude.

Mark