New to Forum, new Kid, testing it out

[Jacotenente]

Thanks - Appreciate all the insights. I haven't changed the six solar panel configuration (series-series-series-parallel) 24v. I tested the long cable run with my Fluke multimeter at the panels and after the long run. The voltage difference was only 2 volts. As for the Tracer 3215RN I had in there...it would read 30+ amps during high sun at around 28-32 volts. I am getting very similar voltage readings with the Kid, albeit, less current. However, the two charge controllers "seem" pretty equal in performance (charging up my battery bank). In my hot garage, the Kid does get quite warm...and I do have a fan blowing on it. It might be a temperature related issue. I will continue monitoring.

This rig is running 24/7 and ultimately powers my fridge and deep freezer. I have been through three inverters (all 12v) and ended up with the Power Bright (3,500 watts continuous). I do agree a 24 volt inverter would be better and wish I had the money to get one...just got the Power Bright a few months ago. I have run the inverter with a 2KW load and it didn't even flinch...solid performer unlike the other ones I had.

Running the batteries in a 24 volt configuration is better, but, right now with my current inverter...have it wired for 12v (1 gauge cables and 0 gauge going into the inverter). Thick cables.

I do like the idea of running the Tracer 3215RN and the Kid simultaneously...when I get more panels. I may do that.

[Free Energy Freak]

(The voltage drop table posted by "Free Energy Freak" looks to be for 12 volts, but we have either 24 or 36 volts nominal for this cable run depending on the series/parallel configuration). The Voc of the Renogy panels is 22.5 volts, so 3 in series should be within spec on the Kid.

Thanks for the correction. It was pretty late at the time I added that chart to my post. In my defence, I had used the same calculator to estimate the voltage drop of his configuration that zoneblue later used. I got in the habit of sticking that dang chart up some time back, without always thinking if I was discussing 24v or 48v systems.

[Jacotenente]

Rewired for series-series-parallel. Took out two combiners. Two sets of three panels. Making better power now.

[acorn]

That's great news. You sure didn't waste any time trying the alternative panel wiring.

Is the heat situation for the Kid still the same? (Garage temp at 95+ degrees and fan as before?)

The voltage drop calculator suggested by zoneblue indicates that at 85 feet, 46 volts input, 10AWG wire, and 10A of current voltage drop should be about 1.7V, a little less than 4%. Voltage at the end of the run would be 44.3 volts. Is this the kind of voltage drop that you're seeing under load?

Was the Tracer able to provide the 30A+ output in similar conditions (inside and outside) as the Kid is seeing now? The panels are going to be pretty hot in your current weather (Wunderground says 100 F and no wind) so their output will be down. I stumbled on your Amazon review of the Tracer and you noted 34A output on 4/24. That day it was 73 F and 15 MPH wind.

Excuse this painful computation, but I'm curious where the power is going. Assuming the panel temperature is 60 C (140 F) in the current conditions:

600W total panel power x (-.44%/ Degree C) x (60 - 25) = 600 x 85% = 510W panel output derated for temp

derate an additional 5% (?) for dirt and dust on the panels:

510W x 95% = 485W

then, we have about 4% cable loss:

485W x 96% = 465W

Midnite Solar doesn't give us an efficiency spec, so assume 95% (?):

489W x 95% = 442W

442W would be 30.5A at 14.5V.

So it seems like your panel configuration is not that over sized under the current conditions (high heat, long cable run). In the winter when it's cool the panels can make more power, but the sun angles will be less favorable given your horizontal array.

Discussion and corrections welcomed...and I'm still curious to hear about Kid performance in high heat conditions.

-Scott

[Jacotenente]

Dead on accurate! Everything I read is correct except for the cable voltage loss (which was 2v instead of 1.4v). Dunno that percentage loss but, I suspect the computation will come closer to my 400 watts/29.1 amps that I was getting today. Yup, garage temps are still really warm (95+). Overall, I was happy to see a few more amps on the Kid after I rewiring the panels. Great work on the computations! It worked! - Chris

[dgd]

Jacotenente

An interesting calculation from acorn and it all looks like  a credible explanation of whats happening. However it doesn't mean everything is just right because you are obviously driving the KID to maximum capacity and doing that will raise the temperature of the KID and reduce overall efficiency.

Since you have a second controller, the Tracer, then it would be quite straightforward to wire 4 of the panels into the KID and the other two into the Tracer.
Then between them you may actually achieve more than 400 watts output to the battery bank. WIth added advantage that neither controller should get too hot or overheat.
Also, interfacing a WBjr with Deltec 500A shunt to the KID will let you see the battery state of charge plus the actual charging current from both controllers.

dgd

[b4solar]

Good suggestion about the WhizBang JR & the shunt.
For maximum battery life a battery temperature sensor is also a great purchase.


link removed by admin

[tecnodave]

Jacotenente,

I have a Kid , a Classic 150 , and several Tracers, the 30 amp 3215RN and the 4210RN 40 amp units.  I have used them on the same system so I will share my experience there.  I assume that you have noticed that you can set way more things with the Kid vs the Tracer. When you set the Kid to the proper charge voltages for your battery set the Tracer will (probably) see this as a fully charged battery and shut down.  This is because the Tracer uses a generic charge profile which is not user adjustable. You can still use them in parallel but what will happen is both controllers will share power in bulk charge state and when adsorb stage is reached the kid will do the larger part of the load. This is not the best way to do this but not being able to set the voltage on the Tracer is the limiting factor here.

I get around this by using my worst producing panels on the Tracers and depend on the power from my Classic 150 and Kid from my main panel sets.

I am going to suggest that if you expand to more panels that you put about 60 percent on the Kid and the others on the Tracer.

It is not a good idea to continually run a controller at maximum power,

That said I am running 1020 watts into the Kid 6 ea Sharp 170 watt 72 cell poly, series stacks of 2 for 70 volt p.v. String and 400 a.h. 24 volt battery, but to protect the Kid I set the current limit down to 25 amps so it will not run at max power. On the same battery set is a Tracer 3215RN with 10 First Solar CdTe panels as fog boosters.  In full sun the Tracer only contributes at bulk charge but when the fog rolls in it does a goodly share of the load.


I have seasonal pea soup fog here on the left coast as I am only 6 miles from the Pacific Ocean so I way over panel.   The Tracers save me from overloading my MidNite controllers.

I am pretty sure that when you use both of these controllers togather you will be buying a second kid.

One word of caution about the Tracer,  they do have current limiting but it does not work weary well as you have found......it will put out more than 30 amps sometimes.......but there are 30 amp fuses directly soldered to the board in such a way that they are very difficult to replace......a tattletale that you have overloaded the unit......yup, I did it....and yup, they made it very difficult to fix

[Jacotenente]

Thanks...sounds like you have a cool set up. I have my solar panels fused separately prior to entering the Kid with a 30-amp fuse. So, a little added protection. It has never blown. Heat on electronics is never a great idea...and my system has been running fine now that I put spacers behind the Kid, took off the back panel, and run a fan. Crossing my fingers. Still have my Tracer 3215RN w/meter ready to install. What about putting an aluminum plate behind the Kid mounted on the wall?

[tecnodave]

Jacotenente

It will help to cool the kid a bit......I have changed mine to marine brackets so it sits more in free air but I leave covers on to help with radio shielding issues. More RFI/EMI is produced with the covers off.
(One of my reasons for not using the Tracers.......they are radio dirty)  I just ordered a second Kid to replace the Tracer in SYS 2 and will have 2 Kid's teamed up on 1580 watts PV in experimenting with follow-me and bully modes.

The Tracers are being phased out due to non-programability. They are ok for generic systems but I like the large format batteries used in industry which have a higher charge voltage profile. The Tracer will leave them at 1.220 s.g. and consider that a full charge. This forced me to run the generator to top off the batteries weekly. Saved fuel costs by replacing 3 Tracers and generator with a Classic 150 and much less generator time will be on the order of $400/ year. Will pay for itself. One Classic =$610USD vs 3 Tracers @ $600USD........no deal....the Tracers have served their purpose, they are ok but not great.......I stick by my reviews on Amazon on the Tracer but these were written before the Kid was introduced, I has only cheaper Chinese junk to compare them to and the SunSavers and such.

td