Solar Panel Question...

Hi Peter
Could you explain what a MPPT regulator is, why it is different and why is it more efficient than a more typical regulator that John has described?
Cheers
daryl

@ daryl

What the heck is an MPPT??


:)

Hi Daryl,

yes no worries.
Think gearbox in a car.

An ordinary solar regulator (PWM, or on/off type) acts like a single speed box.
As long as the clutch is disengaged the motor revs up freely, but the moment the clutch comes on the motor revs drop depending on the actual speed of the car.
Because max motor power has a peak somewhere up high, this power usually won't be available during cruising.
On the other hand, a multi speed gearbox allows the driver to shift the motor revs to the max power point, independent of vehicle speed.

Solar panels, not unlike combustion engines also have a peak in the output power which is visible in the EI diagram of the panel. The panel's operating Voltage could be likened to the motor RPM, and the panel current to the motor torque.

So motor revs are equivalent to the panel's operating voltage, the gearbox is the DC/DC converter inside the MPPT regulator, the driver is the microcontroller, the clutch are the wires between solar regulator and battery, and the vehicle speed is the SOC (battery terminal voltage).

Because in a solar panel, the maximum power point shifts up and down with temperature and insolation, the microcontroller constantly regulates the current through the panel. The algorithm looks for the maximum in the ExI product.

Hope this isn't too confusing.

cheers, Peter

Hi Peter
Many thanks. What is a good brand to purchase?
Cheers
Daryl

Hi Daryl,

a link to a very good unit can be found on our EO profile page:
http://www.exploroz.com/Customers/Battery_Value_Pty_Ltd.aspx

If I can be of assistance please send us a member message.

regards, Peter

Gday...

Hidden in the original post - "I run the fridge on gas."

I often stop for 4, 5 or 6 days - I run the genny every 2nd night, or every night depending how much 'light' I used the night before, and how amenable other campers are.

I always feel guilty using the genny in camp (when others are within 100metres of me). The Honda is very quiet, but I used to dislike people playing music loudly in the bush. We all go bush to get away from noise etc. So I thought solar might alleviate some of my guilt hangups :-)

Cheeres
John

Sorry I note you have fluro's.

Thay arent too bad, maybe a little hungry...replacing them with LED strips will probaly increase yor run time.

cheers

Ross
I was thinking of getting one of those Bushmaster chargers that put out 50 amps allegedly allowing you to minimize charging times when connected to your generator but if what you say about 20 amps being the maximum then that would be a waste of time ! Are there batteries that can take larger charging currents ?
You are right there is good info in this thread
Regards
Jim

I know my 100ah deepcycle gel types only like a max of 20 amps per battery.
If you pump too many amps into them the plates don't like it as they overheat and shorten the batt life dramatically

This usually happens when the charger tries to a discharged battery and the charge rate continues for some period of time.

So if you have two batteries and they are both discharged to some degree then the larger charger may be ok. They usually have a dual setting on them so a lower charge rate may be selectable while the full 50 Amps is also available.
If you go the switchmode type then make sure it has a dual option , it is then more flexible for your needs when the solar isn't able to keep up. eg weather.

The average cranking battery does take more charge current flow because the alternator just tries to bring up the charge as quickly as it can and this can last for some time. These batteries are not as suited to caravan and solar setups as the deep cycle types.

With this stuff, I see it as trying to cover all bases so you are not inconvenienced in what you do while out on the track.
Regards
Ross M