Solar charging

[gaddy]

Hi all
I have been following this thread with a bit of interest,as i was thinking of getting into solar for camping and for the boat , after reading this and other articles on the subject , i think the 1kva honda and smart charger will be staying for a lot longer yet , reliable quite , and simple like me , only use it every couple of days , for about 2 hrs while away , i run 2 x 120 amp hr batteries in the camper on a full charge they will run the lights radio etc for 2 weeks and only use the genny to keep them toped up .
but each to there own this is just what i do
cheers
Gaddy

[Cuppa]

That panel appears to be mismatched to the regulator. I believe those CMP12 regulators are only 12 volt. I think the panel specs in the pic make it a 24 volt panel. This would be unsuitable for charging a single 12 volt battery even though the Steca you've ordered can handle 12v or 24v.

Cabling from panels to regulator, if long enough to be useful needs to be much thicker than 6mm2. For 10 metres 6 B&S is the go (this is 13.2mm2 conductor).

Anderson plugs can be soldered on easily with a blow torch & finished off with heatshrink. To crimp them you'll need a hydraulic crimper or a mechanical one with long enough handles. I bought a hydraulic one for under $70 & it's been good. Crimps from 6mm2 up to 70mm2.

My Patrol's solar system was tested for the first time last weekend & it performed to expectations. With hot weather, mainly heavy cloud cover & camped under trees there was little solar input available. The best I saw were short periods when the panels were keeping up with the demands of the fridge & freezer whilst they were cycling & putting up to 5 or 6 amps of charge into the batteries at the same time. From the Friday arvo through to the Sunday morning batterry charge gradually diminished to around 60% to 65% state of charge, minimum voltage with the 40 litre freezer & 60 litre fridge running was 12.3v. I would have been happy to have gone another 24 hours of similar conditions before choosing to move to a sunnier spot, start the car or switch off the freezer. Lighting & water pump power usage were negligible.
This was with 425w solar & 360ah of batteries. The 400+ kilometre drive home was sufficient for the 40amp DC to DC charger to bring the batteries back to 100%. In most times solar input would be better than we had, but the weekend proved that in the worst solar conditions we have a buffer of at least of around 4 days usage. Most times solar input is better than we had, so the poor weather buffer is, for us, quite adequate. For weekend only usage the system is overkill, but for worry free long term travel I think it about right.

Cuppa

[mudski]

What size,or how many watts are 3 x panel. I'll do some maths, what do you require to run.

Each panel is 60W. so 180W in total I have. The aux battery is a Supercharge D70ZZ 105AH. I just bought a 80L Engel Combi. Prolly too big for my needs, 60L would have been more than enough, but what I paid for it new with a transit bag was cheaper than a 60L by itself...Also will be running two, one metre long LED strip lights.

That panel appears to be mismatched to the regulator. I believe those CMP12 regulators are only 12 volt. I think the panel specs in the pic make it a 24 volt panel. This would be unsuitable for charging a single 12 volt battery even though the Steca you've ordered can handle 12v or 24v.

Cabling from panels to regulator, if long enough to be useful needs to be much thicker than 6mm2. For 10 metres 6 B&S is the go (this is 13.2mm2 conductor).

Anderson plugs can be soldered on easily with a blow torch & finished off with heatshrink. To crimp them you'll need a hydraulic crimper or a mechanical one with long enough handles. I bought a hydraulic one for under $70 & it's been good. Crimps from 6mm2 up to 70mm2.

Well going by the pic cuppa it says 24v on the panel so your right on the panel but the controller I don't know but the Steca will fix that issue.

The 400+ kilometre drive home was sufficient for the 40amp DC to DC charger to bring the batteries back to 100%.

As the Patrol alternator doesn't fully charge the aux battery I take it I need to get one of those chargers too?

[Cuppa]

Hi all
I have been following this thread with a bit of interest,as i was thinking of getting into solar for camping and for the boat , after reading this and other articles on the subject , i think the 1kva honda and smart charger will be staying for a lot longer yet , reliable quite , and simple like me , only use it every couple of days , for about 2 hrs while away , i run 2 x 120 amp hr batteries in the camper on a full charge they will run the lights radio etc for 2 weeks and only use the genny to keep them toped up .
but each to there own this is just what i do
cheers
Gaddy

Horses for courses again.
The big power user in any camping set up is the 12v compressor fridge. If using a gas fridge or an ice box power requirements are minimal so 240Ah of battery will certainly give plenty of light & sound. Using a gennie to occasionally charge those batteries in imho the considerate way to use one if one must be used.

I have to admit that I am a gennie hater. I do have one, a little EU10i Honda, about the quietest you can buy, but given the choice of the sounds of nature or the hum of a generator in the background, nature wins everytime. It's the main reason I like being 'out there', not to hear a bloody motor running & to smell it's exhaust fumes. I bought ours as insurance against the solar system in our bus letting us down, but never needed to use it for that purpose, the only time I used it was to charge the crank battery every couple of days when the alternator karked it, until we could get a replacement alternator. Even then I always let any neighbours know that I would need to run it, & then only during the middle of the day for a couple of hours. We no longer carry it together with the fuel required in our bus. It gets used occasionally at home to power tools out in the paddocks for which it is very good.

I do accept that others find the use of generators to be more financially viable than setting up a solar system although the reduced price of solar panels now makes the costs of ether way of going quite similar, but gennies often get chosen because they are easier to understand i reckon.

I prefer that those with gennies camp away from me or I from them. Problem is that it seems not uncommon for some folk to behave as though it is their god given right to run their noisy stinky gennies whenever & wherever they like, regardless of the impact upon others around them.

Of course carrying a gennie means also having to carry separate fuel in containers.

A well set up solar system, in my view, wins hands down. If properly done it is a source of constant satisfaction that once established is a silent set & forget system.

Cuppa

[Cuppa]

Well going by the pic cuppa it says 24v on the panel so your right on the panel but the controller I don't know but the Steca will fix that issue.

Not if you are planning to charge a 12v battery!

24v panels & regulator will require a minimum of two 12v batteries wired together in series to make them 24v. And then you will need all 24 volt appliances or a means of getting 12v from a 24v system....... either a 24v to 12v converter or a charge equaliser. Don't even think about tapping 12v off one of the 24v pair.

Some MPPT regulators can charge 12v batteries from 24v panels I believe, but have had no experience of this.

An advantage of using 24v is that thinner cable can be used. Many fridges with Danfoss compressors can run on 24v, but other appliances if required are less common & more expensive than their 12v equivalents.

180w @ 24v is equivalent to 360w @12v ...... which is plenty in good solar weather.

As the Patrol alternator doesn't fully charge the aux battery I take it I need to get one of those chargers too?

Probably not if just setting up for trips of short duration (long weekends) if you ensure the battery is fully charged at home using a multi stage mains charger before leaving, & recharge as soon as you get back home. More battery capacity would give you a buffer against poor solar weather.

So if your fridge can run on 24v you will need a second 105ah battery & you can also use 24v led lighting & have a very nice system which will meet your needs. Cable sizing can be revised down accordingly. Each battery should be in roughly equal condition. If you series connect an old semi knackered battery to a new one it will reduce the life of the new one. Each of the pair should be of the same type & capacity.

If your fridge can't run on 24v you could be in a little strife & might be better off using different panels.

If you want to use your fridge for longer periods a dc to dc charger would be a useful & reasuring addition, but if your vehicle is 12v & the 'house system' is 24v this brings added issues.

Cuppa

[gaddy]

yes there are a alot of people that do not respect those around them . we mainly beach camp well away from neighbours and only run the genny if we are out of ear shot of other campers . and never of a night time it is only used to top up the second battery if we dont drive for a few days . you would be the most nogiable person on solar set ups and i have read your posts with great interest , i am sure i will end up with one in the future ,

[mudski]

Not if you are planning to charge a 12v battery!

24v panels & regulator will require a minimum of two 12v batteries wired together in series to make them 24v. And then you will need all 24 volt appliances or a means of getting 12v from a 24v system....... either a 24v to 12v converter or a charge equaliser. Don't even think about tapping 12v off one of the 24v pair.

Some MPPT regulators can charge 12v batteries from 24v panels I believe, but have had no experience of this.

An advantage of using 24v is that thinner cable can be used. Many fridges with Danfoss compressors can run on 24v, but other appliances if required are less common & more expensive than their 12v equivalents.

180w @ 24v is equivalent to 360w @12v ...... which is plenty in good solar weather.



Probably not if just setting up for trips of short duration (long weekends) if you ensure the battery is fully charged at home using a multi stage mains charger before leaving, & recharge as soon as you get back home. More battery capacity would give you a buffer against poor solar weather.

So if your fridge can run on 24v you will need a second 105ah battery & you can also use 24v led lighting & have a very nice system which will meet your needs. Cable sizing can be revised down accordingly. Each battery should be in roughly equal condition. If you series connect an old semi knackered battery to a new one it will reduce the life of the new one. Each of the pair should be of the same type & capacity.

If your fridge can't run on 24v you could be in a little strife & might be better off using different panels.

If you want to use your fridge for longer periods a dc to dc charger would be a useful & reasuring addition, but if your vehicle is 12v & the 'house system' is 24v this brings added issues.

Cuppa

So the panels I bought, which are 3 x 24v wired together is o.k for me to connect to my aux battery only? I'm kinda getting worried now that I have the wrong thing. The Steca I have ordered will be o.k for my setup to replace the existing controller. Sorry if it feels like were going over this again but I kinda want to make sure I'm doing the right thing...

Thanks.

[Cuppa]

So the panels I bought, which are 3 x 24v wired together is o.k for me to connect to my aux battery only? I'm kinda getting worried now that I have the wrong thing. The Steca I have ordered will be o.k for my setup to replace the existing controller. Sorry if it feels like were going over this again but I kinda want to make sure I'm doing the right thing...

Thanks.

Sorry Mudski, you cannot connect 24v panels to a 12v battery. The Steca (assuming it's a PR model) can work with either 24v or 12v, but this will not allow you to charge a 12v battery with a 24v panel.

Because I have never heard of 24v folding panels before I would advise you to check the open circuit voltage of the panels in case they have been mis-labelled. Put them in the sun, put the multimeter onto volts & put one probe on each output cable. If they are 12 v panels you should get a reading of up to about 18v. If they are 24v you should get a reading of up to about 31v.

Find this out first & we then we can take it from there.

Cuppa

PS. I have checked & that CMP12 Regulator DOES have 12v & 24v capability so it is looking like you most likely do have 24v panels, but check anyway.

[the evil twin]

Hey me again. I decided to get out the panels yesty and use them to charge up a couple of batteries. One thing I noticed on the controller that the charge light never came on and the load light was on. Then, I unplugged everything, folded the panels up and took it into the garage and about an hour later I noticed the charge light on the controller was glowing. Not even it sun light and not even connected to a battery. Was gives there?
I have only used these once before and even then I was suspicious that they were not working but I just put it down to not enough sun. So I am keen to work this out.
Heres a pic of the glowing charge light on the controller, the specs on the back of the panel and the leads supplied with the panels. I also have ordered the Steca controller too. Just the cable to get, and some connectors.

Thanks.

One issue you have is that they are 24 Volt spec panels IE the maximum current each one will put out is just over 2 amps.
What that means in practical terms is with a PV controller as pictured is you essentially have the equivalent of one 90 Watt 12Volt Panel (19 volts peak) or a pair of 50's... IE you can only harness less than 50% of the panel rating at 12 volts due to the current limit.

Regards the Charge LED I'd suggest depending on the order you disconnected the equipment that there is enough capacitance to hold a charge sufficient to light the LED for a period of time

Regards the Load LED I'd suggest it is illuminated because you are below the low voltage cut off when the Reg is in 24 Volt mode

Sooo what you have is a 180 Watt 24 Volt nominal setup. If you wanted to you could use that reg with 12 Volt panels but might be better off flogging the lot as a set and getting a 12 Volt nominal setup.

[Cuppa]

Mudski - I was mistaken & ET is correct. I said 180w@24v was the equivalent of 360w @ 12v. I doubled when I should have halved. This changes most of what I recommended, sorry. (it's late & I'm tired)
Assuming you do have 24v panels, ET's suggestion of flogging the panels & getting some 12v panels is the way to go. Fingers crossed that you have bought a 20 amp Steca in which case you will still be able to use it with 12v panels of useful size. If it's a 10 amp model it will be too small if you hope to have panels which will keep up to the needs of an 80 litre fridge.

ET... are you suggesting that the regulator can accept an input @ 24v & give an output @ 12v. I didn't think this was possible but will happily bow to greater knowledge. I thought that nominal 24v in meant nominal regulated 24v out. There are no user adjustable settings on that reg, so how would it know to convert output to 12v? Is the output automatically determined by battery voltage independently of input voltage. If so that surprises me on what is a very cheap reg.

Cuppa