bruce posted:

I agree with Mandrake...if your "big solar panel" is not putting enough power into the battery that you already have to keep it charged and to run your fridge or whatever ...another battery is not going to be much help ...how are you going to charge it ?

blueriderwa posted:

Not sure if you blokes have noticed but we dont have sunshine 24 hours a day ;b (even in QLD)hence the battery has to hold enough power to get through the night, if you happen to get a day of cloudy weather or are shaded by a tree for part of the day you need to be able to store more power than 1 day. The solar panels are in total about 6' x 8' in surface area so are plenty big enough to gather the power needed to fill 2 batteries in full sunlight. The issue is our consumption rate but with a wife and 3 kids and myself we are always going to use a fair bit of energy. Thanks for your feedback.

Mandrake's Solar Power posted:

I think what we are getting at is - you are possibly tackling your problem from the middle rather than either end -
Either you put more power into the system or you take less out .. The extra battery is only going to give you 1 day extra - changing lights to LEDs or changing fridge to a good lower power consumption type will draw less from the existing battery and make it last longer - Alternatively adding an extra panel will put more power into the system and if sufficient would charge your battery as well as running the household electical items ..
Perhaps you could give us some numbers to work with ?
Wattage of the current panels ?
Amphours of battery ?
Current consumption of major electrical items - particularly fridge and lights ,,
There is a spreadsheet available for download in the members fileswao area
Solar Power Calculator - 2nd one down

Its not the absolute calculator but it will give you a very good guide .
Cheers
Mandrake

Member - Mike DID posted:

I agree with Mandrake...

Batteries only store power. If you're running out after a few days, then more power is going out of the batteries than going in (assuming the batteries are fully charged at the start.)

The ONLY options are to a) reduce power going out, b) increase power going in.

Maîneÿ . . . posted:

another option is:-> Increase battery CAPACITY

You need enough 12v battery capacity to last 2 or 3 days when parked under trees or during inclement weather.

It's no value having a large capacity solar system of about 6' x 8' in surface area (~500 Watt Crystaline) and then not having sufficient 12v battery storage capacity to store the power created by the large solar system, as it will fully charge the battery system before lunch and then just trickle charge for the rest of the day.

However if the battery storage capacity is doubled or even tripled the 12v battery power will last much longer and battery system will still be fully charged by lunchtime anyway.

Maîneÿ . . .