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portable inductor? has anybody tried a portable power supply?
- Thread starter budski
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Fearless Disaster
Well-Known Member
Did you do the math to see how much battery you need for how much inductor runtime? I haven't worked much with AC but I imagine there is a meter you can plug between the inductor and the wall to see how much current a session takes, then you could figure out battery size based on how many sessions you want power for.
XoGnosis
Active Member
the cable uses standard xt60 connectors commonly used in radio control hobbies and one of these inline meters will let you track power use during use but it also records watt hours and amp hours since last reset. (I keep one inline on my inductor and use the built in timer if I'm too medicated to count, lol)
Fearless Disaster
Well-Known Member
whatever hardware is available! but if you can get between the inductor and the wall you can account for any losses in the inductor itself. For example if the inductor blows 20% of its power to heat before it gets to the lighter head that might be nice to take into account. If it were me I would use whatever meter was best for my gear explorations and then pad it as necessary. Like build in 20% extra battery capacity or enough for 4 days of use if my max case is 3.
Oh that is good to know! I used a lot of XT30/60/90 connectors when I built my ebike. I am a big fan of them.
budski
cantre member
I do have a xt60 flow meter from my onewheel charger, that should work. If I could make the 40V tool batts I already have run it , extra bonus.
Fearless Disaster
Well-Known Member
That meter sounds perfect! I have never seen an inductor in person. Is the power input really DC? That seems odd for such a powerful desktop device but its not like I've ever built an IH
XoGnosis
Active Member
yes, it's a straight variable voltage power supply providing roughly 18-28v DC. There really isn't much in that big bamboo box beyond a pretty standard power supply.That meter sounds perfect! I have never seen an inductor in person. Is the power input really DC? That seems odd for such a powerful desktop device but its not like I've ever built an IH
what brand 40v batteries do you use, if you don't mind me asking?
I may borrow this idea myself and am looking at a dead Ryobi 40v mower as a parts donor.
Fearless Disaster
Well-Known Member
I checked out the product page for the inductor. it looks like the power input to the VVPS is AC. Is the Idea to skip the VVPS? Or to use an inverter to convert battery DC to AC for the VVPS which then converts it back to DC?
XoGnosis
Active Member
my intention, and what I gather the intent of the original poster, is, is to omit the bulky and redundant ac-dc power supply of the big bamboo box with dial, in favor of a simple adapter with voltage step down (buck convertor maybe?) and an xt60 connector to the existing lighter head.
edited to add that I'm also thinking I may take a much simpler but less flexible path and see how the lighter head behaves when simply fed from a DeWalt 20v battery directly. most of my devices can be heated with it at the 18-20v setting, just slower...
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Fearless Disaster
Well-Known Member
oh thats smart! so the 40V battery output connects to basically a glorified rheostat which connects directly to the lighter head! What put me off the inductor was the need to have a giant box on my desk. Not to drift too far off topic but then it should be possible to just buy the lighter head and hook it up to a different VVPS? One that could be positioned on the floor or mounted under the desk....
XoGnosis
Active Member
Yes, that's the idea, or at least my take on the idea initially proposed of using a power tool battery rather than wall power to drive the inductor.
the box size and shape is EXACTLY the thing I dislike most about the inductor myself, and as far as I can tell, yes it should be very possible to skip their bamboo monstrosity in favor of a separate lab power supply or other vvps in the appropriate range. I previously mentioned that I keep one of those xt60 power meters inline between my inductor power supply (tucked away under a side table) and the lighter head. that meter shows the operating voltage and current, as well as having a timer that counts seconds of power flow and tracks power throughput over time (Amp hours and watt hours). I have to pull the box out to change voltage, which is a pain, so I generally just leave it at 24v and alter my timings.
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Fearless Disaster
Well-Known Member
Maybe something like this could work.
This is a cheapie amazon usb-pd charger for milwaukee m18 batteries that I bought to charge the batteries on the road. If something similar exists for OP's batteries perhaps the cheapie charger could be bought entirely for the housing and battery interface. The buck converter could be put into the housing as well as a lighter jack to keep it all in one tight package. Or if one was feeling electronically inclined one could leave the charging circuit in there too and perhaps add a switch to choose between the two.
Of course this is all way cart before the horse before doing the power math. I'm picturing someone pulling a wagon full of batteries behind them so they can get high on the go
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This is a cheapie amazon usb-pd charger for milwaukee m18 batteries that I bought to charge the batteries on the road. If something similar exists for OP's batteries perhaps the cheapie charger could be bought entirely for the housing and battery interface. The buck converter could be put into the housing as well as a lighter jack to keep it all in one tight package. Or if one was feeling electronically inclined one could leave the charging circuit in there too and perhaps add a switch to choose between the two.
Of course this is all way cart before the horse before doing the power math. I'm picturing someone pulling a wagon full of batteries behind them so they can get high on the go
Fearless Disaster
Well-Known Member
oh that is nice and compact! if you can build in some strain relief a little heatshrink would make it a nice cable when you are all done. if you add an XT connector after the rheostat you could put a meter in there to tune the rheostat and then just leave it minimal.I have ryobi 40v and high amp milwaukee m18, I was thinking of a 3d printed batt lead adapter and add some kind of rheostat before the xt60 plug,
but like i said, step 0 is to do the math
Flotsam
Well-Known Member
I have been playing around with one of these using some IH kits. I have a bunch of these batteries from my tools.
Whatever battery solution you want to try make sure to use either a Battery Management Chip or at the very least a voltmeter chip with it. Bad things happen to any lithium battery when you discharge below a particular level (dependent on battery size V)
Whatever battery solution you want to try make sure to use either a Battery Management Chip or at the very least a voltmeter chip with it. Bad things happen to any lithium battery when you discharge below a particular level (dependent on battery size V)
XoGnosis
Active Member
Ryobi 40v packs have built in BMS and similar simple 3d printed adapters to what was shared earlier in the thread for Milwaukee packs. apparently the Ryobi packs are often repurposed for ebikes and children's riding toys partially for that very reason.I have been playing around with one of these using some IH kits. I have a bunch of these batteries from my tools.
Whatever battery solution you want to try make sure to use either a Battery Management Chip or at the very least a voltmeter chip with it. Bad things happen to any lithium battery when you discharge below a particular level (dependent on battery size V)
Flotsam
Well-Known Member
I have a bunch of those 40 v batteries for my Outdoor Power Equipment , got a chain saw, pole saw, Pole trimmer and regular hedge trimmer...
So i love the battery platform but its a big battery system to lug around. I believe the Ryobi 18 v line also has BMS as well. You can get all those adapters on ebay these days. I have initially gone Milwaukee red because i had a bunch of their 12 v stuff.
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Fearless Disaster
Well-Known Member
I believe every battery pack that is composed of multiple cells has a bms. probably the cheapest one that the manufacturer could find but still. Its not much of an expense and is the reason all the bare cells say not for vaping lol
Flotsam
Well-Known Member
no not necessarily true, in many cases like DeWalt they put some BMS logic in both the tool and the battery pack. and I know that is not true for the Milwaukee 12v i showed before. Tool manufacturers try to force people to buy their batteries as well. Otherwise the economics of it is people would buy cheapest battery and try to adapt it to whatever other brand. In some cases it is some sort of battery identity chip that is the reason (i think there is some multivolt DeWalt like that)
Personally the few times i got a gray market or fake tool battery it has not worked well for me, so i only try to get real brand batteries in some type of package. I have gotten real good service life out of all my tool batteries and cost wise much less than a pair of high end 18650s. and charging is a breeze. You would think there would be some compatibility within a larger brand's battery technology range. Milwaukee Tool is owned by Tectonic Tools Inc a big Chinese manufacturing consortium TTI acquired Milwaukee Tool in 2005. TTI also owns other brands like Ryobi, Hoover, and Dirt Devil.
There was a really good thread i had seen on Garage Journal that had a bunch of data on vendors, BMS etc. i will look to find again
Personally the few times i got a gray market or fake tool battery it has not worked well for me, so i only try to get real brand batteries in some type of package. I have gotten real good service life out of all my tool batteries and cost wise much less than a pair of high end 18650s. and charging is a breeze. You would think there would be some compatibility within a larger brand's battery technology range. Milwaukee Tool is owned by Tectonic Tools Inc a big Chinese manufacturing consortium TTI acquired Milwaukee Tool in 2005. TTI also owns other brands like Ryobi, Hoover, and Dirt Devil.
There was a really good thread i had seen on Garage Journal that had a bunch of data on vendors, BMS etc. i will look to find again
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Fearless Disaster
Well-Known Member
Oh I suppose thats true, one could move the bms to the tool instead of the pack, but like you said then people could use bare cells unless they make proprietary packs for "safety"
XoGnosis
Active Member
or do what it seems DeWalt does and split the BMS duties between the pack, the tool, and the charger...
I had discovered the DeWalt (and apparently Makita) tactic of having the tool handle low voltage shutoff instead of the pack and decided to stick with the larger Ryobi 40v packs that I have at least a dozen of, for availability and simplicity of not having to worry about killing the pack.
To further the actual discussion a little, I reset my inline power meter, set my inductor to 22v and ran a bowl each with my tornado, tempest 2. and then did a worst case check at 28v heating my TA3 and then the tempest 2 a second time.
peak current I saw was just a hair under 10 amps, flirting with 300 watts heating both the tempest and ta at 28v. a more realistic use at 22v with tornado and tempest 2 saw 6-8 amps at peak.
I didn't really record "data" and was more just screwing around
but it's enough that I ordered a sled for those Ryobi packs and will explore further.
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Flotsam
Well-Known Member
you hit on the real issue with this. Its a bit complicated to reconstitute a BMS that is in multiple places
To make this packs you really can't use a soldering iron with all that heat concentrated on the battery cell so there is a special spot welder that can do that. I never bought one of those
Fearless Disaster
Well-Known Member
or do what it seems DeWalt does and split the BMS duties between the pack, the tool, and the charger...
I had discovered the DeWalt (and apparently Makita) tactic of having the tool handle low voltage shutoff instead of the pack and decided to stick with the larger Ryobi 40v packs that I have at least a dozen of, for availability and simplicity of not having to worry about killing the pack.
To further the actual discussion a little, I reset my inline power meter, set my inductor to 22v and ran a bowl each with my tornado, tempest 2. and then did a worst case check at 28v heating my TA3 and then the tempest 2 a second time.
peak current I saw was just a hair under 10 amps, flirting with 300 watts heating both the tempest and ta at 28v. a more realistic use at 22v with tornado and tempest 2 saw 6-8 amps at peak.
I didn't really record "data" and was more just screwing around
does you meter take time into account and report in Ah rather than A? or do you have to time the hits yourself and do the math? Any decent molicel can easily handle 10A, the question is if a heatup takes say 5 seconds with the inductor, then how many amp hours would cover 50 heatups or whatever the design goal is?
For example, here is the info on the molicel p30b:
it can handle a 36A discharge and contains 3.0Ah (10.8Wh). The issue is not if the cell can handle 10A, the question is how many 3 Ah cells will you need to power the number of hits in your use case? since the serial / parallel cell arrangement is already defined for you in the ryobi 40v pack design, the question actually becomes how many hits will you get out of a ryobi 40v pack?
Its also worth considering that lithium ion batteries do not do well when left at very low voltages / empty. Lets assume that each 40V pack will get you one day of usage. If the use case is to go camping for a week i would personally rather find a way to charge the pack on the road rather than leave multiple packs sitting empty for days.
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