Batteries for Newbies

A quick introduction to batteries on the Minolta D7/D7i/D5 for new users.

The D7/D7i and batteries, an Urban Legend is born.

Over and over on the newsgroups and forums we hear from people that don't own a D7 say that they "heard" that the camera "eats batteries", "Gets hot", "Gets so hot that it locks up" or "only gives a few shots". None of these things are true if you have the proper batteries for the camera, but these "reports" have apparently aquired a life of their own, like an urban legend, and continue to be repeated. Believe me, nobody would use a camera like that! There is no stopping this story now apparently. These stories probably had some basis in truth when they started because Minolta foolishly included alkaline batteries in the early D7 packages, and the camera will not run on alkaline batteries.

It does not take much to have proper batteries for the D7, you can get them on sale for as little as $5 per set, and $10 regular price, and they are available almost everywhere locally in the USA. Once you have the proper batteries, and charge them properly,  you should expect maybe between 60 and 120 shots, and about 1.5 hrs of continuous operation from the D7. The camera will not get any more than warm with the proper batteries, even after continuous use.

In a nutshell:

You have to have good batteries. You can't just use anything.


So, "How Many Shots Do You Get?"

You have heard that one before, and seen people answering with various answers. This question is typically asked on a forum about the D7/D7i, sometimes as many as several times per day in the same forum. The problem with this question, and with the answers, is that... as asked and answered they are meaningless. Let me explain why. The main power draw in a digital camera is just having it on. Actually taking a picture does not use that much more power (maybe 10% more), even in the worst case where you are using a microdrive and using the flash for every shot, and only for a brief time. That means that the main thing that controls "how many shots you can take" for typical usage is just is how many times you feel like pressing the button while the camera is on! For example, with the D7, if you only pressed the button once, then (duh!) you would only get "one shot". I can hear it now... "my D7/D7i only got one shot!" If you put the camera in continuous mode, and took shots like crazy, then you would get well over 1000 shots (it has been tried), but nobody is going to actually shoot like that either, you would not have time to pick out subjects.

Neither of these examples represents the way that you will probably use the camera, so a better question would be "how long can the camera stay on". The answer to that question is... you can expect 45 minutes of "on time" operation in the very worst case. Not many people are going to operate the camera in the "worst case" way, you would have to leave the rear LCD on all the time (LCDs are the biggest drawers of power in digital cameras). In the typical mode where most people will use the camera (using the electronic viewfinder set to come on when you bring the camera up to your face, and using the LCD to review some of your shots and maybe format your cards) the camera will last for about 1.5 hrs of continuous on time with the proper batteries (read below!). In the real world, the camera will usually last longer than that because you will allow it to "sleep" or turn it off when you aren't using it.

So the answer to this question is really, "I get as many shots as I normally would take in 1.5 hrs of continuous shooting".


Introduction: Using the correct batteries and charger with the Minolta D7 is absolutely essential to the enjoyment of this camera. Here I will present the minimum that you need to know to get started with the D7. There are a lot of other details, some of which are available in my D7 review, but I am just going to present the minimum detail here that you need to get started.

If you aren't getting at LEAST an hour of on time with your batteries, or if the low battery indicator is coming even transiently on with fresh batteries,  or if your camera is getting hot,  you need to read this. You should be able to get about 1.5 hrs of On time with the camera, and probably over 100 shots with good batteries for typical use. See the "Day in the life of a D7 Battery" page for an example of typical battery life.

Important Main Facts That You Need To Know:

* You can't use alkaline batteries. Ever. Any type or brand. Ever. Forget about alkaline batteries. The camera may not even turn on, or will at the very least malfunction after a few minutes.

* You can't use anything but high quality high capacity NiMH batteries. No other type of battery will work. They MUST be new, and 1600 or 1800 mAH.

* NiMH batteries are rated in milli-Ampere-Hours (mAH). This is a measure of how much current the battery can provide and for how long. A 1600 mAH cell can supposedly provide 1.6 amps (1600 milli-Amps) of current for 1 hr. However, there is no standard as to how this figure should be measured; manufacturers do whatever they want, I guess. Batteries last longer (have higher mAH ratings) at lower current drain. For example at 1.6 Amp drain you might only get 1/2 hour of time (800 mAH), while at 0.2 Amps drain you might get 8 hours (1600 mAH) One manufacturer's "1600mAH" cell will not necessarily be equal to anothers. Since the D7 can draw over an Amp, the rating of the batteries is critical

* The battery charger is just as important as the batteries. A bad charger can not charge good batteries. More below.

* New NiMH batteries have to be cycled several times before they will reach full capacity. Do not be discouraged if your new batteries die early.

* You need to make sure that the battery contacts in the camera are clean.

* Even brand new batteries can have problems for several reasons, see below.

* If your camera is getting hot over the CF socket, or shutting off too soon, or if the low battery indicator comes on during saves with fresh batteries, or if you are only getting 30 shots, you DO have a problem with your battery system. I don't care if your cells are "known good" and you "have the best charger", you DO have a problem.

The details:

* Alkaline batteries, all brands, will not provide enough current to run the camera. NiCd, "Renewal" rechargable alkaline will not run the camera. Only NiMH can provide enough current. For the beginner, get NiMH batteries. For the advanced user, a set of Lithium batteries (not rechargable) can be used in an emergency as an expensive alternative.

*  The secret to NiMH battery problems is called voltage depression. voltage depression is the main cause of battery problems.  Here is the big secret, and it explains why you can have battery problems for seemingly no reason. The more current that you draw from an NiMH cell (any cell actually), the lower the voltage of the battery will be. More current, lower voltage, it is Chemistry and Physics. This is called "voltage depression". How much the voltage will be reduced with a given current draw depends on the internal construction of the battery. Different brands of cells have voltage depression to different degrees. Some are better than others. Manufacturers do not publish figures for voltage depression, however in general higher capacity batteries like 1600mAH and up can provide more current. The mAH rating of a cell does not fully predict how well the cell will do under load though. When a camera like the D7 tries to draw a lot of current from a cell, and the D7 does use a LOT, the voltage drops. When the voltage drops, the voltage converter in the camera has to work harder and gets hot. It might even drop too low to operate the camera; causing the camera to shut off early without draining the batteries. A sign that your batteries aren't up to snuff is if the low battery indicator comes on during normal operation with fresh batteries.

Not all batteries are created equal. Not all cells from the same manufacturer are identical. You need to get some good batteries that have enough capacity to drive the camera, that will not suffer from too much voltage drop when the camera tries to gulp some extra current.

* About chargers. Batteries are just half of the equation. The other half is the charger. Not all chargers are created equal. You need a charger that can properly charge high capacity batteries.

The best chargers are those that monitor and charge each cell individually, and use a high charging current. These chargers monitor the temperature of the cells, and use a pulse current to monitor the charging. An example is the Rayovac PS4 charger. Using a charger like this, you will be able to identify individual cells that are having trouble.

The next best charger type charges the cells in pairs. An example is the Maha 204 charger. This type of charger is not quite as good because it can't detect a single bad cell in a pair, but it is still a pretty good charger.

One unacceptable type of charger is a simple timer charger. These just charge your cells for a fixed time (1 or 4 hrs generally) without any monitoring. This can damage the cells if you charge cells that are not empty, and generally tend to undercharge your cells (because they have to play it safe). They can significantly undercharge high capacity cells since they are usually calibrated "safe" for low capacity cells.

Another unacceptable type of charger is a trickle charger. These use a very low charging current, and generally take overnight or even longer than a day. These chargers are designed with a safety margin so as not to overcharge low capacity cells, and may not be able to completely charge high capacity cells at all, or it may take days to get a full charge on a high capacity cell. If you are using a trickle charger, you may not be fully charging your cells, even if you are leaving them in for over a day.

Using one of the unacceptable types of chargers can result in incomplete charge of your batteries, and early shutdown of your camera. Many chargers cannot charge high capacity cells properly.

* If you have any of the battery problem trouble signs (heating, early shut off, low battery indicator, fewer than (say) 80 shots, or lockups during saving pictures), you DO have one of the following problems.

1) Your cells are just not up to snuff. They may be too old, not able to provide enough current, you may have one bad cell in the bunch. New cells only cost $11 at Wal Mart or Walgreens or K-Mart (in the USA) for a set of 4, go and splurge and get some new cells. It is also possible to get a bad cell in a batch of new ones, it has happened to me.

2) Your charger isn't charging the cells properly. Your battereis may be fine, but the charger may not be charging them completely, or it may have damaged one or more cells in the set by heating.

3) You may need to clean the contacts on your camera.

4) Less likely, but still possible and hard to diagnose is a bad cell in your set.


* Once you get some good batteries, your battery problems will all disappear. You will wonder why you ever worried about it. Typical use for me is about 1.5 hrs of shooting, over 100 shots, using the EVF mostly, but using the LCD as needed to review and delete shots.

* Forget about any old cells that you have laying around. The technology has improved considerably in just the last year. Cells that I thought were "good" for use in my old camera will not operate the D7. New cells are only $11 for a set of 4, don't be cheap!

* Note that new NiMH cells are NOT charged when you get them. You have to charge them first before using them. It will be a couple of cycles before they reach their stride.

* One last thing, you still need to manage your battery life on the D7. The biggest user of power is the LCD screen, which uses as much power as the rest of the camera.  If you leave the LCD on ALL the time your battery life would be cut in half. You should use the EVF (electronic view finder) when possible. The best setting is to have the selection switch set to use the EVF only, and have the EVF set to come on when you put your eye up to it. You can still feel free to review your shots on the LCD, (it will come on automatically if you play a shot, or go to a menu and don't have your eye up to the EVF), it will not harm your battery life much to do this, just don't leave the LCD on ALL the time.

About the NiMH batteries included with the D7.

Well, the truth is that these batteries are marginal for two reasons.

1) They are only 1500 mAH. That is marginal, you should not expect as good a performance from these cells as from better cells. Personally, I would not even try to use them.

2) The included charger is a trickle charger that is not really up to the task. It is NOT able to charge even the included cells overnight! It might take as long as 24 hrs to charge the included cells completely.

How many people do you think throw the included cells into the charger for a few hours, or for just 8 hrs while they sleep before trying their new camera, and then get poor battery life? They have every expectation that the cells would be charged overnight, but they are not. It will take about 24-36 hrs for the first charge!

Battery lore for experts.

Here are some more details on NiMH batteries. You don't need to read this part unless you are or want to become an expert. Because some of this may go against "what you have heard" over the years, I don't expect you to take my word for it. Here is a nice link to a manufactures web page with the real information. And here is another one. Please look at these before writing me to tell me where I'm wrong, I know that this can be an emotional topic for some ;)

1) You don't need to condition your NiMH batteries by discharging them every single time. In fact, doing so would be actually be harmful. The main thing that determines battery life in NiMH is how long you have charged. The more charging, the shorter the life. By draining the cells every time so that they need a full charge, you are insuring an early death for your cells... but at today's prices it probably does not matter much. It certainly will not hurt to "condition" your cells every 50 cycles or so if you want to. Although the manufacturers will tell you that the cells are good for 1000 cycles, typical cells these days have about 400 full cycles in them, you can charge 800 times at half cycle, or 400 times at full cycle... your choice.

2) You do not need to "drain" the batteries all the way before recharging. While there may have been some reason to do this in the past with NiCd batteries, this is actually harmful for NiMH. At the very least it will shorten the battery life as mentioned above. At the worst, it could wreck your batteries if you don't do it right, see below. NiMH batteries do not have a "memory" as NiCd were rumored to have in the past.

3) If you feel compelled to drain your NiMH batteries, you should never drain your NiMH batteries all the way in a flashlight or radio. If you drain the batteres in series like that, one cell is always weaker than the other. Near the end of the "drain" it will become reverse polarized and current will flow through the cell backwards, driven by the stronger battery. If you do need to drain your batteries, you need to drain each one individually.

4) There may be a reason to condition your batteries, but only if you are noticing a problem. This might allow you to resurect a set of dying battereis for a few more cycles, but is it worth it at today's prices? It will not hurt to condition every now and then, say every 50 cycles if it makes you feel better. Most battery chargers with a conditioner do NOT drain the cells all the way anyway, they take the cells down to 1V per cell.

5) Things that promote good life in NiMH are...

* Keeping them charged. Top them off whenever you like.

* Using a fast charger, NiMH actually "likes" fast charging, it prevents formation of crystals that can short out the battery.

* Using a good charger that does each cell individually and most importantly has temperature monitoring; nothing kills an NiMH faster than roasting it.

* Using a charger that does pulse charging with brief a negative pulse which is supposed to prevent crystal formation.

* Not ever reverse polarizing a cell; that causes outgassing and your cell will be killed in short order, the material lost from the cell, once lost, is never coming back.

6) Yes, you sure can operate the D7/D5 on various external battery packs if you like. I don' t have enough experience to recommend any personally, but people say that some are great. Consider though the Amp Hourage of such a pack, there isn't much advantage to getting a 2500 mAH pack and certainly not a 1700mAH pack, when your NiMH cells in the camera are already 1600 mAH or better, all it would do is save you one battery pack change at the expense of having to wear the external pack and cord. Get a big capacity external pack if you want one; some of them are reported to last 3-4 times as long as batteries in the camera.

7) Battery care tips:

* Get two sets of cells at least so that you can operate the camera while you charge. What the heck, get three!

* Mark each set with a marker and keep the cells together throughout their lifetime. This promotes better battery life.

* I carry the cells in tiny zip lock (tm) bags.


Recommended batteries and chargers.

This is just a brief list of commonly available items that I absolutely guarantee will work well and will not cost an arm and a leg. There are many options if you are an expert, including 1800 mAH cells.

* Recommended. RayOVac 1600 mAH. $11 at Wal-Mart, K-Mart, Target, Walgreens in the USA

* Recommended RayOVac PS4 rapid charger. $30 at Wal-Mart, Walgreens, Target, K-Mart (if you are in the USA). Rapid charge of individual cells, with negative pulse charging to prevent crystalization. Really really charges in 1hr or less.

* Recommended Sanyo or GP 1800 mAH cells from They may not really last longer than the 1600 mAH cells from RayOVac, but they do work very well.

* Recommended Maha 204F charger. Charges cells in pairs, but does work just fine for the D7. A lot of people use this charger with no problems. Takes longer to charge high capacity cells. Has conditioning button. One nice thing is that you can use a 12V cord and it is very light for travel. You can buy it from Thomas distributing (