My First MPPT Solar Charge and the Tracer 3215BN

[jrnymn7]

Well, second actually... first one got cut short due to heavy clouds... and a long ways to go to 'full'.

First, I'd like to thank those who were kind and patient enough to help me along this solar path. As BFL once put it, there's lots to learn about solar. All the debates/discussions over pwm vs. mppt, and such, have proven very enlightening and educational, so thank you!

So, here goes:

Bank... 430Ah, four 6's, ocv @ 12.44v, 74%soc, -111Ah's

Solar... two 140w 12v poly panels, in series, manually tracked, thru 50' of 6awg to a Tracer 3215BN MPPT charge controller and MT50 Remote Monitor.

10:50am:

- clear skies

- Isc at the moment was 'about' 9a (x2). (clamp meter not that reliable)

- Voc 20.6v

10:55am:

at Panels... 7.9a @ 31.2v,

at Bank... 18.9a @ 13.0v

The highest amperage I saw all day was at 11:05am, with 19a to the bank. Mostly in the mid 17's to high 18's up until about 3pm. I was a little surprised, given the conditions. A couple days earlier, under mostly cloudy skies, I saw amps in the high 21's several times... but that may have been an edge of cloud effect thing?

At 1:15pm, I switched over to the Solar30 pwm, and saw a difference of 1a to the bank, 17.3a vs 18.3a, for a 5.5% increase by the mppt controller.

Back on mppt, throughout the afternoon amps tapered to the mid 13's range by 6:40pm, and by 7:40pm, amps to bank were in the high 7's.

(At 5:15, I laid the panels flat, east to west, and saw a difference of 5.4a to the bank, 10.4a vs. 15.8a, for a decrease of 35%, compared to tracked.)


Tracer decided the bank was full at 7:50pm, at a little over 7a @ 14.5v. According to the Trimetric; which I believe is very close to being dialed in properly (...will know for sure next time I converter charge); 6.5Ah's were still missing at 99% soc. I usually take things down to less than 4a at 14.5v. This morning, (the next day), after a night of very light loads, ocv was at 12.73v... should be more like 12.77v, so I know the bank was not truly full.

10 minutes after it shut down, the Sun went down behind some distant trees, so the panels crashed, so it wouldn't have made it to full, anyway. And it was not able to go into float mode, so I've yet to see how that goes. But this raises a couple of questions:

? How does the Tracer decide when the bank is at 100% soc?

? Is there a way to re-calibrate it?

Any help would be greatly appreciated.

bn series manual

mt50 manual

In a couple days I'll be doing another run, less deep, and an earlier start, hopefully. That way I can see how the controller handles what it believes to be a full bank.

Another thing I noticed was, when set to 14.5v "max boost voltage", the monitor said 14.6v, and it took the bank up to 14.56v, according to the dmm. When set at 14.4v, it topped out at 14.5v (monitor) and 14.44v (dmm)... which is exactly the voltage I'm thinking will sync up well with my P10 CEF setting of 85%, on the Tri.

There are some other programmable settings I'm not sure about, but I'll post them, later. I'd like to get this '100% soc' thing sorted out first and foremost, seeing as this will be my main means of top end charging.

Thanxx!

[red31]

Your data is awfully confusing, did it go into float? or are you suggesting full is SOC of 100%?

What if keep it going day after day and check it from time to time?

[jrnymn7]

Red,

Yes, I was thinking it went into boost, according to the voltages, but amps would then rise back up when there was a break in the very thin clouds. This gave me the impression it was still in bulk? And I kept checking which mode it was in, and it never once said pwm, only mppt.

Am I misunderstanding the process? Can it be in mppt and boost mode at the same time?

[red31]

I thought it made to boost based on your data,

'Another thing I noticed was, when set to 14.5v "max boost voltage", the monitor said 14.6v, and it took the bank up to 14.56v, according to the dmm. When set at 14.4v, it topped out at 14.5v (monitor) and 14.44v (dmm)... which is exactly the voltage I'm thinking will sync up well with my P10 CEF setting of 85%, on the Tri.'

[jrnymn7]

Red,

During this particular run the Tracer never went out of mppt mode, nor bulk charge. The bank was in the high 90's soc, by the end, but was still able to accept the lower (evening hours) amps from the controller. But yes, you're right... I will need to adjust the boost time; but to whatever is appropriate for any given situation, it appears.

My understanding is, once battery acceptance drops below controller output, the controller will drop out of mppt/bulk mode, and go pwm/boost mode. At that time, any extra amps will simply 'circulate' back thru the panels, and amps to the bank will taper. Knowing how long it takes to top up my bank (and the impending weather) should come in handy when choosing a time frame for boost.

I still have the issue of getting to true full, though. Selecting '100% soc' determines when charging stops, and it's getting to that too early. And I doubt going into boost for a while would change that? Perhaps there are other factors that can be programmed in for determining 'full'? I know it gives me another selection choice, but I'm at a loss as to what to do with it?

Thanks for the video links... hopefully I'll find an answer to my question there.

[red31]

Tracer youtube review 4215bn

2.5 no volum, note @80C, more from direct connect vs MPPT 24v panel
https://www.youtube.com/watch?v=Ws6WHHCfETg

2, MT-50 review
https://www.youtube.com/watch?v=IoaAP61o51o

1, various comparisons
https://www.youtube.com/watch?v=dFuZywwpfaU

[red31]

jrnymn7 wrote:

? How does the Tracer decide when the bank is at 100% soc?

? Is there a way to re-calibrate it?

When does the Tracer go into float? 2 hrs at boost voltage

user defined up to 3 hrs.

ViewStar 10A pwm has the same menu on the front of the controller.

volt comp vs SOC (charge mode) ??????

[BFL13]

jrnymn7 wrote:
So, mppt in parallel? hmmm, never thought to compare that. Not much 'extra' voltage there to work with, but I guess it would be a fair comparison? I guess it's no different than simply running each controller off its own single 12v panel, like in that marine test?

I've been thinking about your results, and was wondering if it's not so much a matter of "measurement error", but one of "data inaccuracy", due to meters/measuring devices rounding up or down? I noticed with the Tracer's mt50 meter, it only goes to one decimal place for voltage... and my dmm does likewise, when in its 200v range, vs. its 20v range, which goes to two decimal places. As a result, it often appears the Tracer is doing better than 100% efficiency.

The idea is to compare 12-12 or 24-24 when controller efficiency is better than with 24-12. As a bonus you can get your MPPT series 24 vs 12 parallel comparison if you are a quick connect artist.

I just did the hot panel test (July came early this year) and will post them for all to take shots at in a new thread.

[Salvo]

What is ocv?
Where did that come from?

[jrnymn7]

So, mppt in parallel? hmmm, never thought to compare that. Not much 'extra' voltage there to work with, but I guess it would be a fair comparison? I guess it's no different than simply running each controller off its own single 12v panel, like in that marine test?

I've been thinking about your results, and was wondering if it's not so much a matter of "measurement error", but one of "data inaccuracy", due to meters/measuring devices rounding up or down? I noticed with the Tracer's mt50 meter, it only goes to one decimal place for voltage... and my dmm does likewise, when in its 200v range, vs. its 20v range, which goes to two decimal places. As a result, it often appears the Tracer is doing better than 100% efficiency.

[BFL13]

You don't need to wait for the solstice. The Declination sort of flat tops either side of it within half a degree approx, so tilt angles the same between now and early July.

Your next task, should you decide to accept it, is run a comparison with the panels in parallel for 12-12 and MPPT vs PWM when ambient is 25C or above. (we will assume that makes panel at least 50C) Insolation the same for each but doesn't have to be at max amps, just fairly good and in the same conditions, to compare whatever amps you get each way.

I can only do this with 24-24 since I only have the one 24v panel, and I would like to see what you get. The "issue" is whether the higher panel temperature that reduces panel power will take away from the "MPPT advantage" compared with straight PWM that uses panel amps that do not reduce with high temperature.

There is no way for me to tell if my own results are unique (and weird?) without a separate example. Thanks

[jrnymn7]

Thanks, BFL,

Understood, I just want know I CAN get to true full, using solar.

I forgot to mention, I did that 74-99% in 9 hours, so not too shabby, at all. Of course, I won't always be there to do manual tracking, so I still need to do a completely flat run, and a few tilted/occasionally-turned runs, simulating what I can likely do when working during the week. Summer solstice is nearly here, so I'll be able to see how things work in the best of conditions.

[BFL13]

jrnymn7 wrote:
Well, second actually... first one got cut short due to heavy clouds... and a long ways to go to 'full'.

First, I'd like to thank those who were kind and patient enough to help me along this solar path. As BFL once put it, there's lots to learn about solar. All the debates/discussions over pwm vs. mppt, and such, have proven very enlightening and educational, so thank you!

So, here goes:

Bank... 430Ah, four 6's, ocv @ 12.44v, 74%soc, -111Ah's

Solar... two 140w 12v poly panels, in series, manually tracked, thru 50' of 6awg to a Tracer 3215BN MPPT charge controller and MT50 Remote Monitor.

10:50am:

- clear skies

- Isc at the moment was 'about' 9a (x2). (clamp meter not that reliable)

- Voc 20.6v

10:55am:

at Panels... 7.9a @ 31.2v,

at Bank... 18.9a @ 13.0v

The highest amperage I saw all day was at 11:05am, with 19a to the bank. Mostly in the mid 17's to high 18's up until about 3pm. I was a little surprised, given the conditions. A couple days earlier, under mostly cloudy skies, I saw amps in the high 21's several times... but that may have been an edge of cloud effect thing?

At 1:15pm, I switched over to the Solar30 pwm, and saw a difference of 1a to the bank, 17.3a vs 18.3a, for a 5.5% increase by the mppt controller.

Back on mppt, throughout the afternoon amps tapered to the mid 13's range by 6:40pm, and by 7:40pm, amps to bank were in the high 7's.

(At 5:15, I laid the panels flat, east to west, and saw a difference of 5.4a to the bank, 10.4a vs. 15.8a, for a decrease of 35%, compared to tracked.)

..............

Thanxx!

My "standard" for expected max amps to the 13v battery for aimed panel wattage is based on 130w-8.2a, so 280w should yield 280/130 x 8.2 = 17.66 amps

You got 19a with MPPT and 17.3 with PWM (at different times), so IMO your set-up is working just fine! 🙂

Choosing the Tracer, with its high Voc limit to let you put 12s in series, was obviously the right choice over the Eco-W with its limitation of 42 or 45 Voc that means it can only do one 24v panel but not two 12s.

I don't fuss about getting to 100% every day on solar. Sometimes you do and often you don't. As long as you get to 100% once in a while and do shallow cycles like 75-95s, you don't need to EQ much if ever. The SG will tell you how that is going.

Good report!