MPPT20CC timer function | Old Renogy Forum

tincup
Guest

MPPT20CC timer function Feb 4, 2017 11:03:43 GMT -8

Post by tincup on Feb 4, 2017 11:03:43 GMT -8

I have read the T1 & T2 sections in the manual several times and am confused and need help is decoding the instructions.

Under T1

"Load will be on for (X) hours after a 10 minute delay since sunset". I THINK that means for example, if the sunset is 5PM and I want the load to come on at 5AM, I would set T1 to 12. Is that correct anyone?

If I disable T1 and T2 does that mean the controller will not charge the batteries?

My opinion. I do not understand why there is even a timing circuit involved here. I have been off grid for almost 10 years with 3KW of solar feeding my living quarters. This Renogy only feeds two 12V batteries in series with a single load of a 24V fridge. I guess I have a simplistic view of solar energy. When the sun is shining the batteries get charged if needed, when the sun is not shining the batteries don't get charged. Someone explain to me why I want the timers set.

Thanks for your time.

Paul

spiderbob
Solar Addict

Posts: 229

MPPT20CC timer function Feb 4, 2017 15:34:02 GMT -8

Post by spiderbob on Feb 4, 2017 15:34:02 GMT -8

For my purpose, I have an RV, I want a light to come on after dark, but both security and for finding my RV when I return from a walk or with the dogs. I also use the same circuit to run an LED when I have it in storage, it's a way to fool someone thinking I have an alarm on. There are countless reasons, but I believe it is more of a personal type of use than any other.

rabird
Solar Fanatic

Posts: 552

MPPT20CC timer function Feb 4, 2017 17:17:01 GMT -8

Post by rabird on Feb 4, 2017 17:17:01 GMT -8

could ya be more specific which controller you are concerned with?

Load control can be timed on after dusk when the panels voltage reaches the night time threshold, then a 10 minute delay before the load ( a night light etc) would be turned on if using the load terminals. Normally the load would last some time or be OFF when the sun starts to shine and the panel voltage exceeds the day time threshold.

It is very common to not use the load terminals at all and hook up 'stuff' to the battery. I use the load terminals on a PWM controller to turn on landscape lights for 3 hrs once the panel voltage has dropped to 5v, ie dusk!

Do you want to time control a load at night? If so you use T1 and T2 and hook the load to the load terminal, if not, hook your load to the battery and disregard the load terminals.

Setting the load to OFF has nothing to do with battery charging, in fact its a way to turn on lights at dusk and off at dawn or some time after dusk and some time before dawn.

T1 of 3 hrs means the load terminals will be on (12v) for 3 hrs after dusk.
T2 of 3 hrs means the load terminals will be on (12v) for 3 hrs before dawn,

The controller assumes a 'nighttime' length until it learns how long 'night' is.

Last Edit: Feb 4, 2017 17:30:19 GMT -8 by rabird

cosmicboss
Solar Lover

Posts: 50

MPPT20CC timer function Feb 23, 2017 13:08:36 GMT -8

Post by cosmicboss on Feb 23, 2017 13:08:36 GMT -8

In other words, NEVER HOOK/CHARGE BATTERIES FROM THE DC LOAD TERMINALS of a charge controller. It is meant to control small DC loads, like a light, to come on and off at pre-set and pre-determined times.

Batteries should be connected only to the BAT terminals of the CC.

The timer is just a freebie feature that most often that not is ignored by most users. In your case it sounds like you have never used it, but if your cabin was just a weekend getaway that you don't visit during the week it may be nice to have a light that comes on at dusk and turns off at dawn to give the impression that someone is home.

I think that is why a timer feature is included.

My CC also has the push-on/push-off feature, probably to power a light in any electrical room/closet, battery storage, etc. it would be a push of a button away.