Senile Texas Aggie - comic relief for the rest of you

[Senile_Texas_Aggie]

I always fully recharge them. I have 3 batteries and 2 chargers. The 3 batteries last as long as we normally feel like working. When I did some research on the Internet about Lithium battery life, I repeatedly read that to discharge a lithium battery past 80% depletion shortens its life. Yet we have no way of knowing how much charge remains. We simply use the battery until the tool we are using (usually the reciprocating saw) no longer works, then switch batteries. Is there a more reliable way to determine how much charge remains in a battery?

 

[Baymule]

That's what I do. How the heck are you supposed to know when there is 20% left on the battery? Saw or drill stops, I get another battery, plug in the other one. I have a Hitachi drill and saw, love them!

 

[greybeard]

I always fully recharge them. I have 3 batteries and 2 chargers. The 3 batteries last as long as we normally feel like working. When I did some research on the Internet about Lithium battery life, I repeatedly read that to discharge a lithium battery past 80% depletion shortens its life. Yet we have no way of knowing how much charge remains. We simply use the battery until the tool we are using (usually the reciprocating saw) no longer works, then switch batteries. Is there a more reliable way to determine how much charge remains in a battery?

 

[greybeard]

I hope everyone knows, that the 20vMAX is 18 volts just as most "20v" labeled batteries are just 18 volts.

 

[Senile_Texas_Aggie]

Mr. @greybeard, sir, you are a genius and I am, well, a Senile Texas Aggie. I didn't remember seeing the indicator above, so I walked out to the shop, and sure enough, there it was. By pressing the battery charge button, the lights will then light up. It may be too late to save these older batteries, but I will know to treat any new ones more carefully! Thanks, Mr. @greybeard, sir!

Senile Texas Aggie

 

[greybeard]

The old way is to check the battery with a voltmeter. 80% of 18V is 14.4V.
It's hap hazard/iffy because you can let a just used battery sit a few minutes and the voltage will be higher after a little rest as the electrons begin to 'settle/even back out' across all the individual areas of the battery instead of being all piled up on the negative side of the last individual battery inside the pack. But, if you know your way around a voltmter and how a Dewalt 20v battery is built, you can also check each cell, as well as total batt pack voltage without taking the pack apart. Most battery makers conveniently label the terminals.
Your Dewalt battery pack will roughly resemble this on the business end:

Placing you vom leads as shown, will display full voltage of the battery pack.
To check each cell, you would check each of c1, c2, c3, and c4 relative to Batt-.
(TH and ID are thermal lead and battery id respectively for use by tool & the charger, TH being an overload protection when the battery is in use, and will also prevent charging if the pack is too hot..often happens when pulled right of the tool after hard use. TH is a thermistor, ID has a resistor. )
Each cell, right off the charger, checked from it's respective terminal, should read just over 4vdc.
For instance.C1 to Batt Neg may read around 4.08v.
C2 to Batt Neg would read a combination of it's voltage and C1's voltage or around 8.16 volts. C3 to Batt Neg would it's voltage plus the voltage of C1 and C2...
If you come up with one cell that shows low (for instance C1 shows 4.08, but checking C2 shows 6.9V, you know C2 is bad because 4.8V of that 6.9V came from C1.
You also have to include checking B+ to B- because there is another cell at the end.

Altho the terminals reflect 4 'cells', there are probably more individual batteries in the pack than 4...perhaps as many as 10 individual little batteries They are all connected in such a way as to make up 4 (or more) cells then combined into one pack. There's a little board inside there as well.
I don't remember the name, but there is a website that shows all this for virtually every battery pack made and explains it much better than I did. Some Russian or Scandinavian sounding name. Starts with an 'S'.

Why would you want to know all this? Each cell inside is identical to the others. If you have a bad pack, save the individual cells that test good and then you can repair any other bad packs you have in the future. Usually just takes a soldering gun.

 

[Latestarter]

I have the same Dewalt batteries and I just use them till the tool starts to "bog down" then stop and swap them out. I've never run the tool until the battery is completely dead and the tool stops working.

 

[greybeard]

All electric motors operate pretty efficiently up to about 10-15% voltage drop with little or no noticeable loss of power.
DC can do it a little better, but not much, especially on battery powered stuff. At beyond 20% drop in voltage, heat becomes a major issue for the battery and heat is the weak spot and downside of all lithium ion batteries. The battery pack may not feel real hot, but inside each of the cells, the temps can get excessive and there is little to dissipate the heat in such an enclosed compact package.
When you run a battery down to the point the motor is noticeably lagging or lacking torque, you're very much shortening the life of the battery because of heat.

 

[Senile_Texas_Aggie]

Thanks, Mr. @greybeard, sir! Although I have probably shortened the battery life of 3 battery packs, I will start checking the charge remaining. Lowes has a sale on Dewalt battery packs right now, so I will probably buy some more. Also, I will make the checks you recommended above for each of the cells and see if there are any bad cells. Maybe I can cannibalize some good cells from the 3 battery packs and end up with 1 or maybe 2 completely good battery packs.

 

[Senile_Texas_Aggie]

Well, folks, I haven't posted on here in awhile, so I thought I would provide an update. (Since my last post, I had been stalking @Mike CHS and just finished a few minutes ago.)

We visited family over Christmas, and again the weekend before New Year's (New Year's Day is my younger sister's birthday). Just before the end of the year, we signed a 5 year lease on our pasture land. The man who leased the land will be responsible for all improvements (lime, fertilizer, weed killer, etc.). I provided him the soil reports I got earlier.

We haven't done anything around the farm. With this really cool, albeit wet, weather we have been having, I have been trying to talk myself into getting out and cutting down the vines, shrubs, and small trees around the edge of the pasture. But after seeing just how quickly the power company was able to trim the edge of the woods (they did in 2 days what would have taken us 2 months to do), I'm not all that eager to get out there and do it the way we were doing it.

When my Beautiful Gal and I were clearing the brush and trees from around the dam of the pond, I happened to watch a YouTube video on the "Outdoors with the Morgans" channel which showed the guy (I can't remember his first name) using a grapple on a tractor. I was amazed by how much he got done using that thing. I don't think I had even bought a tractor at that point, but we stopped working on the pond for awhile while I researched tractors and grapples. We finally decided to continue on the pond before I was able to find a tractor and have a 3rd function valve and grapple installed, so it did not help any with the pond, but ever since I got that grapple I am so glad I did. I can no longer imagine trying to clear brush without it.

So given my experience with the grapple, I wondered if maybe there was something I could find that would do the job easier and faster at a reasonable price. I found the product named BrushShark that looked impressive (see http://brushshark.com/), but the $5,000+ price point had me going OUCH! (That is what my 3rd function valve and grapple combined cost.) So I looked into perhaps renting a skid steer with a mulching attachment would cost. The closest one I could find was in Longview, TX (just under 200 miles away) and the cheapest one there was over $5,000 a week! Another OUCH! So, do you folks know of anyone who has rented or bought any brush clearing equipment that would clear brush and small trees (besides a rotary mower) that I could use around the edge of my pasture, as well as for cutting paths through the woods?

Senile Texas Aggie