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Posts: 5,516
Registered: ‎06-25-2014

Re: T7i Battery Grip.


@John_ wrote:

Batteries can and are often connected in parallel to increase the MAH while the total voltage remains the same. In series the voltage of the batteries adds together while the MAH remains the same., of this I am sure. One basic example is jump-starting a car, the batteries are connected in parallel. The only damage you can cause leaving 2 car batteries connected in parallel together is if the alternator tries to charge them both it could be damaged but not the batteries. In my Logitech mouse, the 2 AA batteries are connected in parallel which makes it last longer, more MAH and I can remove one battery and the mouse still works. 

As far as the internal circuitry, anything is possible.


You shouldn't have a problem connecting two identical batteries in parallel, as long as they start out at about the same level of charge. But if one is fully charged and the other is nearly drained, the weaker battery may try to draw down the stronger one, causing either or both to overheat. Battery chargers are designed to avoid that phenomenon; but if you let a second battery get tricked into trying to function as an ad hoc charger, bad things may happen.

Bob
Philadelphia, Pennsylvania USA
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Respected Contributor
Posts: 1,409
Registered: ‎03-01-2014

Re: T7i Battery Grip.

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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Posts: 10,146
Registered: ‎08-13-2015

Re: T7i Battery Grip.


@RobertTheFat wrote:

@John_ wrote:

Batteries can and are often connected in parallel to increase the MAH while the total voltage remains the same. In series the voltage of the batteries adds together while the MAH remains the same., of this I am sure. One basic example is jump-starting a car, the batteries are connected in parallel. The only damage you can cause leaving 2 car batteries connected in parallel together is if the alternator tries to charge them both it could be damaged but not the batteries. In my Logitech mouse, the 2 AA batteries are connected in parallel which makes it last longer, more MAH and I can remove one battery and the mouse still works. 

As far as the internal circuitry, anything is possible.


You shouldn't have a problem connecting two identical batteries in parallel, as long as they start out at about the same level of charge. But if one is fully charged and the other is nearly drained, the weaker battery may try to draw down the stronger one, causing either or both to overheat. Battery chargers are designed to avoid that phenomenon; but if you let a second battery get tricked into trying to function as an ad hoc charger, bad things may happen.


Great observation and comment, Bob.  

 

That has been exactly my point.  You cannot just simply connect two batteries in parallel, because it creates an electrical hazard.  Some types of batteries can tolerate it, but that assumes that they are manufactured in a similar fashion.  Not all lithium batteries are created equal.  Canon batteries seem to hold their charge longer.

 

Designers of the battery grips cannot assume that both batteries are similar, even though the instruction manual tells you that they should be.  Designers cannot assume that both batteries will be similarly charged, either, even though the instruction manual tells you that they should be.

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"Doctor told me to get out and walk, so I bought a Canon."
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Posts: 1,409
Registered: ‎03-01-2014

Re: T7i Battery Grip.

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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Registered: ‎08-13-2015

Re: T7i Battery Grip.


@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.


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.

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"Doctor told me to get out and walk, so I bought a Canon."
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Registered: ‎08-13-2015

Re: T7i Battery Grip.


@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. 


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.

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"Doctor told me to get out and walk, so I bought a Canon."
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Posts: 1,409
Registered: ‎03-01-2014

Re: T7i Battery Grip.

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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Posts: 10,146
Registered: ‎08-13-2015

Re: T7i Battery Grip.


@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


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?

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"Doctor told me to get out and walk, so I bought a Canon."
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Respected Contributor
Posts: 1,409
Registered: ‎03-01-2014

Re: T7i Battery Grip.

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?

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