Sharing EX1 Battery Power

[Steve Gibbons]

Does anyone have a link to a product that lets you share the EX1's battery to power other devices? I came across one not too long ago but can't find it again.

Thanks,

SG

UPDATE: I believe it was the BEBOB Coco that I was interested in:
http://www.holdan.co.uk/bebob/specs/BEBOB_COCO-EX.pdf

[George Kroonder]

Bebob have one: Coco-EX - 14.4V Adapter for Sony PMW-EX1 HD-Camcorder. B&H carries Bebob gear.

George/

[Brian Cassar]

Just a word of caution about this item. I had bought one and when I attached a Pag light 20 watt lamp to it, the battery shut down. I had then needed to put it on charge to reset it. After contacting the company I was told that the unit had to be modified so as to include a soft start to avoid such problems. They even offered me to change my unit with a new one.

Last week, after hearing nothing from them for two months, I emailed them again. I was told that the unit has been modified but the company have found out that not all BP-U60 are capable of sustaining the same current output. Thus they are advising potential buyers that if the unit will not be used with their low power LED lights, the maximum power one can draw from it is just 10 watts. This is not enough for the 20 watts or more halogen lights.

It's a pity as the unit is really good in size, weight and functionality.

[Craig Hollenback]

post deleted by me...incorrect area...sorry.

[Piotr Wozniacki]

I can confirm what Brian says - based on my own experience, unfortuantely!

With the PAGlight M 20W, the battery fuses out (can be cured on the charger, though). When I switch the lamp on first, and then the camera - they both work OK, but I am very concerned about my BP-60 life...

So, I'm only going to use the Coco-EX with 10W bulb - in those rare situations when the extra brick battery is not viable, and 10W of additional fill light is just enough.

[Buba Kastorski]

Thank you guys, very valuable info.

[Alex Dolgin]

Originally Posted by Piotr Wozniacki

I can confirm what Brian says - based on my own experience, unfortuantely!

With the PAGlight M 20W, the battery fuses out (can be cured on the charger, though). When I switch the lamp on first, and then the camera - they both work OK, but I am very concerned about my BP-60 life...

So, I'm only going to use the Coco-EX with 10W bulb - in those rare situations when the extra brick battery is not viable, and 10W of additional fill light is just enough.

Piotr, your concern is a VERY valid one. I can not understand why they offer the adapter in the first place, as while it makes one feel that the solution is elegant and convenient, it is in fact bad and detrimental to the batteries. They try to mask the fundamental problem with the "soft start" circuit. Even if it works, it does not do anything to preserve the battery. The fundamental problem here is a Li-Ion battery is asked to work harder than it should, and it is trying to protect itself. The soft start circuit would fool the protection circuit, but does not improve the overload situation.
A Li-Ion battery should be able to power your camera for 3 hours or longer. This is a rule of thumb. If by adding more current draw, it ends up discharging in 3 hours or less, it is overloaded, and will not last too long.
HTH

[Piotr Wozniacki]

Alex,

Thanks for this explanation. I only have one doubt: the smaller Sony battery (BP-30) is designed to be drawn by the camera alone in less than 3 hours, so does it mean it will not last long?

[Alex Dolgin]

Piotr, I doubt it will last 3 hour. The U30 is a 2ah battery, the camera is using about 1.1 - 1.5 A, so it should run between 1 and 2 hours I think.
To answer your question, it is borderline. On our site in FAQ section http://dolgin.net/FAQ.htm towards the bottom you can see "Do I need to discharge my Li-Ion battery before charging?" question asked. There are 2 graphs in there, illustrating how a battery performs while loaded at different loads. They are from the Sanyo Engineering manual, which is a bible for the battery engineers. While powering EX1 with a U30 battery, it is loaded at about .75C I think, which makes it work hard, harder than U60 would. Connecting an extra load like an on camera light makes the situation much much worse. That is why I am so upset at the manufacturers like BeBob putting out their sleek product that is fundamentally flawed, and then trying to come up with a band aid fix, which would not work anyway.
Think of a mid size car given a small 100hp engine, and then hooking up a trailer to it...

[Piotr Wozniacki]

Originally Posted by Alex Dolgin

Piotr, I doubt it will last 3 hour. The U30 is a 2ah battery, the camera is using about 1.1 - 1.5 A, so it should run between 1 and 2 hours I think. ...

That's what I am saying, Alex - with BP-U30, Sony is giving roughly 50% usable capacity of the U60, and yet it's the "basic" battery for the EX1.

With the U60 powering both the 15W camera and a 10W (or even 20W) lamp, we're back to the discharge times of the U30 (roughly); so am I right thinking the U60 used in such a way should last (in terms of the life span) as long as the U30, feeding the camera only? Or is it not so much a matter of capacity (i.e. usable discharge time), but the current being drawn?

Thanks in advance for your explanation!

[Alex Dolgin]

Originally Posted by Piotr Wozniacki

That's what I am saying, Alex - with BP-U30, Sony is giving roughly 50% usable capacity of the U60, and yet it's the "basic" battery for the EX1.

With the U60 powering both the 15W camera and a 10W (or even 20W) lamp, we're back to the discharge times of the U30 (roughly); so am I right thinking the U60 used in such a way should last (in terms of the life span) as long as the U30, feeding the camera only? Or is it not so much a matter of capacity (i.e. usable discharge time), but the current being drawn?

Thanks in advance for your explanation!

Yes, you are right. Powering both the EX1 plus a 20W light draws 35W, making the U60 last under 2 hours, which is the same as using the U30 to power the camera only. Ideally, the loading should be such so it last 3 hours or more.

Originally Posted by Piotr Wozniacki

Or is it not so much a matter of capacity (i.e. usable discharge time), but the current being drawn?

Thanks in advance for your explanation!

It is a matter of capacity vs current. A higher capacity battery can easily supply higher current. A high capacity 10Ah battery belt can easily provide 3A without being stressed; a 2Ah battery can not provide 3A for even 1/2 hour, would be hot and worn out fast.