battery monitors

mshen11mshen11 Solar Expert Posts: 185 ✭✭✭✭✭
there are products like the xantrex linkpro or the trimetric that monitors one's battery. but what good are they when your battery's capacity varies based on temp, age, etc...

those machines cant do calucations, so how do you "adjust" for older batteries when using these products?


  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: battery monitors

    The trimetric has a lengthy discussion in it manual about how to configure the meter relative to the battery age and size. It is by their admission not perfect but it it pretty good. It has to do with what you tell the meter in initial set up. For instance my battery is ~450 ah, but I have the meter configured as if it were 400 ah. Also the net charging efficiency factor is adjustable so that as a battery ages you can change the charge efficiency. I'm sure there are some other things in there, I just haven't read it in a while.

    Hope this helps,

  • mshen11mshen11 Solar Expert Posts: 185 ✭✭✭✭✭
    Re: battery monitors

    went through it real fast... certainly much thicker than a page manual from linkpro (that 1 page contains 3 different languages).

    still what caught my attention in the trimetric manual is 'recharge and reset often' because it is goign to be inaccurate.

    is that the only answer? not quite what i was hoping for
  • bryanlbryanl Solar Expert Posts: 175 ✭✭✭✭✭
    Re: battery monitors
    what good are they when your battery's capacity varies based on temp, age, etc...
    The value of the 'electron counters' is that they provide a very precise number that pleases the customer who really doesn't understand the accuracy of the measure.

    They do tell you net charge in the battery with some compensation for important factors if programmed properly and that is good for determining cycle efficiency.

    For a measure of the current state of the battery charge, these devices are secondary measures and should be considered in that light if a proper interpretation of the measure is to be made.

    Net charge is not the same as state of charge and it is often the actual state of charge that folks want to know. These two measures can usually be made to be close enough over the middle of the battery life to keep many happy with the results, though.

    Voltage and specific gravity are primary measures of battery state but they also need proper interpretation and measurement technique.

    One of the more interesting battery status monitors is the Smartgauge which fits the voltage and current profile to a knowledge base to determine its measure. That is also a direct measure.

    Another interesting technique developed over the last 15 years or so is the conductance tester. This infers the battery state from its impedance. They are very good substitutes for destructive tests such as the old standard load testing. (see for the web site of an entrepreneur in this field)

    Voltage with a modern DVM is by far the easiest, safest, and most cost effective way to get an accurate assessment of battery state if you can measure it after the battery has been idle for a half hour or more.

    But electron counters are fun! meters and gauges and panels, oh my! :D
  • RCinFLARCinFLA Solar Expert Posts: 1,428 ✭✭✭✭
    Re: battery monitors

    Many folks have enough trouble just figuring out how to program in A-Hr setting, then, oh my, charging efficiency number.

    Next level of sophistication I would like to see is charge efficiency versus SOC.

    The reset reference is when battery full charging is detected by current drop off in bulk mode. Need to ensure this happen at least every week or two for good battery health. If you never get there because of insufficient charging capability then batteries will suffer anyway.
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