Years ago when Ford still built trucks in Kansas City a friend priced a truck in Des Moines Iowa which is about 3hrs north of KC. He then priced to the same truck here at home. We are 3 hrs east of Des Moines. From KC to here you go through Des Moines. Well the shipping from the KC plant was less here and we are twice the distance.
M18 FUEL Batteries
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Go ahead and put two more in your cart and see what the price does.They're back to $149. I couldn't take it! I had to buy 'em.
michael j
ArboristSite Operative
I really don't need the ones I just bought!
You do not have to buy them but it should allow you to see price fluctuations.
On a semi-related note I am not sure of they have Menards where you live. They are a huge chain of lumberyards in the Midwest. I have been watching their price of 7/16 OSB for the last 9 months. It has fallen and remarkably not went up with to hurricane (at least not yet). Well I am now stuck in a hospital a bit over 3 hrs from home. I checked tonight and it was about $1.50 higher than it had been. I checked my home store and it was still to the same price it was when I left. So there is yet another example of different prices in different locations while still being the same company.
40 years ago in high school the grocery store chain I worked at had a price book that showed all 7 of their store zones. I was always amazed at the differences in price across the 7 zones. Sometimes they were quite large.
That sounds like something Nash-Finch would do.
Eagle Foods.....defunct now
Keep looking for sales or specials where they give you a 5AH.
The 5AH (I have 2) only runs about 10-15 min in the blower and up to 30 for the trimmer and pole saw.
The 8AH (I have 2)can run for 30-60 min in the trimmer/pole saw.
to trim out my driveway it takes all 4 batteries. To do along the road it takes all 4 batteries.
To trim out the backyard it takes all 4 batteries + dropping batteries on the 2 quick chargers.
I have not been able to run 4 hours straight yet with the 4 batteries on the trimmer, and barely make it on the pole saw.
The 5AH (I have 2) only runs about 10-15 min in the blower and up to 30 for the trimmer and pole saw.
The 8AH (I have 2)can run for 30-60 min in the trimmer/pole saw.
to trim out my driveway it takes all 4 batteries. To do along the road it takes all 4 batteries.
To trim out the backyard it takes all 4 batteries + dropping batteries on the 2 quick chargers.
I have not been able to run 4 hours straight yet with the 4 batteries on the trimmer, and barely make it on the pole saw.
One thing to note about Lithium Ion batteries (or really any batteries, but I'll speak specifically about LithIon): The cells inside the batteries don't like having to put out maximum amps all the time. With a 3.0HO, you have 5 cells having to put out all the amps. With a 6.0/8.0, you have 10. With a 12.0 you have 15. More distribution of workload between more cells gives those batteries a longer overall lifespan. Essentially: you get more actual energy out of them because they last longer.
So even though you may think (2) 3.0 HO batteries = (1) 6.0 HO battery in both power output and lifespan, that is not the case.
Another thing to note: don't fully discharge your Lithium Ion batteries. Try to charge then when they hit 25% or so. This will give you a MUCH longer lifespan. Ideally, keep your Lithium Ion batteries between 25%-75% charge. You will get a much higher total amp-hour usage out of them over their life because they will last several times longer, potentially. I learned this a few years ago from a study that was posted some years ago about lithium ion batteries and discharge rates/amounts and charge rates/amounts affecting lifespan.
So, if I were you, and you know you are going to be using some high draw devices, I would invest in a double stack m18 battery (6.0/8.0 HO) as a mimimum. Maybe even a 12.0 (although it's a lot of weight for handheld tools).
michael j
ArboristSite Operative
I do if they drop below the $149 mark.
Kinda. Sort of, if you have any real idea of what individual cell capacity is, what the manufacturer set low voltage cut off at and have any control (which you don't) over max charge voltage. Only charging to 75% is absurd, not running too high a charging rate as to keep the batteries cool is more important then trying to hit some % of charge rate to try and get extra battery life. Kinda like driving your car around with 3/4 tank of gas and never going below 1/4 tank. Doesn't work like that. 10% of capacity left is fine. But with most chargers you have no control over any of this. The lights on the batteries are more or less idiot lights that give you a general idea of the batteries state of charge.
As evident by the many battery pack tear down videos, the manufacturers don't care to balance charge the packs. This is particularly stupid as the internal resistance of the battery is what determines max charge and discharge rates. Your pack is therefore only as strong as it's weakest battery.
As mentioned before the manufacturers give no burst rating or continuous rating, so it's really anyone's guess what the max amp load should be on the packs. It's also hit and miss what cells they are using and the amp hour rating the cells have.
Then we have the ever changing and improving (we hope) electrolytes that they use in the batteries. Newer batteries have been proven to have longer cycle life and the ability to have a deeper round trip cycle as well giving us better then the previous generation performance, even if it is just marginal improvements.
With the packs currently available going larger is still better just for the reason you have mentioned that there are physically more batteries to take the load, but don't for a second assume the smaller amp hour pack can't or won't provide the needed amperage, or taking them to the designed cut off voltage will shorten their lives by any meaningful amount. It won't. You'll still be in the thousands of cycle count.
https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries
Of course, you are right about keeping a battery cool is the single best way to preserve a lithium ion's lifespan. Reducing impact is another. But what I said still stands. I have posted the best website/study I have found. Their whole website is devoted to understanding batteries.
I did the math and testing about 2 years ago with this data and found the LEDs on the M18 batteries are pretty close to what they say in the owner's manual. 1 solid bar is from 10% to around 27% iirc. Just going into the 4th bar is about 75%. With my math and from the very solid information on that site and others, I concluded it would be wise to try to never see either 1 bar or 4 bars on my m18 batteries. (You do need to allow a 5ah M18 battery to show 4 bars when charging for approximately 5 minutes so the voltages balance to around 75% after you take it off the charger.)
Yeah, sometimes I can't pop it on the charger when it shows 1 bar, but many times I can. Sometimes I leave it on the charger too long. Overall, however, it isn't that hard to keep it within the 25%-75% range and there is very solid evidence that doing so prolongs battery life.
Also, while doing my testing, I noticed the battery gets the warmest when it's on the last 15% or so of charging to 100%. This is probably one of the critical factors that affects lifespan, along with resting at a high voltage.
I think the last bit of charging on the run of the mill chargers heats them up from not dropping the amperage down, or the unbalanced cells and higher resistance cells heating up. We don't see this issue with rc batteries, balanced cells with a proper Charge curve Don't heat up like these stick packs do. I suspect if I rigged something up to my i-charger and logged the data with one of my tool batteries vs (not that I have the capability)factory chargers you would see a large swing in amperage at the tail end of the charge cycle temps lowering vs the higher temp and constant current of the factory charger.
I'm also assuming the bmu of the tool packs baytery acts as a high voltage cut off vs my rc charger that monitors individual cell voltage and cuts mains charging and goes into a balance mode through the balance leads.
The sad part about this is it leads to poor cell performance.
I assume it's a cost factor thing for the tool packs. It works good enough and life is good enough for the average user. (Can you imagine the connector to balance a tool battery for a balance board ! Lol)
Battery university is a pretty good resource, I wouldn't say definitive but a good source non the less.
Edit, I had a chance to read over the specific article you posted, updated in 2021 with references from 2016 and 2002. Both references were for the battery test data being referenced. Fairly outdated tests data, however the article is still pertinent to the general point of consumer vs industrial uses.
This is the chart I used to base my testing on M18 batteries a few years ago.
While heat is probably the #1 factor if LiIon battery death, charging to a high voltage is the 2nd leading cause. For this reason, I never store my batteries in my car/other hot areas and never charge my M18 batteries to 100%.
So far, I have seen minimal loss in capacity in my M18 batteries and I've owned most of them for 2+ years and used them quite regularly, sometimes charging each battery in my bank once per day. I have maybe 5 I use regularly out if my 10 or so: (3) 5Ah, (1) 1.5Ah, (1) HO 8Ah. I've recently (6 months ago) added 2 HO 3Ah and have been impressed. I also have 2 brand new 5Ah batteries I am not using and keep at roughly 50% charge.
The plan for those 2 is to use them to compare the capacity of the 3 I'm using now to my brand new batteries to see if my methods to preserve battery lifespan are working. Then, once my 3 5Ah batteries start wearing out, I have 2 new ones to replace them. I don't expect that for a couple years, though.
While heat is probably the #1 factor if LiIon battery death, charging to a high voltage is the 2nd leading cause. For this reason, I never store my batteries in my car/other hot areas and never charge my M18 batteries to 100%.
So far, I have seen minimal loss in capacity in my M18 batteries and I've owned most of them for 2+ years and used them quite regularly, sometimes charging each battery in my bank once per day. I have maybe 5 I use regularly out if my 10 or so: (3) 5Ah, (1) 1.5Ah, (1) HO 8Ah. I've recently (6 months ago) added 2 HO 3Ah and have been impressed. I also have 2 brand new 5Ah batteries I am not using and keep at roughly 50% charge.
The plan for those 2 is to use them to compare the capacity of the 3 I'm using now to my brand new batteries to see if my methods to preserve battery lifespan are working. Then, once my 3 5Ah batteries start wearing out, I have 2 new ones to replace them. I don't expect that for a couple years, though.
@sean donato and @Ethobling are dead-on when it comes to lithium battery health.
You can store a lot of power in a very small and light space, by running very wide charge and discharge cycles, and running your batteries hard, at the expense of cycle life. Someone else here on the forum said their drone batteries get less than 200 cycles! Run very conservative charge and discharge cycles, and you can get 5000+ cycles while still retaining 80% of originally rated capacity, but you'll need more space and mass to store the same amount of power. Pick the cycle life, space, mass, and ultimately, cost ratio, which suits your application.
You can store a lot of power in a very small and light space, by running very wide charge and discharge cycles, and running your batteries hard, at the expense of cycle life. Someone else here on the forum said their drone batteries get less than 200 cycles! Run very conservative charge and discharge cycles, and you can get 5000+ cycles while still retaining 80% of originally rated capacity, but you'll need more space and mass to store the same amount of power. Pick the cycle life, space, mass, and ultimately, cost ratio, which suits your application.
My biggest issue with the battery universe data is its severely outdated and a very small sample size of one type of lithium cell. I've been playing with these in high drain land and air based rc, high powered lights, ups ect since lithium started becoming "affordable." Outside of commercial/industrial there's no real reason to be trying to double the charge cycles at the expense of work getting done. High voltage is 4.2 volts per cell, which is also the industry standard, finding a charger that's below that is hobby or industrial grade and typically programmable. Low voltage cut off is much more important. 2.4 volts lis the latest standard, but for years 3.0 volts was what we went with. The only thing I agree with is 3.0 volts per cell is about the end of the line for high amperage applications, going below that dips under the 10% threshold and dramatically increases battery internal temperature. There are even some guys that won't go below 3.2vpc as a safty measure. This leave over 40% unused battery capacity (Typically, but will depend on many factors) thats too much to leave on the table. Again I equate this to driving your car and never going below half tank.
I'll end with I have lithium batteries, including dewalt and Milwaukee batteries that go back nearly 10 years now. I have yet to have one that has diminished in capacity to the point they are unusable. My rc packs and loose 18650 and newest 21700 batteries I monitor for mah capacity, and check internal resistance often enough to keep on top of battery health. Letting the batteries foe the tools do their thing has worked equally well.
We all have to do what works for us at the end I'd the day. Battery tech keeps moving forward and so must our views of how we utilize them.
There's a lot of work being done on increasing cycle life for solar applications. I'll be running 20-80% or maybe 25-75% SOC on my lifepo4 solar power batteries, specifically because it's thousands of dollars of batteries, and will nearly double the cycle life.
Power tools, I've only had my 80v Kobalt tools noticeably lose capacity. I don't maintain them much at all, I run them all hard, they've only ever been charged in fast chargers, and they get run in the summer heat, and they're going on 7 years old. No clue how many cycles. They still function just fine, I have no plans to replace any of them yet, but I have noticed a bit of capacity loss.
It's much easier to do that with standby power. Having a generator or shore power for back up easily keeps them in a happy place. We skipped over the solar battery back up as it's not even close to economical and life Cycles are expected to end around the 10 year mark. (There was a cycle count we were quoted, can't remember what it was for the genrac vs Tesla) were out of power a lot, and extended outages are normal, not frequent, but enough we've been on generator power for a week already. One to 3 days is normal. Hate being the dead end of the line. Even 8 hours of back up was more then the cost of the solar array. Just not worth it for us. Generator is easier till battery tech catches up.
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