best rechargeables for strobe?

[jzsj0 0]

Hi All,

 

I've pretty much convinced myself (if not my bank manager!) that I need an Inon Z-240 strobe but was just wondering what's the best rechargeable battery that everyone's come across for holding their charge?

 

Cheers,

 

James.

[AndyBarker 6]

Hi,

I have inons 220s & use uniross 2300s & they lasts for a long time, don't know how long

as I recharge before they go flat. (6/8 Dives), but you can get more powerful ones now

& have got 2700s for my Red Sea Trip, also they fit in the strobes with out a problem, I

know that some types do not fit & get stuck. But Im sure you will get other advice from this

forum.

Andy

[james 0]

My favorite are the Maha Powerex 2700's

 

Cheers

James

[Scuba_SI 39]

I heard a rumour that using high mAh in inons can cause the modelling light to burn out unusually quickly.. I use 2700's in my ringflash, but dont use it often enough to verify the claim.

[uw_nikon 0]

If the bulb in the modeling light isn't rated for high current discharge batteries (rechargable NiMH or NiCad), it will burn out quickly.

 

(too much current, too fast = fast burnout; standard alkaline batteries cannot deliver the same amount of current a NiCad or NiMH battery can in a given amount of time.)

 

It shouldn't matter if the batteries are high mA-hr or not. (it's the batteries' discharge rate that will zap the bulb. Something, a resistor, has to limit the current thru the bulb.)

[jzsj0 0]

Interesting replies, thanks. Wouldn't have even thought about the burnout issue that's for sure. I just checked their website and they say:

 

# Batteries:(*6)

 

* AA Alkaline, Nicad, Nickel Metal Hydride, Lithium, Oxyride x 4

(*manganese batteries not compatible)

 

# Recycle Time:(*7)(*8)

 

* AA NiMH batteries: 1.6 seconds minimum (2,700mAh)

* AA Nicad batteries: 1.5 seconds minimum (1,000mAh)

* AA Alkaline batteries: 2.3 seconds minimum (1.5V)

* AA Lithium batteries: 2.5 seconds minimum (1.5V)

* AA Oxyride batteries: 2.1 seconds minimum (1.5V)

 

# Flash Capacity:(*7)(*8)

 

* AA NiMH batteries: approximately 320 flashes (2,700mAh)

* AA Nicad batteries: approximately 120 flashes (1,000mAh)

* AA Alkaline batteries: approximately 220 flashes (1.5V)

* AA Lithium batteries: approximately 380 flashes (1.5V)

* AA Oxyride batteries: approximately 250 flashes (1.5V)

 

# (*6) Oxyride battery voltage is in excess of 1.7V and is fine for firing strobe. However when batteries are still fresh, and the Focus Light is turned on, the sudden high voltage will shorten the Focus Light bulb life. Refer to written cautions on battery packaging warning of shortened bulb life when using these batteries. To prevent shortened bulb life, do not use Focus Light until strobe has been fired at least 20 times at full power. This will reduce the voltage down to conventional battery levels.

# (*7) Full strobe output at 30 second intervals with both Focus Light and Advanced Cancel Circuit OFF, at 25C (77F) degrees.

 

* Tested with following batteries: Nickel Metal Hydride: SANYO Twicell 2700 Series, HR-3UG, 1.2V, 2,700mAh

* Nicad: GP 100AAKC, KR6, 1.2V, 1,000mAh

* Alkaline: Maxcell ALKALINE ACE, LR6(K), 1.5V

* Lithium 1.5V: FUJIFULM/Energizer LITHIUM, FR6, 1.5V

* Oxyride: Panasonic Oxyride, ZR6Y, 1.5V

 

 

 

So. it looks like it's only the Panasonic batteries that can cause an issue - I won't be picking a high voltage battery now!

 

Cheers,

 

James.

[craig 0]

I would be very surprised if high capacity NiMH cells damaged the modeling light.

 

Current is dependent on voltage and the nominal voltage of NiMH is lower than Alkaline or Lithium (for which the bulbs must be rated). The internal resistance of NiMH cells is low but so is Lithium. The highest capacity battery in the world won't deliver current into the bulb if the voltage is too low.

 

A bulb is a variable resistor (resistance varies with heat) and the battery has an internal resistance. The total resistance is the sum of those two. The current that flows is voltage / resistance. Initially, the bulb is cold and its resistance is near zero. Current flows based on the battery's limiting resistance and both the battery and the bulb heat up. Once the bulb is hot, its reistance dominates and the current flow drops. If the bulb never gets hot, the battery overheats and dies quickly. That's why you should turn a light off once it goes dim and yellow.

 

A NiMH AA battery should typically be rated for a current draw 1/2 its capacity. That means a 2000 mA/h battery should be used at no more than 1000 mA. Faster rates shorten life considerably and cause the battery to heat up.

 

Higher capacity ratings do two things. The first is that they obviously raise the 1/2C discharge rate making them suitable for higher loads. The second thing is that they generally have lower internal resistance. That means they deliver more voltage to the load at higher draws. A high capacity AA has the potential to drive a bulb hotter than a lower one, but the real question is whether it can exceed a Lithium for which that bulb must also be rated.

 

I'm using 2700mA Sanyo's and Maha's and the modeling light appears yellow. If it were being overdriven, it would burn white.

 

I think Sanyo and Maha are good cells and both offer 2700mA. I've had problems with GP cells and the Inon contacts. AA batteries do vary slightly in the shapes. The new low-self-discharge batteries are interesting but right now the lower capacity doesn't seem like a good tradeoff. Maybe when they get within 90%+ of the highest cells they will be a better choice.