Nickle Zinc batteries for Surf Dual Field PI

[Finderskeeper]

There has been a few postings about batteries for the White's Dual Field PI. I do not want to use Lithium Ion batteries as they are explosive around water. I hate buying disposable batteries. Plus I like the idea of more capacity for longer sessions without having to recharge or replace batteries.

I have been looking at Nickle Zinc (NiZn) batteries. They have slightly more voltage than standard alkaline (1.6 volts) and a higher mah capacity ( up to 4000 mah) plus they are rechargeable. The NiZn batteries have more voltage than both alkaline batteries and NiMh rechargeable batteries and so here is my question.

Will the White's Surf Dual Field PI machine handle the 12.8 volts? Not sure how the thing is engineered but I figure that an extra .8 volts would not be a problem. But I am not sure on that.

Anyone have any idea?

Here is why I am thinking they might be a good answer:

 

[Larry (IL)]

To be on the safe side, a call to White's might be worth your while but I too don't think the extra voltage would be a problem. I'm pretty sure there is a built in voltage regulator anyway.

 

[Finderskeeper]

I called White's and they told me that some guys run up to 15 volts in their Surf Dual Fields with no problem.

I'm going to get a set for my Dual Field as I said I hate buying batteries more than once. Plus they seem to have the voltage and amps to allow for longer times between charging than Nicads or NiMh's. I also hear that they do not self discharge as quickly as the other types.

 

[Finderskeeper]

Here is a link that shows the advantages and disadvantages of each type of battery.

http://michaelbluejay.com/batteries/types.html#nizn

From the looks of it, NiZn batteries seem to be the best logical choice out there right now.

I have not heard of anyone using them yet in their Dual Fields. They do require a special charger.

 

[Finderskeeper]

The NiZn batteries have a mah rating of 1500 not up to 4000. My bad. Still, with the voltage of over 1.5 for the entire cycle, it still out performs batteries of 2500 mah rating over time.

 

[lucar]

Hello,

I own both a Whites Pi Pro and a Dual Field.
Your post is interesting and while I'll keep using NIMH batteries I'll try to give You an answer.

The following is based on THEORY so any experiment is at YOUR OWN RISK.

Both detectors have similar electronics so I can say that both can withstand a power supply of 15V without damage.
However , judjing from the components maximum ratings,15 Volts is the absolute MAXIMUM and in my opinion it should never be exceeded by any means.

One company that sells NiZn batteries is Powergenix .
Their PGX AA batteries have the following specifications:

AA size package
1.65V nominal voltage
Typical capacity 1500 mAh

These batteries can be recharged at "1C" meaning that You can recharge them in one hour if charging current equals (C)apacity.
Since NiZn batteries are different from all other kinds, a dedicated charger MUST be used and Powergenix sells one that will charge up to 4 batteries in 2.5 hours time.

The standard Surfmaster battery holder holds 8 batteries and You might conclude that 8 x 1.65 Volts equals 13,2 Volts that seems to be way lower than the maximum 15V rating and all this looks OK but unfortunately it ISN'T.

The problem is that Your looking at the NOMINAL voltage and not at the MAXIMUM voltage.
If You take a look at the PGX AA specification You'll see that the charge procedure implies bringing the single AA cell up to 1.9 Volts; this means that POTENTIALLY You could have a fully charged 8 cells battery pack at 1.9V x 8 = 15.2 Volts ! That is the reason why, if You goggle around, many flash/camera owners did fry their equipment!

There is a solution to this: use 7 NiZn batteries and one dummy battery ; 1.9V x 7 = 13.3 Volts maximum rating. So the electronics will be safe.

But what about power supply ratings during use?

By looking at the discharge curve of NiZns at 0.2 discharge rate (more than the Surfmaster maximum power drain), You'll see that the NiZns still provide 1.6 volts when almost exhausted.
So 1.6V x 7 = 11.2V after 9/10hours running time on the surfmaster. This leads to the conclusion that , using 7 NiZn batteries on the Surfmaster during one full day will grant You 13.3 volts at start, and a minimum of 11.2v at end.

Powergenix charger can charge 4 or 2 batteries at once but not only one; so You'll have the added problem of making a rotation among 8 batteries by never mixing a charged and a discharged one.

One more problem: battery life.
If You look at Powergenix documentation You'll notice that they do not specify any number in terms of battery life.
It's well known that the main problem of NiZn batteries is a low battery life. So do not expect much on this side.
It also looks like that new, single NiZn faulty batteries are frequent , so be prepared.

Cheers from Italy (the country where everything is sinking)

Lucar

 

[lucar]

There is also a second option:

use 8 NiZns but always check the total pack voltage with a voltmeter.
NiZns self discharge rather quickly. So If you recharge the day before, I bet you'll have a total voltage lower than 15Volts the day after with the batteries chemically settled, but always check them berfore use.

Bye
Lucar

 

[Finderskeeper]

Thanks Lucar. Yes all what you say is good info.

My talk with Steve over at White's tech center said that 15 volts would be safe, the Surf Dual field can use safely up to 18 volts. He did say that anything over that risks burning out components and at 18, the heat generated may shorten life of components.

I will give them a try all the while keeping close tabs on voltage because as you have warned, that may be a possible problem.

The problem with the ratings of batteries here in the US is that we depend on mah ratings which does not take into account the wattage throughout the useful charge life of a rechargeable battery.

With NiZn batteries, they have a voltage that is useful up to the very end of charge when the Nicads and NiMh batteries have lost their useful voltage long before their amperage has gotten low enough to become non usable and need a recharge. So in effect, the NiZn 1500 mwh batteries have a longer useful charge than a nicad or NiMh 2500 mah batteries.

 

[5900_XL-1]

In my experiences when running the NiZn batteries in my v3i, the has always been at least one dead, unrecoverable cell when I tried running then down much below 13V total. Yea, the factory pack from Whites begins fully charged operation around 13V. Power Genix says that their batteries are effectively dead when a cell gets to 1.6V. Once one sell dies, there's a reverse drain on the adjacent cells and they get killed also.

Since I charge 8 cells, get a total voltage from the pack of nominally 14.4V, and quit using themin the V3i when I see 12.8V-13V, I haven't killed a cell since. It's a wash though since the effective runtime ends up being the same as it is for the standard cells. I'd quit them if I didn't already have so many.

It would be wonderful if you could run these down into the 8V-9V range in the v3i. You can't without killing cells. martin

 

[lucar]

Hello,

this is useful info since on the DF we can't control visually the voltage status of the batteries, so chances are that on the dual you'd easily ruin the batteries...

Lucar

 

[Finderskeeper]

All good points. After doing more research, I see HERE that NiZn batteries do have some problems.

I think I'm going to get a set or two of the Sanyo Enloops. They seem to have the highest satisfaction of the rechargeable batteries by photographers and they really put the batteries through a tough time. Plus they don't require a specialized recharger and that there are car chargers available for them too.

 

[SteveP(NH)]

But I have noticed that about 1 out of every 8 doesn't hold a charge as well as the other 7. I bought 2 8 packs and weeded out the 2 bad batteries and the other 14 work great and hold a charge in cold weather too.