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In which I'm very careful about battery chargers... - Tactical Ninja

May. 29th, 2013

08:48 am - In which I'm very careful about battery chargers...

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So last night I spent some time reading up about LiPo batteries. Why? Because they are really expensive, and I'm planning to strap one to myself. These two factors make it imperative that I learn enough to a) not destroy it by treating it wrong, since I've never dealt with these before, and b) not set fire to myself.

Not setting fire to myself may be coming across as something of a theme here. Hmm..

So the first thing I learned is that LiPo batteries don't just catch fire, they can also explode:



By the time I'd read the first page about them, I was eyeballing my one as if it was a bomb, and having serious reservations about putting it in a belt pack close to my kidneys. However, that page up there (the one about LiPo batteries) tells me that there are four rules for not making your battery go splodey:

1. Don't overcharge it.
2. Don't short it out.
3. Don't incinerate it.
4. Don't impale it on anything.

As long as I follow those rules, I should be good. Also, my one is a hardpack. These are built for remote control vehicle racing, and are actually compulsory in this sport because they are the safest. Realistically, my biggest danger is shorting, and I've been pretty damn careful about making sure that doesn't happen - previously because of not wanting to destroy my microcontroller, but now also because of not wanting to have explosions. Also, the battery will be in a pocket made of 3.2mm leather, attached to a belt made of 3.2mm leather - so that's 6.4mm of essentially leather armour between me and any explosions. What? It makes me feel better!

Urk.

So anyway, my cow butt arrived. Thick leather is thick. Bring on the thumb callouses while I sew this stuff..

Also, I got a press release from the DEA this morning that says they have successfully extradited the ex-president of Guatemala to face charges of misappropriating Guatemalan tax money and laundering it through US banks. I realise that money laundering is illegal, but there are two crimes here - one is money laundering in the US, and the other is stealing vast sums of money from the Guatemalan people. It strikes me as odd that the US can (and will) extradite a person there for the lesser crime of money laundering, and then brag about it. It just seems.. arrogant. Especially in light of the HSBC thing. Just saying.

Comments:

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From:richdrich
Date:May 28th, 2013 10:38 pm (UTC)
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I'm assuming the battery is a semi-retail rather than OEM one (the latter are quite hard to buy, mostly because of the explody product liability issue).

If so you are probably quite safe if you use a factory charger and don't try to build your own charging system (which would be one of the hardest things to do in non-RF electronics). The other thing is to put a good old fuse inline close to the battery so any short isn't catastrophic (and take a supply of fuses with you).

But why LiPO - I thought they were for 100A drains into electric drills and the like? NiMH? Lead acid gel cell (old fashioned, but cheap and reliable)?
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From:tatjna
Date:May 28th, 2013 10:47 pm (UTC)
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Mostly because of the occasional decent sized current draw and requirement for it to last for several hours while burning out people's retinas, along withh being relatively lightweight and coming in a shape that works with my design.

If I find it's overkill, I'll investigate other options.
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From:richdrich
Date:May 28th, 2013 10:56 pm (UTC)
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Actually my bad, I confused LiPo with LiFePO4, which is the battery chemistry used for electric drills.
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From:tatjna
Date:May 28th, 2013 11:02 pm (UTC)
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Y'see, I don't even know what that thing is, so I'm glad I'm not using it. ;-)
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From:ferrouswheel
Date:May 28th, 2013 11:52 pm (UTC)
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Also, to protect against shorts, add a fuse - similar to what people suggested for my lead-acid wifi pineapple battery.
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From:richaarde
Date:May 29th, 2013 12:53 am (UTC)
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But explodey things are awesome.

Yep, our gumminit is arrogant like that. Sorry that our people keep putting assholes into power. *cringe*
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From:tatjna
Date:May 29th, 2013 07:44 pm (UTC)
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From a distance, yes. Attached to my body? Not so much. ;-)
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From:didotwite
Date:May 29th, 2013 05:05 pm (UTC)
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we've got a bunch o lipo.

they come with model helicopters. if you don't recharge them often enough they lose all life and we have to go get someone to put a new little one in their plastic bodies.

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From:tatjna
Date:May 29th, 2013 07:45 pm (UTC)
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Yeah, they seem to be quite fussy about how they're treated and charged. Battery technology is what's letting down pretty much every portable cool thing ever - but hopefully the advent of electric cars will kick development up a gear and we'll get something better soon.
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From:kehleyr
Date:May 29th, 2013 10:07 pm (UTC)
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I was eyeballing my one as if it was a bomb hah I don't blame you!
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