Energizer Energi To Go Step Up Circuitry

[TMorita]

...
I took it apart after the battery door's latch snapped off...the circuit board's photographable if anyone needs a pic

The lithium AAs have about a 1.7v output x2 for 3.4 volts. The NiMH cells are about 1.2v x2 for 2.4 volts. So, the voltage is probably too low on NiMH cells and that's why it stops after 15 minutes.

I was thinking about buying one of these, and modding it to use a 2D cell holder. So, instead of getting one charge from a set of AA cells, you could probably get 4-5 charges from 2 D cells, which is more useful.

Toshi

 

[shadowjk]

I have a 4xAAA converterless cellphone charger. Unfortunately it only works on fresh alkaline/lithiums There's a diode in it to prevent the cellphone from charging the charger, I tried bypassing that one but nimh voltage was still not sufficient.

I haven't actually tried to do any full charging with AAA, if it doesn't work with nimh then it must be pretty useless with alkaline too.

 

[hopkins]

What about adding an external holder for a 3rd NimH AA cell ?
- maybe glue it on the outside? ...and run wires thru the door
so the step up circuit has 3.6volts to work with?
Guess it would depend if the output to the cellphone has a
voltage regulator of some sort.

 

[ltiu]

There are four versions of this for different kinds of phone, and not all have the same list price. Only the Nokia one is really expensive.

Which one steps up to 5.5 V?

As far as I know, the only difference between the different versions for different phones are the power connectors. The battery pack and the included circuitry are all the same.

I got the Nokia one for the same discounted price of $4.17.

 

[ltiu]

I have a 4xAAA converterless cellphone charger. Unfortunately it only works on fresh alkaline/lithiums There's a diode in it to prevent the cellphone from charging the charger, I tried bypassing that one but nimh voltage was still not sufficient.

I haven't actually tried to do any full charging with AAA, if it doesn't work with nimh then it must be pretty useless with alkaline too.

I opened the Energi To Go and took out the circuitry. On the tiny circuit board, right beside the battery contacts are printed the letters:

"ALK +" on one side

and

"ALK -" on the other

 

[ltiu]

I dropped by my local Circuit City and looked for them in vain. None of the sales assistants could remember ever seeing them. Bummer.

What I meant about the price is on the Circuit City website. The Nokia one has a normal price before discount of 21.99, whereas the others have a price before discount of 7.14.

I find Circuit City to be a bit dysfunctional when it comes to prices.

Often, I find their posted sticker price is different from their cash register price.

Also, I often see the same product in two different sections of the store showing two different prices. The Energi To Go I got fits right in to this observation. I found a few Energi-To-Go in two different sections of the store. One had a $4.17 price tag. Another had $7.14. But the cash register's got the $4.17 price.

I recently found some Duracell 223 with a shelf sticker price of $4.49, not too bad, I can get 2x 123 cells out of it for around $2.25 each. I took a couple, but then the cash register says it's actually $4.23. Saving me a few cents per pack!

 

[Zigzago]

I bought one of these last month for my relatively new Nokia phone. My experience is that it works with lithiums and alkalines but not at all with my Ray-O-Vac NiMh batteries.

 

[jzmtl]

Alternatively, the phone's lithium ion cell is 3.6V and maybe there is a way to substitute three NiMH cells.

I always wondered about this, maybe someone can fab up some sort of plug that clamp onto phone cell contact. When you are in a pinch pop out a 123a out of your flashlight and voila, phone has power again.

 

[ltiu]

I always wondered about this, maybe someone can fab up some sort of plug that clamp onto phone cell contact. When you are in a pinch pop out a 123a out of your flashlight and voila, phone has power again.

It should almost be a universal battery contact. You can use any battery, C, D, AA, CR123.

 

[ledaholic]

I picked up 1 of these last night. Popped in the batts and hooked to my Nokia, seems to work ok. Now to measure volts and current, 6 v open circuit. Hmmm, how to measure current easily.. had a Cree sitting on the table with an optic connected and pigtails, just stuck the wires in the charger plug and we have light! Measured the current @ pretty close to 600 mil driving the Cree, cool!

 

[ledaholic]

Seems to work just fine on 2 NiMh cells also.

 

[bcwang]

Wow, that's cheap. I bought one of these for almost $20 a few months ago. I found that some cells don't work with it because the positive nipple is too wide causing it to not make contact past the plastic polarity protector. I also have tried charging my phone using nimh cells until the charger stopped, but the nimh cells were over half full still.

If this can really put out 600ma at 5v, then the draw on the AA is quite high, no wonder it would quit early on nimh if it is expecting lithium voltages.

 

[ledaholic]

If this can really put out 600ma at 5v, then the draw on the AA is quite high, no wonder it would quit early on nimh if it is expecting lithium voltages.

My measurement of 600ma was driving a Cree probably around 3.5v or so. It's probably a little less @ 5v.

 

[BrianChan]

Fresh off the charger, I popped these into the Energi-To-Go. The charging lasted no more than 15 minutes per set before the charger stopped charging. I did this a few times using different Eneloops and Hybrids thinking maybe it's a battery issue. But I kept on noticing that Eneloops/Hybrids do not last long when charging my dead or near dead (one battery bar left) cell phone. My cell phone would not be fully charged yet when the charger would turn off indicating the battery (the Eneloop/Hybrid) is dead.

Whereas when I used e2 Lithium L91, I find I can at least charge my cell phone twice from dead or near dead (one battery bar left).

I did some measurements right before popping a pair of NiMH into it and found out that it needs to have a minimum voltage per cell of around 1.3-1.4v to start it up and charge my phone. Any less than that will not power it. Therefore once you start it up you shouldn't unplug it until the cell phone's battery is charged/AAs are dead as the nominal voltage of a NiMH is less then 1.4v after you start discharging them. A pair is capable of fully charging my Nokia phone which has a 900mAh battery from almost empty.

Man you guys can get them really cheap in the States, the cheapest I can find in Australia is $30 :sigh:

 

[radellaf]

anyone know if these
http://www.amazon.com/dp/B000CMU17I/?tag=cpf0b6-20

with the 1 AA work any better off NiMH?

 

[Illum]

aside from the 2AA, energizer also makes a 1AA version
I'm not sure about the quality or performance of the 1AA, but I think just by looking at the design its a heck of alot more sturdier

 

[Mr Happy]

Well, I found a store that had some of these left on the rack so I bought a handful.

Being the inquisitive soul that I am, I did some experiments on one of them to tease out its innermost secrets.

To begin with I loaded up the output with a low current 6 V bulb. The bulb lit up brightly when it was powered with the supplied lithiums and also with Eneloops. So I got out some multimeters and started measuring.

With both lithiums and Eneloops the output was regulated at 4.95 V while supplying 0.22 A to the bulb. Powered by the Eneloops the current draw was 0.50 A at 2.48 V. This would make the efficiency equal to

4.95 x 0.22
----------- = 88%
2.48 x 0.50

Next I tried increasing the load while using the Eneloops. With a bigger bulb and a 0.5 A load, the voltage sagged a little to 4.6 V. On trying to increase the load beyond 0.5 A using an even bigger bulb, the voltage sagged right down to 2.6 V although the bulb seemed quite bright. (Maybe my meter wasn't reading the voltage very well due to AC content?) I don't know what would have happened if I'd used the lithiums instead; maybe I'll try that another day.

So we have here a nice little booster circuit that is good for maybe 500 mA at 4.5 V when given 2.4 V or so on the input side.

 

[ltiu]

Man you guys can get them really cheap in the States, the cheapest I can find in Australia is $30 :sigh:

Regular price in the US is U$19+.

AND!!! Uncle Sam is giving us US tax payers a rebate check to counter the economic recession! More flashlight and battery purchases!!!

 

[johnny13oi]

Hey guys, sorry for bringing this post back but can anyone confirm that the circuitry in this has a diode in it to prevent the circuit from drawing current from the connected device. I ask this because the phone I have is known to become damaged if whatever is charging it does not have a diode to prevent the current going from the phone into the charging to device. The phone is very expensive and I wanted to make sure that this does not damage it. I plan on using Ni-Mh with the Energi to go so I was a little worried that it might shut off early and then draw the current back from the phone.

 

[GarageBoy]

I have an original charge2go (1XAA) Killed batts FAST (NiMh) You'd need a bunch to charge a phone 1/2way