18 months in the past I purchased a Chevy Bolt for about 1/2 off sticker price. The Bolt has been superior with the only exception that I had no option to cost it at my spouse’s home which is off grid and over an hour away from my home. As a aspect notice I need to say that the important thing to a contented marriage is to have separate homes, I discover that I actually admire my spouse once I go house and he or she will not be round. Once we are collectively on a regular basis familiarity tends to breed contempt. I’ve been struggling to improve her previous system which was solely 1000W of panels once we met and about 1kWh of battery capability. That is no the place close to sufficient to even take into account charging an electrical automobile. This text is about how I went about creating an off-grid system with 4kW of panels and 16kWh of batteries to cost an electrical automobile and why I constructed it the best way I did.
The present photo voltaic system was put in about 15 years in the past and is a 24V DC primarily based system. My spouse had gone via up 3 units of Lead Acid batteries in that point (two of them really did just about blow up) and we determined to change to Lithium. I needed to separate the previous system that ran the home with a brand new system that might run the home however would additionally work as a devoted system for electrical automobile charging. We plan to proceed including panels and need to set up a scorching water warmth pump within the coming years, however the brand new panels with work with the brand new system.
The brand new system is predicated round an electrical tractor I constructed utilizing a salvaged Chevy Volt battery pack (how-to article here). The pack is 16kWh with about 14kWh usable. It is connected to a 3000W inverter and the photo voltaic cost controllers are additionally connected to the tractor. After I want to make use of the tractor or mow the garden I simply disconnect the photo voltaic panels and AC extension cords and do what I’ve to do then come again and plug it again in. We additionally use the tractor as a conveyable energy station to run our electrical log splitter, electrical chainsaw and electrical rototiller. The eTractor is saved outdoors since I’m working the battery with out a BMS and if it bursts into flames I don’t need it to take the home with it. I maintain a big plastic bin over the batteries, inverter and cost controllers to maintain the rain and snow off it. This bin helps the electronics keep hotter within the winter in order that they don’t get moisture buildup inside. This setup is the jankiest of jank, nevertheless it really works fairly effectively and acquired us via final winter simply wonderful.
Attempting to cost an electrical automobile with out a big sufficient battery to soak up the ups and down of the solar peaking out behind clouds and such is a big mistake. I might not take into account making an attempt to run an electrical automobile charger off something with lower than 5kWh of battery capability. I additionally a lot favor the 48v techniques as a result of a lot decrease amperage means you should use thinner copper wires between the inverter and the batteries. The one battery pack I like to recommend presently is the EG4 server rack batteries from Signature Photo voltaic. I attempted to purchase LifePO4 batteries from China final 12 months and it was the worst mistake of my life. You may get prime quality server rack techniques for about $297/kWh here which is sort of as low-cost as shopping for direct from China.
There’s a bunch of all-in-one techniques with the inverter and photo voltaic cost controllers constructed during which are tremendous good, a lot of them might be setup with a 240v setup as effectively (for stage 2 charging which is ~5x sooner). Will Prose’s DIY solar channel is the one to look at with new stuff getting examined and launched on a regular basis. I actually just like the setups he recommends however they’re dearer and have a 50-80w steady vampire drain which I loath to have on our system. If you’d like one of many bigger techniques you’ll doubtless want so as to add 2 further panels simply to compensate for the fixed drain of the upper energy inverters. That being stated the multi functional techniques are a lot, a lot nicer than something I’ve ever whipped up and are lots much less more likely to burst into flames. (if that kind of factor is necessary to you)
I constructed the brand new system with a Renogy Rover 60 Amp cost controller which I paid $297 for on ebay shipped and a 48v inverter I purchased for $300 on Amazon here (this inverter has been shockingly dependable in comparison with the opposite low-cost Chinese language ones I’ve killed). This was hooked as much as 2.6Kw of panels that I purchased domestically new for about 40 cents a watt off Craigslist. Determine one other 10 cents a watt for roof mounting racks and the whole for the entire system is ~$3900 ($1500 Volt battery + $300 MPPT cost controller + $300 inverter + $400 for copper wire + $40 DC circuit breakers + $40 MC4 crimpers and connectors + $280 roof rails + $1040 panels).
I’ve experimented with a cheap $40 PWM 30 amp charge controller from Amazon that I hooked as much as the opposite 1.5kW of panels we have now. It has labored surprisingly effectively for the worth, however it is just about 80% environment friendly the place the MPPT controller is over 95% environment friendly. At first I used to be tremendous excited concerning the PWM controller, nevertheless it simply actually flounders on cloudy days whereas the MPPT controller works surprisingly effectively. There are two different PWM cost controllers with programmable cost limits I’ve purchased and tried to work and each have died. The BSC3048 is the one one I can advocate presently.
The loopy half is if you begin evaluating what number of miles you’ll want to drive to get your cash paid again over simply shopping for gasoline. If gasoline is $5/gal and your automobile will get 30mpg which most econo-crap-boxes the scale of the Bolt get then after 24,000 miles of journey this technique has fully paid for itself. ($4000/$5gal x 30 mpg = 24,000 miles) There’s loads of instances in my life the place I as driving greater than 24,000 miles in only one 12 months, so the payback for off-grid photo voltaic is there for those who’re prepared to soak up the upper buy worth of the car. The most important drawback is that utilizing a system like this the recharging of the Bolt battery is fairly sluggish. I may cost at 12 amps (4 miles of vary per hour), however I really feel like that might stress the inverter so I solely do it at 8 amps (3 miles of vary per hour). Since more often than not the automobile is sitting round not doing something that is actually a non-issue. I don’t cost in a single day, solely when the solar is shining as a result of I don’t actually need to add extra biking to the Volt battery on the tractor.
With a bit of ingenuity and a few elbow grease and quite a lot of luck you may setup an off-grid system to cost an electrical automobile and kick gASS like I did. It’s fairly enjoyable, rewarding and finally ends up making quite a lot of monetary sense fo these of you who like enjoying the lengthy sport and are bored with getting shafted by large oil.