Solar Panels - Information and Questions

[moeee]

Sorry about the layman terms but would really appreciate a laymans response with no disrespect intended.

A 12 volt battery is pretty much a 12 Volt battery.

Picture a 5 gallon bucket and a 44 gallon drum , each full of water with a tap on 'em.
They only pour out water the same , depending on how far you open the tap.

Batteries will also only deliver whatever your device requires.
You can hook up a UHF to either of those battery types and it will run very happily.

Something you best determiner though seeing as you don't seem to comfortable in this area , is that most large trucks use a 24 Volt battery.
Best you double check that the truck battery is in fact a 12 Volt and not a 24 Volt , otherwise its a whole 'nother can of worms.

 

[Gem in I]

got it thanks guys :Y: :Y:

 

[Ded Driver]

Will this one do the trick ?

https://www.prospectingaustralia.co...8022_a2063f1e-c056-4373-a5cb-37266ffafa1a.jpg

ChrisM & Wally69, note in the pic of the multimeter bottom left corner its written 10A max. These multimeters are not great for current testing anything other than low level electronics. Hence the need for a Clamp Meter, or a solid state device that calculates from voltage drop ... these are cheap on eBay .. just search '12V solid state Current' or Amp meter should find them. You need a load on the circuit to get a proper current draw reading.
I would suggest a new controller, either mppt or pwm (most prefer mppt for most efficient solar charging, but pwm suits lead acid batteries best).
If you aren't aware, mppt = maximum peak power tracking. This is basically a DC-DC converter to maintain best volt/amps balance from your solar panels.
pwm = pulse width modulation. This regulates the power pulses to the battery. Lead Acid batteries have longer life & better charge capacity
when pulse charged (1 of the reasons car batteries don't always last a long time)
Also, there are charge controllers that utilise both MPPT & PWM for best of both worlds

 

[iamagoldenoldie2]

gee,,, never knew that a 12volt battery is just a 12 volt battery , so the battery man was pulling my leg, he told me there are several types of batteries each for a designed purpose, like the LA battery (lead /acid) fitted to most cars 12 volt with a 800 odd amp cranking capacity to turn the donk over, then there the SLA type (sealed lead acid ) these are heavy just like the l/a, then theres the AGM (ACID GLASS MATT) these work upside down whatever position you like, and hold a charge for a year but are destroyed when used to start donks, and they are also heavy then theres lithium iron, the new generation battery, light as feathers , all require different charging methods, the deep cycle AGM cost heaps but can supply a constant load down to 70% of battery capacity and usually the 120 watt solar panel will keep them charged up, the standard lead acid battery is considered flat at less than 11 volts mmmm fully charged measure 12. 5 plus volts becarefull of flea bay I bought a 200 watt panel from think out AGM flat after 3 days driving my Bushman fridge that fnnn panel was pushing out a massive 80 watts so was dunn like a roast duck my new 200 watter pumps out 9 amps in full sun so the moral of my story is batteries aint batteries, talk to the experts and the rejuvenation of batterys is crap might pump out 12 volts but no amps amps is the electrical pressure that drives things, if your an out backer buy a CHRISTIE GENERATOR charges a flat battery in an hour, no bull and no battery damage, I got one, proof is in the pudding.

 

[user 7268]

Golden oldie your battery man informed you well :Y: The only thing the same about them all, is they are 12 volt rated. How they deliver power, the applications they are designed for and even the manner and voltages used to re charge are all different. Hence 7 and 8 stage chargers now common place. Manner of use and charging are probably two of the main factors that effect the batteries life and their not a cheap item. The "old type" battery charger is long dead, in fact it won't even put out voltage high enough to fully charge a deep cycle battery. This is why they as in deep cycle batteries and other types don't perform that well just plonked in the back of vehicle without the correct controller, as the average vehicle alternator just doesn't pump enough voltage to ever fully recharge it.

 

[Nightjar]

A good friend of mine (****ook) gave me some valuable advice and I now swear by it.
Bought a fold up twin solar from ebay which come wired parallel putting out 3.5 amps approx.
Wired the same panels in series and now have 7 amps topping battery up.
The down side of this I had to upgrade the solar controller to handle double output.

https://www.outbackmarine.com.au/bl...VqavRViKtVFV2G2Gg70ijBU0VfRdxudsaAlt3EALw_wcB

Have now series wired the two panels on roof of caravan.
No more battery problems and rarely ever have to run generator.

 

[moeee]

A good friend of mine (****ook) gave me some valuable advice and I now swear by it.

What was the advice ?
Was it to alter the original parallel connected panels to series connected panels ?

If that is the case , how would it help ?
Would it work better when lesser sunlight is available like on an intermittent cloudy day?

 

[user 7268]

A good friend of mine (****ook) gave me some valuable advice and I now swear by it.
Bought a fold up twin solar from ebay which come wired parallel putting out 3.5 amps approx.
Wired the same panels in series and now have 7 amps topping battery up.
The down side of this I had to upgrade the solar controller to handle double output.

https://www.outbackmarine.com.au/bl...VqavRViKtVFV2G2Gg70ijBU0VfRdxudsaAlt3EALw_wcB

Have now series wired the two panels on roof of caravan.
No more battery problems and rarely ever have to run generator.

Nightjar that has me confused ?
Wired parallel as the panels were standard, the amps should be higher ? In series the voltage will be higher but amps lower than the same panels wired in parallel? So when you say the upgraded controller handles it? You mean the 24 volts which is what you would get wiring two 12 volt panels in series ?
Two 12 volt panels 10 amp in series would be 24 volts 10 amp . The same two panels wired in parallel would give you 12 volts 20 amps ?
I might be totally wrong here :8 but just hate to see people pumping 24 volts thru their 12 volts systems and controllers .................. nasty result

 

[moeee]

I might be totally wrong here :8 but just hate to see people pumping 24 volts thru their 12 volts systems and controllers .................. nasty result

Nightjar seems to be very happy with his current circumstances.
But you musta went to the same school as me Bogger - (but paid more attention)

 

[Wally69]

Hey Chris, you questioned the current tech vs what you have. Just tested mine, it is about the same size but is a 20w panel, so looks like they have doubled the realestate efficiency between ours and a 120w panel looks about 3 times as big.

Mine is rated about 1.2A but tested at 0.67A at 19v in the winter sun. Based on the calculations a couple of posts up, your two combined should be about the same. Real question is what will it store in a normal day based on those figures and what can it drive. I got mine to run a LED strip light and charge the SDC batteries overnight. I have a handful of 12v 45w 10min rated computer server batteries to hook up to it but havent given it a good test run to see if it is reliable.

An upgrade for me would be enough juice to keep a fridge cold and do the above, already have a 36Ahr Engel battery for the job. I assume it would take the existing panel 0.67A x 19v/12v x 8hrs = 8Ahrs/day or about 5 days to charge it. My fridge will flatten it in 2, so would need 50w at a minimum. Upgrading at 120w and a higher capacity battery makes sense to me as it always rains when I head away.

 

[ChrisM]

A good friend of mine (****ook) gave me some valuable advice and I now swear by it.
Bought a fold up twin solar from ebay which come wired parallel putting out 3.5 amps approx.
Wired the same panels in series and now have 7 amps topping battery up.
The down side of this I had to upgrade the solar controller to handle double output.

https://www.outbackmarine.com.au/bl...VqavRViKtVFV2G2Gg70ijBU0VfRdxudsaAlt3EALw_wcB

Have now series wired the two panels on roof of caravan.
No more battery problems and rarely ever have to run generator.

Hi Nightjar
I just contacted my auto elect and explained what you said to him.
he confirmed to me that you are correct in what you say.
In simple terms when in series you have higher voltage and lower [or constant] amps
When in parallel you have lower [base] voltage and higher amperage.
Theres something more to think about. never thought about it that way
thank you for your input . taken onboard
Cheers
ChrisM

 

[moeee]

This thread is reminding me of the GREAT Film - "A Few Good Men" where Jack Nicholson says "YOU CAN'T HANDLE THE TRUTH"

Sometimes too much knowledge can be dangerous.

 

[Simmo]

You must not have explained it properly to your auto-lecky, or you need a new one!

Where Nightjar is mistaken is putting the two panels in series gives 7 amps, that is incorrect.

Nightjar is talking no doubt about a good MPPT charge regulator, that you could indeed wack between a 24v panel and a 12 v battery.

However, a 12v panel rated at say 24 watts, or 2 amps, in parallel with another, 12v/24 watt panel would give 12v at 48 watts, or 4 amps.

Wire them in series, you will get 24 volts, at 24watts, and 2 amps... but feeding 24 volts into an mppt regulator connected to a 12v battery, will convert that back to 12 volts, and double the current, as the load is the same. (V=IR) so minus inefficencies in the regulator, you will be back to 4 amps.... maybe..

 

[Simmo]

Haha! even my comment is wrong!!
24v @ 24w is 1 amp!! So after conversion, we are back to 2 amps...

 

[Goldchaser1]

Crism its all over the net how series and parallel differ,fairly basic but simmos on the money,ya wont double amps by going in series,your doubling voltage(with 2 panels) and that should be slightly more effecient threw a good controller but its impossible to double the amps by going from parallel to series.....

PS:those panels look like miget twister boards....

 

[user 7268]

:/ I must be in the naughty corner

 

[Simmo]

I think where the idea works good, is if you can get one of those house panels, that are like 24v 160 watt or something...
Wack one of them into a good mppt and to a 12v battery and you have 320 watts @ 12v!!!

 

[ChrisM]

You must not have explained it properly to your auto-lecky, or you need a new one!

Where Nightjar is mistaken is putting the two panels in series gives 7 amps, that is incorrect.

Nightjar is talking no doubt about a good MPPT charge regulator, that you could indeed wack between a 24v panel and a 12 v battery.

However, a 12v panel rated at say 24 watts, or 2 amps, in parallel with another, 12v/24 watt panel would give 12v at 48 watts, or 4 amps.

Wire them in series, you will get 24 volts, at 24watts, and 2 amps... but feeding 24 volts into an mppt regulator connected to a 12v battery, will convert that back to 12 volts, and double the current, as the load is the same. (V=IR) so minus inefficencies in the regulator, you will be back to 4 amps.... maybe..

Thanks Simmo
Im probably to blame for giving out the wrong information to the lekky.
Electrical stuff just frys my brain. Hence the reason for this post. I Just Dont Get It
Its like some sort of wizardry and black magic combined.
Im still trying to ascertain if its worth keeping/updating the system for the amount of power it generates or just scrap it and move along.
Cheers

 

[Simmo]

Thanks Simmo
Im probably to blame for giving out the wrong information to the lekky.
Electrical stuff just frys my brain. Hence the reason for this post. I Just Dont Get It
Its like some sort of wizardry and black magic combined.
Im still trying to ascertain if its worth keeping/updating the system for the amount of power it generates or just scrap it and move along.
Cheers

All good bud!
I think the short circuit current test will make your mind up mate. Your sparky will have one of them for sure.

 

[Goldchaser1]

You must not have explained it properly to your auto-lecky, or you need a new one!

Where Nightjar is mistaken is putting the two panels in series gives 7 amps, that is incorrect.

Nightjar is talking no doubt about a good MPPT charge regulator, that you could indeed wack between a 24v panel and a 12 v battery.

However, a 12v panel rated at say 24 watts, or 2 amps, in parallel with another, 12v/24 watt panel would give 12v at 48 watts, or 4 amps.

Wire them in series, you will get 24 volts, at 24watts, and 2 amps... but feeding 24 volts into an mppt regulator connected to a 12v battery, will convert that back to 12 volts, and double the current, as the load is the same. (V=IR) so minus inefficencies in the regulator, you will be back to 4 amps.... maybe..

Thanks Simmo
Im probably to blame for giving out the wrong information to the lekky.
Electrical stuff just frys my brain. Hence the reason for this post. I Just Dont Get It
Its like some sort of wizardry and black magic combined.
Im still trying to ascertain if its worth keeping/updating the system for the amount of power it generates or just scrap it and move along.
Cheers

Agree,it can get confusing sometimes
Id update,a 100-120,depending on what ya can fit up there would cost prob about $150-200 odd if ya shop about on ebay with a good controller,run rings around those old ones......
The victron mppt little blue controllers are top quality for the $$$,75/10 would be the one to look at....
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com.au/ulk/itm/391421859614
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com.au/ulk/itm/302636055484