1nxtmonster

MiniZip - Compact and Cheap Power for your Lego Creations!

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Hi guys! I'm thrilled to release MiniZip; the adapter that lets you power your lego creations from a 9 volt battery! I am releasing it on Kickstarter to cover the production costs, and I need your help to do so! You can see the full project here:

https://www.kickstar...-lego-creations

Here's a video about it:

Thank you for your support!

Edited by 1nxtmonster

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Thanks! The rechargeable battery that I offer lasts about 1/3 as long as the lego LiPo battery. This doesn't sound like too much, but who completely drains the Lipo box in one session? I found that by charging one battery while using the other, there is rarely a time where I am without a full battery.

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Great! I think you should make a lego casing for the battery ,similar to the SBrick, so its easier to conceal or integrate

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Thank you for the suggestion! I will try to incorporate this into a 'stretch goal'. The reason I have not done this already is that adding lego mounting points would considerably increase the size, something that not everyone wants. Perhaps a self-applied adhesive-backed mounting strip would be ideal.

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Great idea, but I see some problems..

1. A 9V battery will give you roughly 200mAh. If you connect a motor to it, I predict it won't last that long. Also, it's current is limited, so the motor might run slower (especially when the battery gets near-empty).

2. Alkaline 9V (when compared to alkaline AA) has a far worse money-to-power ratio. You just get less power for your hard earned cash. Same for NiMH. But granted, it's more compact.

3. (this really bugs me) 9V is a b* to plug in and unplug. And considering the limited capacity, you'll have to unplug it.. a lot.

4. I don't know where you'll source your 9V chargers and batteries, but be very, VERY wary if they come directly from China. In China there are many manufacturers of both fake brand (some very poor quality battery with a GP logo on it) and ludicrously-bad brands that will happily sell you a 30mAh 9V NiMH battery or something.. But it'll be marked as a 500mAh battery of course.

5. Same for the chargers. These can often carry fake safety-approval test marks. They have probably never been tested and if somebody's house burns down.. Well I wouldn't be able to sleep if I sold those. Again I don't know where you buy these, I'm giving you the warning just in case.

Personally, I think it would be more interesting to have a cable that converts PF to 5.5x2.1mm female power jack. And also make some 5.5x2.1mm power jack 9V sources, like indeed a 9V battery, but maybe also a 3xCR2032 holder (very little power, but very small), 6xAAA, 6xC or 6xD (for all your heavy duty machinery) and 2x14500 (requires a special charger, but might actually be an interesting fairly compact option). Maybe 2x18650. Or even a 9V solar panel, why not! And obviously, it could be connected to a simple 9V adapter, powering it directly from the grid.

With 5.5x2.1mm power jack, you could hook your creation up to anything!

And while I'm at it, since we're on Eurobricks here, it kinda bothers me kickstarter projects always charge quite a bit extra for shipping to Europe. For last words, if I sound negative, I do get why you're making a 9V block PF adapter, but at least personally I'd rather have a more universal solution. Chances are I'm not your target audience, I would probably make my own cable when I decided I need something like that.

Edited by W3ird_N3rd

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W3ird_N3rd's objections not-withstanding, I think this is a great idea. Of course, the technique to do this should be widely known by now, but not many people are great with cutting a splicing, and ending up with a nice, neat cable at the end. The 9V battery offers a lot of flexibility... I would imagine if you're running an RC car or train motor, or operating a crane arm or something, it's probably not for you - but there's a ton of lightweight applications that would make this 10 times better than battery box.

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Looks like a neat solution. What battery controller electronics are included. For exaple, what stops the battery exploding when shorted out. For li-ion what stops the battery completely discharging ?

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These can be made pretty easily for under $5...

I made one a few years ago to run PF off of a 9V incase I didn't have a nearby electrical outlet at shows, it's pretty easy to make... I even spliced and on/off switch into mine so the motors don't take off as soon as you connect them...

Here is an old topic on these....

Edited by Paul Boratko

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I see this working only if there was a 9V block lithium battery or smiliiar. Normal ones simply drain too fast and cannot power too much stuff at once.

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Great idea, but I see some problems..

1. A 9V battery will give you roughly 200mAh. If you connect a motor to it, I predict it won't last that long. Also, it's current is limited, so the motor might run slower (especially when the battery gets near-empty).

2. Alkaline 9V (when compared to alkaline AA) has a far worse money-to-power ratio. You just get less power for your hard earned cash. Same for NiMH. But granted, it's more compact.

3. (this really bugs me) 9V is a b* to plug in and unplug. And considering the limited capacity, you'll have to unplug it.. a lot.

4. I don't know where you'll source your 9V chargers and batteries, but be very, VERY wary if they come directly from China. In China there are many manufacturers of both fake brand (some very poor quality battery with a GP logo on it) and ludicrously-bad brands that will happily sell you a 30mAh 9V NiMH battery or something.. But it'll be marked as a 500mAh battery of course.

5. Same for the chargers. These can often carry fake safety-approval test marks. They have probably never been tested and if somebody's house burns down.. Well I wouldn't be able to sleep if I sold those. Again I don't know where you buy these, I'm giving you the warning just in case.

Personally, I think it would be more interesting to have a cable that converts PF to 5.5x2.1mm female power jack. And also make some 5.5x2.1mm power jack 9V sources, like indeed a 9V battery, but maybe also a 3xCR2032 holder (very little power, but very small), 6xAAA, 6xC or 6xD (for all your heavy duty machinery) and 2x14500 (requires a special charger, but might actually be an interesting fairly compact option). Maybe 2x18650. Or even a 9V solar panel, why not! And obviously, it could be connected to a simple 9V adapter, powering it directly from the grid.

With 5.5x2.1mm power jack, you could hook your creation up to anything!

And while I'm at it, since we're on Eurobricks here, it kinda bothers me kickstarter projects always charge quite a bit extra for shipping to Europe. For last words, if I sound negative, I do get why you're making a 9V block PF adapter, but at least personally I'd rather have a more universal solution. Chances are I'm not your target audience, I would probably make my own cable when I decided I need something like that.

The rechargeable 9v batteries that I offer have 280 mah. I found that by charging one while the other is in use I am hardly ever without a fresh battery.

I found no noticeable performance drop in any of the models I tested it in (RC buggy, rock crawler, mini L motor rally car, etc.) From what I understand of electronics, a battery with a lower capacity can still provide the same power (amperage) but just for a shorter time.

I found the batteries and chargers from a moderately well known brand. I ordered several and have been testing them. In fact, it is those batteries that are used in the video.

The power jack sounds interesting.

Sorry that extra shipping is needed for europe, but I guarantee you that what I charge for shipping is lower than what it actually costs.

Thank yo for your feedback!

W3ird_N3rd's objections not-withstanding, I think this is a great idea. Of course, the technique to do this should be widely known by now, but not many people are great with cutting a splicing, and ending up with a nice, neat cable at the end. The 9V battery offers a lot of flexibility... I would imagine if you're running an RC car or train motor, or operating a crane arm or something, it's probably not for you - but there's a ton of lightweight applications that would make this 10 times better than battery box.

Thanks! Yes, the average diy tinkerer could probably slap together a basic cable. But my hopes are that the good quality and low prices can offset that. The rechargeable batteries and chargers are a real deal breaker in my opinion, as the bulk pricing I found is much lower than what you could get for yourself.

I tested this extensively in models with RC motors (some of my fast buggies) and I found that it was just as fast and powerful. Same thing goes for my rock crawlers, there was no noticeable performance drop either. The only thing that dropped was the run time; the 9v battery tends to drain quicker than the larger Lipo or 6 x AA battery boxes.

Thank you for your interest!

These can be made pretty easily for under $5...

I made one a few years ago to run PF off of a 9V incase I didn't have a nearby electrical outlet at shows, it's pretty easy to make... I even spliced and on/off switch into mine so the motors don't take off as soon as you connect them...

Here is an old topic on these....

I agree, the average tinkerer with electronics know-how could probably pull something off like this. But for those that can't, don't know how to, or want a refined finished product, this is probably the ideal way to achieve it.

I see this working only if there was a 9V block lithium battery or smiliiar. Normal ones simply drain too fast and cannot power too much stuff at once.

The 9v battery will be able to power as much stuff at once as a normal battery box, but just for a shorter time. If you use rechargeable 9v batteries (I offer them on my kickstarter as well as chargers) this shorter battery life shouldn't be much of a problem as you can simply replace the empty battery for a full battery and then charge the empty battery. But keep in mind that the main goal of this is so that you can build more compact models; there is a time and a place for a normal battery box. Like in your fox for instance. But the amount of stuff you can build once you don't have to worry about fitting in a bulky battery box is incredible.

Thank you for your questions!

Looks like a neat solution. What battery controller electronics are included. For exaple, what stops the battery exploding when shorted out. For li-ion what stops the battery completely discharging ?

The battery that i offer is a rechargeable NiMh battery, which is very stable. As long as you don't intentionally short out the battery or dunk the whole thing in water, there should be no risk of shortage. But just to see what would happen I took the whole thing and put it underwater with the battery attached. After sitting there for a while, I pulled it out and disconnected the battery. It still functions perfectly.

Edited by 1nxtmonster

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You should just sell these on Ebay.. You could most likely make more money and reach a greater audience...

You could probably sell a single cable for $15... Easy $10 profit...

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You should just sell these on Ebay.. You could most likely make more money and reach a greater audience...

You could probably sell a single cable for $15... Easy $10 profit...

In order to get a good price on everything (bulk), I need an upfront investment. This is where kickstarter comes in. After the campaign is over, I will sell them on my website or ebay (or both) for $12 - $15. So anyone who gets one now is getting a good deal :classic:

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Made one of these before, a basic RC car lasts about 15-20 mins ://

[edit] an adapter for lipo batteries would be cool. Not like lego ones, I mean like a 'raw' lipo battery.

Edited by MrNumbskull13

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I see this working only if there was a 9V block lithium battery or smiliiar. Normal ones simply drain too fast and cannot power too much stuff at once.

9V lithium batteries do exist, but they are not rechargeable. Also, they are expensive (at least €6 and usually more). 2x14500 Li-ion would be only slightly larger and probably more sensible if you want more power.

The rechargeable 9v batteries that I offer have 280 mah.

That's just what it says on the tin. Did you actually test if it delivers this amount? Many manufacturers (unknown ones even more so) wildly exaggerate this spec.

I found that by charging one while the other is in use I am hardly ever without a fresh battery.

While interesting, it doesn't really quantify much because we don't know how you play with your models.

Some good numbers that can be tested would be better. Charging time, runtime for various motors/lights. Also runtime when the battery has been stored away for a month.

I found no noticeable performance drop in any of the models I tested it in (RC buggy, rock crawler, mini L motor rally car, etc.) From what I understand of electronics, a battery with a lower capacity can still provide the same power (amperage) but just for a shorter time.

That's a difference between theory and practice.

In theory, if your 9V block holds 280mAh it would offer roughly 9*280=2,52Wh, let's just say 2.5. Now in theory, if your microwave oven requires 2000 watts to run, you could run your microwave oven from the 9V battery for about.. 2000/2.5=800 and 3600/800= four and a half seconds. (for the sake of argument assume we have a 100% efficient DC-AC converter)

In practice, I foresee a talking microwave that asks a 9V battery: "Do you feel lucky, punk?".

Available maximum current depends on both battery cell size and chemistry. Lithium-ion and NiMH Low-Self-Discharge provide a fairly high current down to when the battery is near-empty, NiMH provides less current, alkaline provides decent current but declines more quickly. Especially alkaline may be useless with a Lego motor far before it's actually empty. (a clock or remote control may still be able to operate for years when the block can no longer power a motor) A 9V block usually contains 6-7 very tiny cells, so the current is quite limited as it depends on cell size, not battery size. (actually that's putting it a bit simply, but it goes too far to explain everything here)

I found the batteries and chargers from a moderately well known brand. I ordered several and have been testing them. In fact, it is those batteries that are used in the video.

So EBL? From the top of my head, that's a Chinese brand. (correct me if I'm wrong) If you are importing this from China, there's a very real risk it's not even actually EBL. Yes, they even knock off their own brands. For the batteries it's mostly a matter of quality, but if a dodgy charger goes haywire the consequences could be far more serious.

Sorry that extra shipping is needed for europe, but I guarantee you that what I charge for shipping is lower than what it actually costs.

Yeah, USPS is pretty expensive. Given the small numbers I can't really think of a much cheaper option for this particular case.

Just want to say I appreciate you doing this, just be careful.

The 9v battery will be able to power as much stuff at once as a normal battery box, but just for a shorter time.

No, it really won't.

The battery that i offer is a rechargeable NiMh battery, which is very stable. As long as you don't intentionally short out the battery or dunk the whole thing in water, there should be no risk of shortage. But just to see what would happen I took the whole thing and put it underwater with the battery attached. After sitting there for a while, I pulled it out and disconnected the battery. It still functions perfectly.

Actually tested on Mythbusters, they dunked a whole car door plus car battery underwater. Half an hour later they could still roll down the windows. Fact is the voltage is simply too low to create a short circuit underwater. (various other problems would still occur in the long term though, so don't start driving your car underwater now)

Edited by W3ird_N3rd

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@W3ird_N3rd Thank you for pointing out the flaws in my argument.

I will test the batteries for voltage, amperage, mAh, run time on various motors and lights.

I use my MOC's for about 10-15 minutes in one session. Probably every other day, but for the last week I've been using them every day as I was filming a youtube video.

Thank you for pointing out my misconception a of smaller cell producing same amperage.

But in practice I have seen no noticeable performance difference (aside from a shorter run time)

Yes, EBL is a chinese brand but still has good batteries and reviews. I trust my supplier to give my EBL brand batteries.

I got the cheapest shipping I possibly could in the circumstances (have a friend at a shipping business who quoted me the cheapest possible rates)

Thank you for your feedback.

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While it is true that 6AA cell batteries are capable of a MUCH higher current output than a 9V block battery (which has 6 tiny 1.5 cells inside it), in LEGO practice the current is limited to ~1A anyway. So while the 6AA batteries may be capable of much more than 1A, you will never get it out of the battery box. So as long as the 9V battery is capable of 1A, you won't see any practical drop in performance. In other applications (like R/C), the difference would be immediately noticeable and unmistakable.

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Great! I think you should make a lego casing for the battery ,similar to the SBrick, so its easier to conceal or integrate

That seems kind of pointless, lego already makes a case for a 9V battery and has an adaptor cable to connect it to PF motors.

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That seems kind of pointless, lego already makes a case for a 9V battery and has an adaptor cable to connect it to PF motors.
While it is true that 6AA cell batteries are capable of a MUCH higher current output than a 9V block battery (which has 6 tiny 1.5 cells inside it), in LEGO practice the current is limited to ~1A anyway. So while the 6AA batteries may be capable of much more than 1A, you will never get it out of the battery box. So as long as the 9V battery is capable of 1A, you won't see any practical drop in performance. In other applications (like R/C), the difference would be immediately noticeable and unmistakable.

@S.I While some sort of attachment system to lego would be nice, I agree that a full case would add bulk and take away the main benefit of a 9v battery - it's small size.

@Blakbird I will test the 9v battery today for current draw and get back to you.

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Alright, I tested current draw on the 9v battery with a stalled XL motor and got a number of 1.3 A

The lego power function battery box overload kicks in at around 1 A, correct? So therefore a fully charged 9v battery can provide just as much, if not more, current as a 6 x AA lego battery box.

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You should just sell these on Ebay.. You could most likely make more money and reach a greater audience...

You could probably sell a single cable for $15... Easy $10 profit...

15$ for a wire? ಠ_ಠ

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I have used something very similar with a single PF M motor. After running for an extended period of time, the motor started slowing down and smelling funny - any idea why?

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