Guidelines for using a high power incan

LuxLuthor

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Guidelines for using a high power incan & Elite 2/3A Performance Graphs

I'm starting this topic mainly because I received several PM's asking questions about the recent Mac 7,000 lumen 15 cell (Elite 2/3A 1500mAh) NiMH pack in this sales thread, and didn't want to post all this general guideline information in his sales thread.

It is important to recognize that when you move into a 15 cell battery pack, powering a 10.5Amp custom hotwire (64458) light, that you are crossing into the land of the Radio Controlled ("RC") hobbyists in terms of battery pack size, voltages, current, performance, and charging needs....so it is useful to consider (if you can afford it) upgrading your charger and take better care of the batteries. Here are some general guidelines that may be of use to those from that thread, and others who may be interested.

A Buyer In This Thread said:
Hi Lux,
I'm new to the modded mags. I hope you wouldn't mind a few questions.

I got one of the 7000+ Lumen 3" Hotwires from mac. What charger would you recommend for the battery packs you made for these? Would the Hyperion 1210i be a good choice?

Does the charger stop charging when the pack is full (at the end of a cycle), or do I need to monitor it and stop when the pack is warm?
Is it necessary to rest the cells for an hour before using them to avoid flashing the bulb?
The cheapest is to use one of the chargers like this one which goes up to 18V (nominal voltage of your pack) although I would prefer a charger that you can set at a lower charging current than this 0.9 Amp rate for these cells. It will shut off when done, but with this "economical" charger, you will not be able to "bathe the cells in a low 0.1 to 0.2 Amp charging rate" which helps to equalize the voltage among each of the cells every 10-15 charges, resulting in a full, proper charge.

To get more control of your charging, you are now moving into the so called "Hobby Charger" category used by the Radio Controlled crowd....such as the Triton-2 here or I have been using the Hyperion EOS-1210i (towards bottom of page). You have to ask yourself if you are likely to "grow" in this hobby to justify getting a better quality charger. This light has a 15 cell pack, and some of the cheaper "Hobby chargers" cutoff at charging 12 or 14 NiMH cells...so if you want a better charger, you are stuck paying $125 to $175 to get one that will work.

Most NiMH cells will charge up to 1.5V at their peak, and then when full, their voltage begins to drop which triggers the end of charging for the charger.....i.e. most NiMH chargers sense a drop in voltage of 5-7mV per cell as the sign that they are full, and shut off charging. They will get warm/slightly hot at the end of their cycle.

The drop from 1.5V per cell (15 x 1.5V = 22.5V) down to a more stable 1.43V/cell occurs in minutes (15 x 1.43V/cell = 21.45V). These cells will drop under 1.4V per cell in several hours until reaching a more stable "resting voltage."

When you look at my bulb testing here, and take into account the 150-200 milliohm resistance from the flashlight and batteries, you will likely end up dropping another 1.5-2 volts into the 19-20V range to put you in a safe non-flashing range if you wait about 30-45 mins after charge is complete before using.

The main thing to pay attention to when using "high current" cells is how they perform under load....in other words, how well do they hold a decent voltage, and for how long. These Elite 1500mAh cells have a testing profile at cheapbatterypacks.com listed here, which shows their voltage curve over time when subjected to a 20Amp load. The bulb in this light (Osram 64458) is using a 10.5 Amp load, so your performance will be better than this graph, but you have to be realistic in your expectations of run time. Here is how to figure that out.

If a 1500mAh cell can deliver (optimally) 1500mA (= 1.5A) for an hour, then it provides twice as much current 3.0A for 30 minutes. It would give 4 times as much current (6A) for 1/4 hour, or 15 minutes. If 6 times as much current (9A) was needed, the battery would only last 10 minutes....so in this example where the 64458 bulb requires 10.5Amps to light up properly, that is 7 times the nominal 1.5A rating, and will have that higher amp rate sucked out of it in only 60/7 = 8.5 mins.

Now realistically, you are not going to be able to get every last stored mA out of any battery, so a more realistic total run time would be more like 6 to 7 minutes. So this is a "WOW" light, rather than a practical, long duration type of light...and you should treat it as that.

It is also important to not run it continuously because the heat builds up from the batteries being stressed, as well as the light filament heat which in some cases has damaged the coating on some brands of reflectors. I recommend that you use this is 20-30 second bursts, and let heat be your guide (feel the head/body--and stop when uncomfortable). Also, to protect the batteries from over-discharging it is best to stop using the light when you see a noticeable drop in output...which should be at about 5-7 minutes of run time.
 
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puzzl3

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I was just wondering is it possible to get a custom battery pack for this light 7000+ lumens mac's torch that can run longer than 15 x Elite 1500 mAh?
If it's available, how much for each? Thanks
 

LuxLuthor

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I was just wondering is it possible to get a custom battery pack for this light 7000+ lumens mac's torch that can run longer than 15 x Elite 1500 mAh?
If it's available, how much for each? Thanks

It is not possible because for this light (Osram 64458), you need the 15 cells to get the higher voltage, and a cell that holds up to the 9-10 Amp draw rate. Lastly, the battery source needs to fit in a relatively small package.
 

DM51

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This thread was posted at a time when I was away over Easter, so I missed it until now.

Excellent advice, Lux - I've added it to the "Threads of Interest" sticky.
 

LuxLuthor

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Thanks DM, and a belated Happy Easter to you!

I thought I would discharge test some of my new Elite 2/3A 1500mAh cells, and see how it relates to this example 64458 bulb. I used Elite cells that I got last month from CBP, and charged them 20 in a row with magnets connecting at 0.8 Amp until my Hyperion 1210i terminated charging from a dV drop of 5 mV. The Hyperion reported slightly over 1500mAh put into the cells, and they do get hot (115+°F)

I rested the cells for 45 mins, then did two runs at a selected discharge rate to seek some correlation. Note: these cells have not been cycle conditioned or given a forming charge (0.1C x 16hrs), so as to simulate how they would behave to an average user upon purchase.

They all started at 1.43 to 1.45V, and terminated at 0.7V, after which they sprung back up to 1.25V within a minute. The various discharges did not get as hot (100°F) as during end of charging.

First a combination of 8, 8.5, 9, 9.5, & 10 Amp discharges:

Elitecombo.jpg


Then these are thumbnails of each discharge rate, showing comparison of two cells done:




 
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LuxLuthor

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Observations:


  • 1) Note that my tests are not as optimistic as the 20Amp chart posted at CBP from my first topic. There are also variations between cells. This may in part be due to not having conditioned the cells, but more likely it is "performance hype." Only way to be sure is to check again after some conditioning.

  • 2) It appears that with the various discharge rates, a practical voltage under these demand loads is about 1.10 Volts, and about 1100mAh of capacity before voltage drops below 1.0V per cell.

  • 3) When we apply this to the 64458 bulb in this thread where Mac's light uses 15 of these cells, the effective voltage is 15 x 1.1V = 16.5V without considering further voltage drop from setup resistance. Looking at my destructive test chart here, you can see the operating range of this 16.5V setup.
It will use about 9.25 Amps, and you can go over to the AWR Hotrater lumen prediction, or my yellow column for possible bulb lumen ranges. This should last about 7 mins.​
 
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LuxLuthor

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Re: Guidelines for using a high power incan with Elite 2/3A Performance Graphs

I'm now a lot more certain in my previous performance plots listed in the graphs two posts previously. I condition charged 10 of these cells at 0.1A x 15 hrs; waited an hour and discharged to 0.9Volts. Then waited 45 mins and charged @ 0.7 Amps. Then after an hour ran these cells at each discharge rate again, and replaced graphs above.

The above graphs now show the first (black line) of 3 tests as the cycled & conditioned cells. You can see there is very little difference, so I believe these are the actual performances that you will see from the Elite 2/3A cell. Just added a 20Amp to see how close it is to the CBP "optimistic" graph posted on their website here.
 
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AzN1337c0d3r

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The 20A graph link is broken, Lux.

Excellent post as usual. This post pretty much sums up all the data I've been looking for on the Elite 2/3A 1500 mAH cells for the last couple of weeks.

It is interesting to note the conditioned cell did so poorly on the 8.0A test but seemed fine on the other loads?
 
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LuxLuthor

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I was still running more cells at the 20A rate to see if any of them gave better graphs that the one I included above. They were all virtually the same. Refresh page, you will see it now.

I asked Silverfox to look at this and sent an email to Mike @ CBP to get his feedback since my results are so different from his website. I am stunned by these results compared to what I had expected, and what has been represented.

I repeated that 8Amp test with another conditioned cell (from same batch of 10), and got same result.

All these tests started with 1.43 to 1.45 Volts when connected to CBA-II
 
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LuxLuthor

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Well I have good news and bad news. Talked to Mike @ CBP about my graphs, and he immediately responded that it is due to the problems with the CBA-II design. Basically the CBA reports lower voltage because the discharge load and voltage measuring leads are the same, and as such this CBA-II is at best a hobby tester that is most useful in comparing one set of readings to another, but not in obtaining actual, objective measurement data.

I have looked at other battery capacity testing setups, and indeed they do have one set of leads to discharge the load, and another to measure the voltage...so now I am not sure of any of my CBA-II readings...above, as well as the safe lithium battery profiles I ran.

Checking on some other alternatives which I may invest in.
 

AzN1337c0d3r

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Well I have good news and bad news. Talked to Mike @ CBP about my graphs, and he immediately responded that it is due to the problems with the CBA-II design. Basically the CBA reports lower voltage because the discharge load and voltage measuring leads are the same, and as such this CBA-II is at best a hobby tester that is most useful in comparing one set of readings to another, but not in obtaining actual, objective measurement data.

I have looked at other battery capacity testing setups, and indeed they do have one set of leads to discharge the load, and another to measure the voltage...so now I am not sure of any of my CBA-II readings...above, as well as the safe lithium battery profiles I ran.

Checking on some other alternatives which I may invest in.

Im not quite sure why having the voltage measuring device and discharge leads together is a big problem, unless the discharge leads are sufficiently thin to be adding significant resistance to the setup. The CBA-II specs themselves claim to be able to measure up to 40A of current, but there is no mention of accuracy, but I would hope it shouldn't be >25% error ((1.2 - .95) / .95) that you are getting when compared to CBP's graph.

According to CBP's measurement data, the Elite cells hold ~1.2V under 20A load. Ohm's law dictates that they have an internal resistance of ~60 mOhms.

The CBA-II has 13 AWG wires. According to this data chart (http://www.mwswire.com/barecu5.htm), 13 AWG wires have a resistance of 2 mOhms per feet.

You would need 7.5 feet of leads to generate a 25% difference in measurement between measured and actual voltage.

Can you perhaps describe more of your testing setup so that we scrutinize the problem in more detail?
 
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Action

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A quick question. Would you recommend the Hyperion 1210 for a 30 cell pack? I've been thinking a bit about building a 36V light, but I've only got a Schulze which can't charge that many NiMH cells. Any other high capacity chargers out there with greater than 30 NiMH cell capacity?
 

SilverFox

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Hello Action,

The lower end Schulze chargers top out at 30 NiMh cells, but the Next 7.36-12 will charge 36 cells...

Tom
 

SilverFox

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Hello LuxLuthor,

Interesting comments from Mike...

He is partially correct, but is only presenting part of the story.

I ran into the same discrepancy when checking out the CBP 1650 cells. I couldn't get anywhere near the values he was getting with his testing.

There is some resistance in the CBA leads, but you can measure that and adjust your data to eliminate that. At 20 amps my set up reads 0.27 volts low. When I export the data to my graphing software, I simply adjust the voltage when I run tests at higher rates.

When I was checking out the CBP 1650 cells, Mike told me that he was charging them at 2C, then immediately discharging them at the moment the charge was completed. When I ran a set of tests following his testing procedure, my results were very comparable to his.

In the RC world, it is common practice to use cells "hot off the charger." However, in our use, we usually end up with the cells resting a while. Hot chemistry performs much better than rested cool chemistry.

If you want to match his results, follow his testing procedure and factor in the voltage drop with your set up. I would bet that your tests will end up very close to his.

Tom
 

LuxLuthor

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I'm looking at getting the Competition Electronics Turbo GFX 35 which he uses. He did also mention testing with cells hot (lower resistance). I did measure with DMM while discharging and found higher voltage than CBA was logging. Don't know if I want to buy into the "test em hot" since that is not going to be the real world use, but I like getting a more accurate set of readings...and hey, what's another $425 ?
 

Action

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Hello Action,

The lower end Schulze chargers top out at 30 NiMh cells, but the Next 7.36-12 will charge 36 cells...

Tom

Thanks for the info, but the specs I've seen on the Shulze chargers indicated a max of 25V, when 30 cells are in the 36-40V range. Can you confirm that the last version of the old 6 series can do 30 NiMH cells?
 

LuxLuthor

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A quick question. Would you recommend the Hyperion 1210 for a 30 cell pack? I've been thinking a bit about building a 36V light, but I've only got a Schulze which can't charge that many NiMH cells. Any other high capacity chargers out there with greater than 30 NiMH cell capacity?

That was the reason I got the Hyperion 1210i. I have a Larry14K spotlight that has 24 x SubC NiMH cells that it works perfectly. It does have the capacity to do up to 30 NiMH cells.

If you are going to use a higher number like that you should get a beefier 12V power supply. I started with a 12V Pyramid 12 Amp continuous output, and it could not keep running with the power required at my charge level. (It would overheat the PS and shutdown to protect itself). When I upgraded to a 13V 20Amp PS, then no problems.
 
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