Home Made External Battery Pack For Laptop

hi ho everyone !!

Here is a little project that I decided to take on. How many people hate it when your laptop dies in the middle of a movie ? How many people would like to have their laptop run for hours - 7 or 8 hours? How about 12 hours? Taking long airline trips? A flight from Ft Lauderdale (where I happen to live) to Las Vegas is about 5 hours 30 minutes. MY LAPTOP RUNS THE ENTIRE TRIP!! Anyone interested in knowing how I did it? Its not difficult if you have some simple knowledge. I made this web site specifically for the mod community, and please accept my appologies, it is still under construction. New content and new photos will be added throughout the following weeks. I have always been a big fan of not-for-profit DIY or mod web sites, like the Daphne emulator, and other hardware mod sites, since my knowledge is lacking in the programing field, I wanted to focus on something that I know a little about. Here is my contribution.

Here is my web site (still in progress) regarding my external battery pack. I wanted to give an update as quickly as possible but it is still under construction.

I hope everyone enjoys this.

** Site No Longer Active **

Any questions or comments are appreciated, you may email me at ** Site No Longer Active** - MAKE SURE TO USE "BATTERY PACK" in the subject area. Also, this link can be shared with anyone else.

Thanks.

multi007

Note: This idea can be taken much further as will eventually be explained on the web site. I plan to use a pack to power any ac/dc device simply by re-sizing the pack itself.

 

Wow...that seems like alot of work, but I suppose it would be cool to get that much life out of it. I don't think you can carry that many batteries on an airplane now-a-days. Security frowns on it.

Nice mod though.

 

Ive done it 3 times (3 round trip flights which came to 6 seperate times the battery pack was inspected by airport security), and other than the x-ray machine person hand searching the pack before i'm allowed to go, i've never had a problem. The key is to make sure you dont wrap the pack in electrical tape and do not use shrink wrap. If you do, they will require you to cut it open before they let you go. (My 1st time mistake I must admit). But since, I've gotten very good at this at the security post. What I do now is I keep the batteries seperate in a small box from the battery housing. They open the box, see it's batteries, then they look at the plastic battery housing, see its nothing, and let me go. When I get to the pre-boarding area, I put the batteries in the housing, wrap it in masking tape, and im done. I use masking tape for 3 reasons. 1) To prevent shorting should a stray wire fall on top of the leads, 2) keeps the batteries from falling out of the housing - which can and has happened in flight. 3) masking tape is easy on easy off type tape that wont leave any sticky residue to the actual D cell batteries or the battery housing. Besides, once im past the initial security screening, its not looked at again. When I get to my destination (a hotel for example), i simply remove the tape, remove the batteries, charge them up in a nihm d cell battery charge (that was packed in my checked luggage) and charge them up. Then I repeat the process. I think the key here is, if you go to the airport with this, and the pack is completely assembled, it will be looked at with more scrutiny. But all security personnel see it as exactly what it is - batteries and wires.

I love it. As my site says, it is not lite. At 7 pounds, its a chore to carry from the car to the plane, considering the fact that im also carrying a 7 pound laptop too. But hey, a minor discomfort is MUCH better than sitting on a plane for 6 + hours, (longer if im flying to Europe), listening to nothing, or worse, a crying child. Thanks for the comments, more is welcomed.

(I will also use the text of my security post to add to my web site - its a great addition. Hey, USAFdude02, can I have your permission to quote your comment so that I can begin my reply?)

 

Sure, no problem. I would definently add the part about security checks at the airport.

 

looks really cool. I might try it but my laptop already gets 6hrs

 

You can probably get through security faster if you strap the batteries onto your chest with a vest on. Problem is you may end up on CNN. LOL!

 

You should have a look at www.batterygeek.net their systems are under 2lbs and are fairly cheap.


sorry it was .net not .com, also why did you use D batteries? the hardware shop i work at sells AA batteries that are 1.2v and 2600 mA.

 

The link says coming soon.

 

The link works fine, thanks though.

Jason - wow, never seen a laptop get that much. Thats great! Is it a tablet? (Ive seen tablets get that much.)

I know about batterygeek.net. Prices are $200 plus shipping? no thanks. Plus those packs are lithiom-ion, gaurenteed to be dead in 20 months. All lithiom - ion batteries die within 20-24 months. Nihms life are 3 times that. 5-8 years easily. Not to mention, you can replace my nihms with regular D cell alkalines - you cant do that with the batterygeek packs. Its the same old debate though, more power lighter weight = more $$. Lithiom packs are more expensive and half the weight. (You COULD make a pack with lithiom batteries if you want, but the prices will be higher and you'll need to buy new batteries in 2 1/2 years.)

As for AA cells -vs- D cells, D cells hold 10 amps, or 10,0000 Milliamps, my laptop NEEDS at LEAST 4500 milliamps, so the AA cells are useless unless I wire them up in series AND in parallel. Not to mention, the smaller the batteries, the shorter the use of time.

Thanks for the comments though, all are appreciated. Plus it makes people think.

Anthony

 

Nice work!! Great writeup too......I will try that out sometime.

Thanks!

 

10 2600 mA AA make 26. 000 mA while thats not as much as your pack for sure its a hell of alot lighter and would be more practical for every day use like lectures and long meetings. My laptop battery is only 4800mA so 26,000 mA is a fair bit extra. If I wire them in parallel and series then Ill have 5400 per 1.2 volts right? (sorry not to clear) then wire each pair in parallel? to make up the 11 volts I need, Or is it possible to have them in series and paralel at the same time so 2 batteres are 5400mA and 2.4 volts?

 

I have a dell XPS M140 with a 9 cell battery. The most battery life I ever got was around 6.5hrs. Dell claims up to 7. That would be possible with a little undervolting. Some notebooks I have seen with a modular bay, 2 batteries total get around 10hrs. But If I tried a project like this I would try and use AA batteries. I have around 12 that I use for various electronics. They are all 2000-2500mah. My laptop runs off a 11.1v battery. 12x1.2v = 14.4v... My power supply is 19.5v.

So all I would need to do is buy 3 battery cases that each hold 4 AA's. Link them together. Then buy a connector that plugs into my laptop.

It's great that I'm in Taiwan (right now, but from the US) because there are huge electronic stores that have tons of little parts. I should be able to make it for $1-2. Considering I already have a charger and 12 batteries.

What do you guys think? Any advice you can give me? Any problems with my current plan?

 

Well yeah you would have the same problem im asking about, you would have 14.4 volts but only 2000 mA, in series you add the voltages together but the amps stay the same, in parallel the amps add together but not the volts, the only way i know of to wire them in parallel and series at the same time requires twice as many batteries to acheive the same result. Maybe C batteries their 5000 mA but their nearly as big and heavy as D batteries.

 

Your logic is correct about having 10x2600 in parallel for AA, that gives you 1.2v with 26Amh, but you need around atleast 12v, so you need each set 10 in series giving 12v, and you need 10 sets like that( total 100 2600mAHr batteries.

But you will get one heck of battery with around 300wHr( vs your typical 50whr)

You could get it 120wHr with 40 AA batteries.

Anyways, let us know how your project went.

To be frank, though interesting, all this look like not worth to me. Why, I checked the prices for batteries and charger I would spend for making a decent pack, is almost reaching 12-cell battery cost( may be few 20 bucks difference). and also it adds more weight, look silly.

Let us Calculate for V2000/dv1000 series, we buy 12-cell (for $39 more) and also buy a 6-cell from ebay for($60) making total $110 bucks. Two batteries together will work for around 8hr easily, but only adds 1 pound more, and no security checks problem too.

To make battery pack it is almost costing same and you lug another 7 pounds, go thru security hassles,(may look silly too), and carry a masking tape too.

Yes, it is interesting, esp for people like me( I used to build my own Audio amps when I was in college), but again I not sure this is worth, may be small pack good for charging a dying cell phone, or stupid dying palms which looses all the data once battery drains(this is beyond my understanding), but not for a laptop phone.

 

I don't think Li-Ion batteries die as fast as people claim. I've had my Game Boy Advance SP, with Li-Ion battery, for just over 3 years now and the battery life is still good. I'm not sure exactly how long it is but I've not noticed a significant drop.

 

Hi everyone

Sorry but your math is off just a little You cant have it both ways. Either you wire the batteries in series to add up the volts - example - 10 aa batteries with 2200 milliamps connected in series gives you a 12 volt battery pack with a total of 2200 milliamps, OR wire them up in parallel. However, 10 batteries connected in parallel will give you a battery pack with 1.2 (1 point 2) volts of power at 22,000 milliamps, or 22 amps. you could connect a pack in series and paralell. example, 10 aa batteries in series = 12 volts with 2200mah, and 10 aa batteries in paralell gives you 1.2 volts with 22,000 milliamps, then connect both of those packs together to make one pack at 13.2 volts at 24,200 milliamps. (But then again, you're carrying around 20 aa batteries, instead my 12 D cell batteries) - which weigh about the same. If weight is not an issue, then you can use F cell batteries - they come in at about 13,000 to 15,000 milliamps the last i checked.

Here is another battery pack I used as inspiration to make mine.

http://www.dansdata.com/cambattery.htm

Chinna n - no need to make 10 sets, just need 1 set of 10 in parallel and 1 set of 10 in series. And that would work just fine.

As for the lithiom-ion battery life, im using existing laptops owned by my friends as a guide.

Jason - I looked at that laptop by Dell, thats excellent life! They say 4 hours for the 6 cell and possibly 6 hours for the 9 cell. Not too shaby. Imagine what my pack would do for that - imagine 24 hours of constant laptop use!!

But seriously, my laptop I tested this one is a high powered one. abs.com mayhem revolution G4, 2.26 Ghz P-Mobile, 2 gigs ram, dvd-rw drive, 15.4 inch monitor on full bright. The Dell is 14 inch - that alone helps their battery last longer. (not a bad thing for some people).

Also, here is a great graphic for wiring batteries in paralell and series.

http://www.dcbattery.com/connect.gif

Anthony

 

Hey Alex

Sorry, but I refer to high power drawing devices. Portables like ipod and game boy have such a small voltage requirement that the lithiom battery isnt taxed as heavily as a laptop battery is.

Also, my solution isnt the end all to all issues. The reasons I did it was 1, see if I can, 2, save some money, 3 talk about it. Here is a fantastic battery pack for those who want some major, and Im talking MAJOR laptop battery life with a very light pack. But - It is EXPENSIVE. (and will die in 20-24 months)

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2458

Hey Alex - you're laptop would run for days on this!!

 

Wow! I would like to know, if there is work around for the typical electrical principles.

So, you make one set with all parallel, so that set gives 1.2v at 26Ah, and another set, you have all in series , so that gives 12v at 2.6Ah, so tell me how you are going to connect those two to get 12v? ( may be I am rusty with my physics and electrical engineering subject ).

Yes, you can make 12v 5.2Ah ( not 26Ah) with 2 sets , in each set(10 batteries) all are connected in series producing 12v but 2.6Ah, and these two sets connected in parallel make total amperage to 5.6Ah.

Any explanation!?

 

I can picture it in my mind but hard to explain here. I'll try though. Im using some of the web sites I have bookmarked and referred to from time to time to show how big battery banks (for things like solar power, or remote power) can be wired. Lets use a small 2 volt type car battery as an example. D cell battery and a car battery has positive and negative poles. Red and black + and - , so you take 2 car batteries and connect them together using the following diagram - in series...



This gives you a total of 6 volts, and 200 amps as pictured. (add volts, keep amps the same)

Now, lets wire them up in parallel.



Volts stay at 2 volts, amps are added to get 600 amps.


Now, lets combine the both technologies - lets use 6 volt batteries for example.

Here is series and parallel connections for your senario.



This adds up the volts of some batteries, and the amps of others, and you get a total.

If you understand these diagrams, then you can apply it to a small D cell, or AA cell batteries. Of course the main difficulty here would be making a plastic battery housing that is wired like the photo above, since they dont make such a thing in a mass market. Making it from scratch would involve some sort of tape, a big no no in airport security world. (i wish i can film myself going through security so you guys can see its not a big deal to them, but they dont allow photos or video cameras in operation of the security area.) Also, plastic housings are hard to find (impossible) in 10 cell or greater increments. I can only get 8 cell holders, whether its for D cells, or AA cells. (They make 10 and 12 cell holders, but in order to get them on the net, you need to buy like 1000 pieces.)

note: pictures were used from this site. I am not the author of these hand drawings. Thanks to www.otherpower.com for their valuable info

http://www.otherpower.com/otherpower_battery_wiring.html

 

Without knowing how these things work, I would not even question what you said.

If you see explanation give above by you( where you said 10 in series and 10 parallel , connect all those serial again).

See the attached image about what you said, let me know if that is not what you meant. I just draw this thing in mspaint in couple of minutes.

Does not it work, yet it does( with potential problem), but what would be the whr?( it would not be 13.2v 26Ah) And what happens you connect these like and what is the effect voltage drop accross each cell?

See the attachement, let me know if that is what you meant? and if that is right, then we need to go back to the priciples of Voltage, Amperage, and wattage.

 

Good graphic Chinna n,

It looks like it will work, but unless I actually connect it up, I cant tell you for certain. You can definately give it a try - but use 5 batteries instead of 10, this way you're not spending too much time on it. Im not sure what you mean by basic electrical principles. Im not an electrical engineer, so I dont even know what the electrical principles are. It sounds like you know alot more about electricity than I do, but since we're talking about applying this to regular household batteries and we are not using a high level of amps or volts, the only bad thing that has happened to me was that some wires got warm - which is my first clue that i wired something up incorrectly. (Whereas if you are talking about high level of volts, like 110 or 220, or a high # of amps, like 100 amps or greater, then you can forget about getting warm wires if there is a problem - the warm wires wont get warm, they will melt a glowing hot red and start a fire. (Not a good idea, especially on a plane.) Since im using small voltage and small amps, you can tinker around with the pack safely.

 

Ive been asked by a few people where to get the supplies...

I was never able to locate the housings to hold 10 D cell batteries. They make them, but finding them are hard. The web sites that I found wanted to sell me 100 pieces minimum order. So I had to stick with 8 cell and 4 cell holders.

Here's an example of what i've found.

http://www.batteryholders.com/D-CELL.shtml

Here is the 8 cell holder - scroll down to bottom of page.

http://www.minute-man.com/acatalog/D_Cell_Holders.html

and another

http://www.allelectronics.com/cgi-b...gory,INVENTORY.brand,INVENTORY.model&start=16
Also,

I have received several emails from people concerned about airport security, so I have updated the web site and added an airport security section. Also, there are a few missing photos that will be uploaded within the week. Thanks.

Anthony

 

seriously that looks like a bomb really

 

You mention you could buy regular alkanice batteries for your battery pack. Don't do that. You nimh batteries are 1.2v, regular alkalines are 1.5v

That raises overall voltage quite a bit

 

Actually im glad you brought that up. Regular alkalines have a 1.5 volt rating for the first 5 minutes of use, and then it drops off very quickly to 1.4 then 1.3 and then 1.2 all within the first 10 minutes of use.

Also, 10 D cells at 1.2 volts is 12 volts. 10 D cells at 1.5 volts is 15 volts. Voltages for electronics are generally plus or minus 15 % - which means something that needs 12 volts of power, will work just fine using 10 volts or 15 volts. But since alkalines drop in voltage really, really quickly, this is not a concern. (And this was confirmed by 2 electical enginer friends of mine) Dont believe me? Try it with a volt meter. I did. (the testing I did was to use alkalines on a old fashion boom box for 10 minutes, then used the voltmeter and touched the leads inside the box with the unit off, and the voltage was reading 1.3 volts per cell.

But thanks, this was a great question!!

Anthony

 

this may be totally stupid but if i wire ten batteries to give me 12volts at 2600mah, then wire one more battery in to make it 12volts at 5400mah would that work?

 

Nope. Because the amps of the 1st set of batteries are 2600 mah, and the amp from the 2nd battery is 2600 divided by the 13 total batteries, so technically, the total volts would be 13.2 volts, and the total amps would be 2816.66 mah. (the 1 extra battery has 2600 mahs so you are dividing that batteries amps into the 12 others which brings the total amperage down to 216.66, then add that to the 2600 total which gives you 2816.66).

The only way to do this is to use a high amperage battery (at least 4500 mahs for my laptop) and add the batteries together. (and they dont make AA cells greater than 2600 mahs yet..) You'll need to double the amount of batteries since the aa cells are so small and low in amps and connect 1 set in series and 1 set in parallel. See previous page for examples.

Another way to reduce the amount of batteries is to use higher voltage batteries. Unfortunately, "these" batteries are not rechargable and are very expensive compared to the prices we are using for this project. They make a 12 volt single C cell alkaline for outdoor transmittion and monitoring boxes that are rated at 5000mah or higher, however, they are about $30 per battery and once it drained, that's it. To pay $30 to power your laptop for 3 hours or less - not a good idea unless you are Donald Trump.

The best alternative would be to use rechargable lithium ion cells used by consumers for various things. The good thing is rechargable lithium's give 3 volts per battery. So you technically would need 4 of these, instead of 12 D cell batteries. Also, Radio Shack has them, and are about $15 per rechargable lithium battery (much less if you buy a multiple pack), but then you will need to buy a lithium ion battery recharger. The hardest thing here then becomes, finding a battery holder that holds lithium ion cells. (they are of different sizes than traditional AA C or D cells).

But again, this brings up the entire reason why I selected Nihms (Nickle Metal Hydrides). Lithium battery chemestry dies within 20+ months of use. Even though Ive had people disagree with my claims of the life span of a lithiumion battery, it is true. And here is a great site that details why.

http://www.batteryuniversity.com/parttwo-34.htm

 

It's good to know, I wasn't aware of this effect !

 

Here is more about the subject of the variance in voltages between Nihms and alkalines.

http://www.starbatteries.com/batteryfaqs.html#My device uses

scroll down to the question "My device uses 1.5V “AA” batteries. Will my Nimh batteries work even though they are only 1.2V" and read the answer.

this is a great frequently asked question set.

 

how many mah are the lithium batteries? the only ones I can find are ridiculously low.

 

Well.... it depends what you get . You can choose any pack from the list of packs below. For me, I would need to select from 11.1 volts to the max of 18.5 volts.

http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=894

This one is huge and only weighs 3.4 pounds. But it costs $400. But hey, if you need to power a laptop for 15 hours straight, recharge it, and do it again. Go for it. This is great for business travelers.

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2458

 

Hi again,

Here is another experiement that I tried, and it worked. I removed 4 D cells from my 12 D cell pack, and connected a 6 volt battery (you know those lantern style batteries). and I got an extra 69 minutes out of the pack. The obvious con here would be that it is not a rechargable battery, costs about $4 and once its drained, you throw it out. There isnt really much of a pro except I added 69 minutes of use to the battery.

OH well. the experimentation goes on...

I wonder how a 12 volt 100 amp deep cell agm (absorbed glass matt) car style battery will perform? lol