off grid landscaping

it bean sunny again today i brewed solar powered coffee. then i finished the lawn mowing. i used the electric mower with the solar cart. i made a mistake about the current draw of the mower. it is 3 HP and 12 amps not 13 amps. this is for 120 volts and 60 cps. the wagan inverter puts out 120 volts and 60 cps. that means 8.33 amps continuous.

the display on this inverter shows battery dc draw amps then switches over to an alternate display of percent capacity. low values always read zero. the coffee maker shows 75.0 % and it is a 750 watt draw.

i happened to look at the display while the lawn mower was running and the alternate display had 95.0. that means 950 watts just under the continuous rating. the manual states the inverter has overload protection. if a device draws more than 1000 watts continuous it will shut down to prevent damage to inverter or device.

what am i getting at? the lawn mower isnt 12 amps. it runs at 7.92 amps. when i pull back on the start switch the motor takes about 30 seconds to spin up to full speed. i should have plugged it into house utility electric to see if it spins up faster that way. plus i should hook up my kill a watt meter to get some sort of amps and watts usage on it.

this mower is 30 years old. maybe it’s power was over stated so folks would buy it. you know, more power is better. still, i am glad it really isnt 12 amps becuz it would have tripped the inverter. suppose for 30 bucks more you can get a 12  or 13 amp mower folks go for it. the company slaps a higher rating on it’s cheaper model to keep it competitive.

the battery bank is quite drained, close to 12 volts. i decided to hook up a spare 40 watt panel in parallel to increase the charge rate and decrease the charge time.

a clamp meter indicated each panel is charging at 2.55 amps. it is clear now that two 55 amp hour batteries in parallel need 80 watts solar input (in parallel) to charge in a timely fashion. a twin bank on the xantrex inverter had went from 12.1 volts to 12.65 volts in about 2 hours. a single 40 watt panel would probably taken 6 hours to do that. when a battery is near a discharged state it takes the most to bring it up. when it nears full charged then a single panel can do that.

i did some weed whacking and lawn trimming and also some shrubbery trimming with AC corded accessories. the weed whacker draws 3.4 amps and the bush trimmer draws 2.7. i used a 600 watt pure sine wave inverter with three 32 AH batteries in parallel. i wanted to charge the other banks as much as possible and this battery bank is fully charged.

it’s completely possible and practical to do so. sure, i has to drag a cord around but i didnt have to worry about extra utility charges or  portable battery drain. i fully intend to to this when ever it is needed.


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