T7i Battery Grip.

[fewcrank]

I, for the life of me, can't find any battery grips for the t7i. Are they any at all that fit it?

[John_]

Hi Robert, the instructions for the T6i battery grip, which I have stated and I quote " 2 battery packs with different charging levels can be inserted and used without any problems" end quote. There is no danger of overheating or warnings noted anywhere. It only states to use Canon LP-E17 batteries and that's it. Now I do agree that mixing batteries would not be advisable, batteries with the same voltage but different MAH capacities also referred to as "extended use" batteries with standard batteries could cause serious problems. 

I have no intentions to use other than the Canon batteries with my T6i whereas with my Powershot SX50HS and S100 I do use less expensive third party batteries and they work as good as Canon batteries. 

[Waddizzle]

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@John_ wrote:

Hi Robert, the instructions for the T6i battery grip, which I have stated and I quote " 2 battery packs with different charging levels can be inserted and used without any problems" end quote. There is no danger of overheating or warnings noted anywhere.

It only states to use Canon LP-E17 batteries and that's it. Now I do agree that mixing batteries would not be advisable, batteries with the same voltage but different MAH capacities also referred to as "extended use" batteries with standard batteries could cause serious problems. 

I have no intentions to use other than the Canon batteries with my T6i whereas with my Powershot SX50HS and S100 I do use less expensive third party batteries and they work as good as Canon batteries. 

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Good call!  There is no danger because they are not connected in parallel, which would elevate the risk.  

I cannot speak about your Powershot cameras, except that they must also obey Ohm’s Law.

[John_]

Could be or maybe there is a simple surge suppressor which prevents a rapid discharge from one battery to the other in parallel. I am not willing to take my hand grip apart (yet) but I was able to confirm with my VOM that both negative battery contacts inside the grip are directly connected which completely eliminates any series connections. I also saw that with the battery door open the 7 volts is still available at the output to the camera. I suspect the battery door switch, which I could not find, just sends a logic signal to the camera halting the system.

Until someone comes up with the service manual and schematics for the grip I think I am at the agree to disagree stage

[Waddizzle]

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@John_ wrote:

Could be or maybe there is a simple surge suppressor which prevents a rapid discharge from one battery to the other in parallel. I am not willing to take my hand grip apart (yet) but I was able to confirm with my VOM that both negative battery contacts inside the grip are directly connected which completely eliminates any series connections. I also saw that with the battery door open the 7 volts is still available at the output to the camera. I suspect the battery door switch, which I could not find, just sends a logic signal to the camera halting the system.

Until someone comes up with the service manual and schematics for the grip I think I am at the agree to disagree stage

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Agree to disagree about what?  ???  Have you lost sight of my original point?  The batteries are isolated from each other, and that they take turns being used.

Your VOM has confirmed that the negative contacts are connected together, which makes sense.  But, your VOM could not confirm that the positive contacts are connected together, could it?  It could not because they are not.  The batteries are isolated.

Can your camera (T6i?) also read the battery status and serial number, either with or without a grip?  What does that tell you?

[John_]

Ok I do agree that the positive terminals are electronically isolated which makes sense for a couple reasons. What I am still unsure of is how the circuitry works in regards to using both batteries and monitoring the levels. It would be very interesting to see the schematics and theory they use. I still have some things I want to try with mine. Let me ask you, have you ever put a fully charged battery in a grip along with a fully discharged battery? If so what did the level read?

[RobertTheFat]

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@Waddizzle wrote:

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@RobertTheFat wrote:

Isn't it far more likely that the battery switching is done within the circuitry of the grip itself?

Does the camera actually differentiate between the two batteries, as you seem to imply? If so, even that surprises me. I wouldn't have expected the camera to know that a second battery is present.

Full disclosure: My first-hand knowledge of grips is zero. They gave me one free when I bought my 5D4 last spring, but I've never used it. I guess I could live with the additional weight, but the extra size is a show stopper.

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I am almost certain that the batteries take turns being the lead or lag battery.  Ohm’s law says that you cannot connect the batteries in parallel.  You could if you connect them with additional diodes and load resistors, but doing so would only detract from battery life.

When you use a battery grip, the camera can see both batteries separately.  It can display the serial number and remaining charge of each battery.  I wish I knew how to take a screen shot of the rear display, short of taking an actual photo.  It can even display which battery is in which position inside of the grip.

I do not see evidence of any electronics in a the battery tray or the grip.  There might be something inside of the vertical piece that sticks up into the camera body.  The camera can read the real time status of both batteries at the same time, which strongly suggests that both batteries are connected to the camera.  

With all of the extra contacts in the battery compartment, it makes more sense to put any smarts in the camera.  You can implement any battery switching in the firmware.  This is a much better arrangement, and a far less costly arrangement, than putting any electronic components in the grip.

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There are references, in this thread and elsewhere, to the use of 3rd-party grips in Canon Cameras that weren't designed to accept a grip. How could such a grip ever work unless it had the necessary circuitry built in?

[Waddizzle]

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@RobertTheFat wrote:

There are references, in this thread and elsewhere, to the use of 3rd-party grips in Canon Cameras that weren't designed to accept a grip. How could such a grip ever work unless it had the necessary circuitry built in?

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You are comparing apples to oranges.  

You are comparing a third party grip for a camera not designed to use one, to the manufacturer’s grip for a camera that is designed to use one.  If you are not, then we are talking about two entirely different things.

You can safely connect barteries in parallel with a simple resistor, and a diode to prevent reverse current flows.  

[EDIT]. Remember, the question is not can you connect them in parallel.  The question is why do the batteries seem to alternate discharging if they were connected in parallel.  In fact, how can the camera read and identify them separately if they batteries were connected in parallel?  

I conclude that there is zero probability of the batteries being connected in parallel.  It is not a question of can it be done.  It is question of how it is being done inside of the grip.  And, being connected in parallel ain’t it.

[John_]

It could work and those 3rd party grips do work but with limited functions, far less function then the Canon grips. I just saw another 3 party grip today for the T6, it costs a lot less money but you get less too and it had an external remote shutter cord that enables exposures from the grip. The Canon grip has transmit and receive data lines and contacts built in which tie into the cameras communication system enabling much more functions from the grip. There are a lot more components in the Canon grip Third party grip either can't duplicate the data lines and internal parts and programming needed to make them work or won't because it will drive the price up to a point where buying one will not be so attractive.

Besides the functions on the Canon grip, it performs just like an external power bank just like the ones for phones and other devices by pairing up 2 batteries and increasing its capacity 2X MAH while the battery voltage remains the same as a single battery in the camera. The camera would not like it if the battery voltage was double and would go Poof! 

2 batteries with the same voltage and MAH capacity in parallel would equalize so if initially, let's say when inserted one was at 90% and the other was at 80% they would both settle at 85%. 

I suppose Canon could have designed circuitry to switch from one battery to another at a predetermined level into their grips but in my opinion, that would just add unnecessary costs, And how would the battery level indicator react? Would it show a low battery symbol and then all of a sudden shoot back up to full? I have no doubt both batteries are used simultaneously.

[Waddizzle]

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@John_ wrote:

It could work and those 3rd party grips do work but with limited functions, far less function then the Canon grips. I just saw another 3 party grip today for the T6, it costs a lot less money but you get less too and it had an external remote shutter cord that enables exposures from the grip. The Canon grip has transmit and receive data lines and contacts built in which tie into the cameras communication system enabling much more functions from the grip. There are a lot more components in the Canon grip Third party grip either can't duplicate the data lines and internal parts and programming needed to make them work or won't because it will drive the price up to a point where buying one will not be so attractive.

Besides the functions on the Canon grip, it performs just like an external power bank just like the ones for phones and other devices by pairing up 2 batteries and increasing its capacity 2X MAH while the battery voltage remains the same as a single battery in the camera. The camera would not like it if the battery voltage was double and would go Poof! 

2 batteries with the same voltage and MAH capacity in parallel would equalize so if initially, let's say when inserted one was at 90% and the other was at 80% they would both settle at 85%. 

I suppose Canon could have designed circuitry to switch from one battery to another at a predetermined level into their grips but in my opinion, that would just add unnecessary costs, And how would the battery level indicator react? Would it show a low battery symbol and then all of a sudden shoot back up to full? I have no doubt both batteries are used simultaneously.

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No, there are so many false conclusions and assumptions in this post that I do not know where to begin.  First and foremost, you cannot compare a grip made for a camera body that is designed to use one, to a grip for a camera body not designed to use one.  

I have used battery grips on cameras designed to use one made by Canon and Vello.  I have had two 7D2 bodies, one with a Canon grip, and one with a Vello grip.  They were functionally identical in every way.  The only obvious differences seemed to be the physical tolerances of the machining of the mechanical parts, and the shape and texture of the portrait grip itself.

The Canon grip had the identical “rubber” coating, I will call it for the sake of argument.  The Vellow grip had a rubber coating that felt a little different from the 7D2 camera body.  The shape and layout of the Canon grip more closely matched that of the grip on the body of a 7D2, while the Vellow felt like it had a different shape, and the buttons were not quite in the same positions.  I would assume that you cannot make it physically identical without being sued in court.

Do not mistake extended battery life as proof positive that the batteries are simply connected in parallel, which could be an electrical hazard.  Batteries can be connected in parallel with a clever arrangement of diodes and resistors in a fashion similar to a full wave rectifier, which is probably what is happening inside of third party grip for a T5, which had no Canon grip because it was not designed to accommodate one.

There is no denying that a camera can identity each battery separately, including which position it occupies inside of the grip.  This would not be possible if the batteries were connected either in parallel or in series.

I agree with your conclusion that adding switching circuitry to a grip would not be cost effective. How would the battery level indicator react?  Like I have already said, the camera can read each battery separately, which strongly suggests that each battery is connected to the camera body independently of the other battery.  A grip works with one or two batteries.