Solar setup just for tool battery charging

[pepo1]

Being on a tight budget, I just can't afford the large battery bank setups to generate the power needed to run tools in an off-grid situation. I could buy a lot of battery-powered tools for the same price as some of those setups. So, I'm wondering whether anyone could suggest a basic workable system with 2 or 3 battery chargers plugged into an inverter, all powered by solar.

 

[MisterSandals]

I'm wondering whether anyone could suggest a basic workable system with 2 or 3 battery chargers plugged into an inverter, all powered by solar.

My buddy is in your situation for using power tools (lights to chainsaws!) for his carpentry. Its a basic system in his sprinter van. Its been a couple years now and says he ditched his generator and switched to mostly battery tools where he used to have some air tools (nail guns primarily).

200Ah AGM battery (its big and heavy)
2x 100W solar panels (i recommend big cheap panels but he had limited roof areas due to vents and racks)
Morningstar SunSaver PWM solar controller
2000W modified sine wave inverter for tool battery chargers
(optional) 1000W pure sine wave inverter for phones and computers

He has a 3rd panel we could squeeze in with some effort but he says he never runs out of power and the Morningstar Meter (also recommended) almost always shows the batteries fully charged. He has dozens of batteries, often charging as many as he can plug into power strips from his 2000W inverter.

 

[pepo1]

Thanks for that! So the modified sine wave does the job for tool charging. Great. There's a decent saving right there!

 

[MisterSandals]

So the modified sine wave does the job for tool charging.

Yea, it was about 1/3 the cost of the pure sine wave inverter (which he says he is glad he has though it gets used only periodically).

 

[Bluedog225]

My solution was a renogy 100 watt panel, a wanderer controller, a 100 ah trojan deep cycle, a Ryobi 12 volt car charger. No inverter needed. All pretty cheap except for the battery.

I’m not up there much. The 100 watt panel keeps that battery topped up and I can charge the big ryobi 4 ah battery packs all day long. Lots of cheapish, good quality, brushless tools.

It’s working great for my remote weekend cabin.

 

[Substrate]

CAUTION! If there is one place you should definitely use pure-sine wave (PSW) inverters is if using *modern* battery chargers for tools and other devices.

Why? Many chargers base their CV algorithms (and stage timing expecting a clean 50/60hz clock) expecting a relatively pure sine input to their charge circuitry. If you feed the chargers MSW, they may not actually charge your batts properly. Either with over or under-charge or taking much longer than normal.

Not worth the hassle if you want the longest tool battery life. Do a capacity test using at first an msw inverter, and then do the same with a psw inverter as the charge source if you want to see it for yourself.

So what your friend doesn't know is that it "seems to work". But in the long run, he's replacing batteries faster, or not getting the best run times from them. Kids - use a PSW and stop being a cheapskate. Living in the 80's will cost ya'.

 

[MisterSandals]

CAUTION! If there is one place you should definitely use pure-sine wave (PSW) inverters is if using *modern* battery chargers for tools and other devices.

Thanks for the heads up.

Can you point me to any info on this?

 

[Substrate]

Yes - look at the tool charger specs! What they want is *clean* AC, at least somewhat close to what you get at the wall with a sine-wave.

I updated the last post to mention that it isn't just CV, but also a case of circuit stage timing expecting a clean 50/60 hz clock reference. Using MSW skews this reference/clock and can lead to issues or poor performance. The chargers themselves also work harder than they have to.

Can you get away with it? Sure, your buddy is. Things to ask: "Hey, do the chargers ever seem to complete the charge, or do you just pull them after 12 hours?" Any of them get hot during charge?

There will always be exceptions of course. I'm just saying it might be better to not wing-it and cross fingers, and just bit the bullet with a PSW and not have to wonder.