Powerpack for camcorder.

[TwoTeasChris]

(This is about batteries so there's no point going anywhere else on the internet!)

I am thinking of getting a camcorder with infra-red so our son/daughter can go out at night and take badger shots etc.
I suspect they will also need a 12v (CCTV) infra-red illuminator to get decent clips. Attached to a tripod maybe.

What would be a tidy and safe(!) way to make a light Li battery that they could take with them to give 12v for the illuminator and 6 (or whatever) volts for the camcorder? So they could leave them on for several hours. (Would be charged at Hyperion.)

Thanks John!

[Burgerman]

Need details. Of load. (watts, amps or whatever you know) And... Volts/amps of each part. But likely model plane lipo packs would be best.

I considered photographing "beaver" the same way... But didnt want to get arrested.

[TwoTeasChris]

DC power brick for cam is rated 8.4v 1.7a
Bottom of cam says 7.2v

Lamps say "Powered by DC 12V 500mA adaptor". (2 of them)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320534656029&ssPageName=STRK:MEWNX:IT#ht_4015wt_901

[Burgerman]

Any 3 cell cheap ebay lithium LiPo battery will do the lights. 12.6v full, at 3.5v per cell empty thats 10.5v. You dont want to go lower.
Any 2 cell LiPo will give a 8.4v full, 7v empty - will work the camera.

The best discharge voltage is 3.5 to 3.6v per cell. Use a cheap hobby battery checker.

[TwoTeasChris]

I don't know what to get.
http://robotbirds.com/catalog/index.php?cPath=63&osCsid=3de50979435eeb147a5b01d6578a22b5
???

Battery checker? To avoid going too low?

They plug into the little boards that came with the Hyperion. Is that it?

[Burgerman]

The checker lets you do a quick voltage check to make sure each cell is above say 3.5 so you dont ruin the battery.

The batteries all have a connector (a cell tap) that connects to the end of every cell. That connects to the "little boards" and it also connects to a checker.

Ebay, cheap chinese cells are all you need for your application. How many Ah do you need?

[Burgerman]

http://shop.ebay.co.uk/?_from=R40&_trks ... Categories

all 2 cell (2s)

1000mah is 1 Ah...

The biggest cheap ones are 5 Ah (5000 mah)

Cheap 30C 5Ah 2S http://cgi.ebay.co.uk/7-4v-5000mAh-30C- ... 27ae8bfe2a

____________

3S batteries

http://shop.ebay.co.uk/i.html?_nkw=lipo ... m270.l1313

5000 mah 3 cell cheap... Cheap are not brilliant but better than you need. But may not last very long. Maybe a year or so. http://cgi.ebay.co.uk/11-1v-5200mAh-20C ... 230fbbea22

[Burgerman]

http://shop.ebay.co.uk/i.html?_nkw=lipo ... m270.l1313

checker...

I have http://cgi.ebay.co.uk/FUSION-SMART-GUAR ... 4157b61b23 -- way better than you need!

[TwoTeasChris]

How is the voltage of each cell checked with just one wire each?

[Burgerman]

1 cell = 2 wires
3 cells = 4 wires.
5 cells = 6 wires.
My 13 cell powerchair headway pack = 14 wires.... Etc.

Look at the boards that came with the hyperion. The 7 cell slot has 8 wires... Same with connector 1 or 2 on the charger.

It goes neg, pos, pos, pos, pos, etc...

[TwoTeasChris]

Penny's first try with the camcorder and IR lamp. Still waiting for the Li battery so she had to lug a 12Ah Agm over a river, across a field etc. !
http://www.flickr.com/photos/pennyseverythingnature/5644988936/in/photostream

Her flickr photos are amazing.

[ex-Gooserider]

Nice photos... Neat to see, as I remember assorted badgers from kids books and such, but we don't have them over here, so hadn't really seen one before...

ex-Gooserider

[Burgerman]

Flicker has movies now?

Cool pics!

[TwoTeasChris]

Lithiums for lamp have arrived. (Camcorder has huge battery.)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290498141057&ssPageName=STRK:MEWNX:IT#ht_2493wt_1135

5 amp fuse?

Plug into the the 3s socket on the little board then to the front of the Hyperion. Then charge leads.

What settings for charging?

[Burgerman]

LiPo
4.2V and "continue"...
5 amp, or 10 amp shouldnt be a problem... 1C or 2C charge rate. 1 hour or 30 mins...
3 CELL obviously!
watch the voltages on PC -- AFTER the charge till all close to 4.200v, AND almost no amps, and choose cell voltages not pack voltage on graph settings!

And see how crap lead is!

[TwoTeasChris]

LiPo
4.2V and "continue"...

The only place to set V is for discharge.

[Burgerman]

4.200 is standard! You use the TVC to adjust the thing up ur down from 4.200v. So leave it alone!

TCS capacity can be set in 5 percent steps to charge to say 95 percent (to prolong battery life).

And store sets it to charge or discharge to 60 percent for long term (more than a week?) storage and then balance.

And Continue means it doesent stop charging and equalising the cells at the point where it says "done!...

Balance onl;y balances. Charge charges AND balances. You will see it doing it on screen.

You will work it out!

Timer off or the balancing and topping up, will end early.

Discharge volts needs to be about 3.5v per cell. Lower may damage them. Higher will not allow enough capacity.

[TwoTeasChris]

Theoretically,
If they dropped one (without a fuse) in a pond, would it kill the fish?

[Burgerman]

Nope.

[TwoTeasChris]

but it is interesting.

Is it normal for the cells to be so unbalanced in a new battery?

[Burgerman]

No, not unless its been sat for a very long time.

Next time (cycle it to 3.7v) it should be very level.

[TwoTeasChris]

I am draining it with the IR lamp to see how the cells fall.
After 1 1/2 hours cells are at:
4.08
4.04 This was the one that charged to 4.2 straight away.
4.08

Only needs to survive 4 hrs of lamp use so should be okay. And I have another one which is showing 3.9, 3.9, 3.9. Just need to fit connectors.

Will the voltage fall lineally?
Is 3.5v an okay minimum or should I be telling people to stop before then?

[TwoTeasChris]

Might get these:
http://cgi.ebay.co.uk/2pcs-2S-6S-Lipo-Battery-Alarm-Checker-Tester-LED-Buzzer-/120703761361?pt=UK_ToysGames_RadioControlled_JN&hash=item1c1a813bd1#ht_2256wt_1135

"You try to kill my LiPo, I scare your badgers."

[Burgerman]

Voltage drops fast at first for a few percent of the discharge. To about 4.1v Then stays pretty constant, and drops to about 3.7 at 80 percent discharge. At which point (at 1c) stop!

Then it gets to about 3.5 and drops off a cliff...

[TwoTeasChris]

I've ordered the alarmed ones. They are likely to unplug the lamp but forget to give the battery to me for charging. Will go off in their backpacks at 3.8v.

[TwoTeasChris]

Do they need float for battery longevity?

[Burgerman]

No the opposite! They want to be around 50 to 60 percent. Use the hyperion, choose "store"... Self discharge is usually ultra low... Years.

Before you do that use it - not the lamp! - to discharge and graph them to 3.5v...

Then charge by using "store" or charge fully. Both methods balances them too.

[TwoTeasChris]

I luuuuv LiPo.

If I were to fit a 6S 25.2 battery linked to the chair batteries, for extra range, would I need to fit a 'thingy that allows electricity to only flow in one direction that I can't remember the name of' to stop the AGMs charging the LIPos?

edit:
The only good thing about M.E. is when I open parcels that I have ordered I normally can't remember what they are. Prezzies every day!

[Burgerman]

They will not give extra range. The idea was that UNDER SEVERE LOAD the lead voltage will drop to the level of a 6 cell lipo which then helps with the amps... And yes you would need a big power diode. Or the charged lead acid batteries (which are at a higher voltage) will definitely cause you a fire / explosion!

If you want extra range use 8 lithium ion phosphate cells like the headway ones. They have a "matching" safe voltage.

[ex-Gooserider]

I've seen the scary videos about what a Lipo will do if it is abused, but in reality, how big of a hazard are they if you protect them from mechanical damage, only charge them with a Hyperion to appropriate values, and so on?

Is dealing with a Lipo pack like handling other sorts of hazardous objects that will bite you if treated carelessly, but are reasonably safe if you follow the recommended practices - or are you risking an explosion every time you look at them funny?

Would it be possible to build a reasonable powerchair sized system if the batteries were enclosed in some kind of fire / explosion resistant container - possibly with a means of dumping the container in the event of a disaster? (I.e using an "explosive atmospheres" rated electrical box - thick metal, tightly sealed, with only the wire connections passing through the box...)

I know that BM is using LiFe's for the Mk3, but how much of this is being extra cautious vs. a hazard that could be looked at as a reasonable risk? It seems that Lipo's offer enough energy density that one could do a chair that was able to have enough room besides the batteries to have both a functional suspension AND soft ATV tires...

ex-Gooserider