Testing the ??MPPT ?? CMTP02 Controller UPDATE

Hi mena,

Here you go:

mppt thread BFL13

mena661 wrote:
How about a link to that thread there bubba? :)

Roy, don't get mixed up between this test of this particular controller and how solar works in general. The idea here is just to see if this controller is a fake or real MPPT.

So far, my tests have not shown that for sure AFAIK, but indications are that even if it is MPPT you can't use it in normal MPPT situations like running a 230w 24v panel, since we don't know its Voc rating limit.

You might be getting confused because my set-up right now is with not enough solar for the size of battery bank I have (for various reasons) so don't take that as an example of anything.

I wanted to keep the results in the other thread to keep the advice I got on how to test, with the results I get.

Mena just find RJ's thread on "oh, no" --it is all his fault after all! We are talking big bucks here! (not the buck inductor, those money kind :) )

RoyB wrote:
What am I hearing here... I know I need lets say 14.4VDC @ 20AMPS per battery to be able to recharge that battery from a 50% charge state to a 90% charge state or more in a three to four hour time frame..

I think I am hearing that the PANELS are usually rated at 5-7AMPS of usable DC current available which is a big killer of getting the batteries back to a 90$ charge state but by running higher DC voltages from the panels will produce alot more current than the rated 5-7AMPS and possibly end up with 14.4VDC charging DC Voltages at a higher DC Current rate.

i.e. the controller will run at max with much the higher DC Voltages coming from the panel and produce higher DC current then using BUCK BOOST couple this back to the 14.4VDC at a higher DC current. I know I am not explaining this right but is something like this going on with the controller you are testing.

My recent planning is looking at two 100WATT or 120WATT portable panels coupled with a permanent 120WATT panel mounted on my POPUP roof. The normal rated DC output of the these panels specs using the standard type controllers will not produce a usable 14.4VDC at a high enough DC CURRENT to re-charge my batteries in the short 4-5 hours of the panels being in high sunlight in ONE DAY...

Think I am hearing something different now from these tests being performed.

Roy ken

Besides the advantage of the MPPT control, a user will get usable current from the modules on the shoulders of that 4-5 hours a day. My 235w module is still trickling at sundown.

Just boil it out.

PWM, amps, watts to battery.
MPPT, amps, watts to battery.

What am I hearing here... I know I need lets say 14.4VDC @ 20AMPS per battery to be able to recharge that battery from a 50% charge state to a 90% charge state or more in a three to four hour time frame..

I think I am hearing that the PANELS are usually rated at 5-7AMPS of usable DC current available which is a big killer of getting the batteries back to a 90$ charge state but by running higher DC voltages from the panels will produce alot more current than the rated 5-7AMPS and possibly end up with 14.4VDC charging DC Voltages at a higher DC Current rate.

i.e. the controller will run at max with much the higher DC Voltages coming from the panel and produce higher DC current then using BUCK BOOST couple this back to the 14.4VDC at a higher DC current. I know I am not explaining this right but is something like this going on with the controller you are testing.

My recent planning is looking at two 100WATT or 120WATT portable panels coupled with a permanent 120WATT panel mounted on my POPUP roof. The normal rated DC output of the these panels specs using the standard type controllers will not produce a usable 14.4VDC at a high enough DC CURRENT to re-charge my batteries in the short 4-5 hours of the panels being in high sunlight in ONE DAY...

Think I am hearing something different now from these tests being performed.

Roy ken

here's the deal for me. I have the ' Technology Comparison' from Morningstar PWM charge control/MPPT charge control ~ "Typically recommended for use in smaller systems where 'boost' benefits are minimal' MPPT ~ 170w or higher to take advantage of 'boost' benefits more. Me thinks the 'go cheapo folks' are correct for less than 170w as per MS. All will no doubt agree that for large arrays the real (whatever that is is) MPPT is the right way to proceed.


Added side note; I have the 20a CMTP02 ready to be tested soon.

How about a link to that thread there bubba? :)