In need of info and input

kd7irm

New to solar, please be kind.

Just moved onto ranch with the following off grid system and am looking for info and input,
-if it all matches up or seems mismatched?
-best set points for controller and inverters?
-best angles for panels? (outside of Bagdad, AZ)
-how long and how often should gen set be run to fully charge batteries?
-what is the diff between float and bulk?
-should all panels be aimed the same way?

System- (set up to run large home and large shop)

Gen set:
Stamford 15kw 240v, behind a 2 cylinder china diesel.

Batteries:
Deka AVR unigy II 6v 1140AH @8hr @ 1.75 vpc rated. x24

Inverters:
Trace 4000 watt SW4048. x2 (in series stacking)

Controller:
Outback MX-60 MPPT.

Panels:
Photowatt 55 watt x36
Carrizo solar 35 watt x4

(panels are set up on 5 array mounts that i can adjust by hand from east to west
but have no adjustment for north and south angles.)

any and all help, comments and info will be appreciated, thank you.

Cariboocoot

Re: In need of info and input

kd7irm wrote: »

New to solar, please be kind.

Just moved onto ranch with the following off grid system and am looking for info and input,
-if it all matches up or seems mismatched?
-best set points for controller and inverters?
-best angles for panels? (outside of Bagdad, AZ)
-how long and how often should gen set be run to fully charge batteries?
-what is the diff between float and bulk?
-should all panels be aimed the same way?

It's a bit "old tech" but if it works, it works.
Best set points would be whatever it's at now, unless it isn't functioning well.
My favourite panel orientation site: http://www.macslab.com/optsolar.html
Ideally you shouldn't have to run the gen to charge the batteries. What does the MX60 say? When it says "Float", regardless of charge source, they're charged.
To understand the charge process read up on the Battery FAQ's:
http://www.windsun.com/Batteries/Battery_FAQ.htm
Usually all panels are aimed due South or solar South. Sometimes they are pointed differently in order to maximize harvest over the day or clear obstructions or get early/late charging, depending on what was necessary for the site.

So you've got 1980 Watts of one type panel and 140 Watts of the other. These two panels are probably not terribly efficient (old, age loss, Vmp/Imp differences). But 2120 Watts @ say 75% efficiency = 1590 over four, possibly five hours of good sun should see yields around 6 to 7 kiloWatt hours a day.

Your batteries are probably about 1368 Amp/hrs @ the 20 hour rate so they'd want a pretty large current to charge with: 68 to 136 Amps. Obviously this set-up can not supply that. Unless the gen has been used regularly the batteries are probably sulphated and down in actual capacity. Can you check each cell with a hydrometer? You don't know how old they are by any chance?

The Trace inverters were fine units in their day, but that day has gone. Hard if not impossible to get them repaired now should they fail. Or rather when they fail as they eventually will.

Is there any part of the system you feel is not working or needs improvement?

kd7irm

Re: In need of info and input

Thanks for your info, very very helpful.

Most of the panels are from the mid to late 80's with a few that are newer. The mx60 controller was made in 2004, the trace inverters where made in 1995. The deka batteries are new within the last year. The MX60 has never said bulk or float yet, but when the gen set runs, the inverters will go into bulk then float after a good 8 to 10 hours, but again the inverters say it while the mx60 does not. Today after a bit of fine tuning the aim if the panels, the mx60 read 9.6 kWh for the day, the best yet Ive seen out of it. Top wattage output from the panels the mx60 has read at any one time is about 1,450 watts. Why would the inverters got into bulk or float but the controller does not read that at the same time?, when they(inverters) are in bulk or float the mx60 reads only about 53 to 55 amps for the batteries but as soon as the gen set is shut down they drop to 50 or so within seconds, what could this mean?

rplarry

Re: In need of info and input

KD
At first glance I would say you have too large a battery bank, or not enough panels. You might try deviding your bank in half (that may not be possible with your set up) and using a battery switch, only charge half your batteries at a time. That will help get your batteries up to the factory voltage spec. Check the mx60 and make sure it is set to charge your batteries to that factory reccommended voltage also. (look online to see what the voltage should be) Make sure that the absorb time limit is long enough to let the batteries fully charge. When the mx60 is charging your batteries it will display "MPPT" not "BULK" so look and make sure that is what is displayed. When the charge voltage is met the mx60 will then display "absorbing", how long it absorbs is progammable in 1 hour increments up to a 4 hour max. Let it absorb until the amps going into the battery bank gets down to between 1% and 2% of the battery banks amphour capacity. In your case it would be between 14 and 28 amps, Less if you devide the bank in half or thirds. Finally once the absorb time limit is met the mx60 will display "FLOAT" and at that point, if you have set it up correctly you can consider the batteries fully charged.
Good luck,
Larry
PS Is there a battery temperature sensor on your batteries? If not I would highly recommend one.

Cariboocoot

Re: In need of info and input

That the batteries are fairly new is good; keep charging them via the gen and you'll be able to keep them. The panels are definitely insufficient for charging such a large bank. Not sure how big the charger is in those inverters - 50 Amp? 80? The two together should be enough anyway.

I agree with what rplarry says: the settings on the MX60 and the inverters are obviously different and should be aligned. Also the battery temp sensor is a must. You can get manuals on-line for most anything these days, if yours are missing. Outback site has the MX60: http://www.outbackpower.com/pdf/manuals/mx60_pv_mppt.pdf
The Trace manual might be more difficult to find.

What I find troubling is that the MX60 output goes up when the gen is on? It should go down. Sounds lie something isn't wired right, although for the life of me I can't reason how someone could have done it so. This could be related to the mismatched panel issue.

kd7irm

Re: In need of info and input

this may help, the batts are deka avr's models 3avr95-25 im trying, for the life of me figure out what amps i need to charge them and cant get it yet, i know the c/8 rating is 1140ah at 1.75 vpc. they are 6volt batts and have 3 cells each and there is 24 of them. i believe the series voltage for the rack output is 126 volts, i think. these batts are a little confusing in this application.

niel

Re: In need of info and input

ok just a few things i see and note that i did not read the entire thread in depth.

the batteries must be in a series/parallel arrangement as the inverter is at 48v meaning it takes 8 6v batteries to reach that. for 24 batteries this is 3 strings paralleled. from the pdf on the battery
http://www.affordable-solar.com/admin/product_doc/Doc_Unigy%20II%20Data%20Sheet-0919C%20rev_7-07_20090615232306.pdf
one can see that for 24hrs (closest to the 20hr we nominally use here) it is rated for 58a. for 24hrs that's 58a x 24hrs = 1392ah capacity. if you go by the 10hr rate the ah capacity will be slightly smaller. with 3 strings of batteries this is a whopping 4176ah capacity. at the 5% (20hr rate) minimum charge rate we often recommend this will be 208.8a. it will charge at a 24hr rate too (4.17%), but will take much longer and note that these rates are without any other loads on simultaneously to degrade the charge.

kd7irm

Re: In need of info and input

so does that mean i would need 208 amps to all the batteries at once for a set amount of time to get em to full charge? i am little confused, they are all in series and in a rack that can not be changed easily at all.

Cariboocoot

Re: In need of info and input

kd7irm wrote: »

so does that mean i would need 208 amps to all the batteries at once for a set amount of time to get em to full charge? i am little confused, they are all in series and in a rack that can not be changed easily at all.

They can't be all in series: it takes eight 6 Volt batteries in series to make 48 Volts, which is what a SW4048 runs on (nominal Voltages). You have twenty-four batteries? That could only mean three groups of eight wired in parallel, so your Amp/hour rating is 3X that of one battery. If the '20 hour' rate is 1392, your total bank capacity is a whopping 4176 Amp hours. 5% of that (minimum recommended charge rate) is 208.8 Amps. They would probably be better off with 10%, especially if loads are run while charging takes place (this is the case about 100% of the time).

There is no way the solar panels and/or inverter-chargers will achieve this rate of charge.

Step 1: figure out your loads. You've got to get a handle on how much power capacity you actually need. Try to reduce those loads to an absolute minimum, especially eliminating any electrical heating devices. For large, occasional loads you might be better off running the gen to handle them and not trying to supply the power via inverter at all.

Step 2: once you know your daily power requirement in Watt hours you can get an estimate of how large a battery bank you'll need. That will determine what you need for recharging it.

Step 3: reconfigure what you've got. You may want to unload the smaller panels in favour of larger ones, add charge controller capacity, et cetera. Or you may find that conservation is your best friend and you don't need such a huge system. What do we say all the time? A $1 spent on conservation is worth $2 spent on generation!

dwh

Re: In need of info and input

Cariboocoot wrote: »

They can't be all in series: it takes eight 6 Volt batteries in series to make 48 Volts, which is what a SW4048 runs on (nominal Voltages). You have twenty-four batteries? That could only mean three groups of eight wired in parallel, so your Amp/hour rating is 3X that of one battery.

If you don't mind Coot I'd like to re-phrase that just a bit. How about;

That could only mean three strings of eight wired in series, with the 3 strings paralleled. So your Amp/hour rating is 3X that of one string.

That work for you?

Cariboocoot

Re: In need of info and input

dwh wrote: »

If you don't mind Coot I'd like to re-phrase that just a bit. How about;

That could only mean three strings of eight wired in series, with the 3 strings paralleled. So your Amp/hour rating is 3X that of one string.

That work for you?

Yes: clear and succinct!

kd7irm

Re: In need of info and input

Hope this helps a bit,
Here is a photo of the Deka batteries, they are all in series, all 24.... i read in the trace manual that when in series they will have the amp hours of just one battery and the voltage of all of them added up, so that would be..1392 aH (20hr) and a total voltage of 144 volts in series.......right? and if so, how is the trace inverters running? there is two in series (inverters) so maybe that has something to do with that? and the 69.6 amps (5%) to charge would that be ac or dc and for how long? i can only set the trace inverters/chargers in AC amps and they are set at 30 ac amps each, for a total of 60 in series. http://forum.solar-electric.com/attachment.php?attachmentid=1191&stc=1&d=1277227461

solar_dave

Re: In need of info and input

Could they be 4 volt cells * 24 for 96 volts. the charge controllers in series? Hmmmm.
http://www.sure-power.com/live/product/deka_battery/unigyII/avr_45_75_85.pdf
or
http://www.sure-power.com/live/product/deka_battery/unigyII/avr_95_07-33.pdf

from:
http://www.sure-power.com/live/product/deka_battery/deka_battery.htm#unigyII

mike95490

Re: In need of info and input

kd7irm wrote: »

Hope this helps a bit,
Here is a photo of the Deka batteries,.............http://forum.solar-electric.com/attachment.php?attachmentid=1191&stc=1&d=1277227461

Wow that's some floor loading there! I hope that's on a slab .

niel

Re: In need of info and input

nice catch mike as that could still destroy a floor depending on the exact positioning in relation to the joists even with the joists being reinforced underneath as most floor boards will buckle under this.

edit to add:
i was going by what the op wrote,
"Batteries:
Deka AVR unigy II 6v 1140AH @8hr @ 1.75 vpc rated. x24"
in my determination. as it is he will have 1/3 of what i stated in capacity being they would be individual cells. for 1140ah at a 5% charge rate would be 57a minimal. you have 10 kc135s and they are 12v pvs so with a minimum of 4 in series needed 10 will not be divisible so the pvs need to be 5 in series for 2 strings. this should yield around 17a to 18a. rounding to 20a it is still obviously way under as 20a/1140ah=1.75% charge rate if i figured this all correctly.

Cariboocoot

Re: In need of info and input

That does appear to be 24 batteries in series, so they'd better be 2 Volt cells if they're hooked to a 48 Volt inverter.

BTW, as Mike & Niel mentioned, that's a lot of floor weight! Probably over a ton. In that small of an area there would definitely be structural issues. Trust me on this. http://kaleidopsyche.deviantart.com/gallery/#/d256h13

Kamala

Re: In need of info and input

It's 24 single cells with dual posts. So a 48V battery.

This PDF from the East Penn website.

HTH

Craig

kd7irm

Re: In need of info and input

yep, on a slab! lol. they do not look like any of the single cells that they make, and the sticker on the rack says 3 cell, but gives a 2 in the model number so its a little corn fusing.... yes the inverters are in series.

dwh

Re: In need of info and input

Kamala wrote: »

It's 24 single cells with dual posts. So a 48V battery.

This PDF from the East Penn website.

HTH

Craig

Therefore, the battery bank would be a single string of 1140ah capacity at 48v.

EDIT: So each layer has 3 2v cells, and if one layer were wired with three cells in series that would be 6v, but the cells themselves are NOT 6v as was indicated in the OP.

kd7irm

Re: In need of info and input

ok, i think the battery config makes since to me now, thank you all, i was so corn fused. so do you think that a bulk of 55v and a float of 53.8v is too high for them if they are 48v? (deka says something about a max of 2.3vpc max) and if on gen set power how long should they be in bulk rate charging? and what amps AC charge should they be at?

mike95490

Re: In need of info and input

kd7irm wrote: »

if on gen set power how long should they be in bulk rate charging?

That time depends on how depleted the batteries are, and how many amps you feed them.

The charge amps, depends on the capacity of your charger, generator, and what the mfgs specs for the batteries calls out. (I did not find the data sheet for your batteries) but rule of thumb is 10% of C. 1140ah, that would be 114A at 48V, till the voltage comes up, and they go to the next stage. Some AGM batteries are able to charge a 50% of C , but I don't know about yours.

dwh

Re: In need of info and input

So...about a half dozen of these (though a dozen would be more optimal), enough gen to run them and enough fuel for however many hours (or days) it takes to top off that big mother of a battery:

http://www.iotaengineering.com/dls4820.htm

Or one of those and enough fuel for however many days (or weeks) it takes to top off that big mother of a battery.

Of course, I'm exaggerating a little (but not much). If that battery were down at 50% charge, then a single 20a@48v charger would have to run for at least 29 hours to recharge it.

1140ah x .5 = 570ah / 20a = 28.5h

BUT - since the charger will taper off as the battery approaches full, it will take even more hours to push it up that last bit to completely full.

My WAG would be that you'd have to run that 20a Iota for 36 hours or so to get that battery up to full charge IF it was at 50% when you started.

kd7irm

Re: In need of info and input

thank you for your help on this issue i have learned a lot. i already have a charger, 2 trace 4kw inverter/chargers in series, and they can charge at 60amps together in series. they are currently set to charge at 55v/53amps on float for i think 4 hours, same as the mx60 controller (or very close to the same settings). i guess i just need to change the float charge time from what i gather, if i can figure out the 20hr rate for these batteries and if the amps need to be ac or dc, as i can only set the trace at ac amps and i understand that dc amps are 5 time that, i think. any corrections would be appreciated, thanks again.

dwh

Re: In need of info and input

I think you might mean "absorb"?

As I understand it, float is the final "perpetual" stage that keeps the battery topped off.

So if I understand this - there is bulk, which is like "pump the max into the battery that is available" (in your case 60a or so).

Then there is absorb, which is like, "slowly push it up that last bit to completely full".

And then there is float, which is like, "drop down the voltage and just keep the battery topped off with a maintenance charge".

kd7irm

Re: In need of info and input

update:
just picked up a few things. An Outback vfx3524 and epanel, along with 8 crown 6volts (440ah 24volt battery). cant wait to get it all installed!

niel

Re: In need of info and input

good deal and glad you stopped back in to tell us. are you still using the same pvs talked of before?

kd7irm

Re: In need of info and input

Thank you! Yes I will be using the same pv, overall watts are just above the recommended for a 24 volt system using a mx60 but I've never seen the wattage at the rated output, so I'm pretty sure I will be ok there.

kd7irm

Re: In need of info and input

Wow, just got off the phone with Arizona wind and solar where just a few short weeks ago I spent thousands of dollars on a replacement system from them, I am having difficulty with some of the detail about the epanel wiring and install. I was told that midnight has customer service and they might help..... I didn't even get to to questions yet. I expected a little more help than that, am I wrong or is this what I should expect out of them? They seemed very helpful when I was in the process of buying.

Cariboocoot

Re: In need of info and input

Uh, referring you to the company that makes the product is the best thing they could possibly do: no one is going to be able to give you better advice than the maker. You really can't expect a retail outlet to know every install detail of every product they sell.

And no, neither I nor any of the other moderators work for NAWS.

kd7irm

Re: In need of info and input

Yep, your right, I have spent many hours on the Internet and on the manufactures forum with conflicting technical answers, I was hoping to get some real world field answers. The problem is not something the engineer could answer but a field guy would have seen, or a retailer would possible have gotten feed back from customers about.

westbranch

Re: In need of info and input

Have you looked at all the videos? Midnite has, start with "Installing a Classic" and go from there, hopefully you will see/find what you are after.

hth