[PD] batteries for audio cards

[Pierre-Olivier Boulant]

Same here!

I'm just concerned some Li-ion/Li-po batteries do not have an 
over-discharge protection and this could be an issue if you try to 
recharge a Li* battery that's been drained beyond its inversion voltage. 
Ask Boeing about this... ;)
I doubt this has been included in the RME sound cards since they are 
built to take almost any kind of low voltage power (AC and DC).

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
>
>
>     Over-discharging Lithium-ion
>
> Li-ion should never be discharged too low, and there are several 
> safeguards to prevent this from happening. The equipment cuts off when 
> the battery discharges to about 3.0V/cell, stopping the current flow. 
> If the discharge continues to about 2.70V/cell or lower, the battery’s 
> protection circuit puts the battery into a sleep mode. This renders 
> the pack unserviceable and a recharge with most chargers is not 
> possible. To prevent a battery from falling asleep, apply a partial 
> charge before a long storage period.
>
> Battery manufacturers ship batteries with a 40 percent charge. The low 
> charge state reduces aging-related stress while allowing some 
> self-discharge during storage. To minimize the current flow for the 
> protection circuit before the battery is sold, advanced Li-ion packs 
> feature a sleep mode that disables the protection circuit until 
> activated by a brief charge or discharge. Once engaged, the battery 
> remains operational and the on state can no longer be switched back to 
> the standby mode.
>
> Do not recharge lithium-ion if a cell has stayed at or below 1.5V for 
> more than a week. Copper shunts may have formed inside the cells that 
> can lead to a partial or total electrical short. If recharged, the 
> cells might become unstable, causing excessive heat or showing other 
> anomalies. Li-ion packs that have been under stress are more sensitive 
> to mechanical abuse, such as vibration, dropping and exposure to heat.
>

You need to make sure you have an over-discharge protection that cuts 
off the power when reaching about 3.2V per cell (3 cell would be between 
9.0V and 9.6V). I'm not sure I have this in the pack I use... :/

Some more detail to read when you've set your bedroom on fire ;)
http://www.nfpa.org/assets/files/pdf/research/rflithiumionbatterieshazard.pdf


Lead batteries don't like being over-drained either. It's just not as 
dangerous to recharge a Pb that's been drained too much.

Hope this helps.
Cheers
Pierre-Olivier



On 26/04/2013 18:03, Antoine Villeret wrote:
> hey,
>
> i got a car cigarette lighter plug adaptor with my RME fireface,
> so just take a 12V Pb battery from a teenager motorcycle and go !
>
> if you need a lighter solution, look at LiPo battery from R/C model
>
> cheers
>
> a
>
> --
> do it yourself
> http://antoine.villeret.free.fr
>
>
> 2013/4/26 Alexandre Torres Porres <porres at gmail.com 
> <mailto:porres at gmail.com>>
>
>     hey folks, anyone have recomendations for battery packs for audio
>     cards?
>
>     wanna try some stuff going mobile, anybody doing that? Looking for
>     some high capacity for my multiface/RME (takes 9-.12V, 2A)
>
>     thanks
>
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-- 


~    Pierre-Olivier Boulant     ~
-o-     www.puffskydd.net     -o-
~   www.flickr.com/pob31/sets   ~
-o-    www.lepixophone.net    -o-
  

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