Porphyre wrote in to request a deeper look at cordless power tool batteries, particularly their weights, power, and runtime.
Howdy. Idea for an article here. It’s not ‘sexy’ but a comparison article detailing different manufacturers’ battery offerings would be interesting. I’ve been searching online for something like that, but haven’t found it.
I’m thinking different classes of battery (9v, 14v 18/192v) and show the different offerings (nicad, lion, lion extra life), then show the weight and rated amp hours. Maybe throw in any manufacturer supplied info such as runtime or “screws driven”.
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I was looking for this because of Craftsman’s recently release 4ah Lion ‘XCP’ battery. Dang thing costs $99. I can get 3 NiCads for that. I was trying to see how light it was, but CMan’s website was a little contradictory.
Anyway, I think it’d be cool to see a comparo chart… Milwaukee, Dewalt, Makita, Ryobi, Craftsman, etc. Maybe one manufacturer’s 18v batteries are consistently 6oz lighter than another’s??
I am always eager for reader requests, ideas, and suggestions, but I cannot always answer each one positively. This is one of those times when I cannot grant a reader’s request. After explaining in an email why I couldn’t do as the reader requested, I decided to post my initial response here:
To be frank, if I did put together such a comparison, it would be immensely difficult to maintain, and information would be difficult to verify. I put together a battery Ah rating and charging time comparison less than a year ago, and some of the information is already outdated.
Battery weights can potentially change between generations and even manufacturing batches without notice, as brands sometimes upgrade capacities and electronics without making any announcements.
Battery runtime is also impossible to provide, as there are too many influential factors. Batteries’ amp-hour ratings are tool-independent, and should give a good sense of comparative runtime. For the same tool and identical usage pattern, a 3.0Ah battery should provider greater runtime than a 2.0Ah battery.
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Read More: What does Ah mean?
The only way runtime could be measured is if I created a way to consistently and repeatedly drain each battery pack, but even there are so many variables that I wouldn’t be able or willing to stand by any data such testing would produce.
Regarding battery chemistry comparisons, all brands have been moving past NiCd batteries, with even Ryobi and Craftsman offering “budget” Li-ion battery pack offerings. These days there is very little interest in discussion of NiCd battery packs in the power tool industry.
In general, the weight differences between the brand’s 12V Max, 18V, and 20V Max battery packs should be comparable to others in their class. There might be some differences due to battery housing cases or added electronics, but there shouldn’t be any difference between like-class and like-size battery packs.
If I worked out a chart showing the weights of major brand’s battery packs, the result would be a bunch of numbers that don’t really tell you much. There are few conclusions that could be made from such data.
Regarding Craftsman’s C3 batteries, I can’t dig up details about their NiCd battery’s charge capacity, but I know it’s a lot lower than the 4.0Ah of their XCP battery. Craftsman does have 1.3Ah and 2.6Ah Li-ion batteries, but if you want 4.0Ah in a single pack the XCP looks to be the only option.
According to Sears product descriptions, the NiCd battery weighs 2 lbs and so does the XCP 4.0Ah battery. I don’t trust these numbers, as they could be the “package” weight and not product weight, but Li-ion chemistry batteries are lighter in weight than NiCd batteries of similar charge size. It would not be unreasonable for a 4.0Ah Li-ion battery pack to weigh the same as a 2.6Ah or even 2.0Ah NiCd battery pack.
Nick Marques
Well, I don’t agree that you “cannot” do such a comparison, but I agree that it isn’t a meaningful comparison if you did do it. Yes, battery performance will vary by tool and tools will vary by manufacturer.
If I were to test this, I would find a way (perhaps making a custom wire harness or connector) to hook up different brands of 12V battery to a single 12V tool. Special equipment could be used to hold the trigger (in a drill for instance) and measure the RPM over time. Then do the same set of batteries and test on a different manufacturer’s equivalent 12V tool. You probably don’t have this equipment, but it is out there.
This could tell you if one manufacturer’s battery is better, and you could see if it is better across brands.
That said, there’s a lot more important things when buying tools than which has the better battery including tool performance, weight, compatible tools, product line, warranty, availability. For instance, I would take my Bosch 18V with LED meters over any other brand that doesn’t have a gauge on it.
Jerry
Maybe just connect the battery to a row of lots, and see how long before they dim past a certain point. This maybe could be done with just a little wire, and connectors.
Stuart
Common LEDs would take way too long to drain a single battery. That would introduce other sources of error, such as due to different temperature fluctuations.
Stuart
Li-ion batteries tend to be smarter than NiCd battery packs, and the electrical contacts are not simply + and -.
In theory I could borrow or buy an electronic load tester to provide measurably and repeatably drain power, but even then we won’t learn much from the data.
Jerry
My (limited) experience has been that NiCad battery weights seem to vary much more than the Lithiums. Honestly, i think the case might weigh more than the cells, in their case. Anyway, I have found not enough weight difference to really notice when using, within any of the families of lithium packs. To me, all the compact 12 or 18-20 volt packs were about the same, and all the high capacity ones were very close to the same weight within their voltage.
The big thing is the west difference between NiCad & lithium. The lithium are significantly lighter.
As to ratings, in theory, all batteries of the same ah rating should provide the same energy capacity, and likely more difference would be noted in the efficiency of the tool itself (brushless?).
Another thing hard to quantify would be cell life. I have had batteries last for years, and I’ve had them puke out in 6 months. I would be more curious as to which ones lasted more charge cycles or time.
Jerry
I meant weight difference between NiCad and lithium. Dang auto correct.
mikeh
Seems like a lot of work for what would be an unused set of conclusions – what I mean is, most likely the results would be in a generally narrow band, so if you told me a Milwaukee 18v outlasts my dewalt by 30 minutes and weighed a little less I’m not going to start buying Milwaukee tools – it would seem that this study might only benefit a few guys looking g to jump into new tools….pretty small group for the amount of work that would be expended – please use your time for the greater good and give us lots more tool reviews
Porphyre
Thanks again for the personal reply. Keep up the good work here at ToolGuyd! 🙂
Javier
That would be a full time job trying to figure out since like you said they’re always updating packs behind the scenes. Not only that but even within one brand runtimes can vary depending on the tool, brushed/brushless. Also each tool is optimized by the manufacturer differently.
joe
One thing I have learned over the years is that consumer criticism influences evolution. Although this may seem hard to do, it is needed to “influence” manufacturers to get us the best technology out there.
I once tried to learn about battery technology and it took me days reading articles and then you have new batteries in new tools that do not even have documentation….
anyways…I believe your best option would be to get in touch with a guy who does this….here is an example of what I stumbled upon a while back from a guy that knows his stuff…
“A123 APR18650M1 cell have nominal voltage of 3.3 volt and 1000ma this give a 3.3 w/h, output 30amp discharge
sony se us18650vt cell have nominal voltage of 3.7 volt and 1100ma this give a 4.07 w/h, output 15Amp discharge
sony se us18650v cell have nominal voltage of 3.7 volt and 1500ma this give a 5.55 w/h, output 15Amp discharge
sanyo UR18650SAX cell have nominal voltage of 3.7 volt and 1250ma this give a 4.63 w/h, output 20Amp discharge
Samsung INR18650 13q cell have nominal voltage of 3.6 volt and 1300ma this give a 4.68, w/h output 18Amp discharge
Samsung INR18650 13p cell have nominal voltage of 3.6 volt and 1300ma this give a 4.68, w/h output 10Amp discharge
E-Moli IMR-18650E cell have nominal voltage of 3.8 volt and 1400ma this give a 5.32w/h, output 20Amp discharge
dischage rate give you the torque possibility of battery,but the real workhorse is the watts/hour it give you the real capacity of the cell,the power output in the time.
you can make the cost per w/h of battery yourself”