Making a Rechargeable AA Battery Pack

[Used_Cars]

The battery-powered GPS unit I use takes a 3.7 Volt, 1000mAh Rechargeable Li-ion (BL-5B), and despite the specs claiming 96 hours use, I get anywhere from 9 to 12 at most hours.

So I want to make a battery pack of 4 to 8 AA Li-ion batteries in parallel for the purpose of extending the life of the GPS unit.

The problem is with the recharging of the battery pack. I bought a rechargeable unit from Home Depot from some company like Energizer for about $35.00. It plugged into a 110 VAC outlet and had individual "bays" for each AA battery. When I tried to recharge by 4-battery pack, I connected a wire from the positive of the pack to the positive of the recharger, and the negative to the negative and waited about 12 hours. Not only did the battery pack not charge, but the charger is now also broken. No smoke, heat, fire, etc... it's just dead. So I gave up.

But now I want to try this again, this time maybe with some help from people that might know more than I do.

I've read about "limiters" being needed in Li-ion batteries to keep them from overheating and catching on fire, and I'm wondering if this may have something to do with why I failed the first time. Are there "limiters" involved here? Are they put on each individual battery, or are is there some kind of protection circuit built into the charger?

What I'm trying to do is avoid having to pull each battery from the pack and charge them individually. I want to charge the whole pack at the same time, There's waterproofing involved. So those "cartridges" where you load batteries in and out will not work for me. I just want to know if there is any difference to the charger if you connect a single AA Li-ion battery to a slot in the charger and connecting 4 AA Li-ion batteries in parallel. Seems to me the only difference would be the capacity of the battery, and the time it takes to recharge them. But I could be wrong. If I really knew what I was doing, I wouldn't have broken my $35.00 battery recharger.

[capwizard]

Re: Making a Rechargeable AA Battery Pack

My battery-powered GPS unit, battery shorted so I throw away the battery only use 12v DC adapter from cigarette plug, when the car stopp the GPS stop, it has been 5 years still keep going on.

If you need to use battery then use A 18650 3.7v 2200mAh. Charger use this one.

[eccerr0r]

Re: Making a Rechargeable AA Battery Pack

There are protection circuitry for lithium ion cells to prevent it from overcharge/overdischarge, but those are to protect the cells and are optionally built into the cells. Now I don't know what you ended up doing to the charger, but the charger may not be able to handle the current needed when you have a whole bunch of cells in parallel (which will have a current draw of 4 times that of one cell).

Perhaps the charger can only charge one cell at a time per bay. Perhaps there's some other circuitry that weren't defeated when charging a cell outside the bay, that which is hard to tell without seeing the guts of the dead charger.

The charger should theoretically also prevent suicide against overloading the output, perhaps it can only detect shorted cells but cannot deal with cells that are suddenly larger than what they should be. Again no idea without an autopsy.

[budm]

Re: Making a Rechargeable AA Battery Pack

"I bought a rechargeable unit from Home Depot from some company like Energizer for about $35.00" Charger made for Li-on?

http://www.eevblog.com/forum/project...oly-batteries/

[cpt.charlie]

Re: Making a Rechargeable AA Battery Pack

BL-5B batteries are cheap, why not having a few at hand? if you still insist in a battery pack i would use 1850 cells as this kind of cell is quite safe, has good capacity and can be even free (old laptop batteries) and you can find chargers designed for this size of cell.

[sam_sam_sam]

Re: Making a Rechargeable AA Battery Pack

The battery-powered GPS unit I use takes a 3.7 Volt, 1000mAh Rechargeable Li-ion (BL-5B), and despite the specs claiming 96 hours use, I get anywhere from 9 to 12 at most hours.

So I want to make a battery pack of 4 to 8 AA Li-ion batteries in parallel for the purpose of extending the life of the GPS unit.

The problem is with the recharging of the battery pack. I bought a rechargeable unit from Home Depot from some company like Energizer for about $35.00. It plugged into a 110 VAC outlet and had individual "bays" for each AA battery. When I tried to recharge by 4-battery pack, I connected a wire from the positive of the pack to the positive of the recharger, and the negative to the negative and waited about 12 hours. Not only did the battery pack not charge, but the charger is now also broken. No smoke, heat, fire, etc... it's just dead. So I gave up.

But now I want to try this again, this time maybe with some help from people that might know more than I do.

I've read about "limiters" being needed in Li-ion batteries to keep them from overheating and catching on fire, and I'm wondering if this may have something to do with why I failed the first time. Are there "limiters" involved here? Are they put on each individual battery, or are is there some kind of protection circuit built into the charger?

What I'm trying to do is avoid having to pull each battery from the pack and charge them individually. I want to charge the whole pack at the same time, There's waterproofing involved. So those "cartridges" where you load batteries in and out will not work for me. I just want to know if there is any difference to the charger if you connect a single AA Li-ion battery to a slot in the charger and connecting 4 AA Li-ion batteries in parallel. Seems to me the only difference would be the capacity of the battery, and the time it takes to recharge them. But I could be wrong. If I really knew what I was doing, I wouldn't have broken my $35.00 battery recharger.

You could use some Kent brand batteries that you can buy on EBay
But you need to buy the charger for this type of lipo battery it is a 1.5 volt output voltage the run time is pretty good for there size

One note on this battery I would NOT recommend this battery in a high current device and here is why it uses a buck converter board that is at the top of battery which is very small (yes I have taken this battery apart

I would NOT recommend doing this when I did this the first time I hit board and the top of battery got real warm almost to point that it was to hot to touch I did this a second time and this time I was able to get the buck convert board in one piece and this one works

[ I need the buck converter board for a mod on a MP3 player that uses one battery that not last very long on one battery I am going to make a monster battery pack for this player])

I use these batteries in a volt meter and it works very well my son has use it in his Xbox remote controller

OR

These batteries can also bought on EBay as well

Yes you could use Ni-Zn (BPI Brand) but the battery voltage when fully charge is 1.8 volts but the run time is very good but you have to buy the charger for this type battery

I use these batteries in my Mag Light 3 cell battery flashlight that uses AA batteries

But both of these batteries are price-e but to me they are worth the money but each has there place where they can be used

[budm]

Re: Making a Rechargeable AA Battery Pack

"lipo battery it is a 1.5 volt output voltage" LiPo (lithium-ion polymer battery) with 1.5V output? Can you give me the link to that?

[eccerr0r]

Re: Making a Rechargeable AA Battery Pack

Speaking of NiZn, anyone have success with them?
powergenix

[sam_sam_sam]

Re: Making a Rechargeable AA Battery Pack

"lipo battery it is a 1.5 volt output voltage" LiPo (lithium-ion polymer battery) with 1.5V output? Can you give me the link to that?

I am sorry I did not spell the name right but here is the eBay link to it

http://www.ebay.com/itm/252695759650...84.m1436.l2649

http://www.ebay.com/sch/i.html?_from...+1.5V&_sacat=0

I have used the 2800 mill-amp hour batteries but now I see that they have 3000 mill-amp hour batteries I will buy some and try them as well
The AAA batteries are also good --there running time is good for there size -- I have not taken this size apart yet

[sam_sam_sam]

Re: Making a Rechargeable AA Battery Pack

Speaking of NiZn, anyone have success with them?
powergenix

I have not tried them yet but you need to be careful with nock off brands I am not sure if this is the case or not I have only used BPI brand this is the only one that can give you my opinion about

I am going to try the other two brands and see if I get the same results or not I will let you know what the results are

Used Cars *****

One final note what ever type of battery you decide to use please use the right charger with right type of battery please be safe when doing this type of mod

[sam_sam_sam]

Re: Making a Rechargeable AA Battery Pack

The battery-powered GPS unit I use takes a 3.7 Volt, 1000mAh Rechargeable Li-ion (BL-5B), and despite the specs claiming 96 hours use, I get anywhere from 9 to 12 at most hours.

So I want to make a battery pack of 4 to 8 AA Li-ion batteries in parallel for the purpose of extending the life of the GPS unit.

The problem is with the recharging of the battery pack. I bought a rechargeable unit from Home Depot from some company like Energizer for about $35.00. It plugged into a 110 VAC outlet and had individual "bays" for each AA battery. When I tried to recharge by 4-battery pack, I connected a wire from the positive of the pack to the positive of the recharger, and the negative to the negative and waited about 12 hours. Not only did the battery pack not charge, but the charger is now also broken. No smoke, heat, fire, etc... it's just dead. So I gave up.

Did you try to change the li-ion batteries (3.8 to 4.2 volts batteries ) in a nicad type of changer if you did that then you did blow the fuse type resistor in the charger


Most of this type of chargers have a shut off timer that if the battery voltage dose not reach the set point in a certain amount of time the charger shut down or max out the mill-amp output of the charger

Now the charger from Energizer that is 15 minutes charger it works very well it does change the battery in that amount of time but you have to use the 15 minutes type batteries in it for best results

Home Depot dose sell this charger

[budm]

Re: Making a Rechargeable AA Battery Pack

https://metaefficient.com/rechargeab...ies-exist.html

"Lithium-ion batteries normally operate 3.7V per cell — but Kentli put circuitry inside the cells to reduce the voltage to 1.5 volts"
That is why you get 1.5V! I knew there is a catch to get the 1.5V from Lithium batt.

[sam_sam_sam]

Re: Making a Rechargeable AA Battery Pack

https://metaefficient.com/rechargeab...ies-exist.html

"Lithium-ion batteries normally operate 3.7V per cell — but Kentli put circuitry inside the cells to reduce the voltage to 1.5 volts"
That is why you get 1.5V! I knew there is a catch to get the 1.5V from Lithium batt.

In post #6 I talked about taking one apart and the mishap on the first one I tried but second time I tried it I was able to use the buck converter board here is a picture of one

[redwire]

Re: Making a Rechargeable AA Battery Pack

You know GPS signals and water don't work, if you are immersing things.

There are some high-capacity BL-5B battery packs out there, up to 2,850-3,000mAh claimed. That would be at least double the life of your present setup.

AA Li-ion batteries are a total oddball, only Kentli makes them and why bother as they only give ~1,100mAh? Eneloops hold more energy.

You could stay with a single high-cap 18650 cell. There are many off-the-shelf waterproof cases available for them. The 4-pack for bicycle lightning is popular.