Solar/Inverter and car charge system

Steve's right on both counts.

I wouldn't rely on any switch to ensure the inverter doesn't decide to kick in and deliver 240V unexpectedly. The safety issue has been discussed frequently here, and in a metal vehicle is a serious consideration.

Also, as Steve says, it sounds as if you have a 24V panel/s. This will be ok to charge 12V batteries, but it will be important that you have a suitable MPPT controller to get reasonable efficiency. Steve can't publicise his solar shop here, but it's worth a visit at this address. There you'll find attractively priced gear, including controllers.

Cheers

John

Yes, why the hell do you want such a large inverter. An inverter of that size will require a fair bit of power to drive it when you are only drawing small loads. Why do you need an inverter at all.

An inverter of that size will require a 300 A switch if you want to switch it off when it is not being used. This to me is a rather large and unnecessary installation. The supply cable will have to be much larger than starter cable if you are not mounting the inverter right at the battery.

There seems to be a fetish for newcomers to include inverters in their 12 V systems. To me, these are a waste of good battery power. I prefer to purchase small electrical items that are capable of operating directly from 12 V - this saves a lot of power by not transforming your battery power to 240 V and then back to low voltages. If you go to Jaycar or DSE you can purchase 12 V driven power supplies to run your computer and charge batteries in your appliances for less than the price of a good inverter.

PeterD

Hi again,

Thought I had this problem licked.

I decided to go the way of the new regulator as I mentioned in my last post - only after that didI decide to put a meter across the solar panels terminals just to make sure of the output volatage. When I did, it read a constant 20.5 volts, not the 36 as mentioned on the back panel. Is this indicative of only half the panel working (diode short) or is "Nomadic Navara" correct in his summation...
"FollowupID: 678169 Submitted: Wednesday, Mar 10, 2010 at 13:29
Nomadic Navara posted:
Ed - I know that, however he is charging a 12 V battery (which is also a little more than 12 V most of the time.) However, a 36 V panel is an unusual size. Smokey said "the regulator the correct one for that voltage and panel." As the regulator does not appear to be an MPPT type things are not adding up. It could well be the correct voltage panel, someone has confused the 36 cells with it being a 36 V peak power point panel and calculated the current out by dividing 200 by 36.

Smokey - you could clear this up by providing the manufacturer and full model number of the panel."

Details listed on the back of the panel are -

(Tong Lin) PMW 200 PW

Watts = 200
Voltage = (VWP) 36.0 volts
current = 5.56 amps

I opened the connection box at the back and the terminals are covered in a foam like substance. I have started to carefully remove the foam (with plastic tool) and have uncovered so far 3 large diodes. The chap from Esolar suggests to remove all wiring from the panel terminal block and measure the short circuit current and open circuit volts. If I get same voltage, then I have 100 watt unit only. It could also be a diode short - in which case he suggests to remove both diodes and check them and then the panel current and voltage again. When I get all the covering off, I'll send a photo of the terminal block.

I am not overly confident with the above, so would appreciate some direction and ideas.

Cheers

What size battery do you have and what are you running of the inverter?

What make / model solar regulator do you have ?

:)

The controller you gave the model number in the next reply does not look like a suitable one for a 36 V panel. A 36 V panel looks an odd size, is it in fact as 36 cell panel. A panel with 36 cells is the correct size for a simple 12 V controller and battery. (Yes I know you said the current OP is 5.5 A, but things are not gelling.)

Peter, the operating voltage (36V) is indicative of a (nominal) 24V panel...

;-))

Ed - I know that, however he is charging a 12 V battery (which is also a little more than 12 V most of the time.) However, a 36 V panel is an unusual size. Smokey said "the regulator the correct one for that voltage and panel." As the regulator does not appear to be an MPPT type things are not adding up. It could well be the correct voltage panel, someone has confused the 36 cells with it being a 36 V peak power point panel and calculated the current out by dividing 200 by 36.

Smokey - you could clear this up by providing the manufacturer and full model number of the panel.

SmokeyD, sell the inverter to someone who *needs* it, because you definately don't have a realistic use for it at all.

The larger the inverter capacity, the more power it consumes just to run itself, replace it with a PSW Inverter of about 200 Watts max for small applications and will drain your small capacity DC battery, why not add a 2nd identical battery??
(it's like running a V12 supercharged diesel in a VW beatle - total overkill)

Maîneÿ . . .

" the battery is a 75AH deep cycle AGM battery"

- if you run a 1500 watt Inverter at full load it'll draw 150 amps from the battery ! Who designed that sysytem for phone charging and small appliances ???

I've just had a look at the specifications for the E-solar controllers at this link - the price can be found at this link, it is around $200. The price looks too low for an MPPT controller and the specifications also do not mention that it is of that type. I would suggest that your controller is not suitable for the panel. If your controller and inverter are still in pristine condition then then I suggest you seek a refund for them. Purchase an MPPT controller and a 2 - 300 W inverter. An alternate way to go would be to swap the 24 V panel for a 12 V one that is suitable for your controller.

PeterD

Nothing in the published specs to indicate that that regulator is MPPT, which more than likely means that it is not... Which in turn means that it is definitely not the correct regulator to be charging a 12V battery from that panel...
(ergo my previous reply;-))

Have a chat to Mandrake about budget-priced MPPT controllers, or alternatively,
have a look at this one on ebay for what I consider to be the best value-for-money out there atm...

Morningstar MPPT controller on ebay

:)