diy solar

diy solar

Tool Battery charging.

NCLMTom

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Joined
Jun 18, 2022
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What about charging tool batteries directly from a solar panel without an inverter? I have charged up 36 volt tool batteries with a 12v panel and a MPPT boost controller alone. Don't know if this was a good idea, but it worked. I had to wire a broken battery charger to hold the battery. It just seems like a waste of electricity using an inverter going from DC to AC then from AC to DC to charge these batteries. We are a Makita outdoor power equipment dealer, and they have a charger that uses a cigarette lighter to charge. We also carry Stihl and Echo, but they don't have that option. It would be nice to build a system that could do this from solar without an inverter. The problem with the Makita charger using a auto cigarrette lighter plug is that they take a long time to charge. Makita 2 - 18v 5Ah batteries would take 3 hrs 20 minutes. These same 2 batteries last about 30 minutes bring used in a line trimmer. The Makita AC chargers can charge these 2 batteries in about 45 minutes. For a landscaper using outdoor power equipment all day long, they would need about 360 watts/hr charging batteries. California is making these lanscapers convert to battery power by 2024. The pictures posted show what I've tried so far, 36v Stihl seemed to work, the 2- 18v Makita batteries in series didn't (no way to balance charge for that set up). The specs of the panel I used. Seems like the equipment manufactureres would come up with a viable way to charge batteries out in the field. The solar generators with pure sine wave inverters seem like the only option at this point.
 

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Wanted to add one more picture of the MPPT Boost Charge controller charging the 36 volt Stihl Battery. The Stihl charger was gutted and the only wiring was the positive and negative wires to the prongs that go into the battery when charging. I would love to be able to charge these tool batteries quickly out in the field using just solar, but unlike the factory charger, I'm not sure this is the safest way. I know the Stihl batteries have a built in BMS, but not sure other brands have this. Of course the boost controller would have to be set for each individual battery. Stihl is 36 volt, Echo is 56 volt and 58 volt, and the Makitas are 18 volt and 40 volt. Not sure how to do the 18 volt as the boost controller only goes down to 24 volt.
 

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For the sake of longevity of the tool batteries (and potential fire hazard) I would use the proper charger.

If you need to rely on solar charging for a landscaping business, I would suggest that you get a battery and inverter. That gives you some autonomy during clouds, and allows you to use the right AC charger.
 
Yes, I agree. Thanks for the reply! I think having a battery to charge from is going to be necessary. I am just curious if anyone has any ideas on creating a tool battery charger that wouldn't need an inverter, but would charge as fast, and as safe, as a Makita or Stihl rapid charger. They only take about 45 minutes to charge with AC power. Right now the inverter and battery is the only way to go, but does the future hold some sort of DC to DC rapid charging? This would be a game changer for the Landscaping industry in California starting in 2024. The only option, other that a solar generator, is to buy a backpack battery for $1,200 to $1,500 and charge it at home. Wearing a heavy battery on your back all day doesn't sound like fun. I'm hoping for small battery rotaion to keep a landscaper going all day. The biggest question we get from landscapers at our shop is, "How long do the batteries last?" I tell them "all day" as long as you can re-charge them in the field. It seems that there would be an more efficient way to utilize solar power, maybe the manufacturers will think of something in building thier chargers. We'll see.
 
Yes, I agree. Thanks for the reply! I think having a battery to charge from is going to be necessary. I am just curious if anyone has any ideas on creating a tool battery charger that wouldn't need an inverter, but would charge as fast, and as safe, as a Makita or Stihl rapid charger. They only take about 45 minutes to charge with AC power. Right now the inverter and battery is the only way to go, but does the future hold some sort of DC to DC rapid charging? This would be a game changer for the Landscaping industry in California starting in 2024. The only option, other that a solar generator, is to buy a backpack battery for $1,200 to $1,500 and charge it at home. Wearing a heavy battery on your back all day doesn't sound like fun. I'm hoping for small battery rotaion to keep a landscaper going all day. The biggest question we get from landscapers at our shop is, "How long do the batteries last?" I tell them "all day" as long as you can re-charge them in the field. It seems that there would be an more efficient way to utilize solar power, maybe the manufacturers will think of something in building thier chargers. We'll see.
I would shoot an email to the customer service department of a few of the tool companies that you have, and voice your concern. I'm not in CA, but I imagine if they're passing laws that require electric tools there, tool companies would be interested in making 12 volt rapid chargers for vehicles. Of course, the irony would be that people would charge their electric power tools off of their internal combustion engines, rather than use it with solar like you want to do.
 
just seems like a waste of electricity using an inverter going from DC to AC then from AC to DC to charge these batteries.
. Seems like the equipment manufactureres would come up with a viable way to charge batteries out in the field

Well some mfgs have DC2DC chargers for automobiles so you could use that brand. Or get the heck outa Califoamier

For the money, the Giandel 300W ps inverter I have charg my PC batteries fine. By the time you get a 12V - 36V DC charger you’d have spent for a single-point answer. A bigger inverter could run several of what you have now and more. Any brand any charger all the right temp and load comms
 
I suspect that tool batteries are more likely to have all the BMS functions handled in the charger and in the tool itself instead of in the battery. So that's a big reason to use the charger.
 
I suspect that tool batteries are more likely to have all the BMS functions handled in the charger and in the tool itself instead of in the battery. So that's a big reason to use the charger.
I know that the Milwaukee M18 packs have a BMS inside of the battery pack itself, but it has no way to shut off discharge current, so it sends a signal to the tool itself to shut off. Some of the new packs are pretty high-tech, it wouldn't surprise me if some of them need a proprietary signal to start charging.

I think if OP was only using a single brand of electric power tool, it would be much easier, but with so much variance over manufacturers, it would be pretty dangerous to just assume they all have battery management systems inside.
 
I would shoot an email to the customer service department of a few of the tool companies that you have, and voice your concern. I'm not in CA, but I imagine if they're passing laws that require electric tools there, tool companies would be interested in making 12 volt rapid chargers for vehicles. Of course, the irony would be that people would charge their electric power tools off of their internal combustion engines, rather than use it with solar like you want to do.
Good idea shooting them an email. If I can get them past the idea of just making a large backpack battery to power their tools, it might work. Worth a shot! On the internal combustion engine charging, I have to share this story. One of our landscaping customers said in one of the areas he was working, they would not allow gas powered blowers. So he put a Honda genrator on a backpack frame, and plugged an electric blower into it. He said a cop stopped him but couldn't stop him, because he was technically using an electric blower. Can't blame the guy for that idea, Hah!
 
Well some mfgs have DC2DC chargers for automobiles so you could use that brand. Or get the heck outa Califoamier

For the money, the Giandel 300W ps inverter I have charg my PC batteries fine. By the time you get a 12V - 36V DC charger you’d have spent for a single-point answer. A bigger inverter could run several of what you have now and more. Any brand any charger all the right temp and load comms
Thanks for your reply. I've looked at the Giandel inverters, looks like a good company. I looked at the Makita automobile charger and it takes 1 hr to charge a 3 Ah 18v battery. I predict the landscapers using about 400 Wh per hour per person, do it looks like we'll have to go big on battery and inverter set ups at this time. I like the 12v to 36v charging but maybe it's not cost efficient like you said.
 
I suspect that tool batteries are more likely to have all the BMS functions handled in the charger and in the tool itself instead of in the battery. So that's a big reason to use the charger.
Ya, if I knew for sure these batteries could take charging from a boost controller and battery, I'd go forward in putting together some system. I don't know enough about batteries and charging to take any chances. It would be fun to figure something out for this idea, but I'll just have to stick to what works for now. Thanks for the reply.
 
What about charging tool batteries directly from a solar panel without an inverter? I have charged up 36 volt tool batteries with a 12v panel and a MPPT boost controller alone. Don't know if this was a good idea, but it worked. I had to wire a broken battery charger to hold the battery. It just seems like a waste of electricity using an inverter going from DC to AC then from AC to DC to charge these batteries. We are a Makita outdoor power equipment dealer, and they have a charger that uses a cigarette lighter to charge. We also carry Stihl and Echo, but they don't have that option. It would be nice to build a system that could do this from solar without an inverter. The problem with the Makita charger using a auto cigarrette lighter plug is that they take a long time to charge. Makita 2 - 18v 5Ah batteries would take 3 hrs 20 minutes. These same 2 batteries last about 30 minutes bring used in a line trimmer. The Makita AC chargers can charge these 2 batteries in about 45 minutes. For a landscaper using outdoor power equipment all day long, they would need about 360 watts/hr charging batteries. California is making these lanscapers convert to battery power by 2024. The pictures posted show what I've tried so far, 36v Stihl seemed to work, the 2- 18v Makita batteries in series didn't (no way to balance charge for that set up). The specs of the panel I used. Seems like the equipment manufactureres would come up with a viable way to charge batteries out in the field. The solar generators with pure sine wave inverters seem like the only option at this point.
Been awhile since Ive been to this site but your situation caught my eye: personally, I would just run the panels to a solar controller and use its DC output... no need for battery or inverter.

The controller is like a regulator. You know, like I have an old charger that I use for what I call 'force charging'... newer ones don't want to charge something starting off with low voltage.

Point is: my old charger will overcharge if I leave it. That's ok a bit but wouldn't keep doing it. A controller won't do that.

Full disclosure: I glanced through your post and didn't read other answers (somebody might've already suggested a controller).
 
Been awhile since Ive been to this site but your situation caught my eye: personally, I would just run the panels to a solar controller and use its DC output... no need for battery or inverter.

The controller is like a regulator. You know, like I have an old charger that I use for what I call 'force charging'... newer ones don't want to charge something starting off with low voltage.

Point is: my old charger will overcharge if I leave it. That's ok a bit but wouldn't keep doing it. A controller won't do that.

Full disclosure: I glanced through your post and didn't read other answers (somebody might've already suggested a controller).
Oh yea btw, I've seen plenty of panels with battery terminal clips to use as trickle chargers.
 
What about charging tool batteries directly from a solar panel without an inverter? I have charged up 36 volt tool batteries with a 12v panel and a MPPT boost controller alone. Don't know if this was a good idea, but it worked. I had to wire a broken battery charger to hold the battery. It just seems like a waste of electricity using an inverter going from DC to AC then from AC to DC to charge these batteries. We are a Makita outdoor power equipment dealer, and they have a charger that uses a cigarette lighter to charge. We also carry Stihl and Echo, but they don't have that option. It would be nice to build a system that could do this from solar without an inverter. The problem with the Makita charger using a auto cigarrette lighter plug is that they take a long time to charge. Makita 2 - 18v 5Ah batteries would take 3 hrs 20 minutes. These same 2 batteries last about 30 minutes bring used in a line trimmer. The Makita AC chargers can charge these 2 batteries in about 45 minutes. For a landscaper using outdoor power equipment all day long, they would need about 360 watts/hr charging batteries. California is making these lanscapers convert to battery power by 2024. The pictures posted show what I've tried so far, 36v Stihl seemed to work, the 2- 18v Makita batteries in series didn't (no way to balance charge for that set up). The specs of the panel I used. Seems like the equipment manufactureres would come up with a viable way to charge batteries out in the field. The solar generators with pure sine wave inverters seem like the only option at this point.
I keep mentally coming back to your idea... I've rigged up all kinds of stuff. LOL.

Update: I went solar DIY after my house burned down... didn't have insurance so started hoofing up a setup ya know.

1st rig job was get lights... well LED runs off DC so rigged to a power bank. (FYI youtube was full of crap on this). Little USB cord splicing and boom lights w/ a timer.

Rigging continued.

Latest was how to rig up my battery operated mower. Batteries & charger went bye bye. That required some dismantling.

Admire your ingenuity. I tell myself all the time 'think outside the box'.

Also, I'm working on project right now concerning an ac lamp. Removed transformer and want to convert to DC.

Another next on my list is 'why do LED tvs have to be plugged into 115ac outlets'.

Any ideas more than welcomed.
 
Wanted to add one more picture of the MPPT Boost Charge controller charging the 36 volt Stihl Battery. The Stihl charger was gutted and the only wiring was the positive and negative wires to the prongs that go into the battery when charging. I would love to be able to charge these tool batteries quickly out in the field using just solar, but unlike the factory charger, I'm not sure this is the safest way. I know the Stihl batteries have a built in BMS, but not sure other brands have this. Of course the boost controller would have to be set for each individual battery. Stihl is 36 volt, Echo is 56 volt and 58 volt, and the Makitas are 18 volt and 40 volt. Not sure how to do the 18 volt as the boost controller only goes down to 24 volt.
Ok read little more, lol. CA moving towards solar at high pace (related to bad air quality)... so the gas generator in back of the van idea goes out the window. Contractors do that a lot here on East Coast.

Its also quite popular here to see inverters inside vans running off the battery. The folks using ac tools do that here. Gets low then they crank the van.

Anyway listen, charging speed is all in the amperage. Oh you'll be told not to increase but you can. (Watch out for equipment limits).

Admittingly, I spent yrs getting my EE degree but some accrued knowledge has come in handy. I can't wait to complete my setup using two alternator's. Fire got my mhome but hey have the parts. Ball barrings are on bottom of a washer... a box fan has little motor spinning... Imma get the 'no need for a generator' to spin the alternator figured out and the power company can bite me.

Sorry, all over the place with ideas outside the box. You have excellent grasp of that.

If you feel like expanding some ideas cheap, I found an el cheapo site in China to get electronics, banggood.com. Shipping takes awhile... Im tightwad so use ship freight a lot... literally it comes over on a boat. LOL

I have s feeling, you're gonna get like me and start thinking why the heck am I told to do x, when y...

Good luck for real.

I had to do something fast but ran into impossible Code restrictions so ended up rigging battery starter to generator (pullstart cord broker) then ran to AIMS converter to charge my batteries. FYI, charges 2 24v/100ah(paralled) lead acid in 30min... I maxed the amps. Full charge everytime fast.

PS Im feeling like dismantling something now.
 
I suspect that tool batteries are more likely to have all the BMS functions handled in the charger and in the tool itself instead of in the battery. So that's a big reason to use the charger.
They don't; we've disassembled hundreds and I can't remember a single one that didn't have a BMS in the pack itself. They're almost always passive top-balance with minimal actual balancing capabilities, but the protection is there. For reference, the smaller packs marketed as 18v and 20v are 5S (18v nominal), 40v is 10S (36v nominal), EGO 56v is 14S (50.4v nominal), and Greenworks 60v is 15S (54v nominal). Would be happy to provide photos of the guts for anyone interested.

The biggest issue with the packs is the various connection styles that would make any sort of universal charger difficult. Though I love the idea of installing 1kW of panel on top of an (enclosed...) landscaping trailer to charge equipment batteries.
 
They don't; we've disassembled hundreds and I can't remember a single one that didn't have a BMS in the pack itself. They're almost always passive top-balance with minimal actual balancing capabilities, but the protection is there. For reference, the smaller packs marketed as 18v and 20v are 5S (18v nominal), 40v is 10S (36v nominal), EGO 56v is 14S (50.4v nominal), and Greenworks 60v is 15S (54v nominal). Would be happy to provide photos of the guts for anyone interested.

The biggest issue with the packs is the various connection styles that would make any sort of universal charger difficult. Though I love the idea of installing 1kW of panel on top of an (enclosed...) landscaping trailer to charge equipment batteries.
Exactly. The battery connections are far from universal. Took some dismantling my battery mowers to rig up a new battery setup. Of course had to use gas powered mower during this because grass growing doesnt turn off (be nice eh).

The trailer charging station is a good idea and think... this is only during working hours. He could have some backups charging.

Wonder if could wire tool (ditch batt) directly to controller. Gotta make sure enough amps but could. Ha sounds like something I would try.
 
Been awhile since Ive been to this site but your situation caught my eye: personally, I would just run the panels to a solar controller and use its DC output... no need for battery or inverter.

The controller is like a regulator. You know, like I have an old charger that I use for what I call 'force charging'... newer ones don't want to charge something starting off with low voltage.

Point is: my old charger will overcharge if I leave it. That's ok a bit but wouldn't keep doing it. A controller won't do that.

Full disclosure: I glanced through your post and didn't read other answers (somebody might've already suggested a controller).
I do still like the Boost controller idea. One of the problems I've had is charging 18v batteries as it only goes down to 24v. I have the adapters for Makita batteries. I bought a bunch online apparently they are used for RC cars. The Stihl 36v adapter was made from a Stihl charger that stopped working. I just tore the guts out and hooked up the two wires, pos and neg to the terminals.
 
Ok read little more, lol. CA moving towards solar at high pace (related to bad air quality)... so the gas generator in back of the van idea goes out the window. Contractors do that a lot here on East Coast.

Its also quite popular here to see inverters inside vans running off the battery. The folks using ac tools do that here. Gets low then they crank the van.

Anyway listen, charging speed is all in the amperage. Oh you'll be told not to increase but you can. (Watch out for equipment limits).

Admittingly, I spent yrs getting my EE degree but some accrued knowledge has come in handy. I can't wait to complete my setup using two alternator's. Fire got my mhome but hey have the parts. Ball barrings are on bottom of a washer... a box fan has little motor spinning... Imma get the 'no need for a generator' to spin the alternator figured out and the power company can bite me.

Sorry, all over the place with ideas outside the box. You have excellent grasp of that.

If you feel like expanding some ideas cheap, I found an el cheapo site in China to get electronics, banggood.com. Shipping takes awhile... Im tightwad so use ship freight a lot... literally it comes over on a boat. LOL

I have s feeling, you're gonna get like me and start thinking why the heck am I told to do x, when y...

Good luck for real.

I had to do something fast but ran into impossible Code restrictions so ended up rigging battery starter to generator (pullstart cord broker) then ran to AIMS converter to charge my batteries. FYI, charges 2 24v/100ah(paralled) lead acid in 30min... I maxed the amps. Full charge everytime fast.

PS Im feeling like dismantling something now.
I appreciate your input, very inspiring! Right now I am working on running our 2 refrigerators and one chest freezer off of solar at our house. Just bought a cool 3 foot by 5 foot metal shed to build my solar set up in (expandable of course). The power company here shuts off the power from time to time during the day when we are at work, and it would be nice not to worry about our food going bad. I built a hand truck solar generator at our shop to show people what how they can make their own generator. I still have to put a shut off switch on the pos battery cable and the solar input, but here's a picture. I'm going to bring it home and re do it in my new shed. I'll also be able to spread the components out a little for air circulation.
 

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