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@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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