Should I DIY, buy a kit, or maybe not even bother?

[Rick P]

I've been reading and learning about small solar setups because I've been feeling pretty guilty about all the tools and toys I have that run on rechargeable batteries. It's not so much about about saving money on my electric bill as it is about reducing my carbon footprint. I think I'm looking more for opinions on whether or not a solar setup makes sense for what I want to use it for than I am about getting advice on what that setup might be. So, with all that said, let's look at what I'm charging.

We've got two electric bicycles (his and hers). One has a 48 volt 10 amp hour battery, and the other a 24 volt 10 amp hour battery. Then I have my tools, which have 12, 18, and 24 volt batteries of unknown ratings for amp hours. And then a few really small devices like flashlights and cell phones. We ride the bikes almost every day, and those batteries take between 4 to 6 hours to charge with their 2 and 4 amp chargers respectively.

There are other things I could power, but if stopped there, and didn't attempt to power or charge anything else in the garage with solar, would it make sense to even attempt a solar setup just to charge these batteries? If all of the batteries were the same voltage, it might be feasible to get away with just a panel or panels and a charge controller, but what makes it questionable for me is, I think I will ultimately need one or more car sized batteries to store the energy from the panels, and use an inverter to get 120 volts to plug all the miscellaneous chargers into, right?

I see there are some 12 volt, 100 watt packaged kits out there in the $200 range, but they seem pretty rinky dink and I'd still need to buy a battery and an inverter.

What do you think?

[sdold]

I think a grid tie system might make more sense, even a small one would end up paying for itself in a few years and be much simpler. No batteries required.

[Mike90250]

How "invested" and how much do you want to "play" with stuff ?
Simple grid tie is cheap & easy.
Building a rig from scratch and needing different voltage outputs starts gettting complicated quickly

[azdave]

What do you think?

Why install solar panels to charge a big battery then invert to 120 A/C then plug in your various wall plug chargers for all your multiple tool and bike batteries? If people really want to reduce their carbon footprint then take some simple steps like less airline flights per year, combine local driving trips, eat less red meat, buy locally made items and reduce overall consumer consumption by purchasing less new toys, electronics, clothes, etc. until they are actually worn out. Don't have Amazon deliver 3 times a week. All of that can add up to far more carbon reduction than your plan to solar charge bikes and tools plus you'll lower the amount of items going to the landfill in a few years, including the batteries you would need to store power to charge other batteries.

[J.P.M.]

Why install solar panels to charge a big battery then invert to 120 A/C then plug in your various wall plug chargers for all your multiple tool and bike batteries? If people really want to reduce their carbon footprint then take some simple steps like less airline flights per year, combine local driving trips, eat less red meat, buy locally made items and reduce overall consumer consumption by purchasing less new toys, electronics, clothes, etc. until they are actually worn out. Don't have Amazon deliver 3 times a week. All of that can add up to far more carbon reduction than your plan to solar charge bikes and tools plus you'll lower the amount of items going to the landfill in a few years, including the batteries you would need to store power to charge other batteries.

Amen.

OP: As or powering stuff, as others suggest, after reducing your use, go grid tie after you educate yourself about PV and electricity use.

[Rick P]

I think a grid tie system might make more sense, even a small one would end up paying for itself in a few years and be much simpler. No batteries required.

I can't say I didn't expect this response. I have a neighbor who is an electrician, I'll ask him about the feasibility, it's an old house with a detached garage. Luckily, I'm already planning a panel upgrade for the house, which will probably make a grid tie possible.

How "invested" and how much do you want to "play" with stuff ? Simple grid tie is cheap & easy. Building a rig from scratch and needing different voltage outputs starts gettting complicated quickly

To be honest, I didn't want to start with a huge investment, but on the other hand, I don't want to spin my wheels only to find that I should have gone bigger either. This is exactly why I'm posting, to figure this out.

Why install solar panels to charge a big battery then invert to 120 A/C then plug in your various wall plug chargers for all your multiple tool and bike batteries? If people really want to reduce their carbon footprint then take some simple steps like less airline flights per year, combine local driving trips, eat less red meat, buy locally made items and reduce overall consumer consumption by purchasing less new toys, electronics, clothes, etc. until they are actually worn out. Don't have Amazon deliver 3 times a week. All of that can add up to far more carbon reduction than your plan to solar charge bikes and tools plus you'll lower the amount of items going to the landfill in a few years, including the batteries you would need to store power to charge other batteries.

I'm getting the picture that an off grid setup may not be the way to go for us. I'm proud to say though, that we already do pretty much everything else you mentioned, and maybe I shouldn't be feeling quite so guilty. We generally only take one trip a year to take the kids to see their grandparents, one of our two cars is a Ford Focus Electric, the other gets 35 mpg in the city, the house doesn't have AC, we don't eat much red meat at all, we buy local, both of our Ebikes were not purchased new, I bought both in not running condition and repaired them. Most of our clothes are purchased second hand because my wife and daughters love to go "thrifting" and we avoid Amazon as much as possible. But even with all that, global warming has me feeling like we should do more, hence the reason I'm thinking about solar. I'm just not sure about going big on my first attempt.

OP: As or powering stuff, as others suggest, after reducing your use, go grid tie after you educate yourself about PV and electricity use.

What is PV?

[bcroe]

I've been reading and learning about small solar setups because I've been feeling pretty guilty about all the tools and toys I have that run on rechargeable batteries. It's not so much about about saving money on my electric bill as it is about reducing my carbon footprint. I think I'm looking more for opinions on whether or not a solar setup makes sense for what I want to use it for than I am about getting advice on what that setup might be. So, with all that said, let's look at what I'm charging.

We've got two electric bicycles (his and hers). One has a 48 volt 10 amp hour battery, and the other a 24 volt 10 amp hour battery. Then I have my tools, which have 12, 18, and 24 volt batteries of unknown ratings for amp hours. And then a few really small devices like flashlights and cell phones.

I see there are some 12 volt, 100 watt packaged kits out there in the $200 range, but they seem pretty rinky dink and I'd still need to buy a battery and an inverter.

What do you think?

I think (and often have) buying a simple, basic system and putting it to work
will be highly educational, at minimum cost. It will later allow an intelligent
plan for a far larger expansion on the subject, not just a blind leap.

My starting advice though, think about recharging your batteries during the
solar day, avoid high power AC inverters. Avoid massive battery installations.

AZDAVE presents a pretty good check list. Plans have been in place here
for decades, for every item. Though, the original motivation was to keep
my earnings instead of spending them. But they fall into the diminishing
returns methods, which means that more and more additional dedication
produces less and less additional improvement. It took big solar and net
metering with the local Nuke, to get Zero Carbon Footprint for the home
buildings, and with absolute minimum ongoing effort. Bruce Roe

[J.P.M.]

What is PV?

Do yourself 2 big favors in the following order:

1.) Download a free PDF of "Solar Power Your Home for Dummies". You need an education.

2.) Do not attempt anything with respect to alternate energy as DIY.

[foo1bar]

What is PV?

PV: Photovoltaic (ie. solar panels)
Other abbreviations used here that you may see: PoCo (power company) ; AHJ (Authority having Jurisdiction - ex: city's building permit office)

I wouldn't do an off-grid setup for charging tool batteries.

I also would definitely look at doing a grid-tie system since you already have the grid available.

It will probably cost more up-front, but it will likely have better impact per dollar spent. (both measured in environmental impact and financial impact)
And the panel upgrade probably can qualify as part of the solar installation and therefore increase the federal tax credit you can claim.

[khanh dam]

don't bother. but if you really want to play with it. www.batterysurplus.com has some renology panels and inverters and batteries on sale. off grid batteries die every 7 to 10 years, they are not a solution to reduce carbon footprint.

[Rick P]

I thank everyone for their responses to my post, I got the advice I was seeking. In a nutshell, off grid only makes sense where a grid-tie is not an option. That's a bit of an over general statement but it certainly applies in my situation. It was already understood that research and learning should be done if I want to get serious and do a grid tie-in setup, even a small one, but I still appreciate the advice there too.

[chrisski]

The 100 watt kit at $200 is not the final price of everything for the install, and will be far underpowered for what you have asked for.

A 120 volt 2 amp to 4 amp charger means 20 to 40 amps from a 12 volt system. A 100 watt panel may put out 4 to 6 charging amps in max sunlight, but that certainly won’t last the amount of time you need to charge your bikes.

I plug my 18 volt Dewalt battery charger into my inverter, and that pulls 9 or 10 amps from my 12 volt system while the battery is being charged.

So, IMO solar done for “green” reasons is only truly green if using a grid tied system. At best a battery system is probably 5 times you pay your electric company for power per KWh. Even though the power may be “free,” well look like its free, those batteries are expensive. $.13 per KWh is cheap from the electric company.

When I do some calculations where you use 160 ah to charge your electric bike, and charge batteries for four hours a day, that comes to 40 AH, that’s 200 AH. Two of my Trojan Golf Cart batteries are rated at 226 AH,so for $500 for those batteries, 600 watts of panels $600 if you buy 100 watt panels, a decent 1000 watt inverter, $400, and a 100/30 Victron SCC controller, $250 looks like your system would cost $1750. But I forgot to mention a lot of stuff. Hardware including mounting ain’t cheap, so if you’re willing to drop $2500 to make the bike charging and battery charging station happen tot save a few dollars off the energy bill each month, I’d be happy to answer any questions.

[Rick P]

So, if you’re willing to drop $2500 to make the bike charging and battery charging station happen tot save a few dollars off the energy bill each month, I’d be happy to answer any questions.

I was already convinced that an off grid setup was not practical, so I have no additional questions about that, but I do appreciate you doing the estimated calculations to demonstrate just how impractical it would be. I’m looking into what incentives might be available to cover the electrical upgrade my house would need to support a grid-tie setup.

[J.P.M.]

I was already convinced that an off grid setup was not practical, so I have no additional questions about that, but I do appreciate you doing the estimated calculations to demonstrate just how impractical it would be. I’m looking into what incentives might be available to cover the electrical upgrade my house would need to support a grid-tie setup.

Read the Dummies book or otherwise get educated first.

[Rick P]

Read the Dummies book or otherwise get educated first.

I started reading it the first time you recommended it, thanks for pointing out it’s available for free. For future readers, I found it on the https://archive.org website, where there was no BS to download it. It’s almost 400 pages, I’m only in part one but from the index it looks like the book covers everything you’d want to know before diving in.