M18 FUEL Batteries

[OM617YOTA]

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.

Oh yeah, if you're buying an off the shelf Generac or Tesla system, and spec'ing it in to run your whole place just as if it's a normal day, it's stupid expensive. I went DIY, and only for the necessities. Cost the same as a Kubota LowBoy diesel, but "fuel" falls from the sky. If it needs batteries again in 10 years, so be it.

 

[sean donato]

Oh yeah, if you're buying an off the shelf Generac or Tesla system, and spec'ing it in to run your whole place just as if it's a normal day, it's stupid expensive. I went DIY, and only for the necessities. Cost the same as a Kubota LowBoy diesel, but "fuel" falls from the sky. If it needs batteries again in 10 year, so be it.

I'm not knocking the system or the batteries, just the cost. I roughed out a diy system and came in around $12k. The little mosa generator I got blown up for $500.00 put another $300.00 in it and is just large enough to keep the house going sans the hot water heater in summer. Winter it's pretty easy as there are no ac units running. Still have to kill the hot water heater. Wish it was gas...

 

[Franny K]

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.

Are you depleting the batteries all the way? There is likely a thermal cut off as they get hot don't they?

Four hours straight. Might be 3 hours if you had a larger gasoline trimmer?

 

[J D]

As I understand it (as simply as possible), lithium battery voltage range is very dependent on electrolyte which varies across manufacturers & cell design (this variation also makes lithium batteries particularly challenging to recycle).
The lower cell voltage drops the more corrosive the electrolyte becomes to the internals.
Charging an overly discharged battery will cause a film to form on the anode raising internal resistance. Further cycling of the cell will then result in excessive heat &/or gassing (hence the fire/explode concern).
Overcharging (& even just being fully charged to a certain extent) causes other chemistry issues & can lead to thermal runaway (catastrophic failure).
The key thing is the voltage at which problems start will vary a bit, but the further past that point the cell goes & the longer it stays there the more damage is done.
A rough analogy would be to look at battery charge like tyre pressure... if you over inflate it "bang", keep it at max rated pressure & some areas will wear fast, the flatter you let it go the more other areas will wear & if you run it completely flat it will ruin it. Ideally you run it in the mid range... the farther outside that range & the longer you run it there the faster it will wear out.

 

[kenmbz]

Are you depleting the batteries all the way? There is likely a thermal cut off as they get hot don't they?

Four hours straight. Might be 3 hours if you had a larger gasoline trimmer?

I try not to let them overheat and will swap out sometimes.
With the gas trimmer I could go all day, about 1 hour per fill, can carry 2 gallons ready to go.
This battery stuff would have worked better at my old house, just too much edge area here, but it's what I have, looking for another 8ah when they go on sale, that would probably be enough to last as long as I need per use.

 

[michael j]

Well, FWIW, my batteries were delivered to a residence in California. Since I'm in Ohio, it hardly seems to be the right location. Amazon's refunding me.

 

[kenmbz]

Just got another M18 8AH with a "free" 3AH.
This should finally allow me to run the weed whacker and pole saw long enough to tire me out.
takes 3 8AH, to run 3 hours, including breaks.

I still use a gas brushcutter, as I don't see any battery device that can handle that punishment anytime soon.

 

[BusaDave]

Just a FWIW-----just got a flyer from Northern Tool. It also has a couple of 20 off $100.00 orders. The advertised special price for 2 3.0 M18 batteries is 99.00 plus a 20% off coupon on a $100.00 purchase so you will have to buy another dollar worth of products.

 

[OM617YOTA]

Yesterday some Milwaukee kits were half off at Home Depot. $500 off a $1000 kit, $300 off a $600 kit, two batteries and a charger for $100, etc.

Only lasts one day, though. You really need to check every single day.

 

[Ethobling]

Wanted to update everyone on something I recently learned about Milwaukee's batteries/charger.

I recently acquired 14 1.5ah Milwaukee batteries that only charged to 3/4. I'm currently balancing the charge between the individual cells in each pack and getting them to an almost "like-new" state.

Anyway, that's not important. What I found out is Milwaukee's charger only charges the cells to 4.1V, instead of the "industry standard" of 4.2V (which would get the "max" available current from each cell). This means Milwaukee is already doing a bit of battery lifespan lengthening and, effectively, means the charger only charges to 85%-90% of the max charge.

I will update later as to how low the battery will let the individual cells discharge to, since this is also very important to longevity.

 

[Ethobling]

The batteries discharge to 3.0v, which is pretty standard.

 

[sean donato]

The batteries discharge to 3.0v, which is pretty standard.

Interesting, that's lower then I expected. Guess if they arnt charging them to full capacity they may as well take them down the extra .2volts

 

[Ethobling]

Interesting, that's lower then I expected. Guess if they arnt charging them to full capacity they may as well take them down the extra .2volts

Yeah, I guess. I don't know if it really matters much, though. These batteries usually have a cut-off voltage of 2.5v. Also, 3.2v to 3.0v probably only gives them maybe 50-100mah added to the pack's capacity.

Do you have any info on discharge voltage compared to longevity of the cells? I thought I had some, but not really.


Edit: Also, my current sample size is 1 pack, so my data at 3.0v isn't very reliable, yet.

 

[sean donato]

Yeah, I guess. I don't know if it really matters much, though. These batteries usually have a cut-off voltage of 2.5v. Also, 3.2v to 3.0v probably only gives them maybe 50-100mah added to the pack's capacity.

Do you have any info on discharge voltage compared to longevity of the cells? I thought I had some, but not really.


Edit: Also, my current sample size is 1 pack, so my data at 3.0v isn't very reliable, yet.

Sorry, didn't get a notification. No I don't have any information going under 3 volts per cell. Big no-no with lithium polymer. I'm wondering if the different chemistry is the reason for the lower charge and discharge voltages.

 

[Ethobling]

Sorry, didn't get a notification. No I don't have any information going under 3 volts per cell. Big no-no with lithium polymer. I'm wondering if the different chemistry is the reason for the lower charge and discharge voltages.

Probably.

All I know is I try to keep my voltages not too high or too low.

I recently got into the Ridgid platform (Black Friday last year) and am using their batteries the way most would: fully charge and then fully drain; repeat. I want to test and see how long they last/how long it takes them to decrease down to the capacities of my 2-3 year old Milwaukee batteries I've been carefully charging/discharging. I'm running my Ridgid batteries with an adapter in my Milwaukee tools, too. I figured since Ridgid has that LSA, I get free replacements anyway for life, so why not?

Time will tell how well they perform.

 

[user 189850]

Milwaukee M18 Fuel (and M12 Fuel) are my primary power tool line. In the M18 packs, I have 4.0 and 5.0 ones. I do have the 5-inch Fuel grinder, and love it. I will always try and grab a 5.0 (as opposed to a 4.0) if I know I'm going to be using the grinder. I have some 2.0 M18 packs, but I don't use those on the grinder.

On a related note, I had one 4.0 and one 5.0 pack stop charging at 3-bars. I opened the pack, and used an XTAR (any 18650 charger would do), and manually balanced each pair of parallel cells. What is interesting is that I got them to 4.2V/100%, but when I pressed the button, it still did the 1-LED rapid blink (indicating a problem). I put it on the charger, and after a second, changed to GREEN (on the charger), meaning fully charged. And when I pressed the battery level button again, 4-bars. So the charger and the battery had to "talk", so that the charger could tell the onboard BMS (battery monitoring system), you're good to go now. Something to keep in mind if you manually balance your M18 pack.

Here is a 3-D printed dummy cell I use to manually cell balance w/ the XTAR charger (also includes some pics of the setup):

https://www.printables.com/model/198538-lithium-charger-dummy-cell-adapter