Hi Brett

Trying to keep it simple usually comes with some caveats, but I'll try and get things started by drawing on what I've learned from this great forum over the past three years. Yes, another 100 a/h battery will double the storage, but this will mean that your 120W panel will have to charge two batteries instead of one, so you should consider another 120W panel if finances and roof real estate permit (perceived wisdom is that total panel wattage should at least equal your total battery a/h capacity). Ideally dual batteries should be the same make, capacity and age. If you can advise what equipment you'll be running, particularly fridge (compressor or gas), TV and other appliances will allow others with more knowledge than I to give more detailed advice. Knowing what solar controller (make and model) you currently have will also help.

Cheers
Joe

Thanks for your advice much appreciated. I'll double the battery and panels me thinks :)

Brett

Aus-Kiwi wrote:

---

 Adding another battery is like having two bank accounts . 

---

 That is actually a good analogy.  

One person opening a 2nd account won't give any more reserve, will just split income (solar charge) between the 2 accounts (batteries).

The 2 accounts (batteries) are worse off as fees double and neither really increase in value until a second person (panel) contributes.

 

Just make sure the regulator can take the dual output.
120 x 2 =12a approx.

Brett, your Manta Ray will more than likely have a 30 amp regulator and able to run 3 x120 watt panels. It's pretty simple to put another panel on the other side near the door and join that panel into the existing wiring with a couple of 2 into 1 joiners from jaycar. eBay etc. fitting another battery is simple as well. Are you running anything more than just the lights, pump, TV?.

Jon

Shogun wrote:

---

Thanks for that Jon, not running anything apart from my CPAP at night. I'll Suss out a few panels to see what will fit.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Check that the new panel(s) are similar Vmp to the existing one before you buy.

3 panels would be more value to you than 2 batteries....you can not use energy that you do not collect.

Do you use the humidifier on the CPAP? This is the bit that uses most of the power.

 

BTW, the second bank account description should be attributed to Collyn Rivers....

 

Cheers,

Peter

Brett, you do not have to match the existing panel if you have a PWM controller. All you have to worry about is you add a panel with a similar open circuit voltage.