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12v Battery choices - Roll Your Own


Adam Jones

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There have been a couple of threads about building cart power solutions, but I couldn't find much in previous threads about which SLA batteries people had good or bad experiences with.

I know a couple of folks like the 12v 33ah MK cells, and I know that Powersonic 35AH are an old favorite, but has anyone had the opportunity to do side by side tests of different brands?  Or does anyone just have vaguely uninformed guesses they'd like to share?

FWIW, I'm planning to build a couple to use with my PSC Powerstar on my new cart, so any thoughts are welcome.

Thanks everyone,

A.

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As it happens, just yesterday a client inquired about a replacement battery for a Pelican-case power supply Chinhda built for him. I called Chinhda to ask what battery he recommends.

The particular battery we discussed is a bit smaller than what you probably have in mind. It fits into the Pelican 1200 case and there was some effort to source a battery that would exceed 18AH capacity. So, I'll pass on the Chinhda recommendations but you may need to explore the catalogs a bit to find something that exactly suits your application.

Chinhda recommended Tempest batteries because they have tended to have a bit higher capacity than the competition. Since he looked at them, others may have caught up. Here is a link to Tempest batteries:

http://www.tempestbatteries.com/

He told me that he usually purchases from House of Batteries. Again, there may have been some changes in intervening months as I can't find any Tempest batteries on the House of Batteries site. Still, they seem to have an abundance of batteries to sell. Here's a link to their site:

http://www.houseofbatteries.com/

Finally, in looking over the possibilities, we noticed a good candidate from Power Sonic. Since we were looking at a 21AH battery to fit the smaller case, I won't bother with a link but just suggest that you review their line in the House of Batteries on-line catalog.

Hope that helps.

David

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I am also interested in this thread.  My Pelican batteries sat idle for too long, it seems, and even after a good charge they have failed.

It is VERY rare that I need one.  In fact, I only took one out today to do a test on the whole "ticking" in the car thing (using a block battery vs. my PowerStation to power my car rig).

But I do like to have these batteries on hand, so I will probably replace the cells and do a better job keeping them charged.

Robert

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Always store lead-acid in a charged condition. Never allow the open cell voltage to drop much below 2.10V/cell. Apply a topping charge every six months or when recommended.

Avoid repeated deep discharges. Charge more often. Use a larger battery to reduce the depth of discharge.

Prevent sulfation and grid corrosion by choosing the correct charge and float voltages. If possible, allow a fully saturated charge of 14h.

To reverse sulfation, raise the charge voltage above 2.40V/cell for a few hours.

Avoid operating lead-acid at elevated ambient temperatures.

Note: Wheelchair batteries don't last as long as golf cart batteries because of sulfation. The theory goes that a golf cart battery gets a full 14 hours charge whereas a wheelchair only gets 7 hours while the user sleeps.

Link: http://batteryuniversity.com/learn/article/how_to_restore_and_prolong_lead_acid_batteries

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Oleg

If I remember correctly, from another thread, there is a problem using a Lithium battery with a PSC UPS.  The battery has a higher voltage than the charging circuit.  The battery is used until the charging circuit is at a higher voltage and THEN the power is coming from the UPS and not the battery, resulting in a partically or mostly discharged battery.  So instead of being able to run for XX hours on battery, there may only be an hour or two remaining.

I emailed PSC more than a year ago, inquiring about a new version of the UPS units that was built to work with some version of Lithium chemistry.  The response at that time was they were looking to see what chemistries would be available in a couple of years and expected the price for the new chemistries to drop significantly.

Ray

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Thanks all!

I'm with Robert in rarely needing to run the full cart off the battery for very long, mostly I want it to cover me on kick outs and when the genny gets killed during a DVD mirroring. 

I see that batteryspec.com sells the Tempest batteries that David mentioned, with pretty reasonable shipping rates, so that's sounding pretty good.

Being that shipping sometimes almost equals the price of the battery, I might just see what I can find locally.

I've also got to agree with Oleg that I'd rather be using Lithium technology, but I want to wait until some new chemistry hits the market in the next couple of years.  Til then, I'll keep the LiIons powering the bag setup & keep the cart thoroughly primitive [power-wise.]

I'll report back.

A.

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why to waite , its already there , it reminds me the stupidity of using dvd ram , till the new media will hit in in hollywwod  :-)

for me lithium ion is already 5 years old , sorry ,my last nickel metal  bp-90 died few years ago, and  SLA -  you must be kidding , i have a strong back for sex life  not for punishment :-)

There is a lot more involved than just stupidity for the continued use of DVD-RAM or any optical media in our work --- but you know that and you just couldn't resist using the word "stupid" in a sentence.

As for the continued use of sealed lead acid batteries for CART power, there are still compelling reasons to stick with this older technology. I totally agree with the use of different battery technologies for bag work where the requirements beyond just voltage and current are much different. Light weight, portability, interchangeability, high capacity in a small container, fast recharge, these are all important factors --- SLAs possess almost none of these qualities but are still quite appropriate for use in a cart based power supply.

So far, RemoteAudio is the only company that I know of that has explored using batteries other than SLAs for a cart based power supply with their Meon product. I know of no individual who has built a cart based power supply for themselves with anything other than SLAs. For the power supplies that I have built, SLA batteries are the best choice (not "stupid") and the use Lithium batteries would create more problems than it would solve. The only advantage the Lithium batteries have for the sort of power supply I build, is the weight factor. We all know what the "L" stands for in SLA batteries (but no, it hasn't affected my sex life).

I have used several sorts of SLA batteries, Yuasa, Power Sonic, Panasonic, a few no-name off brands, etc., and because of the design of my power supply, the best batteries for me are Alarm/Security type batteries rather than golf cart or wheelchair variety. The supplies I build (and I haver discussed this before) do not have a charging circuit and the batteries do not go through repeated discharge - charge cycles. Simply stated, constant 13.8 volts DC floats across the battery when AC is available and the battery begins to discharge only when the AC is pulled. Therefore, you can see that a battery designed for an alarm system or emergency lighting system where AC is available most of the time, is the best choice.

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Indeed , that  is why there are so many movies about :-)

Of course  let not forget these and  the people with big carts ,  let say  with  power hungry Yamaha, mini macks and all the ridiculous stuff as comtecks transmitters and 40 inch monitors to see the boom shadows .

now  they would be able  to  run 12 hours on that battery -  so i call it kind of evolution:-)

Now , if mr  Mayer  read these lines , i guess he needs to think about redesign the power star for next generations .

How would you get along w/o a Comtek TX?  I may be very small and portable these days (pretty much), but I still often have 10 to 15 people who want headsets (and a big monitor to watch) no matter how mobile I am.  Producers want me to keep those folks happy (and away from the camera and talent, thus the headsets.)  They will pay for those headsets, since the clients "touch" them.

phil p

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btw how long should I last on a Panasonic 65AH SLA when my cart draws 3.5A? Shouldn´t I get at least 10h until the voltage goes down to 12.0V? Just got 6.5 hours tested in my appartement. If shooting outside with lower temp even less probably.

Time for a new one or still ok?

Theoretically, it's 65 divided by 3.5 (which is about 18 and a half hours), however, to see the actual discharge characteristics, with some online research you should probably be able to locate a product sheet that will show the expected discharge curves (time vs voltage at various current draws).

John B., CAS

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" Time for a new one or still ok? "

Ohm's law: 3.5 amps x 6.5 hours = 22.75 AH (delivered)

" Theoretically, it's 65 divided by 3.5 " gives you the potential,of a new and fully charged battery, but in practice, figure to use less than  90% of that capability and remember that the potenital capacity will decline with age and use.

and

" How would you get along w/o a Comtek TX? "

no need to;  many years of successful use of the small, light Comtek and Lectro TX's with 9v batteries

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I guess that I'm in the minority here since I use Lithium batteries for cart power. 

With my newest cart build (I need to post pictures since I'm a couple of cart versions behind in doing that), I use a dual NP-1 battery box which feeds a PSC Cart Power distro.  From there, the cart has its own distro which routes through a control panel that includes a power/current/voltage meter. 

Since I'm using a dual supply, I can swap batteries one at a time without taking the cart off-line.  This gives me a lot of run-time, as I have ten IDX Lithium NP-L7S 68WH batteries available (68WH at the voltage these batteries operate at is about 4.5AH each).  And, yes, I have been extremely happy with these batteries.  Some of them I bought used in great shape -- a win/win.  I own several chargers, so I have them available both in the studio and in my portable kit without packing and unpacking.  I also use these batteries for my bag kit.

I had to have PSC make a special version of the Cart Power because of the way it works.  Basically, the Cart Power is designed so that when you have A.C., the unit's 12v. power supply is what is feeding the outputs, but when the power supply voltage drops, the battery input to the Cart Power unit will then be feeding the outputs (a simple diode arrangement). 

However, since the lithium batteries show about 15v.-16v. when fully charged, with a standard Cart Power unit, first the batteries will power the outputs until their output falls below what the Cart Power's power supply is feeding, at which time it takes over.  With these Lithium batteries, that would mostly discharge them before the A.C. source kicks in -- not good. 

The simple solution is that PCS puts a slightly higher voltage supply in the Cart Power unit, a 15v. supply (which can be adjusted plus or minus about 10%).  They had made this version before for someone else so I had them make one for me.  Bottom line:  It works great.

I had explored various other Lithium possibilities, but realized that one of the best solutions was to use the NP-1's I already had and simply add to them.

Not much weight for the Cart Power (compared to many other solutions), and really light weight with the IDX Lithiums (compared to my SLA supply).

It's a great arrangement for how I work.  Normally, there's A.C. available but, if necessary, I can go a really long day on battery power alone.

John B., CAS

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I guess that I'm in the minority here since I use Lithium batteries for cart power. 

- snip -

Not much weight for the Cart Power (compared to many other solutions), and really light weight with the IDX Lithiums (compared to my SLA supply).

John B., CAS

That's a very good arrangement I think particularly because you can use the same batteries for total mobility (bag work) or for your cart power supply.

-  Jeff Wexler

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Theoretically, it's 65 divided by 3.5 (which is about 18 and a half hours), however, to see the actual discharge characteristics, with some online research you should probably be able to locate a product sheet that will show the expected discharge curves (time vs voltage at various current draws).

John B., CAS

I know what I should get but practical exp is smthing else. Specs of the Panasonic LC-X1265 says 20hrs when drawing 3.25A until cut off voltage 10.5V but I was told to calculate with half the capacity to get realistic hours. But even then 35AH and 3.5A should give me at least 10hours.

Will see if a new one gets closer to the 18-20hours as I have just got another LC-X1265 on ebay.

Matthias

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I know what I should get but practical exp is smthing else. Specs of the Panasonic LC-X1265 says 20hrs when drawing 3.25A until cut off voltage 10.5V but I was told to calculate with half the capacity to get realistic hours. But even then 35AH and 3.5A should give me at least 10hours.

Will see if a new one gets closer to the 18-20hours as I have just got another LC-X1265 on ebay.

Sorry, I wasn't meaning to tell you something you already know. 

Was your current figure theoretical or measured?  As you may also already know, you need to take into account, that on much of our gear, the current requirements will rise as the supply voltage gets lower.

Please, let us know how it specs out with the new battery.

With a new, quality battery, and all conditions taken into account, you should get within "shooting range" of the theoretical (minus a small percentage for "overhead").

John B., CAS

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From my experience, and this is very un-scientific, the only way to really determine with any accuracy how long you will be able to power all the gear on the cart is to power all the gear on the cart and wait --- when supply voltage gets too low for any piece of equipment you will be able to look at the clock on the wall and get the best indication of overall run time. I am a total math-illiterate so I have never even bothered to go the calculation route. For the record, my cart power supply which is based on a 20Ah SLA will run all the gear on my cart for 5 hours. I have almost nothing on my cart that is a big current draw and everything is native 12 vdc power.

-  Jeff Wexler

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Oleg, you got me interested again into looking at lighter weight alternative batteries for my cart power (the whole cost thing is not my main concern but the weight is). What I have discovered while researching some of the Lifepo4 batteries you have been recommending is that they may not work for the sort of power supplies I have been building using SLAs. Evidently, the Lifepo4 type batteries do not like  to have constant current regulated voltage floated across the battery as I do with the present power supplies. The Lithium batteries are really designed to be the source of DC for the load, discharge gracefully and then be re-charged quickly (and with many re-charge cycles possible for the life of the battery).

From someone who knows a lot more about battery chemistry/technology than I do, I would like to hear about whether some sort of constant duty charger (silent) could be built to allow me to utilize these Lifepo4 batteries but in the same manner as I have used the SLAs.

-  Jeff Wexler

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Just remember you can not ship more than a 7 gram Lithium content in a battery on an airplane. that translates to 95W or so at 14.4 V. details on the IDX batt site.  You can ship several of these in one container on the plane.

I dont think you can airship big LI - be they PO or other suffix

http://www.idxtek.com/lithium-ion-transportation

wolf

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re Batteryspace: we have been using smaller Li batts from them for 5+ years. I have a computerized battery discharge tester. Generally I am not overly impressed. they do degenerate over time. One clue might be that they now show country of manufacture for their cells. The Japanese and Korean ones are more expensive probably for good reason. It has not been long enough to note this in testing.

Older NP-1 by IDX rated at 50 W last barely 3 years  only double of old nicad chem.

Lead acid can be stored at 10.8V for a 6 cell batt. We strongly believe after 15 years of this in Panasonic. they do last 6 years, a few last 8 years, all are good for 5 years.

nothin' wrong with LEAD !! if they get abused ( over-discharged) by renters, they are cheap enough to throw away.

I have a 15 page research paper. if anybody plans on reading it write to me and i WILL EMAIL IT.

people pontificate endlessly here but noone does the research and experimental work.  Clairmont builds still SLA batts (panasonic and the Gates type for custom sizes)  for cameras that draw 7-9 A.

wolf

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