Alkalines versus rechargeables in portable flash

[rodeo_joe1]

<p>There was a bit of a debate in a previous thread about whether the higher voltage of alkaline batteries affects the output power of battery-operated flash units. This prompted me to do a bit of checking, so I tested 10 assorted flashes, fitting them with fresh alkaline primary cells and with rechargeable cells to see if there was a measurable difference in output. I used Shepherd FM-1000 and Quantum Calcuflash meters to measure the light output, with the following results:</p>

<p>2 cheap old (late 1970s) Miranda/Hanimex hotshoe flashes showed 1/3rd of a stop difference in output, with the higher output from the use of Alkaline cells.<br>

1 equally old Toshiba hammerhead gun showed the same increase in power of 1/3rd stop.<br>

7 samples of more modern (post 1980) flash from Canon, Nikon, Sunpak, Nissin, National, Osram and Metz showed no variation in power between using Alkalines and rechargeables.<br>

The recycling time of all the flashes was noticeably reduced by using rechargeable cells.<br>

Where there was an increase in power, it quickly faded after using the disposable cells for a short while.</p>

<p>My personal conclusion from the above is that the use of alkaline cells doesn't significantly improve the output power of flashguns, if at all, and that the extra expense of disposable batteries certainly isn't worthwhile.<br>

I still have a few more old strobes lying around that I haven't checked yet, but I suspect the results will be similar.<br>

Perhaps others might like to check out any strobes they have available and post their findings?</p>

 

[starvy]

Joe,

Fascinating study. I have used alkalines in the few important shoots I have done as a fresh pair never fails. I've found my budget rechargables to be good enough for casual shooting but they do seem to take a little longer to refresh.

[bebu_lamar]

<p>NiMH, the rechargable batteries, could cause damage to older flashes. Many older flashes have warning about the rechargable in their manuals. The NiMH could recycle too fast in some of these old flashes and burn them out.<br>

Your finding about the alkalines giving you more flash power on older units makes sense. Older units never stop charging the capacitor as long as you leave them on. Newer units would shut off the charging circuit when it reaches a certain voltage. So with old unit, if you fire the flash 30 seconds or so after the ready light comes on you would also have a higher flash output.</p>

[rodeo_joe1]

<p>BeBu, define "older units". How far back do we have to go? Every flash that I've come across built in the last 30 years or so cuts off the inverter oscillator after a pre-defined capacitor voltage is reached. The inverter then cycles if the charge falls back below some threshold.</p>

<blockquote>

<p>"Older units never stop charging the capacitor as long as you leave them on." </p>

</blockquote>

<p>That can't be so. Charge = voltage across the storage capacitor plates, so whether the inverter shuts off or not, the charge can't continue building indefinitely otherwise the capacitor would eventually be blown apart from overvoltage breakdown. No matter how old the flash unit design is, there must be some regulation of the capacitor voltage and thereby of the charge and power output. In the case of "always on" inverters the excess charge is probably shunted away via the indicator neon.</p>

<p>The inverter oscillator on those cheap Hanimex/Miranda units can actually be heard to shut down and cycle. But they're so badly designed that the hotshoe centre pin voltage is <em>negative</em> with respect to the shoe - meaning that they won't even fire on any modern digital camera, or would cause damage to the camera. Bad design is just plain bad design no matter how old or new it is. I only threw them into the test as examples of the cheapest and nastiest flash units available - before I cannibalise them for spare parts.</p>

[andix]

<p>While I don't debate the almost scientific approach to this test - which in itself is a big achievement - I am a bit surprised to find out that the OP found the recharging time to be <strong>faster with alkaline batteries</strong>. It seems to contradict everything I worked with (EXs, SBs and a couple of pre-1980 old monsters) where rechargeables yeld a faster recharge rate. Are we sure it's not a typo? I'm just asking for some clarification.</p>

[bob_sunley]

<p>Not a typo at all, and I'd suspect you haven't ever bought a new from the store electronic flash that came with a rechargable lead acid wet cell battery in it either. :) They were common in large flashes in the 1960's.</p>

<p>The inverters in some older flashes are very voltage sensitive. 1.565 volts per cell or 6.25 from a 4 cell pack of new alkalines is way higher than the 1.2 or 4.8 volts from a pack of rechargables. Old electronics designed for disposable batteries consider 1.2 volts per cell an almost dead battery.</p>

<p>I've got a really old flash (late 1960's I think) that won't even light up the ready light on rechargables, it works fine on alkalines. Most mid 70's and later flashes were designed to work on both types of batteries.</p>

<p> </p>

[andix]

<p>I'm thinking now that there's a factor missing from the equation - the alkaline batteries haven't been on the market that long. I remember them around mid- to late- '80s. Before them, there was something zinc-carbon or zinc-chloride... I forget what was in them but they were not alkaline (or marketed as such) for sure. Also, I'm not sure they were commercially available before the '80s either (not where I lived back then, Europe.)<br />And all those pre-'80 flashes were using them.<br>

@Bob Sunley - maybe the flash you're talking about has to do with the voltage rather than the amps? As in, 1.5 V in Alkaline vs. 1.2 V in rechargeables?</p>

[frank_skomial]

<p>There is no general rule for all flash types and all types of batteries, so one's tets results are applicable for that setup, and another test setup could possibly yield a different results.</p>

<p>As an example, I have Sunpak 611 huge power handle mount flash, that is designed to work on Ni-Cad rechargeable 4 C type batterier. (also a 510 V, and an AC adapter).</p>

<p>Nic-Cads have nominal voltage 1.2 V, and recharge the flash fast, as advertised, providing strong current without much of voltage sagging.</p>

<p>The 611 flash instruction allows Alkaline C type batteries, but only in an emergency situation.<br>

To my painful surprise, the best 1.5 V Alkaline batteries kept for the emergency backup, were charging for 4 to 10 times longer than the Ni-Cads, and after few cycles the charging to full charge was not possible to obtain.</p>

<p>Since Ni-Cads have much stronger allowed current drawn than Alkalines, the Ni-Cads worked OK, while some fresh brand Alkaline were unable to finish even a single full charge and charging took forever... </p>

<p>I case of this huge flash, the higher voltage of Alkalines did not help since they wer unable to provide the strong initial current, and were prone to voltage saging. The stronger current on Ni-Cads was the normal way to use the flash, even if they were of lower voltage.</p>

<p>For smaller flashes, where the initial current draw may not be that large, perhaps Alkalines will not drop the voltage that much (voltage sag), and behavior for smaller flash could be a different one. </p>

<p>At the time Sunpak 611 was on the top of the brand, Ni-Cads were the only rechargeable batteries available. Now, we have better rechargeable battery technologies, but they do not make them in C type/size. Since the flash is not a TTL type, it acts as an additional studio flash, or not used at all.</p>

<p>It works Ok (or rather slow recharge) from an underpowered original Sunpak AC power adapter. The Sunpak 510 volts batteries are no longer available...</p>

<p>The a bit smaller Sunpak flash 522 that I also have, it uses 6 AA size batteries, and the story about Alkaline versus rechargeable could be different, or different for even smaller shoe mount flashes like Vivitar 285... but this text is already too long to coninue.</p>

<p>This is good that people test, and share their results. Thanks.</p>

[rodeo_joe1]

<p>Mihai, Bob. Sorry if the wording in my first post was ambiguous:</p>

<blockquote>

<p>"The recycling time of all the flashes was noticeably reduced by using rechargeable cells."</p>

</blockquote>

<p>That should have read that the recycling time was noticeably <em>shorter</em> when rechargeable cells were used. Recycling time using alkalines was longer in almost every case, and lengthened very noticeably as the cells wore down. In fact I was shocked by how quickly the alkalines appeared to get depleted, since all the instruction manuals indicated that alkaline cells should deliver a higher number of flashes than rechargeables. But then most of those instruction books were probably written when NiCds had a paltry capacity of 500mAh or so.</p>

<p>Quite honestly I'd find it difficult to justify the use of alkalines on any count. That extra 1/3rd of a stop wouldn't really sway me, even if the strobe I was using did exhibit that behaviour. If you're working that close to the limits of the flash's power, then you probably need a better strobe! Taking cost and ecological considerations into account, rechargable cells would definitely seem to have the upper hand.</p>

[bob_sunley]

<p>I agree with you Joe, and understood your first post. The original nicads were a very low mah, can't remember the specs but 500mah sounds about right.</p>

<p>Frank, I have a Sunpak 622 as well, I have both a nicad pack and a C cell battery holder, use four 2200mah AA NiMH cells in it with the sleeves than Sanyo ship with their kits, it works well and is a lot cheaper than recelling the Nicad pack. If your not moving around, try a 6 volt gel cell, the recharge time is amazing. One of these days I'm going to make a couple of inserts for the c-cell holder to take 5 AA NiMH cells, light weight, high capacity and fast recharge times. <br>

I suspect those C cells you tried were getting old, or of a design with high internal resistance to give them a long shelf life. I've use some and the recharge time was ok at first, but they did wear out pretty quickly on full power flashes. Others were like yours, they sucked from the get go.</p>

<p>Depending on which cameras you have, there are TTL-OTF modules for the 622, I have them for both my F3 and Pentax 645 film cameras, but there are none for digitals. They work perfectly.</p>

<p> </p>

[bebu_lamar]

<p>Hi Joe! Most small flashes in the 70's were not designed to be used with rechargeable and because the NiCad (at the time there was no NiMH) would recycle the flash too fast and deliver too high current. <br>

Older flashes do not shut off the inverter circuit although it won't charge the capacitor to very high voltage because the limit is how high the voltage the inverter circuit can put out. In theory it would take forever for the capacitor to reach the same voltage as the inverter as the charging is slowing down the nearer the capacitor voltage is to the inverter voltage. So when the ready light is on, the capacitor is literally full but if you leave it for longer the voltage would reach higher although not by much as you found out.<br>

Newer flashes would shut off the inverter circuit when the capacitor reaches a certain voltage and turn back on when the capacitor loses its charge (even not fired). That way you would charge the capacitor to a more constant level and save battery as the inverter circuit would waiste energy.</p>

[frank_skomial]

<p>Thanks Bob,<br>

I did not suspect an AA size battery to work for a C type battery, but apparently the NiMH or hybrid like Eneloop are significantly stronger.. may be I will find a better use of the Supak flash.</p>

 

[bob_sunley]

<p>The nicad C cells in the Sunpak are 1800 mah, the Eneloops are 2200 mah, so the AA cells are a somewhat higher capacity, and way better than a decade old set of nicads. :)</p>

<p> </p>

[craig_shearman1]

<p>"alkaline batteries haven't been on the market that long. I remember them around mid- to late- '80s."<br />I've been using alkalines since about 1975. I was into Super 8 movie film at the time, and the manufactures all recommended alkaline because of the heavy current draw from the cameras' motors. Duracell was the more prominent brand over Everyready at the time. </p>

[bob_sunley]

<p>They came on the market in the 1960's.</p>

[bob_sunley]

<p>I should have added: and in perfect timing with the introduction of the transistor radio. :)</p>

 

[frank_skomial]

<p><em>"alkaline because of the heavy current draw from the cameras' motors</em>" - and that camera motor needed constant current flow, that seems nothing when compared to demand for instant flash loading of a flash, that lasts short time, but sags down the alkaline battery voltage. All depends on the flash size and design (electonics smarts).</p>

[Gary Naka]

<p>Frank<br>

Check this out. C size NiMH cells, 5000mAH (5AH) capacity.<br>

http://www.thomasdistributing.com/C-Low-Discharge-Batteries_c_925.html <br>

With this kind of stuff available, I decided that I wasn't going to bother recelling the NiCd packs of my 611. I would just use C size NiMH cells.<br>

You do have to buy a charger that will handle C size cells. </p>

[frank_skomial]

<p>Thanks Gary,<br>

The C size NiHM perhaps would be the best. I did not know they made them.</p>

[rodeo_joe1]

<p>Glad to have hammered one more nail into the coffin of that annoying little drum-banging bunny! ;-0</p>

[william_linzenmeyer]

<p>I want to switch to rechargeable batteries for my Nikon SB-900 and don't have a clue as to what I need to be looking for. Is there a preferred brand, or does that matter? Low discharge or Regular? Anything I want to look for or avoid? Any help would be appreciated.<br>

Bill</p>

[ken_max__parks]

<p>I've been using Lithium batteries for fast charge in the three Metz 45 CL-4 flash units and the only issue is that the units will overheat if used too fast, say 30 flashes within 5 minutes. The units will shut down and will not charge; that might be due to a thermal-resistor that protects the units.</p>

<p>I would have to acquire more research and information as to this overheat issue. It's a pain when shooting a wedding. I usually ending up swapping the unit out for one that has not been overheated. Then when the previous unit cools, I do a quick swap.</p>

<p>Better than any shoe mount flash in that I have the ability to adjust the output, full power, 1/2, or 1/4 and I shoot manual. The GN is 148 as compared to the lower flash output of the Canon 580EXII. The Canon flash is used for the formal setting shots and the Metz for the group shots and reception. And I keep about 42 lithium batteries on hand per wedding along with the 50+ NiMH rechargeables available as backup.</p>

<p><br /> I NEVER use alkies!</p>

<p> </p>