OT - portable 12 v power / charger

[donradick]

OT topic, but probably useful for the boom box builder projects.

I've got a portable project idea that will probably use 12V dc computer fans.
Looking at options, and I have rapidly come to the conclusion that I want to use commodity
power cells (Li-ion? / Lipo?) and a commodity charger - that should provide the best
cost/performance for the project.

But I'm unsure which way to go - use 12v cordless tool batteries and chargers,
use Drone Lipos at 11.7 V, or use cell phone 3.7v batteries in series.
I'm guessing that I'll want maybe 7-9 Ah total capacity, maybe more or less.

Any advice on cheap(ish) components?

Don

[Whitneyville1]

DO NOT use Li-Po/Li-ion cells without protective circuits on them, and you MUST use a rather expensive Li-Po charger. The fire/explosion danger is very real. Be safe and use either NiMH's or a sealed or gel lead-acid batteries as they aren't nearly as volatile. You CAN use "12 volt" (11.1 V actual ) Li-Po power tool batteries and chargers, but if you draw current from them faster than the battery is designed for, or run it "dead", the danger of fire or explosion returns. Several European countries have banned Li-Po's in cell phones and laptops and use the MUCH more expensive FeLiPO3 batteries.

[donradick]

Thanks dude.
I'll drop any LiPo efforts. This device will be portable, so weight is a big consideration.
Maybe NiMH is the way to go, since air-travel folks are so concerned about Li-Ion batteries.

I see now that NiMH 12v packs and chargers are pretty cheap.
Hm,, also found some "TalentCell" Li-Ion 6000mAh packs and chargers on Amazon for about $30.

[Millstonemike]

DO NOT use Li-Po/Li-ion cells without protective circuits on them, and you MUST use a rather expensive Li-Po charger. The fire/explosion danger is very real. Be safe and use either NiMH's or a sealed or gel lead-acid batteries as they aren't nearly as volatile. You CAN use "12 volt" (11.1 V actual ) Li-Po power tool batteries and chargers, but if you draw current from them faster than the battery is designed for, or run it "dead", the danger of fire or explosion returns. Several European countries have banned Li-Po's in cell phones and laptops and use the MUCH more expensive FeLiPO3 batteries.

What he said ...

unless your really into battery technology. I'm currently using an 18 aH, 6S (~22v) LiPo pack for my boombox. It has 60 individual cells and a computer charger with DIN9 connector to "manage" each cell via the battery management electronics in the pack.

So if weight is an issue and LiPos are ideal for that, may I suggest a off-the-shelf system such as show below. One of many to be had but beware fleabay and the like for overstating capacity and suspect quality - battery mgt. A good 18 aH sealed lead acid battery and SLA smart charger will run you about the same amount. If you decide to go lead-acid, I can point you to my go-to battery/charger combo.

[donradick]

Thanks Mike -

for my design, it looks like a 8 oz Li-Ion battery will be perfect, but I don't know how much run time I'll actually get until I build
a lab unit. Good to know there are high capacity alternatives if I need more runtime.