DIY Battery Packs

Gurrie said:

Anyone tried making a diy battery pack out of 2300mAH AA NiMH
batteries?

Given that the capacity of these batteries are getting quite high I was
thinking of making up a pack as it would also be quite light. Just
wondering if anyone else has tried this.

Craig

I've made a set, but they're the batterys with tabs on that you solder
together to make a pack. I've got two sets, one is 2.5 amp hour and the
other is 4.5 amp hour. Both are 12 volts and have 10 cells each. I use
them to run my Twin 5 watt Luxeon headlights. Make sure you use a smart
charger. They aren't called AA size, there's a whole range of sizes for
rechargeables.

Marty

"Marty" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Gurrie said:

Anyone tried making a diy battery pack out of 2300mAH AA NiMH
batteries?

Given that the capacity of these batteries are getting quite high I was
thinking of making up a pack as it would also be quite light. Just
wondering if anyone else has tried this.

Craig

I've made a set, but they're the batterys with tabs on that you solder
together to make a pack. I've got two sets, one is 2.5 amp hour and the
other is 4.5 amp hour. Both are 12 volts and have 10 cells each. I use
them to run my Twin 5 watt Luxeon headlights. Make sure you use a smart
charger. They aren't called AA size, there's a whole range of sizes for
rechargeables.

Marty

Now there's an idea.....make a 6V battery pack out of AAs with solder tabs
(5 cells), hide it in the handlebars of my mountain bike with a power
connector in the plug on the end of the bar (sorta like the end of a
Vistalite nitestick). Then I could mount a lamp on the bar end and run the
cable up the lizard skin thingo that I have got on there. Wonder if I could
manage to fit a battery pack in each end of the bars and then have a light
on each bar end???

Might need some investigation in the shed this weekend!!!

Gags

Marty <[email hidden]> wrote in news:[email hidden]:

Quoted message said:

I've made a set, but they're the batterys with tabs on that you solder
together to make a pack.
Make sure you use a smart
charger. They aren't called AA size, there's a whole range of sizes for
rechargeables.

Marty

How do you smart charge with the battries soldered together?

I bought waterproof poly carbonate to two way switches a strip of junction
terminals? and a 6 x AA size battery holder.
First two way handles Input from generator - lights/ 0. Second switch
Output is from batteries /generator. NiCads rated for 1.25 V, system based
upon 6V max. Seems to produce about 5 V at the output. Works ok so far. Am
considering having the input connected to the batteries to charge during
daylight ie input from generator, output to batteries. Does anyone know the
particulars of cycling the charge in dry cell AA nicads?

g

"Gurrie" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Anyone tried making a diy battery pack out of 2300mAH AA NiMH
batteries?

Given that the capacity of these batteries are getting quite high I was
thinking of making up a pack as it would also be quite light. Just
wondering if anyone else has tried this.

Craig

Peter Gordon <petergo@_deleteme_.netspace.net.au> wrote in
news:[email hidden]:

Quoted message said:

How do you smart charge with the battries soldered together?

They *should* be alright as they're all getting charged/discharged at an
equal rate, so they can just be treated as one big battery. It's when/if a
set of batteries get unevenly discharged that the problems start.

Graeme

Peter Gordon said:

Marty <[email hidden]> wrote in news:[email hidden]:

Quoted message said:

I've made a set, but they're the batterys with tabs on that you solder
together to make a pack.
Make sure you use a smart
charger. They aren't called AA size, there's a whole range of sizes for
rechargeables.

Marty

How do you smart charge with the battries soldered together?

The smart charger comes with a lead that you connect to the battery. The
charger charges the pack, not the individual battery. And it's even
smart enough to detect the correct voltage to charge at. On my battery
charger leads I've got a plug of the same type as the battery pack so
that it just plugs staight in.

Marty

On Fri, 13 May 2005 at 00:55 GMT, Graeme (aka Bruce)
was almost, but not quite, entirely unlike tea:

Quoted message said:

Peter Gordon <petergo@_deleteme_.netspace.net.au> wrote in
news:[email hidden]:

Quoted message said:

How do you smart charge with the battries soldered together?

They *should* be alright as they're all getting charged/discharged at an
equal rate, so they can just be treated as one big battery. It's when/if a
set of batteries get unevenly discharged that the problems start.

I had 3 sets of AA cells for my old light, such that each set of 4 got
recharged for exactly the same amount of time, and discharged for
exactly the same amount of time.

Yet, after about 20 charges, one of the sets was deteriorating. So I
set out to fully discharged all the cells in it, and after a while,
some popping sounds came from the battery. It turned out one of the
cells was at 0 volts, and the others were still at 1.2. I charged
that one up fully, then charged the other 3 up separately, and they
have been fine ever since.

All batteries are born equal - some more so than others 🙂

Tested the niteflux lastnight - didn't come back from MBTC via the
yarra trail and gardiners ck, so didn't get to test it in much
darkness, except for a little bit near the rail line at Toorak road.
The 15w (24 degrees from the specs, IIRC) casts a beam that can be
seen even when street lights are around, and the 5 watter (10 degrees,
IIRC) can't be seen very easily in such circumstances. I tested in my
backyard, and it seems when you are in the smallish beam, it blinds
you, and when out of the beam, it is still very visible.

The battery only got mildy warm in the initial charge I gave it.
Reading the manual - it does seem that it is indeed a smart charger.
Getting mildy warm is not a worry - it is only a worry when it gets
hot, but I guess I didn't leave it on long enough to test whether it
trickle charges properly. They *do* recommend not to leave it
connected for 36 hours -- remember charge time is 8 hours -- I guess
the trickle charge current is still significantly higher than the self
discharge rate of the NiMHs.

--
TimC -- http://astronomy.swin.edu.au/staff/tconnors/
size doesn't matter, resolution matters:
Hmm, I might be able to use that one tonight. -- someone on /.

Graeme said:

Peter Gordon <petergo@_deleteme_.netspace.net.au> wrote in
news:[email hidden]:

Quoted message said:

How do you smart charge with the battries soldered together?

They *should* be alright as they're all getting charged/discharged at an
equal rate, so they can just be treated as one big battery. It's when/if a
set of batteries get unevenly discharged that the problems start.

Graeme

I suspect he has in mind the type of charger where you put individual
cells into slots in a charger.

Marty

Marty <[email hidden]> wrote in news:[email hidden]:

Quoted message said:

Peter Gordon said:

Marty <[email hidden]> wrote in news:[email hidden]:

Quoted message said:

I've made a set, but they're the batterys with tabs on that you

solder

Quoted message said:

Quoted message said:

Quoted message said:

together to make a pack.
Make sure you use a smart
charger. They aren't called AA size, there's a whole range of sizes

for

Quoted message said:

Quoted message said:

Quoted message said:

rechargeables.

Marty

How do you smart charge with the battries soldered together?

The smart charger comes with a lead that you connect to the battery.

The

Quoted message said:

charger charges the pack, not the individual battery. And it's even
smart enough to detect the correct voltage to charge at. On my battery
charger leads I've got a plug of the same type as the battery pack so
that it just plugs staight in.

Marty

Long ago, I modified a camcorder charger to smart charge my
NiCad battery pack and it worked fine. It had a switch for setting
the voltage of the battery pack. From memory it was 4.5, 6, 9 & 12 V.
It worked well. Along came NiMH and the battery pack was getting too
hot to hold comfortably so I concluded that the charger was not
detecting when the battery pack was fully charged and I could easily
cook my batteries so I stopped using it.

Good smart chargers are readily available for individual batteries
but I don't know of any 6 or 12 V smart chargers. Is there one
on the market in Australia? Maha sell them in the USA but they
are not for 240 V power and they don't ship to Australia. Thus,
my initial question.
Cheers,

Peter Gordon

You can modify the charger that Oatley electronics sells to charge anything
from 4.8 to 12 volts. It detects full charge on NiMh and NiCad cells and
switches to a "maintain charge" regime. Instructions for modifying come
with the charger. You'll need to be able to solder and work with switches
and resistors.

See http://www.oatleyelectronics.com/battery.html Part no ZA0100
--
Regards
Bob Chambers
"Marty" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Peter Gordon said:

Marty <[email hidden]> wrote in news:[email hidden]:

Quoted message said:

Peter Gordon wrote:

>Marty <[email hidden]> wrote in news:[email hidden]:
>
>
>
>>I've made a set, but they're the batterys with tabs on that you

solder

Quoted message said:

>>together to make a pack. Make sure you use a smart charger. They aren't
>>called AA size, there's a whole range of sizes

for

Quoted message said:

>>rechargeables.
>>
>>Marty
>
>
>How do you smart charge with the battries soldered together?
>

The smart charger comes with a lead that you connect to the battery.

The

Quoted message said:

charger charges the pack, not the individual battery. And it's even smart
enough to detect the correct voltage to charge at. On my battery charger
leads I've got a plug of the same type as the battery pack so that it
just plugs staight in.

Marty

Long ago, I modified a camcorder charger to smart charge my
NiCad battery pack and it worked fine. It had a switch for setting
the voltage of the battery pack. From memory it was 4.5, 6, 9 & 12 V. It
worked well. Along came NiMH and the battery pack was getting too
hot to hold comfortably so I concluded that the charger was not detecting
when the battery pack was fully charged and I could easily
cook my batteries so I stopped using it.

Good smart chargers are readily available for individual batteries
but I don't know of any 6 or 12 V smart chargers. Is there one
on the market in Australia? Maha sell them in the USA but they
are not for 240 V power and they don't ship to Australia. Thus,
my initial question.
Cheers,

Peter Gordon

The best one seems to be the MW7168.
http://www.master-instruments.com.au/browse/Model/MW7168.html

There have only been good comments about it, but you need to run it off a
12 volt supply or a car battery.
It's what I use.

Marty

Pat and Bob Chambers said:

You can modify the charger that Oatley electronics sells to charge anything
from 4.8 to 12 volts. It detects full charge on NiMh and NiCad cells and
switches to a "maintain charge" regime. Instructions for modifying come
with the charger. You'll need to be able to solder and work with switches
and resistors.

See http://www.oatleyelectronics.com/battery.html Part no ZA0100

It says you need to buy a new plug pack for higher voltages and also the
charge current is low for if you want to fast charge nicads. Other than
that it looks ok. But I've played with a few chargers and the one I
presently use is the one I'd recommend. I built a Jaycar kit smart
charger and it was problematic. When you're going for a ride in the bush
at night you have to be 100% sure that your batteries are fully charged.
Mission critical!

Marty

The extra price of Oatley's 12 V plug pack is small compared with the quite
high cost of branded chargers. (And they sent out two of the "remaindered"
chargers (and plug packs) in the packet for the price) The benefit for me
with this charger was the much
reduced cost over proprietary models. It looks as tho it was a Camcorder
battery charger in its "youth". Discharge function is built in with LED's
to indicate state of charge/discharge. I've measured 500 mA output for
this charger - its OK for my homemade 7.2 V AA cell bottle battery, and for
my 9.6 V tube pack of 8x3.6 Ahr Sub C cells

See my light & battery at

http://tinyurl.com/bshlr

The battery hangs from padded velcro under the top tube. The shells are
designed to fit onto Cateye cam locked headlight brackets.

- charge takes about 8 hours for the 3.6 Ahr battery - not overly quick, but
overnight at least. Charge rate is too high for AAA. I'd like to be able
to regulate the output current without disturbing the end of charge sensing,
so I can charge the AAA's, but I'd need superior electronics skills.

Bob Chambers

--
Regards
Bob Chambers
"Marty" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Pat and Bob Chambers said:

You can modify the charger that Oatley electronics sells to charge
anything from 4.8 to 12 volts. It detects full charge on NiMh and NiCad
cells and switches to a "maintain charge" regime. Instructions for
modifying come with the charger. You'll need to be able to solder and
work with switches and resistors.

See http://www.oatleyelectronics.com/battery.html Part no ZA0100

It says you need to buy a new plug pack for higher voltages and also the
charge current is low for if you want to fast charge nicads. Other than
that it looks ok. But I've played with a few chargers and the one I
presently use is the one I'd recommend. I built a Jaycar kit smart charger
and it was problematic. When you're going for a ride in the bush at night
you have to be 100% sure that your batteries are fully charged. Mission
critical!

Marty