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I made an external battery for my Air

cloylover said:
Thanks for blocking the reverseable setup idea. I really have no use for the old mac batteries anyways, just thought that the casing was really small.
In fact, if I can figure out what the 9 wires coming out of the mac battery protection board does, I can use one of those as a board.
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To use the Apple circuits you'd have to reverse engineer them, and duplicate the necessary necessary circuit elements built into the laptop—I don't think its worth the effort.
So far, the only protection board I can reuse right away are these 2s 7.2v boards I harvested off of 2 HP 7.2v batteries. They are 8 cell battery with 4 in parallel, so if I connect those in series I should get my 14.4, and then from the control board it should be pretty simple. Only for soldering balance charging wires it can be tricky. Any ways, great ideas.
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I'm not familiar with those, but if they have complete charging and protection circuits they should work just fine.
PS: 2 ideas for mobile charging I want to run by you guys, cause all of you seem very smart. 1, I bought a 3 to 1 plus USB outlet cig lighter socket connector, I want to connect 2 small solar panel running at 12v to 2 of the socket and then 1 dual cig cable to the car cig socket and the battery bank, but will this charge the battery at all? being that the car battery is at a lower voltage than the battery bank.
I mean I can surely harvest only 3s and have it all work at 10.8v with minimal customization, but I kinda wanna be safe on some cells failing, as it all inevitably happens.
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I'm not sure that I'm following you, but it sounds like you mean to two different voltages of batteries with a single source. If that's so, just put voltage regulators on the battery charging inlets and you'll be safe.
I already bought 20 4s wires, can I use them as 3s wires and abandon the 1 extra wire?
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Yes; see the battery cell wiring diagram I posted earlier in the thread.
And 2, If I were to abandon temp control protection, and just put them in a modified Rubbermaid icebox, which will protect me from it in case things do go south, will that work for charging? I mean when running I have a vented box I made to sit it in the rear passenger side of my car, and there's always the smart option of draining one battery at a time, so it should be pretty safe, but charging is something I am still weary about.
Let me know, thanks.
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Some chargers have built-in temp control; I don't think its necessary, because you're not charging in a small unventilated space, but its up to you. Charging should be done in a fire-proof container, and one big enough to allow plenty of air around the battery.
I bought this one cig lighter converter that comes with 3 cig socket and 1 usb, will that work by itself?
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It should.
I agree, A, charging is not a waste of battery cycles, because if you keep it constantly above 50% with fewer deep drain, you can easily get up to as many as 10 times the cycles as if you were to drain your battery completely. Skinny may be a smart guy, but he's misleading people in thinking lithium ion bats are disposable ones.
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The cable from the Airline Adapter will allow you to keep the Laptop's internal battery above 50%, but Apple isn't selling those adapters anymore, and I think most people will be using the cable from the AC charger. With that cable, the laptop will use the external battery to charge the internal one, which IS a waste of cycles. I'd like to see where you got that 10 times as many cycles info; I haven't seen that anywhere, including from Sony and the Battery University. In any event, charging a battery to use to charge a battery is terribly inefficient, because charging always incurs losses.
And two, I too have a travel charger, and it will not charge the internal battery with the external. This is one better function than just the wire from a MagSafe adapter, which I also have.
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The Airline Adapter, yes? Unfortunately, Apple quit selling them, and I think that most people—myself included—just use the cable from the AC adapter for both; the Airline Adapter cost too much for me to want to buy just for the cable. As mentioned earlier in the thread, if you run off of the external battery first, it won't charge the internal one.[/QUOTE]
 
The cable from the Airline Adapter will allow you to keep the Laptop's internal battery above 50%, but Apple isn't selling those adapters anymore, and I think most people will be using the cable from the AC charger. With that cable, the laptop will use the external battery to charge the internal one, which IS a waste of cycles. I'd like to see where you got that 10 times as many cycles info; I haven't seen that anywhere, including from Sony and the Battery University. In any event, charging a battery to use to charge a battery is terribly inefficient, because charging always incurs losses.

Well, I am no expert on this, but there was a research at one of the universities for lithium battery aging and degrading, and 90 to 100% charging will allow a safe 1500 cycles, while deep drain may cause service or repair notice within 200 cycles. On the other hand, 200 cycles of 100 is 20k % while 1500 charges of 10% is 15k discharge, so efficiency will not be as much the issue.
 
Well, I am no expert on this, but there was a research at one of the universities for lithium battery aging and degrading, and 90 to 100% charging will allow a safe 1500 cycles, while deep drain may cause service or repair notice within 200 cycles. On the other hand, 200 cycles of 100 is 20k % while 1500 charges of 10% is 15k discharge, so efficiency will not be as much the issue.
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Okay; that DEEP draining is when the battery's charge drops below the limit set by the battery's protection circuit, not the normal discharge of use; i.e., in a well designed system, the battery cut-off will cut the battery power to the device before it reaches that unsafe level of discharge, but if the device is stored in that condition the battery will continue to discharge below the safe limit, or even until its death. As long as you recharge the battery after it has been shut down by its circuitry it'll be okay. I never run the battery to its shutdown level, and for storage of 3 months or more it should be stored at 30 to 50% charge.

It is a confusing bit of a problem that they use the same word, "discharged," to mean two different things.
 
So I got this S4 14.4 HP laptop battery

skinny*k said:
Okay; that DEEP draining is when the battery's charge drops below the limit set by the battery's protection circuit, not the normal discharge of use; i.e., in a well designed system, the battery cut-off will cut the battery power to the device before it reaches that unsafe level of discharge, but if the device is stored in that condition the battery will continue to discharge below the safe limit, or even until its death. As long as you recharge the battery after it has been shut down by its circuitry it'll be okay. I never run the battery to its shutdown level, and for storage of 3 months or more it should be stored at 30 to 50% charge.

It is a confusing bit of a problem that they use the same word, "discharged," to mean two different things.
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So I got this S4 14.4 HP laptop battery, I was thinking about linking another 16 cells to them in parallel. Like 4 in a bundle soldered onto the original 8 cell battery, and if the 8 cells gave 63wh like it says on the sticker, then making it 24 cells should triple the battery capacity or just about. I will try to use only the + and - wires from the battery's board, as I cannot figure out the other wires, I will solder 5 wires onto each dundle for balance charging. Will this work? Let me know if there's anything I should look out for, thanks.
 
getbatterybox.com

Great guide - you are pretty tekky to make it yourself!

I am not as advantageous and brave to build battery pack - just scared if something gets shorted.

Neither I am willing to cut my adapter cable to use HyperJuice so I just bought one of these www.getbatterybox.com - works well so far and charges my iPhone as well.

Cheers.
 
skinny*k said:
To use the Apple circuits you'd have to reverse engineer them, and duplicate the necessary necessary circuit elements built into the laptop—I don't think its worth the effort.
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So I already made two generation of external batteries based on my original plan. They are both 4S lipo battery packs, one 16 cells pack which gives a good 3 charges to macbook air, and the 24cells second generation battery give even longer life. I can install cig lighter sockets for it to run my fan for about a month or to use solar panel powered imax b6 charger to slow charge my battery.

I have opened up a macbook pro and reverse engineered the battery connection, I was able to get a 11.33, 7.4 and 3.7 or so reading out of different connections, it seems that three wires to the right are possitive and three wires to the left are negative, so I can build a reverse adapter for just that to drain power out of each brick separately and balance charge them only with a laptop. Any ways that's still a work in progress.

I will share my design for external batteries.
 
Why did you rap it in Electric tape, it looks like C4! at least rap it with white electric tape and multiple colors haha. But nice project, you didn't have to use any regulators?
 
Great to see people are still building these, and respect to cloylover for the project he is attempting.

I took the 5th broken cell out of the battery I had but it never worked again, granted I didnt try much :D
Maybe one day I will dust it off and see if I can get it working again :)

Keep it going people.
 
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sebseb said:
Why did you rap it in Electric tape, it looks like C4! at least rap it with white electric tape and multiple colors haha. But nice project, you didn't have to use any regulators?
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It does look very much like a C4, but that was a prototype, and the setup is not permanent due to the need to find perfectly balanced cell pairings. I didn't have the patience to work out the capacity of every cell, so I played by ear, anyways, I took apart my first gen product to make an instructable, and shared that for free, if you want to see, the end product is decent looking.
Some dude made a 3 hour battery for like 60 bucks, so I calculated mine to be more around 30 if done cheaply.

Here's my instructable if you're interested, I get more power from it than the 200+ dollar item. I also own a chugplug, but that thing is a joke compare to this.
I have balance wires, so I can plug voltage readers and buzzing alarms on it.
http://www.instructables.com/id/How-to-make-an-external-battery-pack-for-macbook-a/
 

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The-Pro said:
Great to see people are still building these, and respect to cloylover for the project he is attempting.

I took the 5th broken cell out of the battery I had but it never worked again, granted I didnt try much :D
Maybe one day I will dust it off and see if I can get it working again :)

Keep it going people.
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I don't own like the newest version of Mac, so my numbers might even come out better with the hasbro generation of macbook air.
I am no expert at this, in fact I got the idea from this very thread to build a battery, and it took me a few months to actually do it, would have been nice to have this badboylast time I was travelling. Check it out.
http://www.instructables.com/id/How-to-make-an-external-battery-pack-for-macbook-a/
 
Chipg said:
Hope this helps some more:


This is the battery I chose for size and weight, it weighs 419 grams so that’s less than half a kilo, it’s a 4400 mAh 14.8 volt 15C (discharge rate) Li-Po type = same type as Apple uses for the Macbooks: http://en.wikipedia.org/wiki/Lithium-ion_polymer_battery
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=17816

Hobby King sells larger and smaller batteries, pick one that’s best for your time requirements, the 4400 mAh 14.8 volt one I use (in the above link) provided me with 6+ hours and was still going strong, it’s 65 watts, the Macbook Airs factory battery is around 50 watts. Here is a link to a larger 8000 mAh 14.8 volt battery: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=20823 and here is a link to a smaller 3000 mAh one for $20: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=15010 this little light battery should be about 44 watts.

The cool thing here is that you can size your batteries however you want, some people might want one big daddy and others 2 or 3 small ones...

Order these 4mm bullet connectors, pack of 10 = $3.64
http://www.hobbyking.com/hobbyking/store/__9283__HXT_4mm_Gold_Connector_w_Protector_10pcs_set_.html if you decide to order different batteries some might have a different connector than the 4mm bullet plugs on them so remember to check and order the correct connectors if necessary.

This is the charger I bought, it is a smart charger that works with any Li-Ion/LiPO battery pack with capacity > 1000mAh that has 1-4 cells, it auto shuts off so you cannot overcharge the battery: http://www.all-battery.com/UniversalSmartChargerfor3.7-14.8VBatteryPack-01281.aspx

Buy a new or used Apple power supply that has the mag safe plug, I bought one used for $20, I had to crack mine open with a bench vise to remove the plastic casing, then unsolder the two wires from the mag safe wire, one is white, the other black then solder on the 4mm bullet connectors that will plug into the battery, the white wire is positive and goes on the side of the 4mm bullet plug connector that has the red wire for the battery and the black wire is negative and goes on the 4mm bullet plug connector that goes to the batteries black ground wire. It’s really simple to do, I did not take pictures during that process, I didn’t think there would be this much interest. the only 2 wires used coming out of the battery pack are the red and black ones.

Plug it into your Mac and you now have portable power that will last for hours!

I wrapped mine in black tape so you couldn’t see the Zippy brand and writing but here is a pic so you can see the size, my Air is the 13” one.
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And here you can see how it perfectly fits in the little side pocket in my laptop bag.

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Hello, i made a battery thats 18v for my macbook pro 17". When i measure the volt output on the original charger, it shows that there are 9 volt coming out from each +/-(There are 2x +/- pins). But from the pins on my battery it shows 18v on both 2x +/- pins. Is this a problem? Havent dared to connect it to my macbook
 
mikk2690 said:
Hello, i made a battery thats 18v for my macbook pro 17". When i measure the volt output on the original charger, it shows that there are 9 volt coming out from each +/-(There are 2x +/- pins). But from the pins on my battery it shows 18v on both 2x +/- pins. Is this a problem? Havent dared to connect it to my macbook
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I don't think it's a problem. As long as the polarity is okay, it'll work. I've seen off-brand chargers who do the same thing; they just have 18v on the pens instead of the 9v that the original chargers have.
 
So i made it now. but when i connect its to the laptop, nothing happens. im using 5x 3.7v Li-Ion batteries. i cant figure out what is wrong
 
Well, when you connect the laptop, it'll put some resistance on the battery pack and current should start flowing. Sometimes that causes the voltage to sag beneath a minimum level (say, 15 volts). So you probably want to measure the voltage and current when the pack is actually in use.
 
Long time, no writing :D So, i dont know how im supposed to measure the voltage and current when its connected to the laptop, your help is very apriciated
 
Monkeyat said:
I'm also glad this is keep going! I've made my kit back in 2012 and it's still working great! I've even improved a little bit ;)
Right now I've two LiPo batteries (3000 and 3600mAh), a car charger and the last acquisition: a 12V to 5V 3A double USB converter so I can also charge my iPad mini AND my Samsung Galaxy phone using the batteries!!!

150130113523902101.jpg
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I would like to make one of these myself, only kinda hoping to be able to use 4s setup instead of 3s.
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skinny*k said:
To use the Apple circuits you'd have to reverse engineer them, and duplicate the necessary necessary circuit elements built into the laptop—I don't think its worth the effort.

Reverse engineering is useless with Apple. I made an macbook pro work with external battery soldered as the original flat cells into the battery management system, but Apple made sure their hardware is not reuseable as the circuit had a capacity lock on it. You cannot calibrate the battery, so it will drain all 5800 or so mah from the battery and shut down, although the battery is still at 85%. So that idea is blocked.
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mikk2690 said:
Exactly what do you mean :D ? The laptop needs 16.5 volt
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I have heard that 3S batteries might work too, and they would be better if you have an airport device from Apple back when they used to make it, so you can use it as a car battery and have many more applications. I personally use 4S batteries which does 14.4v to 16.8v, it works both on air and on pro, pretending to be the adapter without the airport unit. I do own an airport unit, and using that gives more power and stability to my battery, but the protection circuits I bought to use as BMS are all 4S. If you are using 5S, there's a chance your voltage is too high.
 
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