High power but low weight batteries?

[Daniel Kelly (AKA Jack)]

Hi,

Please could you recommend a supplier for high power (but low weight)
batteries? Ideally I need something that can beat these specs:

12V
6Ah
400g

I'm building a wearable system for recording many many hours' worth of
video. I need any voltage upwards of 5v.

Thanks,
Jack

 

[CWatters]

"Daniel Kelly (AKA Jack)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in message
news:c3sn8l$25vc$1@uns-a.ucl.ac.uk...

Hi,

Please could you recommend a supplier for high power (but low weight)
batteries? Ideally I need something that can beat these specs:

12V
6Ah
400g

Those figures imply a capacity of 72WH or an Energy Density of 180WH/Kg
(Watt-Hours per Kilogram)

The relevant figures for different cell technologies are (very
approximately):

Lead Acid : 35
NiCad: 35
NiMH 55
Lithium Ion 150

So only Lithium cells can meet or beat your target specification.

However you then say...

I need any voltage upwards of 5v.

So your spec is really ...

5V
6AH
400g

Which works out at 30AH or 75WH/Kg .... but you still need Li cells.

Colin

 

[CWatters]

Now that I've read your other post...

I recommend you stick to NiMH cells. Lithium polymer cells are difficult to
charge unless you really know what you are doing. There is a much greater
fire risk with Li. For example if you overcharge NiMH cells they get hot and
you damage the pack a bit. If you abuse Li cells the same way they can get
into a thermal runaway situation that doesn't even stop when you disconnect
them from the charger - they really do catch fire.

Colin


"CWatters" <colin.watters@pandoraBOX.be> wrote in message
news:f7y8c.48863$OP2.3401832@phobos.telenet-ops.be...

"Daniel Kelly (AKA Jack)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in
message
news:c3sn8l$25vc$1@uns-a.ucl.ac.uk...
Hi,

Please could you recommend a supplier for high power (but low weight)
batteries? Ideally I need something that can beat these specs:

12V
6Ah
400g

Those figures imply a capacity of 72WH or an Energy Density of 180WH/Kg
(Watt-Hours per Kilogram)

The relevant figures for different cell technologies are (very
approximately):

Lead Acid : 35
NiCad: 35
NiMH 55
Lithium Ion 150

So only Lithium cells can meet or beat your target specification.

However you then say...

I need any voltage upwards of 5v.

So your spec is really ...

5V
6AH
400g

Which works out at 30AH or 75WH/Kg .... but you still need Li cells.

Colin