Power tool batteries as power source?

[wjeeper]

I have a Jeep Cherokee that I am setting up that has some power needs to sort out. Been looking into a dedicated 2nd optima battery. By the time I add a 2nd battery, a charge controller, wires, etc, etc the system is starting to get $$$$$ and complicated. Another concern for me is space for a second battery is limited with my platform. Adding a 2nd battery under the hood means modifying the air filter box, inside the vehicle is really tight on space too and underneath the Jeep is not really an option. Also as a design criteria I am trying to use components I already have on hand.

Had an idea on my way to work that I want to run by the gurus! My thought was to run one two of these battery adapters and two Ridgid 9.0 AH lithium batteries underneath the rear seat:

Should be a simple robust battery system that is isolated from the vehicle. Plus i would have the added bonus of swapping spare batteries and the ability to run power tools with the same batteries at home or out on the trail.

Components I am thinking of running off of the system:

• LED Rock Lights: 2 maybe 3 for camp illumination (LINK)
• LED Dome Lights: 2 for the interior (LINK)
• Espar B4 heater when its cold
• A 12v fan when its hot

Planned use/ thoughts:

• KISS: I want to keep the system/ Jeep as simple and light weight as possible. Jeep is being used as a place to sleep, not much more.
• Summer trips 2-3 night duration. More frequent fan use, occasional heater use in the mountains. Light use is less (more hours of sunshine), so I think the batteries should be adequate
• Winter trips overnight duration. We really don't do much winter travel. Most trips to south/ central Utah. Drawback is more light use (shorter days) and frequent heater use at night only.
• 18 volts:
  • LED lights are a non issue running on 18 volts, already hooked them to a battery as a test.
  • I seem to remember the heater saying 12-24V on the side (not sure if that means it has to run on either 12 or 24 volts or anywhere between?)
  • DC brushed motors can run on different voltages right? The fan I have is like one of the ones you use to see in the front window of a school bus.

Here is my big question: sizing the battery system. Would 2 of these 9.0AH batteries service the system and my planned use? Has anybody run across a system like this before, or am I swimming in the deep end without my arm floaties again?

 

[rayra]

Your idea makes some sense especially if you are already invested in one of the power tool ecosystems and have the batteries available to you. But I disagree with your cost assertion on the 2nd battery. It's only expensive if you choose expensive components.

Ryobi's ONE+ ecosystem already has a lot of devices that do what you want and their tools are good. They even sell garage door openers designed to use their batteries as a power backup.
You aren't going to get a lot of heater time out of one.

https://www.ryobi.com.au/power-tools/products/list/family/one-plus

Amazon.com: Ryobi 18-Volt/120-Volt One Plus Hybrid Fan [Bare Tool Only] by Ryobi : Everything Else

Buy Ryobi 18-Volt/120-Volt One Plus Hybrid Fan [Bare Tool Only] by Ryobi: Everything Else - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

And as the OP mentions, you can tote a battery-powered driver, a chain saw, portable worklights, fan etc. They've even got a nice little boom box, all using the same batteries. But you'll want to rig a charging station for them in your vehicle. They're aren't going to last long under heavy or prolonged use. They're not meant to. You're expected to use one up while another charges, and swap batteries in the middle of a project. IIRC I drove about 100 deck screws with a standard battery and had to switch.

Frankly I'd strongly encourage a second battery that matches your primary and some sort of solar solution to extend. (of course I do, that's what I did)

eta ooh, now that I've read and said all that, I need to add / rig my second ryobi charger in my rear cargo area power module. Or better yet find a 12VDC version and hardwire it.
well at least one cig adapter 12VDC charger exists already. Could just plug it in when needed. safer that way anyway.

RYOBI ONE+ 18V In-Vehicle Dual Chemistry Charger for use with 12V DC Outlet-P131 - The Home Depot

RYOBI introduces the 18V ONE+ In-Vehicle Dual Chemistry Charger for use with 12V DC Outlet. The RYOBI 18V ONE+ In-Vehicle Charger is compatible with all RYOBI 18V ONE+ Ni-Cd and Lithium-Ion batteries.

www.homedepot.com

 

[luthj]

9AHx18V = 162 watt hours. Not a lot of power, but could work depending on your needs. You will need to sit down and do the math.

As far as output goes, you will want to get a DC-DC buck converter to output 12V regulated. 15A units aren't very expensive and are pretty efficient.

 

[VanWaLife]

It looks like the heater draws 1 to 3 amps at 12v depending on setting. I'd definitely check with manufacturer about whether it will even run at 18v, and whether that is healthy for it. So that's somewhere between 18 and 6 hours of runtime with 18AH of battery assuming no losses due to incorrect voltage, which is not a good assumption. I think running 12v devices at 18v is the hurdle you'll have, except for the LED's, which should be fine.

Rigid makes a pretty nice 18v fan. I think it is only a matter of time before they make a 18v powered device with 12v lighter output; you could wait for that. But it doesn't look like they make a car charger for their 18v batteries...that would deal-break their platform for me.

M12™ Cordless Power Port

Use the M12™ Cordless Power Port from Milwaukee Tool to charge up to 5 small electronic devices with a single, portable unit.

www.milwaukeetool.com

M18™ Power Source

www.milwaukeetool.com

 

[luthj]

Something like this may work. Depends on input voltage range.

Amazon.com: Kohree DC/DC Converter Regulator 24V Step Down to 12V 20A 240W Golf Cart Low Voltage Reducer Buck Transformer Waterproof: Electronics

Buy Kohree DC/DC Converter Regulator 24V Step Down to 12V 20A 240W Golf Cart Low Voltage Reducer Buck Transformer Waterproof: Power Converters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

The Espar 12V units typically max out around 16V.

 

[john61ct]

Problem is the manufacturers regularly chop and change their "standards".

Ryobi ONE+ series being the only exception.

And converting up/down to get 12V compatibility adds expense and complexity.

And the cost per kWh is super high.

And the LI chemistries they use, last only 10-20% of a proper LFP bank.

And are very dangerous due to fire risk.

Other than that, great idea.

 

[DaveInDenver]

And the cost per kWh is super high.

I was thinking that, too. Seems like it would getting power storage at a premium. Seems these particular batteries go for about $100 each so it's a bit more than $11 per A-hr (but at 18V so $0.62/W-hr). A Battleborn is about $9/A-hr (albeit at nominal 12V), a premium Odyssey is about $4.50/A-hr ($0.36/W-hr) and plain old flooded is probably on the order of $1/A-hr. Obvious lead acid has a significant downside of weight and less useable capacity. I'd probably not invest much going this route unless you already have the tools and want to stock up on batteries.

Edit to add: Just looking for lithium motorcycle batteries thinking they'd be cheaper. It appears a 20 A-hr generic "ExpertPower" is $180 at Amazon. So that $9/A-hr spot again. But nominally 12V so it's $0.75/W-hr so maybe it's actually less expensive to use cordless tool batteries. Interesting.

https://www.amazon.com/dp/B07X523S96/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B07X523S96

 

[VanWaLife]

Ryobi's ONE+ ecosystem already has a lot of devices that do what you want and their tools are good. They even sell garage door openers designed to use their batteries as a power backup.
You aren't going to get a lot of heater time out of one.

Whoa, looks like they make a 18V DC to 110V AC inverter. That is real nice.

18V ONE+™ POWERSOURCE 150 WATT BATTERY INVERTER | RYOBI Tools

RYOBI specializes in making pro-featured power tools and outdoor products truly affordable. RYOBI is the brand of choice for millions of homeowners and value-conscious professionals.

www.ryobitools.com

 

[john61ct]

I was thinking that, too. Seems like it would getting power storage at a premium. Seems these particular batteries go for about $100 each so it's a bit more than $11 per A-hr. A Battleborn is about $9/A-hr, a premium Odyssey is about $4.50/A-hr and plain old flooded is probably on the order of $1/A-hr. Obvious lead acid has a significant downside of weight and less useable capacity. But even a super premium brand like Battleborn is cheaper. I'd probably not invest much going this route unless you already have the tools and want to stock up on batteries.

Edit to add: Just looking for lithium motorcycle batteries thinking they'd be cheaper but it appears a 20 A-hr generic "ExpertPower" is $180 at Amazon. So that $9/A-hr spot again.

https://www.amazon.com/dp/B07X523S96/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B07X523S96

Ah is the best unit for actually measuring with a coulometer, but you really need to convert each different voltage to Wh or kWh for apples to apples.

 

[DaveInDenver]

Ah is the best unit for actually measuring with a coulometer, but you really need to convert each different voltage to Wh or kWh for apples to apples.

I corrected my original post. Didn't register these were 18V.

 

[john61ct]

**If** you really wanted to use NMC/NCA chemistry for a DIY 18-20V LI portable powerpak

you can find much cheaper sources for the cells and rig a module box that would give much more efficient energy density.

But going this route at least guarantees good quality cells without doing the sourcing research.

Note going this way, get the 12V charger, not via inverter, if off grid efficiency is important.

 

[wjeeper]

Lemme see if I can multi-quote this without messing up.........

Your idea makes some sense especially if you are already invested in one of the power tool ecosystems and have the batteries available to you. But I disagree with your cost assertion on the 2nd battery. It's only expensive if you choose expensive components.

I'd probably not invest much going this route unless you already have the tools and want to stock up on batteries.

I already am pretty heavily invested into the Ridgid ecosystem. Already have a bunch of their tools, batteries and chargers. I even have adapters to run the few Hitachi tools I own on Ridgid batteries. I also am looking for a "good excuse" to buy some of the bigger batteries for running the power tools.

And as the OP mentions, you can tote a battery-powered driver, a chain saw, portable worklights, fan etc. They've even got a nice little boom box, all using the same batteries. But you'll want to rig a charging station for them in your vehicle. They're aren't going to last long under heavy or prolonged use. They're not meant to.


Frankly I'd strongly encourage a second battery that matches your primary and some sort of solar solution to extend. (of course I do, that's what I did)

The interchangeability/ flexibility is exactly what drew me to this idea. Using a 12V charger would extend the usefulness of the concept. Although as VanWaLife has pointed out there doesn’t appear to be a 12V charger for Ridgid. I wouldn’t even consider going 12V Jeep- 120V inverter- 18V charger, I assume that would be wildly inefficient.

A second battery and solar isn’t a bad way to go. The space in this XJ is a premium, my trips are short in duration and not as frequent as I would like. Tying down a whole power system to a vehicle seems like somewhat of a waste.

Not a lot of power, but could work depending on your needs. You will need to sit down and do the math.

Are there any online calculators out there?

Its looking like the Espar heater may not make the cut for this power system. I thought it would be pushing the limits. A heater is something the wife really wants and I have one just sitting on the workbench crying to be put into something. (got it for free, and honestly don't know if it works)

If crossed the heater off the list this system seems way more reasonable

Just looking for lithium motorcycle batteries thinking they'd be cheaper………snip……maybe it's actually less expensive to use cordless tool batteries. Interesting.

I looked into the lithium motorcycle batteries for about ten seconds, they are spendy lil guys! Its interesting that the price of power tool batteries is not that out of line compared to lithium motorcycle batteries. Starting from scratch, a solar panel and lead acid battery would kill this idea from a cost standpoint. Since I already have a grundle of batteries and the chargers going with tool batteries is appealing.

I not overly savy with electricity. I do have a decent grasp of the DC basics. I really appreciate the input!

 

[Ducstrom]

Neat idea. Pretty sure that I read somewhere that the BMS is in the tool on the Milwaukee stuff so that the overdischarge protection comes from the tool. Something to think about anyway.

 

[wjeeper]

Theoretically does in using an 9.0 AH, 18 v battery imply:
9.0 Amps will run 1 hour @18v
or
1.0 Amp will run 9 hours @18v

Lets just say I do lighting (and have a little fun with it) on these batteries
Rocklights= 1.5a total @ 12V
Dome Lights= .64a total @ 12V
4X 12" LED Strips= .5a total @ 12V

how long would these last on a single 9.0 AH battery all running at the same time?

 

[VanWaLife]

Theoretically does in using an 9.0 AH, 18 v battery imply:
9.0 Amps will run 1 hour @18v
or
1.0 Amp will run 9 hours @18v

Theoretically it implies both these things.

Lets just say I do lighting (and have a little fun with it) on these batteries
Rocklights= 1.5a total @ 12V
Dome Lights= .64a total @ 12V
4X 12" LED Strips= .5a total @ 12V

If you are powering 12v devices with 18v they will be running at 18v. If they work at this voltage, they will either be putting out higher wattage than advertised, or drawing less current than advertised, or burning up the extra voltage with internal voltage regulation. To answer your question I think the theoretical limits on run-time would be 3-4.5 hours (rounding up to 3A power draw total).

Just going to throw this out there-you really wouldn't tax the stock battery much with your rocklights and dome lights. For camp lighting and fan, rigid makes both fans and really nice lights for their 18v system. And this:

18V Portable Power Source | RIDGID Tools | RIDGID Tools

RIDGID introduces the 18V Portable Power Source. This tool features a built-in USB Port to charge most devices on the jobsite.

www.ridgid.com

If you want to bling up your camp lighting, I just got one of these from Amazon:

Power Practical

Power Practical, makers of Luminoodle lights, Sparkr electric plasma lighters, and Pronto Portable battery packs.

powerpractical.com

Comes with a remote. Very nice.

So I know this is unsolicited advice, but if it were me I'd run rocklights and domes to the existing circuitry, get the rigid 18v fan, cordless lighting, and USB power source, maybe a luminoodle or two. That might be a more versatile set up than hardwiring everything back under the seat. The fan and lighting would have practical uses beyond the truck.