DIY Lithium Poly dive light

[Dale]

Very dense as to capacity.

3.3 volts per pack, two pack sizes (so far) at 10AH.

.307 x 2.835 x 7.17
.354 x 2.323 x 6.142

They require a circuit board to monitor charge/discharge. The board
comes in two flavors. One will equalize the discharge across batteries,
the other just monitors current in/out. Prices are $10 and $40.
Battery packs are $45.00 (or thereabouts). The circuit board has a
socket for a "fuel gauge" that will tell you the state of the pack with
five leds.

http://www.batteryspace.com/index.as...&Category=1085

http://www.batteryspace.com/index.as...OD&ProdID=3206
<http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3206>

http://www.batteryspace.com/index.as...OD&ProdID=3324
<http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3324>

http://www.batteryspace.com/index.as...OD&ProdID=3190
<http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3190>

[datamunk]

.....no idea. hah

[MadDiver]

DIY Lithium Poly dive light is not a good idea at all because Lithium Poly hates sea water and it can be dangerous in a dive ligh.

[Reg]

Originally Posted by MadDiver

DIY Lithium Poly dive light is not a good idea at all because Lithium Poly hates sea water and it can be dangerous in a dive ligh.

Wouldn't this be the same for NiMh/Nicad?

[Dale]

The trouble with any low internal resistance battery (LiPo, NiMh, NiCad) is that they have little internal resistance and when dead shorted (as in seawater) produce near infinite current until they explode.

The advantage of LiPo is extreme energy density. I made a wet cell NiCad pack some time ago, 6 volts at 35Amp Hour (180 Watt Hours). The canister was 6 inch PVC aobout 30 inches high. A 180 Watt Hour LiPo pack is 3 inches in diameter and about 8 inches long.

[NeveSSL]

Originally Posted by Reg

Wouldn't this be the same for NiMh/Nicad?

No, it is not. They are completely different chemistries.

The lithium batteries are very dangerous if not used correctly. Yes, they're used in our cell phones, laptops, etc., but to DIY stuff with lithium is very dangerous.

Check this video for a demonstration of what happens when you overcharge: Lipo Battery Fire

Unless you are experienced in dealing with these batteries (most likely from RC airplanes... thats how I'm familiar with them), then flat-out leave them alone as far as DIY goes. A LOT of people have lost homes and vehicles due to these batteries. They're not dangerous in and of themselves, they just require very special care that is not anything like NiCds and NiMHs and thats what makes them dangerous... the human factor.

Brandon

[marchand]

Lithium iron oxide (LiFePO4) would be what I would use. Doesn't have the explosive characteristics of lithium ion and good density as well.

[Doug B]

Originally Posted by NeveSSL

No, it is not. They are completely different chemistries.

The lithium batteries are very dangerous if not used correctly. Yes, they're used in our cell phones, laptops, etc., but to DIY stuff with lithium is very dangerous.

Check this video for a demonstration of what happens when you overcharge: Lipo Battery Fire

Unless you are experienced in dealing with these batteries (most likely from RC airplanes... thats how I'm familiar with them), then flat-out leave them alone as far as DIY goes. A LOT of people have lost homes and vehicles due to these batteries. They're not dangerous in and of themselves, they just require very special care that is not anything like NiCds and NiMHs and thats what makes them dangerous... the human factor.

Brandon

I also fly radio controlled airplanes. Brandon's right. Lipo cells can easily explode if not charged properly, and handled carefully. There are lots of videos on youtube. NiCAD and NiMH are a lot safer for the "average joe" who wants something rechargeable. You can get NiCAD and NiMH in 2500 mah cells - fantastic power, and easy charging.

Unless you have the proper battery charger and balancers, don't play around with Lipos.

[NeveSSL]

Should you choose to become familiar with them, though, I highly recommend the iCharger 101B. Absolutely awesome features for the price.

Brandon

[warscout2]

so lithium ion is not a good choice would a lead acid work well i know they are heavy but it could help me lose weight of my belt.