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Moderator H/PC Vanguard Posts: | 2,832 |
Location: | Choking on the stench of ambition in Washington DC | Status: | |
| Hi, Folks,
I'm looking for an external battery to power my UMID M1 MBook.
The rub is, I need 9.5v. I have an external battery that will do 9.0v, but I'm getting a weird sound from the device which says at the very least, it's undervolted.
The M1 is an old device, and non-usb (meaning a need for the proper adapter) external batteries are few and far b/w.
As always, any advice would be much appreciated,
Jake |
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Global Moderator H/PC Guru Posts: | 7,188 |
Location: | USA | Status: | |
| If you are looking for only a power supply, then the ASUS EE PC power supply should work well, you will just need to solder on the correct plug. If you are looking for a battery only to make it portable, then the cheapest way to go would be a simple 12v batter that you could wire a variable POT in series to reduce the voltage to 9.5v...you'd waste some power to heat on the POT...but it would work fine... |
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Moderator H/PC Vanguard Posts: | 2,832 |
Location: | Choking on the stench of ambition in Washington DC | Status: | |
| Hi, Rich!
Many thanks for the quick post. Man, I dunno: dumbing down a 12-volt battery sounds above my pay grade. You're much more the master at that stuff than me, with all your batt rebuilding.
Any actual ready-built battery come to mind?
Jake |
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Global Moderator H/PC Guru Posts: | 7,188 |
Location: | USA | Status: | |
| There used to be nicad 9.5vdc batteries for portable power tools...but you would need a special charger then.
Another option would be a series-parallel configuration of nicad batteries. Most are rated at 1.2v, so 8 of them in series would be 9.6v. Probably 3 rows would be enough to supply a funtional current source to power you handheld for an hour. But you would have to recharge the cells...and that would take a while.
Somewhere here I posted my AAA battery adapter for a MP880 that worked great! Same idea really...
If you had a car adapter for your handheld, then hooking that up to a small 12v motorcycle battery would give you juice for all day! I see them on ebay for about $35... |
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Moderator H/PC Vanguard Posts: | 2,832 |
Location: | Choking on the stench of ambition in Washington DC | Status: | |
| Very intriguing. I actually have seen a car adapter sold for this device. Lugging a motorcycle battery might be prohibitive, but I wonder if something smaller might work. Many external batteries out there, but they only have 9v setting.
Jake |
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Global Moderator H/PC Guru Posts: | 7,188 |
Location: | USA | Status: | |
| Actually any 12V battery would work. For instance, search eBay for "ADT 804302 CASIL 1240"
It's a 12V battery that is only 3"W x 4"L x 4H" and supplies 4000mAh of current. But it is a dry cell battery needing an electrical charging circuit with overcharge protection to charge it.
A typical small 12V wet cell battery measures about 3"W x 6"L x 4"H...but supplies a whopping 8500mAh of current and can be charged with any cheap $10 trickle charger.
Also there are a ton of 9.6V ni-mh batteries with chargers for sale on eBay. 9.6 is a standard for R/C cars and helicopters... |
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H/PC Sensei Posts: | 1,169 |
Location: | Russia | Status: | |
| Quote Rich Hawley - 2015-11-21 8:52 PM
8500mAh of current
Ah denotes capacity for a given voltage, not current. |
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Global Moderator H/PC Guru Posts: | 7,188 |
Location: | USA | Status: | |
| Don't get all technical on me Alt Bass. The voltage for a battery is fairly constant. In my post above, a 8500mAh battery will supply 8.5 amps of current for 1 hour. So if your handheld draws 1 amp of current, you can operate for 8 1/2 hours before recharge...ideally.
I might be wrong...Ah has never been a component of voltage directly...at least not in my training... |
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Moderator H/PC Vanguard Posts: | 2,832 |
Location: | Choking on the stench of ambition in Washington DC | Status: | |
| Rich, with these 9.6v chargers you've suggested, how would a user connect the proper adapter tip? Do they have a universal slot that can take a variety of tips? I remember that being the case for the old Radio Shack a/c adapters.
Jake |
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Global Moderator H/PC Guru Posts: | 7,188 |
Location: | USA | Status: | |
| Almost all the time the tip or center core is positive voltage....but you need to find a compatible tip, and then using a multimeter figure out which is the positive lead... |
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Moderator H/PC Vanguard Posts: | 2,832 |
Location: | Choking on the stench of ambition in Washington DC | Status: | |
| This looks like something that even the hard-of-thinking like myself could manage, and it's a battery pack specifically for the M1 MBook:
http://www.pocketables.com/forum/showthread.php?t=2415&page=3
I have not found this hardware (other than the batteries ) on USA Ebay and Radio Shack is no more. Where might I look for an 8-AA battery pack that would have a variety of available tips?
Happy Thanksgiving to anybody celebrating it today,
Jake |
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Global Moderator H/PC Guru Posts: | 7,188 |
Location: | USA | Status: | |
| Actually they are pretty common, you are just using the wrong eBay search criteria. Now you can buy a 8 cell holder which is even better.
8 x 1.2V NiCad batteries = 9.6V total if in series. Alkaline are nominally 1.5, so 8 x 1.5V = 12V which might be too much.
Anyways, check out THIS auction...it would be just what you need I think based on that post you listed.
(snap.bmp) Attachments ---------------- snap.bmp (504KB - 0 downloads) |
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Moderator H/PC Vanguard Posts: | 2,832 |
Location: | Choking on the stench of ambition in Washington DC | Status: | |
| I think that's it. Rich, thanks! Just bought it. Rummaging around, I found a 4-aa Radio Shack battery pack with a universal female end (instead of the bare leads ). Lo and behold, the male tip I had placed on it (to power an Oregon Osiris, a Psion Series 5 knock-off ) is the same tip for the M1 Mbook.
I'll try to upload a picture of the 4-aa pack I have because I don't know the search terminology for finding an 8-aa pack with universal female end.
Thanks again,
Jake Edited by Jake 2015-11-26 6:44 PM
(2015-11-26-002_1.jpg) Attachments ---------------- 2015-11-26-002_1.jpg (71KB - 0 downloads) |
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Global Moderator H/PC Guru Posts: | 7,188 |
Location: | USA | Status: | |
| As far as I know, only Radio Shack sold those things with the universal female sockets, mainly because they sold the tips individually. However, you can go anywhere and buy a cheap universal a/c adapter and get a variety of plugs to fit that socket. Just a matter of cutting off the cable and splicing it onto your AA battery holder.
Tips by themselves are available as well. Check out eBay and search for "universal 2 pin tips"
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Moderator H/PC Vanguard Posts: | 2,832 |
Location: | Choking on the stench of ambition in Washington DC | Status: | |
| Many thanks for your clear explanations. I think I'll just cut off the cable for my 4 aa holder and splice it on the 8 aa holder.
To do this, I would just need wire strippers and electrical tape, no? I'll double-check, but the white-stripped wire of the 4 aa holder connects to which color of the 8 aa holder, black or red?
Jake |
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