IMREN IMR 26650 Batteries, are these the biggest tubular batts?

[Alaskan]

OK, I saw that on some batteries, a pulse current rating which was much higher than constant. I've been scouring the net looking for a 4 X 18650 parallel battery holder, found one but not sure it can be used, the current rating would need to be much higher than it was designed to be, from the looks of it but if I remove the module and make my own contacts to the case, maybe it can work:

Spark 18650 CR123A Battery Holder USB Charger for SX5 Headlight | eBay

 

[RYDorDIE278]

I think the NCR18650pf will be suitable for your application, they are rated for 10A constant drain but myself i would take it easy and not drain 5A or more out of them to keep them cool and prolong there life, im not telling you to get them im just saying to consider them, I have purchased them from bangood at cheap prices and although i was sketchy they all turned out fine with similar weights and exactly the same voltage upon arrival, the Internal Resistance of them were all quite close although i only checked the IR with OPUS dreamcharger, again i am not telling you to get them from Bangood im just sharing my experience
Happy TrailZ.....

EDIT: If you find some good battery holders that are not rated for the AMPs you need you can always put a blob of solder on poor positive terminals put Larger wires leading from battery holder and do a "copper braid" mod to the springs to decrease resistance etc,
if you know what your doing...

 

[Alaskan]

It would be much easier for the machinist I am working with if the diameter of the host is smaller, but the current draw is so high I am afraid if I make it any smaller (for the handle) than four 18650s in parallel, with two sets of them in series to produce 7.4 volts, the run time will be fairly short before a recharge is needed when pulling 18 amps total current.

Having four of these batteries wrapped in a bundle in parallel would be under 40mm diameter, the host adding more diameter. I'm perfectly happy with up to a three inch diameter host, perhaps larger, and a 40mm battery pack is just over 1.5 inches, small to me, very small. I was considering using a four inch diameter lead acid cylindrical battery in another IR host I want to build someday, so the size of this builds battery pack seems very moderate to me.

 

[rhd]

Consider this type of config:
Solarstorm L3 7xCREE XM-L2 U2 CW/NW LED 6x18650 5000-Lumen Stepless Brightness Flashlight_Blackshadow_Electronics Wholesale - Powered by ECShop

Or, switch up chemistry, and use 3x of these in series:
A123 System High Power Nanophosphate LiFePO4 18650 Rechargeable Cell: 3.2V 1100 mAh, 30A Rate, 3.52Wh
In a carrier like this:
DRY 3x18650 Battery Carrier_Torch Host_Torch Components_Electronics Wholesale - Powered by ECShop

EDIT:

You wouldn't even need three, just two would possibly be fine. Looking at the voltage curve of an NDG7475, you're at 5.3V @ 2.5A.

Two of these in series would give you 6.4 V nominal:
http://www.batteryspace.com/A123-Sy...O4-26650-Rechargeable-Cell-3.2V-2500-mAh.aspx
and would handle 120A, lol

You'd want to investigate this further, but it looked to me that, based on the discharge curves I found, you'd see at least 5.8V through most of the LifePo4 discharge cycle.

That leaves 0.5V of overhead for the buck, which should be fine if it's a decent buck.

 

[Alaskan]

I like it, 30 amps each, I'd be far under that for current draw from each battery, but I wanted at least 5000ma total capacity as a minimum, twice that is where I'd be happier. If I could find a battery holder for those allowing four or more in parallel, as long as the machinist doesn't have problems from the diameter, that could work for me. Maybe I can get him to build a battery holder which can take four or five of them in parallel with another set in series to bring the voltage up to where I need it, but six of these in parallel and doubled up (2 packs in series) would be better as far as capacity.

Edit: I just found a photo of a nice looking 4 battery holder out of a EYE40 flashlight, if I can use this, or something like it with big enough contacts between two packs when in series, I might be in business, providing this isn't too big for the milling equipment being used to build the host:

Only problem with this is that I found the price of the EYE40 flashlight is too high to buy even one much less two to use the battery pack from. If I can buy a replacement battery holder for one, then maybe I have found one, it looks really good to me, even if I have to solder on top of the circuit board traces to thicken them up for higher current, providing there is enough space to do that.

 

[rhd]

Here's yet another option to consider (and probably the way I'd go). How about using a 14.8V Lipo?
ZIPPY Flightmax 2200mAh 4S1P 20C (USA Warehouse)

That guy can handle 44 Amps constant, 55 to 66 Amps burst.

Plus, it's 14.8V nominal, and 12V at it's lowest discharge. So you can use 1 driver per 2 diodes in series. That makes your driver setup more efficient, because your current sensing/switching/inductor resistance losses are divided in half (only incurred once per two diodes).

If your machinist can make the body tube fit a 33x35 LiPo, that's the route I would go
If you need it a bit smaller, this one is 34x23
http://www.hobbyking.com/hobbyking/...y_1800mAh_4S_20C_Lipo_Pack_US_Warehouse_.html

Remember also, when comparing capacity with this setup, you need to double the capacity if the LiPo pack in your head for comparison purposes, because this setup drives 2x diodes in series on each driver, and thus pulls half as much current from your cell. So a 14.8V LiPo in this config will drain half as fast as a 7.4V set of 2x Li-Ion cells of the same capacity driving 1x diode per driver.

 

[Alaskan]

Thanks, I was looking at some packs much like that on ebay earlier today. I like the way the wiring is simplified if I just use the regular driver which comes inside of each of the DTR modules, but their is a price to pay for that, I believe the duty cycle of the DTR 520nm 1.3 watt output laser diode module is limited due to the driver inside getting too hot if on too long, regardless of how well you have the module heat sinked. I will mum this over for awhile, appreciate the help, maybe I should go with a driver like you suggest, if I can find the right one, I have seven diodes to drive at 2400ma each.

I understand what you are saying about how the pack you show is really twice as efficient when driving two diodes per driver.

From all of the help I have received in this thread, it appears using 18650 batteries in parallel produce more capacity for the diameter than any other battery or combination of batteries I can get. If anyone can clue me in to something better, please let me know. I prefer a cylindrical battery holder over battery packs of other shape. I can find cylindrical battery holders, but so far none I have found are high enough quality for high current.


Edit: The high quality EYE40 holder I thought might work produces more voltage than I wanted because the batteries aren't all in parallel.

Edit again: I have an idea, I can combine three of these: http://www.batteryspace.com/A123-Sy...PO4-18650-Rechargeable-Cell-3.2V-1100mAh.aspx using a 3X battery holder but make three tubes each holding three of these batteries in parallel with each tube holding two or three in series. This would produce plenty of voltage as well as current for a high power portable laser.

 

[Jstr]

I may be wrong, but I think it would work to simply drill four 18650 sized holes in the host rather than one big one if u see what I'm saying. The machinist would need to ensure that the positive battery contact touched all four batteries, and it would be easy to make the negatives all connect to the tailcap.

I believe this may be simpler.

It would look like this from the negative battery view except with some space between the smaller circles.

 

[Alaskan]

I like that!

 

[LarryDFW]

There are some new "power 18650" cells that I would use .

They are the Samsung 18650 cells with 2500mah capacity and a 20 amp current rating.

These would work with three in parallel and not require such a large diameter . .

LarryDFW

 

[Alaskan]

Looks like I am going to use 3 x 18650 batteries in parallel, could use more capacity than 2500ma, but the current drain is great for those.

Edit: I found a ebay seller: hkequipment, who will sell some 4 X 18650 holders which appear to be high quality. Although NOT in parallel from what I see in the photo. Maybe they could be modified for that:

$48 for two.

 

[Alaskan]

Recently obtained a laser pointer which uses the 26650 battery and looking for a good battery.

What is the highest capacity 26650 battery which will maintain its voltage the longest under a moderate load of 10 to 15 amps? Right now I only need 5 amps without much voltage drop but will need more draw later for another project.

Looking around the net, there are numerous remarks about batteries having bad specifications, unable to meet their claims. The two which do, such as Sony and Panasonic, do not make 26650's. So far, through my searches online it seems the higher capacity 26650's are not always the best for maintaining voltage.

Appreciate more than one recommendation, thanks!

Edit: This Bestfire 26650 60A 6000ma battery looks interesting but I don't believe their capacity claims:

http://www.ebay.com/itm/2-Purple-Be...0A-Rechargeable-Battery-6000mAh-/181584480456

 

[VisibleGreen]

I think 26650 and larger batteries are still new territory for laser hosts afaik. I have a lot of potential hosts that I could offer to this fine community but lack the funds to start out a business.

 

[IWIRE]

People go "gaga" over 32650s because they sound great from a dick measuring perspective

:crackup: Ok. I've missed this place. You still make me laugh. If Alaskan hadn't sent me a PM with a link to this thread I would have missed that.
Thanks to both of you :beer:

I made a New Years resolution to stop working my life away and find a balance. Hopefully it works out for me and I can get back to building and having some fun. So far so good. They wanted me to work this weekend, I said "Suck my see above quote" LMAO !

Good luck with your build Alaskan, hopefully the info I finally sent helps. Your build sounds really interesting !