DIY power tool battery powered compressor?

[Greg_E]

Been thinking about this for a bit... Has anyone used 18 volt power tool batteries with their automobile powered compressors? I have a ton of Ryobi batteries and would probably get an adapter like this

I checked and most all the 12 volt tools are 12v max or 10.8v nominal, so not an option.

Specific compressor is a Benjamin Traveller Gen2.

To make life easier on the batteries, I'd use with two 9 amp packs in parallel which would be about a 1.5C discharge rate. A pair of 6a packs would also be OK for a little over 2C discharge. I see at least 24 amps shown on the meter when the compressor runs, and it is listed as 26 amp draw.

In theory these devices are designed to handle 16 volts from the vehicle, so the 18 volts should be OK. I may pull the top off my compressor tonight and take a look, but would like to hear if anyone else has done similar and how well it works and what kind of run times you get.

[Chickenthief]

A 12V motor run at 18V for prolonged time under severe load is a nono, thats a 50% (severe) overload.
Stick to the advertised 12V batteries ie 3 LiPo cells. 4 cells at best!

That said.
A "typical" 12V compressor will consume some 250-300W while running under load.

Bear with me as this math really ($uck$) is translated to "not worthy" by the sites autocorrect, doing Imperial!!!
Well that flew under the radar!

So 250W/12V = @21Amps, 300W/12V @25Amps.
That can be scaled up or down so:
A 4Amp battery = (4/25 to 4/21) = 9½-11½ min runtime.
A 5Amp battery = 12-14 min runtime.

An item running a current of 21Amps in an hour with a 4 amp battery/supply will only run 4/21= 11½min before the battery is empty. 4 amps (run for an hour/60min) drained at 21amps is 4/21= 11½MIN.

[Chickenthief]

Disregard

[Greg_E]

I have the cover off looking to see what the motor might be... There are zero markings on anything in here except the control circuit board which has New Warrior on the silk screen.

So yeah, 18 volts might not be a good choice! And I don't think it will be worth the cost of a 30 amp DC to DC converter. I'll have to get a meter out and check the voltage from the PS, nominal from a running car will be 13.8-14 volts, but 18 is probably a stretch too far.

[Greg_E]

The PS puts out 13 volts idle and pulls down to 12.4x volts at 3000psi. 18 is probably too much unless I can find info on this motor to see if it can operate at 18.

[Greg_E]

Sent an email to the manufacturer, hope they reply.

http://www.new-warrior-compressors.com/por/10.html

[45WLA]

The power tool packs are usually built up from 1.2v cells to a 'nominal' voltage and the power tool motors are usually high speed, lower drain motors than HP compressors. That's how a Dewalt 18v tool can be run on a 20v battery with an adapter.  I'm not sure it would be a very viable idea to use use the 18v tool battery on the 12v HP compressor.
I've got a 12v sealed battery from a kid's ride on vehicle that I'm going to use for the same purpose some day, but it's 12v and for heavy discharge use. Plan is to change the connectors and charge with a trickle M/C charger. We'll see, but that's 12v to 12v.
Good luck.
 

[Greg_E]

Bringing this back up... Started thinking in a different way, not that I like this choice, but it should work for any 12volt vehicle powered compressor.

20ah Lipo battery pack, should run my Benji compressor for an hour. https://hobbyking.com/en_us/turnigy-high-capacity-battery-20000mah-4s-12c-drone-lipo-pack-xt90.html

Thinking about this, still want to run on the tool batteries that I own, but this might be a choice.

[Wayne52]

I know that Bin Tac sold his compressors with a battery pack that would be good for 1/2 hour of use which would be plenty for out hunting purposes.  I see Wes has more of the Xisico compressors in stock right now and they probably won't last long, If I needed a compressor I'd probably go for the deal that he's got on them but already having the F10 and tanks that are transportable I have no need.  I'm sure that those compressors he has will sell out very fast because there is a big demand for them these days.  They seem to be a reliable compressor for the cost of them.

[sb327]

Not sure if one of those would work for you. Might be worth an experiment.

Dave

[Greg_E]

Yes, A DC-DC converter might work, and way cheaper since I already have batteries. I'll look into this a bit more and see where the loses go, but might be a good idea. The 40 amp version was a little cheaper.

I know my Benjamin compressor is rated 26 amps at 12-13 volts and I normally see 22 amps on the meter they have mounted (if that is real, it's temperature on other models).

More digging now.

[edit]found one that says 15 volts to 12 volts at 30 amps and is sealed, $22usd. I think I'm going to order one and a pair of battery holders and give this a try. I'd much rather order more tool batteries that I can use on multiple devices, than a couple really big Lipo packs that I can't use anywhere else. And it is Prime shipping.

Alternate for other people would be 40/60/80 volt tool packs, I have a few 80 volt tools (snow blower, chainsaw) that I might try if this doesn't work. Not sure why I didn't think about a DC-DC converter before, I could have had this done months ago!

Only other thing I may need are some big diodes, if you want to run dual batteries, you really should have a diode on each to prevent a back charge. If one pack is really weak, the other could cause a failure by back charging it. But I think that may be version 2, need to see how well it runs with the cheaper version 1.

[Greg_E]

Went with a 40 amp converter, I read about a bunch of these failing early when running up near their limits, since I know I'm going to need 26amps, decided I better go a bit higher for a little more over head. But everything is on the way to make version 0.1.

[sb327]

Good decision. I try to always keep a large overhead with these cheap electronics. Keeps the heat manageable.

Dave

[Pellethuntr]

Neat project Greg!

I was actually thinking about buying another Yong Heng compressor and doing a motor swap for portable air. I have a 3000 watt motor here that I salvaged from a treadmill and a pile of 20v DeWalt battery packs OR I was thinking I could power it with a small gas motor fairly easily as well. Food for thought for us guys that can't afford a $1k portable compressor.

[Rob M]

best way to go is a 4S lipo battery , and a balancer charger..  Get the matching anderson(xt90 or whatever ) connectors for the compresor, done..Simple , way more discharge rate than needed , and the BMS is external in the charger. you wont need 20 ah , more like 5ah for the amount of shooting you will do in 1 day., really , when are you going to run the traverler compressor for an Hr straight in the field.. or even get 2 swap em as you need to

[Greg_E]

An hour straight, never. But four 15 minute fills would be just about every time I go. Even worse when I only get 3 shots per fill on the new high power big bore that I'm waiting for.

[Greg_E]

I think I have all the parts to prototype this, need to find my box of heat shrink and get the soldering iron out.

[sb327]

Don’t let any of that magic smoke out of anything!

Dave

[Greg_E]

No magic smoke was loosed during the production of this adapter!

Seems a little slower than running on AC, which is strange because the AC to DC power supply inside only puts out around 12 volts under load. I'll have to check the voltage on this DC-DC converter under load and see what's happening. But it ran to 3000psi into the dead head plug. These 4ah batteries dropped a bar while it was running, jumped back to full when the compressor stopped. Still going to recommend bigger packs for anyone that tries this.

I'm still really tempted to just connect the batteries directly and see what happens. If I could buy a new motor at a reasonable price, I'd give it a go.

[Rob M]

the motor in the compressor is a cheap scooter motor , almost indestructible.. Youre dropping 18 down to 12 i assume , the problem is the converter youre using has a very limited amp rating , so its a choke point not only for voltage but also for current .. In other words, amps are the issue with speed for this application , not the output voltage .. having said that , running 18v direct is a bad idea, because the piston would also be moving 1.5 times the factory speed.