Xantrex C-series charge controllers - CM panel

16 Posts
Feb 15, 2009 10:11 pm
Xantrex C-series charge controllers - CM panel

I was wondering if anyone knows whether (in Diversion Load mode) the readings on the CM display - Amps, Watts and cumulative Ampere-Hours - reflect only what's gone into charging the batteries?  In other words, when there's power being burned off on the dump load, is the display telling you how much energy your wind turbine is generating - or only how much of the energy is being transferred to the batteries?

220 Posts
Feb 22, 2009 02:39 pm
Re: Xantrex C-series charge controllers - CM panel

 hi bruce,

 still looking for that info for the c-series cm display, and to keep your thread alive. everything i see so far is saying.. no, it does not add power totals to the running counts. i'm sure a few of the other folks here are having a stab at trying to find a definitive answer for you. we see lots of wording like "depending on application" and the recommendations of dedicated diversion loads like water heater elements which would lead one to believe that the diversion power is unregulated and has not been sent through the controller. generally this "extra" power would not want to be added into the battery charge totals so we know where we are with our battery bank.

 i can see how knowing what that total production is would be of some use, especially during testing and evaluation of a new product. we can always put in some other inline meter to measure that diverted power then add it to the cm reading totals. or meter the input before the c-40 (or 60) and subtract the cm for the diverted totals.

 so it looks like you are in the market for a controller with metering abilities? if someone had a c-series with the display running wind or hydro it would be easy to tell if the cumulative totals are adding up during diversion. anyone?

 perhaps consider the c40/60 without the cm/cmr and go with the pentametric with multiple shunts for the logging.

 have fun,

cheers, dave
16 Posts
Feb 22, 2009 08:00 pm
Re: Xantrex C-series charge controllers - CM panel

Hi Dave,
Thanks for your observations.  I've been spending quite a bit of time in the field lately because we're getting into the windy season - prime time for testing. 

Between a call to Xantrex customer service (India?) and my own observations using an ammeter inline with the output of the rectifier, I have determined that all of the information on the CM front panel relates only to what's going on with the diversion load.  This has been verified in a number of ways including the fact that the "Amps" and "Watts" readings are always 0 until the dump load starts to warm up, at which time they indicate values (along with the Amp Hours).

To me this feature is not very useful, as I would really like to observe the charging energy the unit is producing and have a log of Amp Hours since the last time I checked the system.  With an anemometer showing average wind speeds, this could actually be useful performance data.

On the other hand, from a circuit design standpoint, I can see how they can't monitor the power going into the battery, since the controller is wired in parallel.  However, the dump load is on a series output from the controller, so they are able to monitor the activity on that circuit.

220 Posts
Feb 22, 2009 10:59 pm
Re: Xantrex C-series charge controllers - CM panel


 thanks for clearing that up."I have determined that all of the information on the CM front panel relates only to what's going on with the diversion load." nothing beats actual testing, and i see now (block diagram pg3 of c40 manual) that this is the only measurement possible with the controller behind and in parallel to the battery bank. so the batteries always hold the rectified turbine output down then the voltage increases to our set point then starts the metered dump through the controller. still leaving us in the dark as to battery inputs..however, in the case of fully charged batteries the metered readings will be our generator output. still somewhat useful.

 i have had good luck with these little meters. note: always keep a load on them.


 this meter will run standalone with a 9v battery for 3 months and continuously using our battery bank. maybe put one between the bridge output and the bank?

 good luck with the testing, good data speaks volumes about a product and the integrity of the folks behind it

best regards, dave

edit: rereading your post, surely you can't mean you are loosing your "total amp hour data" between visits? if so we must be powering down sometime between readings.. curious.
« Last Edit: Feb 23, 2009 12:09 am by david ames »
16 Posts
Feb 23, 2009 08:40 am
Re: Xantrex C-series charge controllers - CM panel

Hi Dave,

Thanks for the tip on the meter - they would be very useful and I'm going to order a few.  I'm not losing amp-hour data between visits.  Probably just losing my ability to construct a proper sentence!


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