Pelican battery pack

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Archive 2009 · Pelican battery pack

Graham Mitchell
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p.2 #1 · Pelican battery pack

400d wrote:
You can however, build a pack with cells (http://tinyurl.com/yz9ykw3) in parallel connection:

Actually that can be a poor idea in practice. See 12.2 here, for example: http://homepages.which.net/~paul.hills/Batteries/BatteriesBody.html

400d wrote: I am wondering why would you need 400A?

I am planning to use a 5kW inverter, 12V.

I was hoping to be able to use a battery lighter than the lead acid ones I use in my current 1.5kW setup, but for heavy duty applications they still seem to be the only practical option.

Nov 09, 2009 at 12:53 AM

400d
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p.2 #2 · Pelican battery pack

Assuming the cells are from the same batch, I doubt it would be a significant problem, except the QC of the battery is really poor. The example shown under 12.2 is hard to achieve in the first place, 13.2V and 10.5V, that must be one really bad cell for its voltage to drop that quick under any load. From my experience, LiFePO4's voltage is very stable under load, usually around 3.2-3.3V.

There is no single cell (including Li-Ion) on the market which has a capacity of 60Ah and current rating at 400A. Since the 5kW inverter is already 30lb, there won't be much difference if you use 200Ah cells. If you can use 24V or 48V inverter instead, you will need only 1/2 or 1/4 amps of draw @ 12V.

Nov 09, 2009 at 08:09 PM

Graham Mitchell
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p.2 #3 · Pelican battery pack

400d wrote:
If you can use 24V or 48V inverter instead, you will need only 1/2 or 1/4 amps of draw @ 12V.

True, and I would prefer a 24V unit in some ways, but they are many times the price of the 5kW 12V unit I found.

Nov 10, 2009 at 12:23 AM

dmward
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p.2 #4 · Pelican battery pack

Have you done any field testing with this remote power source?
Given the size and ability to deliver reasonable recycle for an AB800 it would be perfect for a mobile rig.

Would like to hear your impressions after using it in the field.

Nov 10, 2009 at 09:55 PM

BSHuff
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p.2 #5 · Pelican battery pack

Just one random thought here. I used to race RC cars. We went through a TON of batteries, when ever a new higher capacity cells came out the old ones were 'no good' cause they were non-competitive. Plus they were top condition for a season or so, and would get relegated to practice use only. Why am I talking about this? If you can find a RC racer, you can find a source of 'bad' batteries that you could probably pick up at a nice discount. They have plenty of usable life left for this type use, you might loose 10 full power shots by using 'used' batteries. Big thing with NimH or Lipos is to keep them charged, and don't leave them in the closet for a few months.

Nov 11, 2009 at 04:46 AM

bacilonur
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p.2 #6 · Pelican battery pack

Hey David, I used it for about an hour on Saturday and it worked great. I was mostly around 150-220ws and recycling was plenty fast. I just did a max pops test with a B800 and I got 172 pops. That was during just 15 minutes, so you'll probably get at least 10% more in the real world when you're not shooting that fast and making the inverter work so hard--I know I tend to shoot around 100 frames/hour.

Recycle started at around 2.5 and ended at 2.7s right before it died, which is pretty good. The next test I do will be with a few monos plugged in at full and minimum power. With a replacement battery just $60 and 1.5lbs, it's a good idea to keep on on hand. I'm going to use velcro to strap the pack inside the case, so swapping ou the battery should take about 10 seconds.

Huff, that's definitely a good idea if all you want is a random pack to throw in a soft case or if you're looking to make your Vagabond lighter, but I'd rather pay the $60 so that I can get the most power per square inch.

Nov 11, 2009 at 06:30 AM

Alan Goldstein
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p.2 #7 · Pelican battery pack

That pack is very interesting. I only have Alien Bees B1600s. Would it work on those? I presume it would take five to six seconds to recycle to full power. I like the idea of it being small - perhaps just for when I need to run a single light on batteries at lower power for a few flashes. (I shoot interiors so I might have a battery unit hidden where it is hard to run AC.) But I also might want another unit with faster recycling and more capacity.

Would I get better performance (faster recycling) going to a heavier 300W unit? Are there similar larger cells for higher capacity batteries? (Although several small packs could be ok.)

Any advice is appreciated.

Edited on Dec 01, 2009 at 09:34 PM · View previous versions

Dec 01, 2009 at 04:02 AM

bacilonur
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p.2 #8 · Pelican battery pack

Hey Alan,

A B1600 recycles in about 4.8 seconds. With the PLMs and HOBD and the new 11'' reflector, 640ws isn't as necessary IMO. A pack this small works better with a B800, but you can easily make one a little bigger for the B1600. My third pack is a Pelican 1120 with a 9 12Ah D cell pack, yielding about 55% of the VB2's battery capacity. Two packs, two ABs, two Nano stands, and all the cables and triggers you need fit right in a 1510 w/ dividers. :-)

Dec 01, 2009 at 05:18 AM

Alan Goldstein
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p.2 #9 · Pelican battery pack

bacilonur wrote:
Hey Alan,

A B1600 recycles in about 4.8 seconds. With the PLMs and HOBD and the new 11'' reflector, 640ws isn't as necessary IMO. A pack this small works better with a B800, but you can easily make one a little bigger for the B1600. My third pack is a Pelican 1120 with a 9 12Ah D cell pack, yielding about 55% of the VB2's battery capacity. Two packs, two ABs, two Nano stands, and all the cables and triggers you need fit right in a 1510 w/ dividers. :-)

Thanks, I do need high power fairly often and I have several large Balcar battery systems for that. The advantage of the small battery pack is that it works on the ABs, is inexpensive, and I can have it available for occasional use - often way lower than full power. Such as inside a shower or as an accent light.

I never figured that a 180W inverter would be strong enough. But if you say so, I may build one. Again, you don't see much advantage in going with a 300W inverter considering the added weight?

Dec 01, 2009 at 09:55 PM

bacilonur
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p.2 #10 · Pelican battery pack

You can use a 300W instead, but then your all-up weight will be about 9.5lbs instead of 5.5lbs (using the same battery pack with a 180W inverter and a smaller Pelican). The smallest Pelican you can fit a 300W is the 1200, which is basically the same size as a VB2. Still half the weight, though.

Dec 01, 2009 at 10:45 PM

TomRittenhous
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p.2 #11 · Pelican battery pack

This thread has given me an idea. I have a Norman P808 which is a fairly compact pack system. So, I have been thinking of maybe making one of these units in a flat case that would clamp up to the bottom o the power pack, making it a 800ws battery portable unit. Since the Norman only has a 7amp circuit breaker it ought to work well in such an mode.

Unfortunately, it will be awhile before I have any spare change to do something like this.

Dec 01, 2009 at 10:47 PM

Alan Goldstein
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p.2 #12 · Pelican battery pack

bacilonur wrote:
You can use a 300W instead, but then your all-up weight will be about 9.5lbs instead of 5.5lbs (using the same battery pack with a 180W inverter and a smaller Pelican). The smallest Pelican you can fit a 300W is the 1200, which is basically the same size as a VB2. Still half the weight, though.

Thanks,

I'll may build the 180W unit with a small battery pack. I'll probably use a Rubbermaid type container. What stopped me from getting the Vagabond is that I already have a lot of battery gear that is big and heavy. But I might be able to justify a light weight unit.

Dec 01, 2009 at 11:12 PM

rickboden
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p.2 #13 · Pelican battery pack

This is an interesting project and thanks for sharing it. I am a big fan of Eneloop batteries and was wondering how well they might work in this. I believe the D cells are 5Ah. Too much weight?

Dec 02, 2009 at 01:56 AM

dmward
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p.2 #14 · Pelican battery pack

I have the components ordered to build one of these. They should arrive within a couple of days.
I am wondering were you got the larger capacity D Cell battery. That would be a nice option.

Dec 02, 2009 at 04:41 AM

bacilonur
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p.2 #15 · Pelican battery pack

Here are a bunch of shots.

This image is copyrighted by the owner

That other pack is the Pelican 1200 and the 12aH D cells I bought here: http://www.batteryjunction.com/tpeh-td-12000.html

They won't fit the 1050, but that 3x3 configuration fits the 1200 perfectly. Using 9 cells instead of 10 will yield 10.8v instead of 12v, but that fits within the 10-15v power range just fine.

Dec 02, 2009 at 10:05 PM

JohnJ
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p.2 #16 · Pelican battery pack

Is there a particular way that NiMh batts need to be configured? I've read/heard that they can discharge each other but I don't know how or why.

JJ

Dec 24, 2009 at 12:07 PM

bacilonur
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p.2 #17 · Pelican battery pack

No idea. All I know is when you make the pack, all the batteries have to be at the same level of charge or discharge, otherwise they'll charge assymetrically and your capacity will start decreasing. Also, they're standard NiMH cells so they lose around 5-10% of their charge after the first couple days and then around 1% per day. But unlike Li-ion and SLA, they like being discharged completely.

Dec 24, 2009 at 03:41 PM

lafashionphoto
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p.2 #18 · Pelican battery pack

Awesome freaking post! I'm going to have to do this myself...

I only use B400's now since the high output beauty dish and PLM system. I dont ever use any more power then 160 WS this is absolutely perfect.

Cant wait to build one! one light bag to whole battery pack/mono lights/camera? how perfect!

Dec 26, 2009 at 04:47 PM

tetrode
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p.2 #19 · Pelican battery pack

What a great DIY! Thanks for patiently sharing the details with us bacilonur. You've single-handedly caused a run on AIMS 180 inverters.

I'd like to ask about one detail: What did you decide to do about providing a charging port? Your original rough drawing included a port for the charger but I don't see it in the photos. Did you decide to just unplug the battery pack from the inverter an plug it into the charger?

My AIMS 180 has been ordered and I hope to duplicate your project.

Thanks again.

Dave F.

Dec 27, 2009 at 12:06 AM

bacilonur
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p.2 #20 · Pelican battery pack

Glad you guys like it!

Dave, I changed my original plan of having a small fan and a charging port for a few reasons:

The fewer connections and attachments you have, the fewer things can go wrong. I had originally envisioned something like a miniature Little Genny 400 pack that you wouldn't have to open up for any reason, but with how small, light, and cheap ($60-ish) a spare 5ah/12V battery is, it's pretty easy and convenient to pack a spare pack in case you need it, and it takes about 30 seconds to swap out the velcro and switch the connectors.

I was expecting more heat to be generated. In my tests, the battery barely rose above ambient and the inverter's air exit wasn't too hot. Come summer, I'll cut a hole on the other side so that the inverter's fan has an escape outlet going straight up (when it's hanging on a stand), so it should do fine in a hot environment.

And last, it would be really tight inside the 1050. 16awg cables don't fold that easily, so you'd have to be pretty meticulous about shutting it just right and getting all the cables folded up right inside. And then you'd have even less room inside for air to circulate so the fan wouldn't make such a big difference.

I may still work something out for a direct charging port on my bigger pack with the 12aH D-cells, as that has a lot more room between the pack and the inverter and on the side of the pack.

Oh, and something you guys should do differently from my first one (which I'm now in the process of changing) is using Deans connectors instead of Tamiya connectors. Deans are stubbier but come out smaller and easier to twist around in a tight space, and lots of RC'ers say they're much more reliable. Just a couple bucks to change if you already used Tamiyas. And if you're gonna put a fuse on the battery, get a set of mini fuse holders from Radio Shack, they're a bit smaller than your standard fuse.

Dec 27, 2009 at 03:57 AM

shoebox9
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p.2 #21 · Pelican battery pack

Cool stuff-

bacilonur, do you have a link to the pre-packaged 10x cell at www.cheapbatterypacks.com ? I can see the individual cells and the copper connetors, but not the pre-assembled and shrunk wrapped set.

Also, are you sure your current recycle speed limitation is the inverter and not the battery pack? I'm thinking of building a kit for fun, and am trying to figure out which batteries to use with a 380w inverter. I had been thinking two parallel sets similar to yours (or 10x D's), but now I'm starting to wonder if I'm underestimating these little guys. It's recycle speed rather than number of pops that interests me.

Dec 27, 2009 at 05:05 AM

bacilonur
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p.2 #22 · Pelican battery pack

Hiya Shoebox, you have to go through their custom pack form. Select 10 or 12 cells, double flat configuration, Elite 5000, 16awg, then female Deans or Tamiya.

All the data I've gathered on this project suggests that the inverter is the bottleneck.

I had a few discussions with Mike, the owner of CBP, and he assured me it could handle at least 5C (25A). Then I tested the inverters on my cigarette lighter and got the same recycle time. And my times are basically the same as the original Vagabond 150W, which all matches up.

Running two packs in parallel or series (to get 24V) would work fine as long as you charge them separately. For a 380W inverter, a single 12aH D-cell pack should work fine. Depending on the size of the case you've got, you can use anywhere from 9 to 12 cells for a 12V inverter.

Dec 27, 2009 at 08:02 PM

shoebox9
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p.2 #23 · Pelican battery pack

What size are the Elite 5000 cells (ie similar length to AA's but twice as fat)?

Also, I wonder how much the inverter in the Vagabond II weighs, and what it's dimensions are? Obviously it can handle quite a bit of current, but the heavy SLA (and the fact you are always carrying the charger), make the VBII a lot heavier than it needs to be.

Dec 27, 2009 at 10:26 PM

supergimp
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p.2 #24 · Pelican battery pack

Really great stuff here, guys. Thanks bacilnor for sharing all this. I really dig the DIY stuff and how you can tailor it for your own needs. I'm curious as to your thoughts about the value of this solution. I've been planning the purchase of a Vagabond II for awhile now, but this DIY solution is really enticing (and looks like a fun project). However, when I look at what I need, I'd like to be able to power at least 2 AB800's in the field and while I know I could do this with a VBII (and even three in a pinch), I would need two (or three) of the DIY packs to achieve the same result. At about $180 ($60-battery, $100-inverter, $20-case and misc parts) do you guys feel the size/weight advantage of the DIY pack is worth the extra expense to get the capacity (assuming I'd have to build at least 2 DIY packs vs. 1 VBII), and how would the capacity of two lights on their own DIY packs compare with two lights on one VBII?

I really want to dive in head first and build a couple of these babys, but the $299 VBII seems like a lot for the money and even more so when compared to doing the same task with the DIY pack.

Dec 27, 2009 at 10:42 PM

bacilonur
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p.2 #25 · Pelican battery pack

Sub-C's are a little shorter than AA and yes, almost twice as fat: http://en.wikipedia.org/wiki/List_of_battery_sizes

The VB2 inverter weighs about 5lbs, which is heavy for a 300W unit. You can get an Aims 600W unit in about the same size and weight.

Dec 27, 2009 at 10:43 PM


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