Mixing Alkaline batteries.

Is it ok to mix different kind of alkaline batteries? Like for example, my 3xD maglite. In a pinch, can I use 2xD and 1x AA (with adapter)? How’s the runtime?

Once the capacity of the AA is depleted the D cells will reverse charge the AA battery resulting in a high risk of a leak, so it’s not recommended.

I would stay away from alkaleaks in all devices that you care about. Or if you do use them, make sure you remove them ASAP.

I would instead use NiMH, even if it meant using 3 (preferably eneloop) AAs in adapters.

^This!

I can't stand alkaleaks.

I'll take a quality LSD cell, like an Eneloop, any day of the week.

But alkaline has lots more capacity vs nimh, no?

I'm not sure about that, but...

Do you want to ruin whatever you put your alkaleaks into, and do you want to keep on buying disposable batteries over and over again when you can use quality rechargeable batteries instead?

Always use batteries of the same type and charge level. Rechargeable LSD batteries have more usable capacity than alkaline batteries because of their flat discharge curve.

What’s a good brand rechargable D cell with high capacity?

I don't know if there is one.

What many people do is get "3 AA to D battery adapters", and then use something like AA Eneloops in the adapters.

...

Here's a pretty good adapter on Amazon.com:

https://www.amazon.com/dp/B01MEF4K44

I have a 3D Maglite in the car. After 7 years, batteries still good, no leaks. Batteries long expired. Using Duracell D.

Alkalines only leak after they are depleted and left inside device.

If you are diligent enough to change batteries BEFORE that critical level, you will likely neve have a problem.

Nope, not even close.

Alkaleaks and heavy duty batteries will leak even if they're never used, and are still sealed in their original packaging.

Ask Lightbringer if you don't believe me.

The way he describes how easily those batteries will leak is hilarious, and sadly true.

Yes, but also no - depends on how hard you work them. Alkalines generally good for low draw- at low rates they’ll outlast NiMh, ie. clocks, TV remotes, etc.

Have a look at the excellent comparators on HKJ’s website

You’ll be able to compare the cells that have been tested, there are tick boxes to show the current draw, at higher currents, NiMh do do better than Alkalines.

!

!

In general they leak when they are empty.
They do sometimes empty themselves and leak before they are even removed from the package.
At times even full batteries in the package and unused will leak but its not as common as emptying itself then leaking.

Good Alkalines have a capacity of 2500ish mAh. But at a very low draw rate, remotes, clocks and so forth. At high draw they can die after 500-1000mAh.

NiMH have typical capacities of 2000-2500mAh. They can put this out at low and high draws. But they sometimes have trouble with constant power draw like clocks even when they are not empty. Don’t put them in fire alarms.

Nope, nope, nope.

I’ve had Costco packs of Duracells only a couple of years old start leaking still in the new packaging. And that’s just one of many instances where I’ve had Duracells and Energizers leak long before they were discharged. Discharge greatly increases the risk of leak, but alkaleaks leak. Any time.

My rule of thumb, is never use alkaleaks in any device that is worth more than the batteries. If the device is worth more than the alkaleaks it fits, it’s worth NiMh.

Agreed as above…use same size/capacity cells. You can get spacers so you could run all AA if you wanted, but I would not mix the D and AA together unless it’s emergency use for a short time and you replace them asap.

I’ve lost two D and one C Maglite to leaky alkies (Duracell and Energizer). One of those had half-empty-ish cells and sat for a couple years…oops. The other two were just failures with fresh cells that were lightly used and I don’t think ever sat for more than a month. Got two of those three replaced - one each from Duracell and Energizer, but Energizer denied the claim the second time (few years later). Maglite - I think out of good faith - replaced an AA minimag for me after those cells welded themselves in place and I explained how I finally tried to use a long lag screw to extract them…that was nice of them. Basically now, alkalines can suck it as far as I’m concerned. The few things I have around that I still use them in, I now always remove the batteries and put them in when I need to use it.

I don’t own any NiMH D cells but we have some at work where they occasionally get used in a Maglite 2D light. Actually I should check on those because I’ll bet there junk at this point. But as of a few years ago the Tenergy cells did fine, certainly seemed to have more capacity than alkaline but I never measured and I’m not the one to charge those up. I think alkies are around 2500mAh or a little better but they can’t sustain loads very well. Not sure how much an incan bulb can pull in those lights. The NiMH seem to reliably give at least 8000mAh these days and I think the newer Tenergy and Powerex/Maha are around 9000. Generally will lose a little initial brightness compared to alkaline but it doesn’t take long before the NiMH will keep the discharge curve flatter for most of its capacity (that of course gets steeper the higher the current draw is but still better than alkaline). I’ve generally heard just mediocre things about the Tenergy cells. Had a few of their AA years ago and they weren’t great but they seem to be better these days. Not many decent choices with C and D size. It’d be nice if someone did lithium primary in those sizes.

A few links if you want to give NiMH a shot. Be sure your charger will take these larger sizes.

These are made in Taiwan like their other lsd cells…not sure how good they are/aren’t but other sizes are pretty decent: Powerex Precharged D Batteries 2-Pack | Powerex by Maha Energy

Powerex: https://www.amazon.com/Powerex-Self-Discharge-Precharged-Rechargeable-MHRDP2/dp/B01G3SS8VK

Tenergy Premium which seems the best choice: Amazon.com

Tenergy Centura, lsd (don’t get the Centura Lite, not for this flashlight): https://www.amazon.com/dp/B01ASF24WI/

Also don’t get the Tenergy with the old blue/grey wrapper if you see those. The Premium is a better updated version. I have a couple of the Premium in C size and they’re good so far.

I thought it’s between 10000 - 20000 mah according to Google.

Oops, I should have mentioned all my capacity numbers are for AA batteries :blush:

Not accurate in my experience — I live a few blocks from a major earthquake fault with a high probability of shaking in the next few decades, and so I have a stash of tools that includes several packages of alkaline cells suitable to pass out to the neighbors with cheap flashlights once the dust settles. I go through the cells every year. Out of packages of four, or eight, or a dozen alkaline D cells well within their freshness date, I often find at least one cell frosted over with alkaline leakage.

Those cells still test good enough, close to 1.5v. That’s the real issue with alkalines and LEDs —- a leaking alkaline cell can still be pushing enough volts through a LED flashlight to light up, so you don’t get the warning you get from a dim orange incancescent bulb.

True, alkalines are more prone to leak when depleted. But they may also leak brand new in the package, I can assure you from experience.