Master_Scythe

worship me..... WORSHIP ME!.... DO IT NOW!... ok fine... lol

i took it upon myself to go to my main community when it comes to electronics, and... heres what came up

http://www.atomicmpc.com.au/forums.a...p=0#msg-114752

we have discussed how it works, why it IS safe, batterie voltages and sizes, and its all easy to understand.

Snerkel i'm going ot have to correct you there. u said 4XAA's but only NiMh... why? 4XAA"s = 6v, the correct voltage would be about 6X AA"s (alkaline) 6 X 1.5v = 9v. or if u can find a holder for this many, 8! (8 X 1.5v = 12v, its a car charger, the car provides 12v, and can give up to 15ish, so the charger will ahve some leeway).

So, in conclusion. this IS safe. the charger is limiting it to 5.4v ougoing, so no matter how much u run through it, it'll be 5.4v. ALSO, with the IC chip, making sure it only gives out 5.4v, u wont risk running your PDA on less when the batteries get low (or so we at Atomic suspect)

the best bet is AA's, 6 of them work well, 8 is 12v, but if 9v batts work fine, stick with 6 AA's because that = 9v.

I will be performing this mod hopefully this weekend if i can find a cheap PSP charger.

good luck to all! read the link!!

BTW. general disclaimer, not responsible for random stuff you do or follow in this post, etc etc. u know the drill. whatever you do, you do yourself. not my problem.

thanks for your time.

EDIT: SNerk, i re read, no limiters etc. ok, thats unsafe though because of possible underpowering and its just crude. ur right i see, but i wouldnt risk it on my investment.

PDAAddict

@ Master Scythe:

if 6 AA = 9v, why not use 1 9V battery instead? Why are AA batteries safer?

__________________
Regards,

PDAAddict
Palm M125 -> Tungsten E -> Axim X50v

mphayvanh

Originally Posted by Master_Scythe

worship me..... WORSHIP ME!.... DO IT NOW!... ok fine... lol i took it upon myself to go to my main community when it comes to electronics, and... heres what came up http://www.atomicmpc.com.au/forums.a...p=0#msg-114752 we have discussed how it works, why it IS safe, batterie voltages and sizes, and its all easy to understand. Snerkel i'm going ot have to correct you there. u said 4XAA's but only NiMh... why? 4XAA"s = 6v, the correct voltage would be about 6X AA"s (alkaline) 6 X 1.5v = 9v. or if u can find a holder for this many, 8! (8 X 1.5v = 12v, its a car charger, the car provides 12v, and can give up to 15ish, so the charger will ahve some leeway). So, in conclusion. this IS safe. the charger is limiting it to 5.4v ougoing, so no matter how much u run through it, it'll be 5.4v. ALSO, with the IC chip, making sure it only gives out 5.4v, u wont risk running your PDA on less when the batteries get low (or so we at Atomic suspect) the best bet is AA's, 6 of them work well, 8 is 12v, but if 9v batts work fine, stick with 6 AA's because that = 9v. I will be performing this mod hopefully this weekend if i can find a cheap PSP charger. good luck to all! read the link!! BTW. general disclaimer, not responsible for random stuff you do or follow in this post, etc etc. u know the drill. whatever you do, you do yourself. not my problem. thanks for your time. EDIT: SNerk, i re read, no limiters etc. ok, thats unsafe though because of possible underpowering and its just crude. ur right i see, but i wouldnt risk it on my investment.

You're just too cool. I've read the posts from Atomic. I feel a little more confident with the lesser capacity 9v for this design. 6 AA will be the next charger I build. Thank you for the input -- I love this community! PS- Post what you come up with and pictures too soon!

new2axim

Quote:

Originally Posted by Master_Scythe worship me..... WORSHIP ME!.... DO IT NOW!... ok fine... lol i took it upon myself to go to my main community when it comes to electronics, and... heres what came up http://www.atomicmpc.com.au/forums....&p=0#msg-114752

This really isn't rocket science. I'm not sure why you had to go to the "Maximum Power Computing" website to figure out how many volts you get when you put some batteries together.

And I would rethink your statement of "no matter how much u run through it, it'll be 5.4v" You're talking about a cheap adapter made out of plastic and a dollar worth of electronics. Like I said before, the car adapter is made to take 12v DC and turn it into 5.4v DC for your Axim. If you tried jamming 120V through it instead of 12v (or 9v), I think you'd find yourself with a fried adapter.

Additionally, I'd bet you big money that this adapter isn't even converting 12v to precisely 5.4v Take a multimeter to it and see what you're really getting out of it. It's a cheap and inprecise item.

new2axim

Originally Posted by PDAAddict

@ Master Scythe: if 6 AA = 9v, why not use 1 9V battery instead? Why are AA batteries safer?

I don't know why AA batteries would be safer, but I'd think AA batteries would be a better bet because:

(a) they're cheaper
(b) they're more common (I'd bet you have more AAs in your home than 9v batteries)
(c) you're going to get more 'energy' from six AA batteries than you are from one 9v battery. IOW, the 9volts you're getting from the AAs should last longer than the 9volts you get from a single 9 volt battery.

The OP reported having problems using AAs. I'm not sure why that would be, but if this is all being attached through a car adapter, I'd just take 8 AAs in series (1.5v * 8 = 12v) and rig that up instead of 9volts.

Snerkel

Originally Posted by Master_Scythe

Snerkel i'm going ot have to correct you there. u said 4XAA's but only NiMh... why? 4XAA"s = 6v, the correct voltage would be about 6X AA"s (alkaline) 6 X 1.5v = 9v. or if u can find a holder for this many, 8! (8 X 1.5v = 12v, its a car charger, the car provides 12v, and can give up to 15ish, so the charger will ahve some leeway).

My unit powers the Ax directly.

Using 4 AA Alkalines in series would give over 6 volts when fresh, this is too high a voltage for the Ax directly but not high enough for a voltage regulator such as the one you are using.

NiMH give a little over 1.3 volts when fully charged, so you get about 5.4 volts. I have just been trying my setup, its been running for just over two hours playing movies (Bluetooth ON WiFi OFF) and it is still going strong (green LED on).

As I said you don't need any kind of regulation as the batteries are supplying the correct voltage for charging the Ax. The unit is very neat as it is only a battery pack and a cable, you don't get any losses as you would running through a regulator.


All in all it is very simple and cheap to just use the 4 NiMH AA batteries and the holder.... KISS

kandieman101

Originally Posted by Snerkel

My unit powers the Ax directly. Using 4 AA Alkalines in series would give over 6 volts when fresh, this is too high a voltage for the Ax directly but not high enough for a voltage regulator such as the one you are using. NiMH give a little over 1.3 volts when fully charged, so you get about 5.4 volts. I have just been trying my setup, its been running for just over two hours playing movies (Bluetooth ON WiFi OFF) and it is still going strong (green LED on). As I said you don't need any kind of regulation as the batteries are supplying the correct voltage for charging the Ax. The unit is very neat as it is only a battery pack and a cable, you don't get any losses as you would running through a regulator. All in all it is very simple and cheap to just use the 4 NiMH AA batteries and the holder.... KISS

But then don't you run into problems if the batteries are not near 100%?

Snerkel

Originally Posted by kandieman101

But then don't you run into problems if the batteries are not near 100%?

Nope, NiMH batteries tend to have a consistent output until nearly flat. Don't forget that even when the NiMH batteries expire you still have a fully charged Ax. After approx three hours of run time the battery pack is still outputing 4.78v and is holding the Ax at 100% charge.

A couple of sets of batteries should give over 6 hours with the Ax -processor- on Auto, more if you set it to power saving and reduces the back light level.

One thing to note - not sure how you would go on getting on a plane with the home made chargers
:exc:

Master_Scythe

the reason to use AA's instead of 9v's is because AA's provide longer power.

ndepuy

Hi Y'all I just wanted to put my 2 cents in on this, I'm currently in the Air Force as a electrician on F-16s and was an electrician on cars for 8 years. Any where from 9v-15v should be fine as this is the normal operating range for a cars electrical system. (cranking to running) This car charger manufacturer has to have taken in to account these variables (as well as higher extremes) if they want to stay in buisness. Personally, I'll be building one of these as soon as I am able to get the parts. Take your time, ask questions and use you multimeter and all should be good.
ps if you have trouble soldering you can use in-line splices too. Look at any auto parts store and describe/show your project to the guy at the counter he should be able to help.

Grant837

Here's an idea: buy a cheap 12 or 14.4 volt rechargable drill (with extra battery if possible) and build around that...maybe find a spare car cigarette charger socket so you can use the a car charging cable with this thing, or in the car... Its bigger, but should last for ever between charges....

Paul123

So in other words, the 9 volts won't fryt he axim, but a longer lasting solution is needed?

ndepuy

9v to the Ax WILL probably fry it. We're talking about stepping it down with a transformer (car adapter) to the required 5.4v (roughly.) As to the drill idea that (depending on the design) would work too except for it might be bulky(er)