[Babylon]

Also, I would suggest that two x 6 volts @ 200 AH "golf cart" type batteries in series are better than two x 12 volt @ 100 AH batteries in parallel. You have 1/2 the number of cells to check (6 cells vs 12 cells for 2x parallel batteries--Plus you can take your volt meter and do a quick check on each 6 volt battery's voltage (charging, discharging, resting). It is much easier to find problems this way. Measuring across 2x 12 volt batteries in parallel--Even if one battery has a "weak cell", you could not find that with just a volt meter. more

[srf21c]

$60 USD and is "good enough" for our needs. A DC Current Clamp meter is very easy to use (and very safe)--You just clamp the cable for each battery string and measure the charging (or discharging) current. You are looking for "differences" (one string taking too much charging current or supplying very little load current--A couple of examples). more

[wereHamster]

If you are going to be paralleling battery strings, and just very handy for general debugging--See if you can justify a DC Current Clamp DMM (digital multi-meter). This one from Sears is more

[Bit-coin]

But there are better solutions . . are they really GEL cell batteries or AGM? Those are very different but appear similar. GEL's are usually the least desirable for RE use, the most fragile lead acid type when it comes to use and care. An AGM is different from what most of us refer to as GEL. And most 12 volt batteries of any type are not usually true deep cycle batteries. You will find AGM and FLA true deep cycle batteries in 6 volt sizes. Two in series to make 12 volts.

[chr15m]

I called Ryobi after I bought this pack and three different people told me this pack "should" fit. My reply was "should" or "will" fit? Big difference. The last one I talk to was someone (whom I conversed with last year on a different subject) basically said the same thing. They do not have these packs available to them so they do not really know. Another really bad business move. No physical product to clarify questions by. These aren't riding ,mowers we are talking about so space is not a issue. [links]

[YeahR]

Ryobi came out with a 6ah 40v battery pack last year. This year they introduced a 7.5ah pack which is physical larger than their standard 4 & 5ah packs. Enough so, as far as I can tell it will not fit into their older mowers due to it's height and the sloped front of the battery compartment.

[knascit12]

Also note the manufacturing dates of both packs, they differ only by one week 1945 vs 1946 (2019 week 45, 2019 week 46) here

[Tim]

Take a look at the attachments. I wasn't fully aware of the other larger pack size when I ordered it (new, unopened, off eBay). Luckly, I purchased the smaller 6ah pack.
The 1st & 3rd attachments are the larger 6ah packs. The 2nd is the 7.5ah pack. The 4th attachment shows the difference between a 4ah, a no-name import and the larger 6ah packs. The last two show the 2 different battery pack numbers. The '1' is the smaller, the '2' is the larger. here

[KyleBles87]

There are a few dedicated, intelligent reviewers over on Amazon and one of them did some measurements and the feeling, the finding was the 'fake' 6ah packs are really just under 4ah which is I what I figured before even reading the review.

[Hal]

Due to their popularity, many designations - although outdated - have been retained. The ANSI (American National Standards Institute) designations e.g. are no longer officially valid - nor are those from JIS (Japanese Industrial Standard). Former ANSI terminology is now used only for size designations. The original designation AA, for example, was formerly used for an R6 sized (Mignon) zinc-carbon battery, using natural manganese dioxide. Today "AA" is frequently used as a size designation, irrespective of the battery's electrochemical system. [links]

[adhocimperium]

Batteries standardised by the IEC (International Electrotechnical Commission) have a clear, internationally valid designation. However, the use of this designation is voluntary, so it is unnecessarily appear on every primary battery. Nevertheless, the manufacturer's designation and the battery voltage are always printed on the battery housing.

[concetxo01]

The main numbers used for the most common NiMH and NiCad battery sizes are: here

[RogerRabbit]

here

[kldunc]

[michb]

This size flashlight battery is one of the most popular in the custom flashlight world. Pretty much every recent “custom” flashlight uses this battery, and for good reason. The latest generation of 18350 have relatively good capacity and allow flashlights to draw high amps for insane output. With only a slightly larger diameter and longer length than the venerable CR123a, there are a myriad benefits to the 18350. This is the format that I use most for EDC. Some may find it a little too robust relative to the CR123a, but the trade-off of greater output, capacity, and rechargeability is worth it to me. The Oveready BOSS 35 is a well-known, custom flashlight that uses the 18350 battery. here

[Jason]

As a comparison, pictured here from right-to-left are two IMR16340, a standard li-ion 16340, and a standard CR123a battery. here

[dorothymedney]

One of the easiest ways to get a general idea of what size battery you’re looking at is by noting the battery’s name. The size of AA/AAA/C/D batteries are common knowledge, but take for example the not-so-common 10280 battery. Even if we’ve never seen or heard of the battery before, those numbers tell us the battery’s dimensions: 10mm x 28mm. The “0” at the end denotes a cylindrical diameter. Now that I’ve explained battery nomenclature, let’s go over some of the most popular battery formats in EDC flashlights.

[piotrp]

There’s no definitive guide to which flashlight you should purchase, but the battery format of your flashlight is undoubtedly one of the most important things you can consider. [links]

[eurekafag]

Some manufacturers also have begun offering both an 18350 body and a longer 18650 body with their flashlights. Cross-compatibility between the two body sizes allows users to reap the benefits of both worlds, and adapt as the situation requires. [links]