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I made an external battery for my Air

MacModMachine said:
Hi, I cant wait to see the runtime for you , i have a 2008 macbook alum. i would love to have a couple spare packs to give me 3-4 hours extra runtime.

please post your results when you get a chance to fully test it.

Thanks!
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I will :)

Well you wont need several packs to give you another 3-4 hours.
If you lets say only are doing word processing, or watching a movie in quicktime with screen at 50% or below then the battery consumption is very low and a single 5000mAh battery should be give you at least another 3-4 hours especially if you plug in the battery from the start when the internal is still full because then the computer will draw the power it needs from the external and not charge the internal aswell.

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My charger has just arrived in the mail. The iMax B6.
I now need to purchase the correct cable to connect the output ports to the bullet connectors on the battery as the charger didn't come with the cable I need. Sigh :D The charger does not come with a DC cable though, which is weird but the cable from the LED screen seems to work.
In the first attached picture you can see what came with it.
Second picture shows the connectors on the right side and the third picture shows how the connector on the battery fits perfectly into the balance charging socket of the B6. Fourth picture are the features it has.
It cost me 32€ but I have seen pay now auction is ebay for as low as 19,95€ or 23,95€. This charger seems very sophisticated and when I have tried it out I will see if I can recommend it or not.
Question: At what current should I charge the battery? I can choose from values between 0.1A up to 5.0A.
Whats best? 5cell battery, 5000mAh
Cheers people.

Just tested the charger by touching the crocodile clips to the bullet connectors and it worked flawlessly. Charger detected the amount of cells etc and started charging. Im buying the right cable tomorrow
 

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I bought my Apple magsafe power supply/cord from OWC used that came with a money back guarantee that it worked, they have deals all the time on used ones, it does't really matter what watts it is because you will be throwing the transformer part away and just keeping the magsafe wire.

The-Pro, nice charger! I think I'm going to order a charger that will balance all the cells, the one I posted did not. Can you provide a link for it?

"Question: At what current should I charge the battery? I can choose from values between 0.1A up to 5.0A.
Whats best? 5cell battery, 5000mAh" - I'd keep it at 1 amp or below, trickle shares are the way to go IMOP for a better safer charge, all the stories you hear about these batteries blowing up is from hobbits who are fast charging them.

Your 25C battery should be way more than enough discharge rate for your Pro.

Here is a video about how to spot a fake ib6 charger that you bought: http://www.youtube.com/watch?v=kziSFSQvxr4

Hobby King who sells the batteries also sells this charger for $39.99 here is a link to the version that lets you charge from with either a 12v car battery (great for camping) or 110/240 volt wall plug: http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=6478 I think I'm going to order this charger so I can balance the cells in my battery pack, this will make it last longer.
 
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I will find a magsafe locally on ebay, easier for me then order from the states :D
Well I bought mine from ebay from a big reseller. Im in Germany so the link wouldn't help you at all since its ebay germany and you are in the states, right?
Thanks for the video :) I definitely have the real one, scratch thing and everything on the back. The more expensive one that aren't from china seem to the real ones. I was lucky, just didn't feel like ordering from hong kong. :D

Thank you, I will stick with 1A then. Any idea on how long approximately a charge would take?
Great, good to know, I don't do anything intensive on the go so its not like the battery will have to pump out electricity to power my pro :D
Yeah thats the exact one (your link from hobbyking) just with car battery support. So far it seems to be a great charger. Very nice quality, all aluminium.
I thought its best not to save to much money on the battery charger, I don't want my battery to explode :D I should be able to use my battery for a while. Charger has a storage charge aswell. Great stuff!!!
I had the idea of just unsoldering the crocodile clamps and putting on bullet connectors instead so I can charge the battery. I just finished getting the clamps off when my soldering iron lit up in flames :D It was very old and not very good, so I ordering a new one from amazon a minute ago. Arrives thursday, so I can solder the bullet connectors on and then start testing then :)
 
Some of you guys are a lot more technical than me so please feel free to jump in anytime and correct me if I'm wrong.

It is my understanding that 5,000 mAh is 5 amp hours, 1,000mAh = 1 amp hour so your battery you bought (The-Pro's 5,000 mAh 18v) would take roughly 5 hours to recharge at 1 amp charge rate. If you set your charger (do not recommend) to 2.5 amps then it will take 2 hours to recharge. At a very slow trickle of .5 amps it will take 10 hours to charge, these times would be for a completely dead battery.

Hope this helps some & please let me know your real world times / experience.
 
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@ The-Pro,

Thanks for the iStat Menu tip, I just downloaded the free trial, I just noticed it shows the battery pack voltage (of the external battery pack) so I am no longer going to use the external LED voltage monitor that I talked about a page or two back. http://bjango.com/mac/istatmenus/

For my Air it's showing:

DC Input Voltage: 16.5
DC Amps: .73
DC Watts 11.3

Is there a way to set an alarm so when the DC input voltage gets to a certain point it will notify me or is there an app that will do that?
 
Well that sounds quite logical what you wrote. I read something similar on the net somewhere, so it could be correct.

Istatmenues really is a good tool. Im getting DC in of 0.62-0.74A and DC input of 12.5-14W. That doing practically nothing on my MBP, jus slight surfing, typing here, CPU usage 5% and under. Im not getting a DC input voltage though. What reading are you looking at?

Not that I am aware of. I dont know of an app like that either but maybe someone here on the forums with knowledge in how to program something like this could throw it together?

Do you have any idea why the light on my magsafe stays on after its unplugged?
 
The-Pro said:
Well that sounds quite logical what you wrote. I read something similar on the net somewhere, so it could be correct.

Istatmenues really is a good tool. Im getting DC in of 0.62-0.74A and DC input of 12.5-14W. That doing practically nothing on my MBP, jus slight surfing, typing here, CPU usage 5% and under. Im not getting a DC input voltage though. What reading are you looking at?

Not that I am aware of. I dont know of an app like that either but maybe someone here on the forums with knowledge in how to program something like this could throw it together?

Do you have any idea why the light on my magsafe stays on after its unplugged?
Click to expand...

in iStat Menu click on the temp reading at the very top of your screen, look down the list for 'Voltages' then look for 'DC In' that is the input voltage from either the power wall plug or external battery.

My mag safe light goes out after a couple minutes when it is unplugged.
 
Chipg said:
in iStat Menu click on the temp reading at the very top of your screen, look down the list for 'Voltages' then look for 'DC In' that is the input voltage from either the power wall plug or external battery.

My mag safe light goes out after a couple minutes when it is unplugged.
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Weird I don't have DC in under Voltages, I have it under Current telling me the Amps :D
 
I have the full paid for version. I don't have DC IN under voltages.
Yeah could be possible its only on the MBA.

Would you have any idea how I could tell how much charge my battery has?

Chipg said:
My mag safe light goes out after a couple minutes when it is unplugged.
Click to expand...

Ahh ok, ill unplug it and let is sit for a couple mins see what happens.
 
Well this is what it shows on the screen when charging
The second picture is from the manual, says what is what on the display.
The charged capacity reading starts at 00000 every time, guess it indicated how much charge has been added.
The charger cuts of at 5000mAh, so i guess it detects it when the battery is full.
For some reason my charger says: end voltage 21V, (5S). This means according to the manual that that value is the final voltage when the program (in my case balance charge) ends. Since this is a 18.5V battery is it correct?
 

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Make sure you are charging your Lipos with a Lipo specific charger, and ALWAYS use the balancing plug and select the Balanced Charge mode. You should also be using a fireproof lipo bag to charge them in just in case.

Something like this.
 
The-Pro said:
Well this is what it shows on the screen when charging
The second picture is from the manual, says what is what on the display.
The charged capacity reading starts at 00000 every time, guess it indicated how much charge has been added.
The charger cuts of at 5000mAh, so i guess it detects it when the battery is full.
For some reason my charger says: end voltage 21V, (5S). This means according to the manual that that value is the final voltage when the program (in my case balance charge) ends. Since this is a 18.5V battery is it correct?
Click to expand...

I think it is correct, my 14.8 volt battery shows 16.5 volts when fully charged.
 
marioman38 said:
Make sure you are charging your Lipos with a Lipo specific charger, and ALWAYS use the balancing plug and select the Balanced Charge mode. You should also be using a fireproof lipo bag to charge them in just in case.

Something like this.
Click to expand...
Thanks, that bag is interesting, im going to look for one of those.

Chipg said:
I think it is correct, my 14.8 volt battery shows 16.5 volts when fully charged.
Click to expand...

Ahh ok, seems normal then.
I fully charged my battery and I will start testing tonight probably or tomorrow morning.
 
The-Pro said:
For some reason my charger says: end voltage 21V, (5S). This means according to the manual that that value is the final voltage when the program (in my case balance charge) ends. Since this is a 18.5V battery is it correct?
Click to expand...

Yes, this is normal. Each LiPo cell is rated at 3.7V, so your 18.5V battery obviously has 5 cells. The voltage of each cell when fully charged is 4.2V, so when fully charged your 5 cell battery should have a total voltage of 21V.

You should always use a balancer when charging your LiPo battery to prevent too much voltage going to one of the cells, this will damage the battery and possibly start a fire. You should also have an alarm on your battery when you are using is to prevent over discharging your battery.

You should also use a connector between the battery and the MagSafe connector and not solder the battery directly to MagSafe cable. This way you can easily and safely disconnect the battery from the MagSafe and connect it to your chager/balancer.

If you do not understand how LiPo batteries work and what their ratings mean, you need to educate yourself about them before using them. They can be dangerous. These links have been posted before but clearly people aren't reading them. They should be read completely and fully understood before you begin.

Complete Guide to Lithium Polymer Batteries

Understanding RC LiPo Batteries
 
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Brandon0448 said:
EDIT: Also for charging did you just leave a bit of the bullet connectors exposed so you could hook the alligator clips from the charger to it? I can't really tell from the pictures you posted. Thanks!
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Chipg said:
Yes, that is exactly what I did but I ordered the 4mm bullet connectors from hobby king (I put a link in my write up) that I'm going to put on the end of the charger so I can just plug the charger in.
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Maybe I am misunderstanding, but leaving part of the connectors exposed is idiotic at best. This could easily lead to your battery short circuiting if they touch which could cause it to explode or ignite a fire.
 
Creek0512 said:
Maybe I am misunderstanding, but leaving part of the connectors exposed is idiotic at best. This could easily lead to your battery short circuiting if they touch which could cause it to explode or ignite a fire.
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They can NOT touch, they both run through a plastic connector that keeps them separated, you'd have to see it to understand but I did order more bullet connectors that I'm waiting on that I will put on the end of my charger so I can plug it into the battery pack and not use the alligator clips.
 
Okay, I just wanted make sure that other people who may not be as knowledgable didn't misunderstand the comment about leaving things exposed and end up hurting themselves.
 
Creek0512 said:
Okay, I just wanted make sure that other people who may not be as knowledgable didn't misunderstand the comment about leaving things exposed and end up hurting themselves.
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I appreciate it and thanks again for posting this link about Li-Po batteries: http://www.rchelicopterfun.com/rc-lipo-batteries.html

I have around 75 cycles on my 4400 mAh 14.8v $28 battery and not one problem but it's good to keep everyone educated about Li-Po batteries.

Anyone besides The-Pro make one yet?
 
Chipg said:
I have around 75 cycles on my 4400 mAh 14.8v $28 battery and not one problem...
Click to expand...

Chip, thanks for the info. One question, though: How are you gauging when your external battery is almost dead and in need of recharging? (so as to not over-discharge it?). Is there an easy way to know the charge left in the external battery? I think I'd be overly aware and paranoid if I couldn't get reassurance to know its level.
 
fathom said:
Chip, thanks for the info. One question, though: How are you gauging when your external battery is almost dead and in need of recharging? (so as to not over-discharge it?). Is there an easy way to know the charge left in the external battery? I think I'd be overly aware and paranoid if I couldn't get reassurance to know its level.
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I never did, I had no problems with 75 ish discharges and recharges but after reading the info about Li-Po batteries I think I should be more safe?

Yesterday I started using an app I talked about that shows the battery pack voltage, when it gets to 12.8 volts I unplug it. The app is iStatMenu

In the past I am guilty of drawing it lower (with no probs), I used a multi meter to check the voltage, never had a problem.

Fast charges / discharges are why they mostly get a bad rap... I drained my nephews RC car battery to ZERO volts 10 times in a row and it did NOT explode so there you have it.

I'm not here for capital gains, I do not rep a product or try to sell one or try to hurt others that do, it's just a hobby for me.
 
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Monkeyat said:
I'm just waiting my to build the kit. I've actually found a very nice option to the MagSafe cable, a car charger with an USB port included! I'll adapt it to use both, the battery and the adaptor. Take a look :
Image
So, as soon as the battery arrives and if I'm not on my vacations, I'll post some photos :cool:
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Can you provide a link please and how much was that?
 
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