[Viktor’s] laptop needed a new battery; he had the trade off between carrying around a cheap but heavy sealed lead acid (SLA) battery, or buying an expensive but light Li-Ion battery. Figuring his old laptop was pretty heavy already, and having an unused SLA available, re-purposing it for his laptop wouldn’t be too much of a hassle. Using a boost converter he built out of a custom dip MAX668, he is able to output the necessary 5 amps required. An MC 34161 voltage monitor chip is planned for future revisions, but he’s currently running it just fine. Check out some of his other cool hacks on Karosium.
Related: MSI Wind extended battery
Who would voluntarily lug around an SLA?
how long does the battery last
Yeah. See the Mac Portable and the Powerbook 100…
@babble
His site says 30 minutes.
Doesn’t seem that portable… but, then, msybe the doesn’t need it to be that portable. Regardless, it’s always cool to see what kind of ingenious solutions people come up with using spare parts and spare time. Needs more arduinos, though.
I did the exact same thing back in 2000… except that i didnt know what i was really doing. and the only thing i did was a conection straight to power jack and the 2 leads from the battery. worked pretty good. xD
All that just to run my Windows 95 ? I am flattered !
@Bill Hates
The laptop’s running Linux
Keep hatin’
I have a laptop running off a SLA using a car adaptor – the Asus Eee 701 can be picked up & held easily with just two fingers, but the 24kg 70Ah SLA needs two hands to pick it up. No they don’t go travelling anywhere :)
I estimate I’ll get up to 48 hours runtime but haven’t tried running it flat yet.
those sla batteries are heavy – my ups takes one and when you remove the battery it gets about 7 pounds lighter
also expensive ups ones r about $30 each
IDK, about lugging it around anywhere. but there’s a few folks who live off the power grid that are interested in this kind of thing. Use a couple of solar panels and or a wind mill along with a charger and your all set. Don’t need the laptop to waste cpu time to do power monitoring. desktop pc use way more power then the laptops which is another reason why off griders use laptops.
Build the converter so if fits into the battery space and it would be even better.
i had a similar situation and i handled it in a similar way
only i used a 12v to 115ac adapter and generic laptop power adapter
hmm I always wanted to make something similar for when im traveling. But Lead in a box is not an elegant way.
Nowadays 60 to 70 Watt LiPo pack are about 50 dollar/euro.
Am I the only one who noticed the strange wording in the description? It says he used a boost converter to get the 5 amps necessary. He used it to get the _voltage_ necessary at that current.. I know that’s what was meant, but the wording made it sound like he built a current-regulated supply.
It is of course possible to have a current-regulated switching converter, but that’s not what is happening here :)
Sorry for the nitpick!
I read it as he had to build his own converter to get one capable of handling the 5A draw.
I wonder if he tried the Battery reconditioning technique in the laptop resurrection and upgrade article back in 2005?
I did this a couple of years ago got like 10 hours worth of charge
Just want to point out I’m doing a similar thing with my PSP atm. Scrounged an old SLA from a wheelchair and I have a luggage bag to carry it around in, best thing is I can also use a beagleboard with it if want.
how lame is this website…
When I did something similar, I used 6 Cyclon D batteries (http://www.advancedbattery.com/itemdesc~product~ENERSYS%200810-0004%3B%20CYCLON%20D%20CELL,%202.5AH~ic~2V2.5T1JBU.htm). Seemed like a good idea at the time, since I had originally pulled them out of some portable piece of HP equipment I found.
Why do batteries gradually lose their ability to hold a charge?
gotta get me a new laptop at some stage