NEED Uber powerful Li-Ion pack

[Flashanator]

Need some help with getting the lightest & smallest Li-Ion setup to power a 1000w (28v, 35a) Light. I want serious runtime, well over an hour. If the pack is over 12kg then I wont worry. But I want as much (ah) as possible.
I kinda thought about using 8 (12kg total) Li-Ion Cylindral Cell: 3.7V 60 Ah

Would 60ah give good runtime? Maybe I could make it into a backpack. Im use to 12kg weight.

Any other suggestions. Think NiMH would be way too heavy.

 

[IMSabbel]

I wouldnt take that cell.
I personally am not one of those "OMG lithium-ion it will explode" crybabies.
But you will be dealing with about a Kg of pure lithium side. Thats enough to cause quite some problems, potentially.

If i were you, i would scavange DeWalt 36V battery packs using safe A123 cells.
One of them is 36V 2.4 Ah and about 1Kg.
So you need two of them instead instead of one of the BIG batteries you mention, but it would still half the price.

take a look here: http://www.rcgroups.com/forums/showthread.php?t=587606

 

[DM51]

A pack made from 18650s would probably be the cheapest way to go. 8 cells in series would give you 28+V, and then you just work out how much run-time you want, to see how many parallel stacks you would need.

For example, assuming 2,200mAh per cell, to get 1 hour at 35A, you will need 16 cells in parallel. The configuration would therefore be 8s16p. For 2 hours, 8s32p.

That's a whole lot of cells (128 of them per hour of run-time). I would be very wary indeed about using Li-Ions like that. All you need is for a few out of the 128 to go wrong…

You should consider safer chemistry like Li-Mn or A123. Bigger, but safer.

 

[SilverFox]

Hello Flashanator,

I think you can get around 1.5 hours of runtime if you build a pack using 4 of those cells in series. You will want to make sure you have an adequate protection circuit that will work at the loads you have.

Your problem is going to be finding a charger. The 4S configuration is no problem, but finding a charger that will charge in the 12 - 60 amp range may prove difficult. The Schulze 10.36-8 would probably be OK, but you would be looking at around 8 hour charging times, and it is best to charge Li-Ion chemistry attended.

Another option is to use a 4S Li-Po 3700 mAh pack and parallel 10 of those to get your 1 hour run time.

Interesting project...

Tom

 

[IMSabbel]

A Li-Po pack that with 1kWh?
I wouldnt want to drop that light

 

[Mark620]

so you are not against spending over $4000.00US for a battery pack?

 

[Mark620]

If I were you I would seriously consider 3 car batteries.

 

[lasercrazy]

How about 2 of these in series? http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4151

 

[Flashanator]

Thanks for the suggestions.

Would it be possible to get a custom made single 1 peice battery? 28v 50-60ah?

 

[DM51]

LuxLuthor makes Custom NiMH Battery Packs, but I don't know whether he might consider doing something like this with Li-Ion cells. You could do worse than ask him, in that linked thread, or by PM.

Those Li-Po packs suggested by lasercrazy might be your best bet. They look pretty good, and have built-in protection circuits, but $995.50 each.......!

 

[Flashanator]

Hi,

Say with two of those in series (29v, 50ah), how much runtime can i expect just before it starts to dull down in brightness? I guess by then it would start to damage the Li-Ion pack?

thanks

 

[karlthev]

Hey Flash, why doncha get in touch with LuxLuthor, I'm sure he'd be happy to build you a $40,000, 800 pound powerpack! Better yet, invest in a 100 foot extension cord---Helluva lot cheaper and runtimes like you won't believe! Get 'em at Lowe's or Home Depot.:devil:



Karl

 

[LuxLuthor]

 

[paulr]

I think I'd look for a way to use the 36V DeWalt pack directly, without taking it apart.

 

[Flashanator]

But can I trust LuxLuthor?

He might slip some Kryptonite in there & Im done for.

 

[karlthev]

Nah, trust 'em with your life--others certainly have!:devil:



Karl

 

[LuxLuthor]

What's a little Kryptonite among friends?