Recent Posts

Thanx Amy!! Your knowledge and insight is most valued!!!!!!

Right, 60W is the instantaneous draw. Over 1 hour, it is (60 Watts x 1 hour = 60 Watt hours). Over 24 hours it is (60W x 24h = 1440Wh).

Darn! I had an itchy debit card for that big boy! Is it a fair assumption when I'm looking at idle consumption  that if the rating is say, 60 watts, will that equate into 60wh therefore equaling 1440 wh per day? I understand most inverters go into a power save mode that use considerably less current. But am I looking at the numbers correctly?

Sorry, my PC was messed up, I was looking at the wrong prices. You are right. I updated my reply with the right prices, and swapped to a different charger to get you back on budget.

Am I looking at the wrong price guide? The samlex 1500. Sells for 519 an the iota sells for 257?

Hi Amy!! Thanx for the reply! That new samlex inverter charger is a monster!!! I like it! But the link says it's 1300 not 900? I could swing 900 for that bad boy but 1300 is a lil too far out.  The idle consumption looks great on it as well!

You are fairly limited in that price range for the features you want. Samlex just came out with an incredible new pure sinewave inverter/charger, EVO. The 2200W 24V model is $1300. https://www.altestore.com/store/Inverters/Off-Grid-Inverters/2000-to-2999-Watts/Samlex-EVO-2200W-24V-Pure-Sine-Wave-InverterCharger/p11913/

To stay within your budget, and because you don't have high wattage needs, the idea of having a separate inverter and AC charger may be the way to go. The Samlex SA-1500-24 would give you plenty of room for the surge of your tools, and is over $500. https://www.altestore.com/store/Inverters/Off-Grid-Inverters/1000-to-1999-Watts/Samlex-1500-Watt-24V-Heavy-Duty-Inverter/p9791/.It has a low power mode to save energy at under 1.5W.

Then an Iota AC Charger at around $200 would keep you in budget, https://www.altestore.com/store/Charge-Controllers/AC-Battery-Chargers/Samlex-SEC-2415UL-24-Volt-15-Amp-Battery-Charger-UL/p10217/

Sorry for the delay in answering.
1. Depending on where you are, and how hot the roof gets, the standard space of the L-foot plus the width of the rail is generally enough air space between the roof and the panels. If you are in extreme heat, additional standoffs or a longer L-foot may be helpful to increase air flow and keep the panels cooler. For metal roofs, I like the EcoFasten L-foot with the EPDM bushing to help seal the hole. They are available in 3" or 6" lengths, for a higher mount, https://www.altestore.com/store/Solar-Panel-Mounts-Trackers/Roof-Mounts-for-Solar-Panels/Flashing-for-Roof-Mounts/EcoFasten-Solar-SIM-L-102-6-Tall-L-Foot-with-Simple-Seal-Bushing/p11108/ .
2. It depends. There are calculations to determine the length of the lag bolt needed that include wind loading for your area and type of wood for the rafters. Let's assume 10.6 sqft per panel and 4' spacing between L-feet (3 rows of 11), that would require 60 roof connections. Assuming the array needs to withstand 50psf wind uplift force the equation is 50 psi x 10.6 sqft = 530 lbs per panel x 33 panels = 17,490 lbs for the array / 60 L-feet = 291.5 lbs per L-foot. There is a chart in the Wood Engineering and Construction Handbook for what length Lag bolt is needed based on if the rafters are Southern Yellow Pine, White Spruce, or Douglas Fir. For example, a 5/16" bolt in White Spruce can handle 227 lbs per inch. 291.5 lbs / 227 lbs = 1.3" of the lag bolt must be in the rafter. Add an inch for going through the L-foot, roof, underlayment, etc, and you need at least a 2.5" stainless steel lag bolt. I'd use 3" for good luck ; )
3. Yes, use stainless steel lag bolts.

Amy Beaudet
Solar Queen
altE Store

I forgot an important factor... I have a budget of around 600-800 dollars. Also, would it be feasible to buy a seperate compatable charger and a smaller, more effecient inverter?

Hello all,  I'm finally ready to replace my unreliable, modified sine wave inverter with a quality unit and my numbers have me perplexed! I'm hoping y'all can shed some light on me and share your knowledge and maybe even make some recommendations!
I'm currently using a "royal power" 1500w msw 24v inverter... It's installed in my off grid cabin that is supplied by 800w of panels, an mppt controller and 465 ah 24v agm battery bank.
My calculated loads are very small. in fact, my estimated wattage with everything in the cabin on I only about 400 watts! That includes my water pump, freezer, tv, laptop, and lights! That is not taking into consideration surges or the occasional use of a vacuum cleaner or circular saw. (Which both act really weird with my current inverter)
My dilemma: I really like the idea of getting an inverter charger! I have a generator I can utilize for back up charging in case of sun issues. The idle consumption of the inverter chargers has me worried as well as the lack of smaller units available. I was looking at the aims 2000w pure sine inverter charger and it's idle consumption is roughly 60 watts! That's 1400ish watts in a 24 hour period!!!! My system is only designed to use roughly 13-1400 watts per day! I also looked at the magnum 1800 watt inverter charger and yes the idle consumption is lower but it is modified sine wave. I understand my wattage requirement are small but I do like the idea of having a big enough inverter to handle occasional tool and vacuum use. Can anyone shed some light on this subject? I would like to make a purchase before the end of the year to take advantage of the tax incentives.