One thing going for the MILWAUKEE Lithium-Ion batteries is the 28volts.
Do a Philip Taylor and leave the cells in the pack.
Its good for a 10 ft drop as is.
28volts is suitable for a few of our bots; the dewalts 36v is a bit high. _________________ Satisfaction is proportional to effort and results.
Mon Apr 16, 2007 8:11 pm
Karmond
Joined: 16 Jun 2004
Posts: 97
quote:Originally posted by Rotwang:
One thing going for the MILWAUKEE Lithium-Ion batteries is the 28volts.
Do a Philip Taylor and leave the cells in the pack.
Its good for a 10 ft drop as is.
28volts is suitable for a few of our bots; the dewalts 36v is a bit high.
The packs are rated at their max voltage. The A123 cells are actually 3.3v nominal so the dewalt packs are actually 33v. The eMoli cells are 3.7v nominal, so the Wilwaukee packs are 25.9v.
I was thinking about going for eMoli cells until I found that they drop their voltage and AH the more current you pull out of them. They're only 10-15C 3000mah cells too, so you can't try and get any more than 45A continous out of them, but at that point they're giving you less voltage and mah than the A123 cells.
Mon Apr 16, 2007 8:40 pm
Rotwang Experienced Roboteer
Joined: 15 Jun 2004
Posts: 1589
Location: Vic
I think you need to have a word with Dewalts and Milwaukee Karmond; they are the ones claming the 28 and 36-volt figures.
I only used their numbers to avoid confusion.
I prefer to talk number of cells so a 7 cell pack in this instance.
Reboot runs on 3 100 w scooter motors 2 for drive and I for weapon.
I think the E Moli can handle that
Charging is another factor. _________________ Satisfaction is proportional to effort and results.
Mon Apr 16, 2007 9:20 pm
Karmond
Joined: 16 Jun 2004
Posts: 97
quote:Originally posted by Rotwang:
I think you need to have a word with Dewalts and Milwaukee Karmond; they are the ones claming the 28 and 36-volt figures.
I'm not saying there's confusion about it, just fact. They're using the max figures of the cells rather than the nominal values that you're used to with NiMH and NiCad cells. It would be like claiming an 9 cell NiMH pack was 12v, which is true... for the first few seconds.
But ignore what I said about eMoli dropping V and AH under increased current, I'm stupid and all batteries do that. However the drop in MAH for the eMoli cells is quite significant under current in comparison to the A123 M1 cells.
Ok I concede I made a mistake; the Milwaukee packs are labelled V28 not 28V.
I think if you take a second look at my original post and take my comments in context you will see that I was speculating on using the complete packs in there original form, not taking them apart and reconfiguring them.
This is why I resorted to the manufactures labelling system. _________________ Satisfaction is proportional to effort and results.
Tue Apr 17, 2007 12:37 pm
ffej Experienced Roboteer
Joined: 22 Jun 2004
Posts: 595
Location: Kurrajong, NSW
The E-Moil's also (aparently) have an internal "fuse" (think IBC) that will take your pack open circuit if you draw more than ~60A . . . kind of a bad way to fail. _________________ Jeff Ferrara
fb@ffej.net
ffej.net
Tue Apr 17, 2007 1:28 pm
Karmond
Joined: 16 Jun 2004
Posts: 97
quote:Originally posted by Rotwang:
I think if you take a second look at my original post and take my comments in context you will see that I was speculating on using the complete packs in there original form, not taking them apart and reconfiguring them.
This is why I resorted to the manufactures labelling system.
I wasn't in disagreement with anything you said in particular in that post. Just pointing out that the labelling wasn't 100% accurate. You asked in a previous post about the cells:
quote:Originally posted by Rotwang:
Just wondering if anyone has tried the MILWAUKEE Lithium-Ion batteries. They claim 4-volts 3 amp hours.
I guess my post would have been better in response to that.
quote:Originally posted by ffej:
The E-Moil's also (aparently) have an internal "fuse" (think IBC) that will take your pack open circuit if you draw more than ~60A . . . kind of a bad way to fail.
I don't know anything about this fuse stuff, but considering the cells go to 60 degrees celsius at 45 amps it's probably a good thing.
Tue Apr 17, 2007 3:10 pm
cerberus3112
Joined: 05 Dec 2005
Posts: 497
Location: Mt Druitt,Sydney,NSW
I know this might sound a bit stupid but is there anyway to check if rechargeable batteries are any good prior to charging????
I dont want to charge them unless I know there good I believe that they might explode _________________ A journey of a million miles begins with a single step followed by a hell of a lot of other steps so get walking
Tue Apr 17, 2007 10:20 pm
Totaly_Recycled Experienced Roboteer
Joined: 15 Jun 2004
Posts: 1346
If in doubt charge them with a very low current 20 to 50 mili amps for an hour or so and then check iff they are geting warm and chect that they are holding a voltage it also depends greatly on the type of rechargable batery as wel .
Tue Apr 17, 2007 10:44 pm
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
depends what you mean by "good" if you mean worn out and you have a good charger like a triton they just flat out wont accept that much capacity, bring them to the next event if you want..
if you have to charge them with the stock charger just keep them close, feel them every few minutes make sure there not catching on fire etcetc _________________ www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz
Tue Apr 17, 2007 10:51 pm
Fish_in_a_Barrel
Joined: 30 Sep 2006
Posts: 673
Location: Perth, Western Australia
What would lead you to believe that they are dead?
We've had some rechargeable nicads floating around our house since I was a kid, (gee, they were expensive ). They are still able to hold most of their charge .
Tue Apr 17, 2007 11:39 pm
cerberus3112
Joined: 05 Dec 2005
Posts: 497
Location: Mt Druitt,Sydney,NSW
The fact that they have been sitting in my back yard for about 2 years and a few are a bit rusted.
I have two boxes of about 400 each so I didnt want to have to try to charge them all (or at least as many as i need which is about 40 or so)
also if it helps they are sonic nickel cadmium c size 1.2 v 1800 mAH and they recomend that you charge for 14 hours at 180mA _________________ A journey of a million miles begins with a single step followed by a hell of a lot of other steps so get walking
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However the drop in MAH for the eMoli cells is quite significant under current in comparison to the A123 M1 cells.
). They are still able to hold most of their charge .