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After much, much consideration I recently bought cordless lawn gear. A mower with battery and charger and a line-trimmer skin. I could have bought petrol stuff for considerably less than half as much.
Thing is with this stuff, it comes with a 3 year commercial-use warranty on the battery and 5 years on the gear. The battery I got is about 350 bucks but it's just made with 'std' 20A discharge 18650s and a potted management circuit, as long as you don't bust the sleeves of phase-change material that helps manages temps it's a fairly straight-forward operation. The battery has it's own fan too and even discharges itself to storage voltage if not used for about a month..
Perhaps one of the more important aspects of success is as you mention, adequate connectivity between cells. Guess what? You can buy spot-welders intended for doing battery terminals for surprisingly little money. The price of reasonable cells in most any replacement job will in fact, be larger!
30 or 40 aussie bucks will buy something
DIY Portable 12V Battery Storage Spot Welding Machine PCB Circuit BoardB;S* | eBay
Mini Welder Pen Display Spot Welder Machine Equipment 18650 Battery Powered AU | eBay
But that only matters if you can't find cells that already have solder-tags welded to them. You should be able to solder them without being worried about overheating the cells. I soldered directly to the outside of some 18650s last week with a 75w PWM controlled iron - tags on some NiCads should be a doddle with the help of a soldering third-hand.
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NiCad batteries are notorious for failing very early if you don't deplete them almost completely before recharging them. (This does not apply to other technologies, like lead acid or lithium.) Try to run NiCad batteries down to close to zero before recharging them. If, for example, you start recharging them when they still have 80% charge left, they soon lose the 80% capacity that you never use. For this reason I avoid NiCad at all cost.
Also: Cadmium is an extremely toxic carcinogen and I believe these batteries should be banned.
Get me coffee and no one gets hurt!
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It is a waste... but maybe you can turn it into a corded one if you can find a power adapter with the correct power output.
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Try a three-day regime of charge overnight, disconnect in the morning. Run the device for a couple of minutes straight after disconnecting.
Has worked for me on several occasions. It also helps if you never let the battery go much below 40% of its capacity, as this shortens its life.
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Something that I don't think has been mentioned yet. There is a big difference depending on battery chemistry.
Older cordless tools used NiCd or NiMH chemistry, almost always made up of "sub-C" cells. One clue is that the nameplate voltages are multiples of 1.2V.
They like being stored fully charged or nearly so. As someone else mentioned, they can sometimes be refreshed by a few deep cycles, although they don't like deep cycling as routine. Those battery packs often fail with a single cell in the series string going low or even reverse voltage (and unable to pass useful current).
The good news with these is that, if you can open up the pack, they are quite easy to rebuild with sub-C cells (get the ones with solder tags welded on).
Newer cordless tools, particularly the "impossibly powerful" ones, use some sort of Lithium battery chemistry. Unless you really know what you are doing, or have a friend who does, I'd keep my fingers out of the pack. They are lovely batteries when well kept (balanced, etc) but also fire-prone if abused (or sometimes even just looked at the wrong way). I'm sure some of our RC modeler friends can chime in on this one. Lithiums are generally happiest if stored part-charged.
Not a battery expert by any means, but I've been around the traps.
Cheers,
Peter
Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012
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I bought a cordless strimmer (OK, before anyone says it, it has a nylon cord to actually cut the grass so not completely cordless). The battery (according to the charging unit and its on-battery tester) is fully charger but the unit does nothing. I've pulled the strimmer to pieces and all of the wires look OK.
I also have a cordless lawn mower. The batteries take a couple of hours to recharge and have a run time of ~30 mins. So, with two batteries, it is 1 hour mowing, 1 1/2 hours watching TV, 1 hour mowing. A spare battery is £70 and I do not know how much a 2nd charger would be. I saw a strimmer with the same battery pack for £90 - I thought that would be a good investment just for the battery, but the small print says it doesn't come with the battery or charger.
So. it's back to long cables and extension leads for me.
Having said it, I have two cordless drills and they are good! More powerful than my corded one.
How long before people with electric cars realise that they have fallen into the same trap?
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jsc42 wrote: How long before people with electric cars realise that they have fallen into the same trap?
After about eight years and a bit.
Which is after the first owner.
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jsc42 wrote:
How long before people with electric cars realise that they have fallen into the same trap?
The sad part about that sentiment is that car manufacturers are vowing to become all electric within the next few decades.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
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If they can sell more cars.
I don't think they care what cars they are as long as they sell.
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5 years ago I bought a cordless drill.
1 year ago, I could not even drill a hole in a package of butter.
I looked around for a replacement battery and found one.
The downside was that while the drill was £41, the battery was £35.
And a brand new model of the drill was just £33.
So while you might get replacement batteries, it is not always smart to buy them.
First, look around if there isn't a better value for money replacement.
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JohaViss61 wrote: brand new model of the drill was just £33.
33 for a drill ? That maybe explains it.
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And it was a Black and Decker.
The DIY stores are always promoting stuff. It is like a battle between them
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JohaViss61 wrote: The downside was that while the drill was £41, the battery was £35.
And a brand new model of the drill was just £33. This is why I buy around November/December when I can get a drill motor, two batteries, charger, and case for $100. A lone battery is around $55.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
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Too bad they never break down in October/November/December, but in February/March/April
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Sorry but Ryobi would like to have a conversation with you. Same battery interface with full backwards compatibility going back to 1996.
Furthermore, most of the rest of the companies had to standardize as well because of their (Ryobi) stalwart dedication to the same battery voltage and interface.
Now if you want to cheap right out on something from Princess Auto, Harbor Freight, Canadian Tire or some other truly house brand tool from your local hardware/department store, then yes. You will likely find disappointment.
As to any of the complaints about power or runtime, it is clear that any of you making such a comment have never used Lithium Ion tools. I will use my 18v LiIon tools far faster than any of my corded equivalents for both the cordless AND power convenience. Add in the fact that newer brushless motor tools have been added to the Ryobi lineup and now you have even more power and longer runtime. And again... All on the same battery standards since 1996.
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As soon as I put Dyson here, im sure people will be shaking their heads.
Anyhow, got a handheld vacuum cleaner near 10 years ago. The battery which at the time rated to last 10 minutes, which for a daily quick run around small house is usually plenty.
Move 5 years on, that was maybe 5 minutes. So gave in last year and look up knockoff replacement. Keep in mind the battery unit on these things is designed to clips out easily.
Yet Dyson do not seem interested in over priced selling on the battery unit, instead change a little plastic connector num, which likely i could shave of and still connect..
Im here like im will to shove money in your face, but nah, same tech in a very slight different housing.
But knockoff market was good. Battery with double capacity then the dyson branded (its more cells inside and dyson which is purposely weighted to feel heavy instead of using the space, not surprising)
Battery worked great, until it ran out and went to plug in the power charger.
No charge. Odd that the charger has more detection prevention then the main unit.
Initially gave up, went back to 2-3 minute charge battery.
Then tried lookup battery charger, ok price. and works just fine.
Again, same battery 99% of shape still in use by Dyson, but every year they change the connector so they can market changeable battery but still keep in obsolescence
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On the battery there will be a model number. Put that model number into duckduckgo search engine and see what you get. I have an old Black & Decker battery electric mower (old as in late 90s) and I can still find batteries for it.
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NiCd batteries need to be used regularly to be able to hold a charge. It's a poor choice for something that's going to sit unused for most of a year (not that it was your choice). You might have better luck with lithium batteries. There are also battery repair stores all over the place, so they might be able to extend your tool's lifetime when it comes to that.
A cord on a hedge trimmer is going to be just as annoying if your hedge is large. And eventually the plastic insulation on the wiring is going to break down. Maybe you'll get twenty to thirty years out of it. Plan your budget accordingly.
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I bought several products from a "universal" line of small battery-powered devices, figuring that the battery packs would be replaceable and interchangeable. Not only did the battery packs die, but the company didn't add any models to their line, so both the product and its entire concept became obsolete.
Some of the motors for these battery-powered devices make good robot effectors.
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No Science here but if you are going to purchase a cordless anything
in the Power Tool Visit the local Pawn Shop and look at the brands and
the type of Battery the tool requires and the motor type Brush less
vs Brushed
You will find very few Milwaukee M 18 Lithium Brush Less tools
Ryobi 18 Volt Lithium Brush Less Tools
If you are shopping NEW this is a way to weed out what you do NOT want
Ryobi and Milwaukee are both owned by Hong Kong based manufacturing company Techtronic Industries
The price difference is HUGE by my standard that said I still believe you get what you pay for
Side Note I have a 20 year old Dewalt Corded Drill will drive screws in 2 in OAK with no effort
the Milwaukee Fuel Hammer Drill takes longer and more effort
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We've used a local place that would take those packs apart and rebuild them for us. I think it was Batteries Plus.
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batteries plus will rebuild the batteries for you.
To err is human to really elephant it up you need a computer
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I used to use rechargeable nicad batteries with bicycle lights. I learned from the seller that you have to fully discharge the battery before recharging it, otherwise it develops a type of memory where it will not hold more power than you usually use.
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An 18v Ni-Cd battery is not going to last very long. All the cells are in series, and so they all discharge and charge at the same rate. But since they don't have exactly the same capacity, the weakest cell will end up being fully discharged first (and possibly reverse charged, which is especially bad for Ni-Cd cells), and it will be fully charged before the others, further stressing it. Once this cell goes bad the whole thing is toast. So fully cycling an 18v Ni-Cd battery can cause it to go bad sooner than mostly discharging it.
I have several of the Ryobi one+ series of tools and batteries. All the Ni-Cd batteries have long ago gone dead and been discarded, and all the Lithium-Ion batteries I bought are still going strong. Yes they cost a lot more, but they are well worth the difference in price.
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