DC Solar Trailer set up with 10 extra panels.

[Cking11]

Hello all,

I'm very new to the solar world and learning as I go but I'm running into trouble getting my batteries to charge and would love some input on settings/ setup/ any help to get me rolling in the right direction. Thank you in advance to all who contribute.

I recently bought a patch of dirt to live on to sum it up shortly. I am living in a 36' fifth wheel on the property while I build and found a DC solar trailer with a 10K diesel generator for what I felt like was a fair deal and was hoping to run my trailer/ set up while I build. Im hoping this topic has come up in here before and there are some people familiar with these trailers.  But in a quick breakdown I'm running 2 sunny island 6k inverters, midnite classic 250 charge controller, 2 540AH 48V lead acid forklift batteries, and 10 260 watt panels. I live in AZ and have full sun from 7am to 7pm roughly and have not once been able to get a charge from my solar system. I run my generator every night for 5 hours to charge my batteries back to 99% SOC and it will run my trailer all day but slowly brings my SOC down to 50% when I start my generator back up. My trailer is running 240V roughly 20A or a little under in most cases because of the A/C units.

Things I've tried so far.
Batteries seem to be in great working order and storage seems adequate for my need. I can shut them down at 9pm at 99% SOC and when I get up in the morning 5AM there around 75%

I have recently added 10 more panels to my array 10 Canadian solar 240W panels. Here is where my fun starts the original solar trailer is wired two sets of 5 panels in series to the combiner box the two sets are in parallel so the voltage stays below the 250 max my classic 250 can handle. Normally they ran around 150V roughly 15A coming in. I added two new panels to each of the original 5 so now I have two sets of 7. (I tried 8 but my voltage was at 259 and it kicked out the charge controller). This helped and I was running 175V about 19A. So I added a set of splitters in the one leg and added the last 6 panels wired in series and connected in parallel and bumped up my breaker in the combiner box to a 30A 300v breaker (box didn't have enough room for a third breaker). So I now have two sets of 7 panels and a set of 6 panels . I was bringing in 195V at 33A total today and hoping to get some charge but still nothing. Any suggestions or hit me in the forehead info because I'm doing things completely @^# backwards is greatly appreciated.

Sorry for the novel just not sure how to shorten that up.

[FNG]

Are you saying that with the battery at 99% SOC you shut off everything and its down to 75% in the AM? That seems excessive if everything is off.

At the end of the day these trailers where not really balanced. 1100 AH of lead acid would like to have 110-160 amps of dc charge current and would likely have a bare minimum of 55 amps to even charge without sulfating like crazy, A Classic 250 is good for about 55 amps so by design they are very lopsided.

Then take into account idle draw, two sunny islands and a classic will pull about 65-75 watts continuous and if memory serves there are timers and other stuff on these trailers so maybe closer to 100 watts so that alone is 2.4kWh a day

Last advice I can offer is do not mis match strings, Each strings voltage needs to be within 10% of each other so the one string of 6 if the VOC of that string is a lot lower it will likely cause a power loss not gain. You may need to unplug one out of each string of 7 and don't worry about pushing the envelope on voltage, Keep the voltage lower so things run cooler and last longer. It seems like you have 20 modules, I would wire them for 4 strings of 5 each string, Yes this means you need a new combiner box but it will be much better in the long run. Another thing you can do is look to upgrade the Classic 250 to a classic 200 and go with strings of 4 instead, The 200 will process a lot more power.

At 240 ish watts times 20 modules you have around 4800 watts of PV, Thinking about losses and temperature I would suspect you would see about 75% of that so 3600 watts in perfect conditions, divided by the 50 ish volts of the battery thats 72 amps, This is why I suggest the Classic 200. If you are only seeing 33 amps something is not right I suspect inbalance in voltages. Can you supply us the VOC of each model module as well as the ISC of each module type? Or images of the labels on the back.

[Cking11]

Thank you for getting back to me it's much appreciated.

The over night battery loss from 99 SOC to 75 is running both A/C units in my trailer all night so roughly close to 20A still. When everything is off they don't lose any SOC.

Wow that's a lot more amperage then I was thinking they would need (that's why I'm here) so in my brain I'm thinking I'm using 240V and roughly 20A with everything running the closer I can get or exceed that the better but that sounds like I'm thinking all wrong.

So your saying I would be better off running 4 sets of 5 panels and having my voltage around 150V with higher amperage the better? When I looked up the specs on the classic it showed max of 54A at 104 degrees or higher so that was barely enough to charge the batteries? I am not familiar with the classic 200 other then it has a 200V max can it handle more amperage? I'll look up the specs.

I'll check what my separate sets are putting out and make some adjustments to get them as close together as possible.

I tried sending this before work this morning and attaching pics of my battery and module info but my pics were to large and it erased the entire message so I'm not sure how to add smaller pictures I'm not familiar with forums either but I will see if I can figure it out. Thank you again for the info feeding my generator with these fuel prices is killing me and I need to get this sorted out.

[Cking11]

I have 10 of these modules that came on the dc solar trailer

[Cking11]

These are the 10 panels I added to the trailer

[Cking11]

This is my battery info I have two of these.

I do have another question when I first got my solar trailer with no load hooked up to it at all I had the panels folded out and charge controller on and in still never charged my batteries? Is there a guide to how I should set up the settings on my classic 250 as far as I can tell I think I'm where I need to be for settings but some conformation on that would be very helpful also I have my eq and mppt set at the 57.1 and float is 54.1 I believe if I remember correctly which is the default settings for the controller on a 48v system if I'm not mistaken. Do those settings sound right or is there some adjustments I need to make aswell

[boB]

I would say to note the PV input voltage, battery output voltage and status from lower right of the screen, like MPPT, Absorb, Resting etc...  Also the power.

Maybe a picture of the MNGP screen would be best ?

During the day of course.  Might give a clue.

[Cking11]

Here is a pic of it running currently. It does have the current limit light on occasionally.

[boB]

OK.   This picture looks pretty normal.

Besides current limiting, take a picture if you find it doing something weird.

[UpNorthMan]

My knowledge is limited, but your voltage settings seems to be low. Also does the classic read the same voltage as the batteries, or does it need to be calibrated. Maybe others with more experience can comment.
Ed

[Vic]

This is my battery info I have two of these.

I do have another question when I first got my solar trailer with no load hooked up to it at all I had the panels folded out and charge controller on and in still never charged my batteries? Is there a guide to how I should set up the settings on my classic 250 as far as I can tell I think I'm where I need to be for settings but some conformation on that would be very helpful also I have my eq and mppt set at the 57.1 and float is 54.1 I believe if I remember correctly which is the default settings for the controller on a 48v system if I'm not mistaken. Do those settings sound right or is there some adjustments I need to make aswell

Hi cking..,

The main charge settings on the Classic,  are Absorb, Float, and EQ voltages.  What are those settings in the Charge menu?
What is your Absorb time setting?

If 57.1 volts is the Absorb voltage that is quite low.  Would expect that you would want this to be 60 V, or above.  Eq would normally be 63, or even above that, for these forklift batteries, with probable high Specific Gravity electrolyte.  Float at 54-ish, is probably fine.

Later, Vic

[Vic]

... and,

Do you see any model number for the batteries,  the cell type seems of little use, so far, in searching the web.

Do you have a Hydrometer of Refractometer, so that you can measure the strength of the electrolyte (the SG)?

Thanks.  Vic

[Cking11]

Thank you all for the replies

Sorry for the late response I sent this Saturday but my service out here is not great and I didn't realize it didn't go through.

As far as battery info unfortunately that is the only tag/sticker on them I'm not sure about a model number.

I did change up my Eq voltage to 63v, my absorber is now at 60 V and I left the float at 54.4 v so far this hasn't made an improvement on any outome effects.

I was curious yesterday afternoon not a cloud in the sky I had direct sunlight on my panels and my batteries were at 75% SOC my voltage was fluctuating between 65 and 210, amperage between 4 and 42, watts from 240 to 1700. And the charge controller was saying float MPPT why would it be in float with batteries at 75%? Is that normal

[Vic]

So, if you are seeing SOC on the Classic, guess that means that the trailers came with the WhizBang Jr.  If so, the SOC gets reset to 100%, when the Classic makes its transition to Float, at the end of the set Absorb time.  The longer the time lapse between these events (speaking of days), the less accurate can become this SOC reading.

If you are seeing, "Float MPPT", that should mean that the CLassic had finished the Absorb stage.

Question:  What is the Absorb time setting in Charge>Charge time menu?  It would normally be several hours, if the batteries are discharged to about 80, or 85% SOC.

Am in the middle of a project,  back later,  Thanks for the added info, Vic

[Cking11]

I'm reading my SOC off of my inverter not the classic sorry I didn't make that clear I don't think it has the wiz bang jr. I only see absorb on my classic when my generator is running and charging my batteries and that's controlled through my inverter as well.

My absorb time setting on the classic is 2hrs and EQ is 1 hour not sure if that's anywhere near what it should be that's where it was set when I bought the trailer.  And to answer an earlier question I do not have a way to check the electrolyte in my batteries.

All the setting on this trailer for the most part were set when I bought it I wonder if I would benefit any from going through the start up wizard that first shows up when you install a new classic. Any thoughts on that?

I've been looking through different configurations or my modules to get the 3 separate sections I'm running to be as similar to each other as possible. The best case of three sets of 6 would put me running  180V , right close to 50A, 4500 watts coming in if all conditions were perfect? Is that a realistic amount of power coming in to charge my two batteries? If not what would you recommend?