What is the best affordable electronic battery monitoring system

[Trim50]

I looking to buy the best electronic battery monitorig system I can get for less than $500...any suggestions?

[Rick]

Dollar for dollar the best REAL battery monitor is the E-Meter (Link 10) or the Link 1000. The Link 2000 will messure two battery banks OR one bank and a charge source such as a PV array or windgenerator (measures accumulated energy delivered).

What I call a REAL battery monitor is one that not only shows the usual Amp-hours but actually measures true energy into and out of a battery bank (kilo-Watt-hours) and one whose measurements are stable for long periods of time and over a wide temperature range.

The Link 10 has an optional battery temperature sensor (otherwise you enter it manually). The Link 1000 is temperature sensor "ready" yet I do not know if Xantrex is making the temperature sensor for both of these products (not originally designed by them).

[Trim50]

Originally Posted by Rick

What I call a REAL battery monitor is one that not only shows the usual Amp-hours but actually measures true energy into and out of a battery bank (kilo-Watt-hours) and one whose measurements are stable for long periods of time and over a wide temperature range.
.

Yep, that is what I'm looking for! Thanks

[GordMay]

Rick really knows whereof he speaks.
Xantrex Link 2000 Integrated Battery Monitor and Inverter/Charger Control
$409.99
Xantrex Link 2000 - Xantrex Heart Freedom Marine Chargers/Inverters

Xantrex Link 1000
Integrated Battery Monitor and Inverter/Charger Control in a Single Panel
$248.99
Xantrex Link 1000 - Xantrex Heart Freedom Marine Chargers/Inverters

[EngNate]

Newmar DCE-VAH-110

Pricey, at US $399 list, but very high quality, has NMEA data output, and 1-1/4" / 31mm digits. I will sell them for $329.

[Jay Knight]

I have the Link 2000 and have been very happy with it! No problems in 5 years. It is electrical "gas gauge" and is pretty user friendly.
Jay
Orion 33

[Vasco]

Only problem with the Link is it'll sometimes reset to zero on "amps used" when charging even though you might still be -20 amps or more. This happens soon after the charging has stopped. Cannot find out why and I have checked other Links and they do the same. Spent most of the first season with one trying to figure this out without any luck. I look at it as a "guide" and not as an accurate indication of state of the battery as far as "amps used" goes. I have the 2000.

[CSY Man]

I like this unit.
Had it for a couple of years, including the optional
battery temps sensor. Price around $200.00 or so.

[Paul Elliott]

Originally Posted by Vasco

Only problem with the Link is it'll sometimes reset to zero on "amps used" when charging even though you might still be -20 amps or more. This happens soon after the charging has stopped. Cannot find out why and I have checked other Links and they do the same. Spent most of the first season with one trying to figure this out without any luck. I look at it as a "guide" and not as an accurate indication of state of the battery as far as "amps used" goes. I have the 2000.

I believe that this happens when the AH calculations get "out of sync". This can happen when the battery is only lightly cycled for a while. There is a Xantrex tech note that discusses "negative and positive amp-hour accumulation". The -20AH you see is in fact not correct, and when the battery is finally more-deeply discharged and then fully recharged, the Link monitor recognizes the fully-charged battery condition and so recalculates the battery state (back to 0 AH).

I see this happen often, and sometimes the accumulated AH error can be over 100AH (I have about 1000AH of 12V batteries). It can be annoying, but it sure feels good when I am charging and all of a sudden the battery monitor jumps to a fully-charged indication.

[fla.sailor]

I think I want one of these suckers, but my charger is not a xantrex. How well does the Xantrex 1000 work with other chargers??

thanks!
-dennis

[Pblais]

I think I want one of these suckers, but my charger is not a xantrex. How well does the Xantrex 1000 work with other chargers??

You would be better off getting the Link 10 stand alone monitor for one bank Link 20 is for two banks. It needs no connection to any charger or inverter. It only connects to the battery bank(s).

[Vasco]

Originally Posted by Paul Elliott

I believe that this happens when the AH calculations get "out of sync". This can happen when the battery is only lightly cycled for a while. There is a Xantrex tech note that discusses "negative and positive amp-hour accumulation". The -20AH you see is in fact not correct, and when the battery is finally more-deeply discharged and then fully recharged, the Link monitor recognizes the fully-charged battery condition and so recalculates the battery state (back to 0 AH).

Paul,

Interesting but this happens most of the time. Whether the battery is lightly cycled or deeply discharged (50%). I watched this for nearly six months, every day when I first got the Link. I was anchored for the whole time. Starting with a "full" battery, discharge it 200 amps, charge the battery putting in 150 amps. Stop charging and it'll reset from -50 to 0. I have used 200 amps, put back 150 but the Link says I'm back to "full". If I kept charging the amps would still go in and reduce the -50 but if I stop charging the Link says I'm "full". If I did this 3 days in a row (I kept all the numbers in my log) I'd be down 150 amps on paper but the Link would say I'm topped right up. I cannot understand this. At first I thought that it might be my wind charger interfering with the process of charging from a Honda 2000 but whether I had the KISS on or not this "error" would crop up. I have learned to live with it and do not take the Link as an accurate reflection of the state of discharge but as a "guide" to the state of the batteries. I have read the manual a hundred times but cannot figure this out. If the Link is an accurate reading of amps used and amps charged how does one account for the difference. I should say, because I thought it might be that the batteries were losing their capacity, I did this again last season with brand new AGM's and got the same funny result. Beats me.

[Paul Elliott]

Rick,

Here is a link to the tech note: http://www.xantrex.com/web/id/74/docserve.asp

This describes how the "surface charge" is replenished at about 100% efficiency, rather then the 90% (or so) efficiency you see when replenishing the bulk charge. The Link2000 calculates all charging at the 90% (or whatever efficiency has been programmed). Thus, when lightly loaded and near full-charge, the effective recharge is under-calculated.

I believe I see this happening when VALIS sits in her slip or at anchor, with little or no load. I have a decent solar bank (300W), and I don't think the trickle charge the controller puts into the bank is being properly accounted for.

This doesn't explain what you and I see during periods of hard usage, though. On passage, I will run for a few days, with the solar panels giving me a power surplus during the day, but not quite enough to compensate for the evening's consumption. I probably run about a 150AH deficit over the 24-hour day, and after two or three days I will run the engine to charge the batteries up to around 80% (or if the charging current has dropped significantly). Occasionally during charging, the AH display abruptly resets from some large deficit, and shows a full charge with 0AH shown.

This isn't the surface-charge phenomenon that the tech note describes, and I have no explanation for it. Like you, I use the Link2000 as a rough guide only. I monitor battery voltage as well, and my AGM bank, installed in 2002, still seem to be operating at full capacity. I did a load test last summer before leaving for Hawaii, and the bank seems to be healthy -- so I'm not going to worry about the discrepancies. An explanatin would be nice, though.

[Rick]

There are several parameters which govern when the Link (10, 20, 1000, 2000) monitors declares a "full" battery thereby resetting any negative or positive accumulation of Amp-hours. The first is the set of "charged" parameters outlined in the manual. The second is the declared value of "n" used in the Peukert calculation (effective whenever a battery is discharged in the region of current value that the Peukert effect is valid). The third is declared or measured battery temperature. The forth is the requirement that the amount of true energy removed from the battery gets replenished IN ADDITION to the "charged" parameters being met. The fifth element is the declared value of efficiency (often set too low for the newer AGM batteries, for example).

A secondary effect is the validity of the claimed capacity of the battery but don't worry this one unless you are attempting to make lab tests using the monitor.

Once the charged parameters are met in addition to the energy return requirement the indicated number of Amp-hours is reset to zero and the fuel guage flashes one of the green Leds to indicate that the battery is "full". Once there is ANY discharge from the battery the "full" indication is reset and the fuel guage is static. This phenomenon may be somewhat of a point of confusion when a charger is constantly on line AND some dc loads cause the battery to provide some current when the charger fails to have instant regulation response before kicking in the added current requirement from the exact time prior to when the load came on. In addition, if there is poor line regulation of the charger the same thing may occur.

For high quality AGM batteries the value of "n" is closer to unity than many flooded-cell batteries and the efficiency is much higher than 90% in many cyclical applications. So, if you are consistently showing a negative number of Amp-hours at the time of a "full" declaration consider setting the efficiency close to 100% and "n" close to 1. If you experience cyclical charges and discharges which do not cause load currents equal to or greater than the 20-hour discharge current rating (divide the number of Amp-hours of the battery bank by 20 to get that value of current) AND you are able to find an efficiency value which causes the displayed number of Amp-hours to coincide with zero at "full" then you can make experimental discharges with heavier currents that put the battery into the Peukert effect and then change "n" incrementally until, again, the "full" value of
Amp-hours coincides with a zero reset. This is a tedious manual method of making a real-world determination of efficiency and "n".

A further refinement may be made by changing the default values used for the charged parameters.

[EngNate]

...I was just finishing this when Rick Posted... charged paramaters:

Check setup parameters: Declared AH , Charged Volts , Charged % are what the Link actually uses to determine when full charge is reached. The sudden change from -X to 0 AH is the meter synchronizing, and it is virtually certain that the set paramaters have been met when this happens, e.g.: A 500 Declared AH setting will synchronize (be declared fully charged) when charge current falls below 10 amps while voltage is at or above the charged volts setting. The meter must synchronize regularly to be accurate, errors accumulate rapidly when this doesn't happen. Turning off the charger during the last 10-20% of charging will create the same paramaters the Link is looking for, especially with light or no loads on the batteries. If your situation is that charging power is available intermittently, especially if also relatively low capacity (less than around 15% of bank AH) it would be appropriate to increase the Charged Volts setting to prevent the meter from synchronizing prematurely when charging is interrupted or sustained loads exceed the charging capacity, causing the same effect. The way I'd determine the setting would be: Fully charge the batteries by keeping voltage uninterrupted at 13.8 to 14.2 volts until the charge current is flat (no longer diminishing). Select V on the meter, turn the charging source off, and note the voltage reading after a minute or so when it is steady. Set the Charged V to that value. If you find the meter still seems to synchronize prematurely, increment the setting higher. If the meter will not synchronize at all, increment the setting lower. The Charged % setting should not normally not be changed from the factory set value of 2.