Hi Mick

Yes you can use that panel(s). If you have a 12V battery setup then you will need to use a MPPT regulator to output suitable voltage for them. Be careful to note the ratings are suitable for the total watts of the panels.  If you have a 24V system them any type of regulator would work but a MPPT one will be better.

These are largish panels and do need to be well supported along their length. In fact I would put a soft support under the center to help the glass panel a bit on the rough bumps.

Note also that the cheap MPPT regulators are fakes and do not really work properly as MPPT but may work as a simple regulator. The cheapest brand that I know works OK is Tracer, which are available in all the usual places at a good price. You could google for more information, or search for information on this forum with the "search" function in the blue strip up the top. It has been discussed here not long ago.

Cheers Jaahn   

-- Edited by Jaahn on Saturday 8th of July 2017 03:25:23 PM

goldcoaster wrote:

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Thanks Jaahn,
It will be a 12v system. So how do I calculate the size of mppt to the amount of watts.
Cheers
Mick

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 Hi Mick

Just look at the specs for the different units and use the max watts for your panels.

Because the MPPT controller takes higher voltage from the panels and converts it to lower voltage for the batteries, the battery current is increased proportionally, so you must be careful. But the maximum wattage of the panels always remains the same.

Here are some specs taken from an Ebay add;

Item	Tracer 1210A	Tracer 2210A	Tracer 3210A	Tracer 4210A

 Item  Model                       1210                           2210                          3210                          4210       

Max. PV input power	130W/12V 260W/24V	260W/12V 520W/24V	390W/12V 800W/24V	520W/12V 1040W/24V

 

So you have 2x 185 W = 370 Watts max panel power.

so model 3210 should be OK at 12V nominal battery voltage.

Search for Tracer solar controller and look at the units available. There are several model available now. You can also get a remote meter to fit to it so you can see what is happening to your system when the controller is hidden down near the battery.

  Cheers Jaahn

PS If the panels are flat mounted on the roof then the wattage can be a "bit"over as the panel output is always lower and the controller would self-limit the current in the unlikely event of it ever being too high. 

-- Edited by Jaahn on Sunday 9th of July 2017 01:13:55 PM

kezngaz wrote:

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Would the controller have to be able to accept 36.2 v
Or 45.3v, just for furure reference?
Thanks.
Kezngaz.

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 Hi Kezngaz

The controller must be able to accept at least the Maximum panel voltage. But better ones and MPPT good controllers are usually rated at much higher voltages.

EG From the same Tracer unit the specs are 100V. So you can even use the panels in series. Which may have some advantages, perhaps ? However not to my liking with these 24V type panels on a mobile home/caravan roof. 90 volts DC is too high for me !  

Max VOC ---- 100V

Cheers Jaahn

-- Edited by Jaahn on Sunday 9th of July 2017 10:59:45 AM

What if you had two or three batteries charge them in 24 or 36v . But feed off 12v .off EACH Battary ??

Jaahn ,
If I read your post right , you wouldn't use these panels.As I got these panels free , 6 of them , should I put them on my house instead of motorhome and buy other panels . My last motorhome had 450w supplying 3 x 120ah Batteries , never had a problem running out of power , fridge/freezer 190ltr 12v/240 , 60ltr Engle, lights, TV's and other things so I would like the same in the new motorhome.
Cheers
Mick

Aus-Kiwi wrote:

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What if you had two or three batteries charge them in 24 or 36v . But feed off 12v .off EACH Battary ??

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 Aus-Kiwi,

It is consider very bad practice to use a string of batteries for charging but use the individual batteries  seperately for 12v power. It will lead to unbalance in the batteries and they will start to charge to full at different times. The charger will not be able to sense this, so it is a short cut to a stuffed battery. It is hard to say whether the over charged one will fail before the under charged one 

Do not go there is the simple answer. If you have 24V truck then convert the system to 24V house or fit a 24-12v converter. Probably worth less than the first battery to fail.

Jaahn

-- Edited by Jaahn on Monday 10th of July 2017 09:25:59 AM

Jaahn wrote:

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Aus-Kiwi wrote:

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What if you had two or three batteries charge them in 24 or 36v . But feed off 12v .off EACH Battary ??

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 Aus-Kiwi,

It is consider very bad practice to use a string of batteries for charging but use the individual batteries  seperately for 12v power. It will lead to unbalance in the batteries and they will start to charge to full at different times. The charger will not be able to sense this, so it is a short cut to a stuffed battery. It is hard to say whether the over charged one will fail before the under charged one 

Do not go there is the simple answer. If you have 24V truck then convert the system to 24V house or fit a 24-12v converter. Probably worth less than the first battery to fail.

Jaahn

-- Edited by Jaahn on Monday 10th of July 2017 09:25:59 AM

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A BIG DITTO

Hi Mick
Can you see a diode in the panel electrical box?

The reading you asked about is the OCV, the Open Circuit Voltage, 45.3V for this panel. That is the highest voltage that the panel can reach when it is in full sun and not producing current. So a controller must be able to take that voltage so it does not burn out. The Tracer in my example will take up to 100 volts so it is quite safe to use.

Jaahn

Got it, thank you.
Kezngaz.

Bagmaker wrote:

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if you open the black box there should be a couple of terminals with the wiring attached to.
Between (or kind of between) the terminals there should be a small diode, half the size of a cigarette butt, probably black with a couple of colored lines going around it.
Without this diode the panel shouldn't be put in parrellel with other panels, they will drain each other of potential charge, especially in partial shade.
Its no big deal to fit a diode yourself.
99% sure it will have one but best to be sure

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 Hi Bagmaker

You are correct in asking him to check this but perhaps he does not have the knowledge to do so. In fact these house panels may have two or three diodes in there on the cell string connections. Mine do ! They do not usually fail so perhaps best left alone and see if they work ok if you do not know enough.  Get somebody to check them if there is a problem, as you said they can easily be changed with items from an electronics store.

NOTE for other peoples information do not pay big dollars for these diodes as some 4WD and solar retailers charge, "because they are special" or similar rubbish. Very ordinary spec items in electronics stores.

Jaahn   

Aus-Kiwi wrote:

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This will do it .. Our old bus was 24v the house batteries where charged as 24v wired in series . BUT the feed to house batteries was still 24v to four 6 volt batteries . Then 12v off them . Had NO issues with any going flat over the other as they drawed off EACH battery evenly ., 24 in series while the 12v wired in parellel . Worked great for 8 years .

-- Edited by Aus-Kiwi on Wednesday 12th of July 2017 05:57:05 AM

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 Hi Aus-Kiwi

You have hijacked this thread The OP asked a straight question and i  answered it to help him. He is unfamiliar with the technology so it has taken a few answers. Another person has asked a relevant question which was also answered in several replies. All good I think ! Might be of help to others too

However you have thrown something different into the thread which I think will confuse !!  Now you have shown a picture of a PL60 regulator which is not suitable for the job the OP asked about  WHY ??

If you want to have a discussion about your experience with an unusual battery setup then START A NEW THREAD Plenty of forum space to go around. Others may have some experience and could contribute. Might be of interest to others.

Jaahn

Aus-Kiwi wrote:

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This will do it .. Our old bus was 24v the house batteries where charged as 24v wired in series . BUT the feed to house batteries was still 24v to four 6 volt batteries . Then 12v off them . Had NO issues with any going flat over the other as they drawed off EACH battery evenly ., 24 in series while the 12v wired in parellel . Worked great for 8 years .

-- Edited by Aus-Kiwi on Wednesday 12th of July 2017 05:57:05 AM

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 A lot of potential problems 

How did you ensure they drew from each 12V set evenly

How do you balance charge them, so that one is not overcharged or one undercharged

I suggest that readers do not attempt this

There are ways it can be done safely & easily ,but requires a 24v >12V DC converter 

I'm a bit lost here so maybe someone can explain the bit that doesn't make sense. The MPPT controller mentioned could handle the 2 x 185w panels in series or parallel as far as voltage is concerned, but isn't that controller limited to 10 amps @ 12v nom. output. If MPPT controllers really worked the way the salesman says then the combined 2 x 185w would equal 370w and a full conversion to 12v nom. would be over 30 amps, even higher if the battery voltage was less than 12v as in deeply discharged. Surely this means a controller capable of handling up to 100vdc input and 30 amps output min would be required, if they really worked like the salesman claims then more like a 40 amp output.
As far as max DC voltage goes and the electrical regulation..... always has been a bone of contention but the rules say 120vdc and 5% ripple current. Still no work from the authorities if the 5% is over and above the 120vdc or if the 5% is peak to peak and therefore actually 120vdc plus 2.5%. All theoretical of course because the peak voltage is only seen as open circuit voltage and therefore zero current, but a line in the sand must be drawn some where so 120vdc is the one they chose. the actual operating voltage would be much less even with the panels in series, in the case of these 2 panels around a max of 72vdc ( Vmp of 36v x 2 panels) but likely to be even less than that, so reasonably safe if safe practices are followed.
Will any controller actually get 2 x 185w out of these 2 panels in normal solar conditions, no, to get a better idea of what (watt) can be expected assume roughly 70% of the rated output, anything more is bonus but can not be expected as a sure thing.
Did that help or muddie the water a bit more?

T1 Terry

My apologies Jaahn, I read the number as ending in 10A as being a 10 amp controller. The reality of the efficiency of MPPT charger conversion from panel rated output in watts to battery charging output in watts would still be around 70% with the panels in series, less with them in parallel under anything but perfectly balance solar coverage across both panels, so 30 amps would be fine.

As far as DC voltage killing you, 60vdc won't kill you if there is zero current, you know that as well as I do, the old points ignition coils put out a lot more than 60vdc but didn't kill people, just bit like pit bull.... the new electronic capacity discharge ignition will kill because it is back up with quite a few amps to sustain the arc. Therefore the open circuit voltage is not the issue and I did mention safe working practices when working with and solar and this includes covering panels if they are connected in series, if the bit doesn't send you flying the arc will damage wiring connections. Simply connecting a 48v battery to an inverter without precharging the capacitors will fry the terminal off the cable end....... it won't kill you but the scare might :lol:

T1 Terry