Solar charger for Dewalt 20v 9ah battery system?

[icedragonmx]

If I had a Goal zero Nomad 28 Plus (28Watt) panel that is used for the iPad and GPS on canoe trips can I rig a ride along charger system for the Dewalt 20V batteries using the following items…

Solar Panel – Goal Zero https://www.goalzero.com/shop/foldable-solar-panel/nomad-28-plus-solar-panel/

https://d4td1un6f2hha.cloudfront.ne...l-8-ca6e/b4f9c73b499df7bd4fc590b41b72bb87.jpg

Adaptor cord (switch to female 12V end) – https://www.goalzero.com/shop/cords-adapters/8mm-12v-car-charger/

Charger for battery - https://www.dewalt.ca/en-ca/product...ax-lithium-ion-vehicle-battery-charger/dcb119

https://images-na.ssl-images-amazon.com/images/I/71NqppgSrRL._SL1500_.jpg

What controller would I need to use to place between the panel and the charger so that I don’t kill/overcharge the 20V Dewalt batteries ??? Looking for a light weight solution if possible and no mods to the panel or the charger as both would be used for their intended purposes for the majority of the time. Just wondering if I can combine parts I have into a working system?

Thanks for any help on this!!!

 

[IdaSHO]

I really doubt that small panel will be enough to even power the charger.

That charger is designed for a negative ground system that uses a vehicle battery/


On that small panel, the moment the charger starts to charge, the system voltage will most likely drop well below what the charger probably needs.

Worth a shot I guess, but dont be surprised if it is a complete failure.

 

[icedragonmx]

I really doubt that small panel will be enough to even power the charger.

That charger is designed for a negative ground system that uses a vehicle battery/


On that small panel, the moment the charger starts to charge, the system voltage will most likely drop well below what the charger probably needs.

Worth a shot I guess, but dont be surprised if it is a complete failure.

It looks like I may be asking too much from the panel to charge something of this size

 

[Bbasso]

How much does the dewalt charger draw? I didnt see that mentioned...

 

[llamalander]

Not sure about the DeWalt in particular, but an 18v. Makita charger is rated at 70 watts and draws about 5.4 amps at 12.5 volts.
Generally it charges more slowly than the 110v. charger, perhaps 2/3 to 1/2 as fast.
The input voltage is 12-24, I've never tried it below that. Nor have I tried a sufficient voltage but inadequate watts...
You may have better luck with a 24v. solar setup, but it would likely have to be at least 80-100 watts- too big for a canoe, but small enough to pack in a truck.
But if you have a truck, charge your battery with whatever panel you can (or not) and charge your tool batteries while you're driving.

 

[DaveInDenver]

You need to know what the charger is designed to do. It may not deal with the high voltage of a solar panel correctly, either not pass much power when above it's expected source voltage or worse it will go out of regulation and just pass short high voltage pulses to the battery.

Since it's designed as a boost it may be safe and not damage the battery but also won't work efficiently directly from a solar panel. I'd crack open that charger and see what's going on under the hood before I risk a battery.

Found this video that indicates the DCB119 runs about 60 W. He's using an intermediate battery and controller, so the DCB119 is running from a nominal 12V source. That's probably what I'd recommend, at least a small solar controller and battery in the system to smooth the source power for the charger.

 

[Ducky's Dad]

Not necessarily relevant to OP's question, but the video makes a point of running the truck while charging batteries. FWIW, I have charged Dewalt batteries all day long from my dash power ports without starting the truck, running two chargers simultaneously on two ports, and swapping out batteries sequentially as they are depleted. No problems with the batteries, the chargers, or the truck, but my starting battery is a Grp 31.

 

[DaveInDenver]

I suspect the reason he noticed is that at charging voltage slightly more power will be transferred, so it'll be a little faster is all running at peak efficiency. Who knows, it may not even have a low voltage cut off (from a 12 V perspective) and may even run off a 6 V battery. That's maybe unlikely, dunno the specs for it.

 

[icedragonmx]

Thank you to all for the feedback on this. Sounds like the limiting factor is the panel being to small for the charger (DeWalt listed at 12V @6.0amps or 72 Watts for the imput) Might have been a better idea if I was using a 100W panel but that is way to big for the solo canoe use. I guess I can bring a battery with pre-charged as a reserve for when the panel can't be used but no way to top it up during the canoe trip. I am still very new to the solar stuff so still need to figure out the size vs use issues. Was hoping I could run this without a middle battery+controller type system like shown here -

Edit - the charger sounds like it can switch off automatically if there is issues with the source - quoted from the manual - "PROBLEM POWER LINE - Some chargers have a Problem Powerline indicator. When the charger is used with some portable power sources such as generators or sources that convert DC to AC, the charger may temporarily suspend operation, flashing the red light with two fast blinks followed by a pause. This indicates the power source is out of limits."

 

[Bbasso]

It draws 6 a then you'd need atleast 100wt of solar to make it work properly, keeping in mind the loss that happens with solar harvesting through the day.
As others have mentioned, I'd run a small battery to even the power supply to the dewalt. And a cheapo SCC too.

Good luck.

 

[e60ral]

goalzero panels generally run double the cost of good panels from other brands if you do decide to do this