Breaktru Forum
eCigarette Forum => Modding => Parts for Mods => Topic started by: Claviger on June 06, 2014, 04:13:32 PM
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Found this a couple days ago. It's an easy answer to over charge / over discharge protection.
http://www.batteryspace.com/pcbfor74vli-ion1865018500batterypackswith9ahighcurrentstartup.aspx
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That one is designed for standard Li-Ion cells. Most people are using the high drain cells, but if you're using standard Li-Ions that's an easy way to protect them if they don't have protection.
One issue with that board is it lists resistance as 50 mOhms which is high. You're going to get considerable power loss at higher current demands. High drain cells typically have DC resistance under 20 mOhms so that's a relatively high insertion loss. It sort of defeats the point of using a high drain cell to begin with.
The over-discharge protection is only 2.3V. It's only the latest high drain cells I've seen with a discharge limit that low. I haven't seen a standard Li-Ion lower than 2.5V. You really don't want to regularly take a cell to its limit. You don't gain much run time doing that and it greatly increases wear.
The quiescent current draw for that board is 20uA which is high. In a general sense it's not a high demand, but for a protection board it is. They're usually a uA or two. If using the board with other electronics that have an idle draw, those currents can add up fast and then you have a situation where the device can drain the cells when left idle for too long.
I'd have to say the e-cig application range is pretty limited for that protection board, but if you fit into that range the product can be useful.