This could be easy or it could be hard.
If what you replace it with has to fit into the exact same size whole it might be difficult. What you have is 2 (or possibly 4) good sized lithium ion polymer (LiPo) cells. (Polymer refers to the fact that the battery is actually inside of a plastic POLYMER bag.) Finding an exact size replacement, with more capacity, will be difficult because there are no standardized sizes.
I could not tell if the charging electronics were inside that thing you were holding.
The only "standard" cell size is an 18650 (18mm X 65.0mm; slightly larger diameter and length of a AA battery). Each cell is 3.7V when it is fully charged and top quality cells are >3000mAh, so 4 (2 series, 2 parallel, 2s2p) would give you 6000 mAh, 50% more than what you have.
If you don't understand what I just wrote, then you don't want to be messing around with this stuff ! Hooked up wrong, it could explode/catch fire !!
Best place to buy your cells is eBay. Stick with Panasonic, LG, Samsung or Sony. Only buy from Japan, Hong Kong or US supplier.
This could be easy or it could be hard.
If what you replace it with has to fit into the exact same size whole it might be difficult. What you have is 2 (or possibly 4) good sized lithium ion polymer (LiPo) cells. (Polymer refers to the fact that the battery is actually inside of a plastic POLYMER bag.) Finding an exact size replacement, with more capacity, will be difficult because there are no standardized sizes.
I could not tell if the charging electronics were inside that thing you were holding.
The only "standard" cell size is an 18650 (18mm X 65.0mm; slightly larger diameter and length of a AA battery). Each cell is 3.7V when it is fully charged and top quality cells are >3000mAh, so 4 (2 series, 2 parallel, 2s2p) would give you 6000 mAh, 50% more than what you have.
If you don't understand what I just wrote, then you don't want to be messing around with this stuff ! Hooked up wrong, it could explode/catch fire !!
Best place to buy your cells is eBay. Stick with Panasonic, LG, Samsung or Sony. Only buy from Japan, Hong Kong or US supplier. 4 should $30. If you have the space, make a 2s3p pack and get 9000mAh ! There are places that will build you what you want but of course it will cost you.
..... some how I feel like baited... (the chump have an oscilloscope and ask this question)
short answer is NO.... long answer maybe .... probably some better way if you just get a dc-dc converter from ebay to charge your existing LiPo battery... convert it down to 8.4v to charge them.... or what ever volt needed to run your oscilloscope. ALl you have to do is come up with a base to house your Dewalt battery or what ever battery..
I think other than the battery chemistry is different LIPO and LI=Ion...the one in your oscilloscope have 2 cells each of 3.7-ishv have it's own charge controller ( that little circuit board).... if you hack out the power tool the cells are usually 18650, usually they don't have charge controller and arranged in either series for 5 cell or series-parallel for higher capacity modules. Probably for that 5AH battery a 2x 2500mah cells are in parallel then 5 set of that in series.... to get a 5AH capacity....
Even if you hack it out and rearrange it for yours 5x in parallel and 2x of that set in series to get that 7.4v, you'll still have to find a 2 cell charge controller (the one in your dewalt battery pack is a 5 cell charge controller).... some newer 18650 cells comes with a build in charge controller,... but mostly likely not the cells from the power tools you scavenge.
http://batteryuniversity.com/learn/article/confusion_with_voltages
http://www.all-battery.com/protectivepcbsforli-ionandli-polymerbatterypacks.aspx
and yea disclaimers, read those other ppl's warning....
You have some misinformation... 18650's are 4.2v full charged, 3.7v @ nominal charge, and the low voltage cutoff is model dependent, but is generally between 2.8v-3.2v. Currently best available capacity in a commercially available cell is 3500 mah.
I agree with you on how dangerous this is. To anyone who is thinking about trying to make a pack on your own, this is very dangerous. You need a properly engineered battery management system to control the charge and dischage rates and provide protection. Failure to do so will most likely result in an extremely dangerous fire with gases violently venting from the cells at 1500+ degrees farenheight.
So do you think the LiPo cells in the original battery pack use some "other" magic chemistry and don't have the same voltages ? 2 cells in series would give 7.4V. The pack clearly says 7.4V.You have some misinformation... 18650's are 4.2v full charged, 3.7v @ nominal charge, and the low voltage cutoff is model dependent, but is generally between 2.8v-3.2v. Currently best available capacity in a commercially available cell is 3500 mah.
You need to use cells in pairs to get the proper voltage.i understand fully what your saying. the off brand dewalt battery has the controller electronics inside the pack. i believe i can fit 5 batteries in that same space.
I assume there is a charger either built in to the device or external, Why not "use what you got" ?Now its just a matter of finding a controller or a way to charge them safely??
I can probably put an external port on the battery housing and buy a charger that would handle my hack job battery pack.
You need to use cells in pairs to get the proper voltage.
I assume there is a charger either built in to the device or external, Why not "use what you got" ?
"Adding on" to the existing pack (external parallel) will just cause that external pack to be sucked dry continuously trying to recharge the old original.
Do some more exploration of that original pack. Let's see what else is inside without destroying it.
A 4 cell 3500mAh would cost <$30 assuming you can solder it up. A 4 cell "flat" pack would measure 65mm thick X 260mm wide X 65mm high.
I am willing to bet, that DeWalt pack uses 18650 cells.
Gave up on your Amazon Fire/Lab Nation scope ? For that to be a real winner, you need the 10" version of the Fire $$$ and for LabNation to speed up the sample rate (250-500MS/s) and double or quadruple the stored waveforms
Forget odd numbers ! Too much pain.so it looks like i can squeeze 7 of those 18650 batteries into the housing.
The "best" chargers charge each cell (or cell wired in parallel) individually. There are good generic chargers out there (SKYRC 6BAC) that meet the requirement but they are >$50.Will my O-scope be able to keep track of the charge level of the battery? provided i find a charging solution for the pack.
So what your saying is that i can use the electronics from the original battery pack with the 7 18650 cells that i took from the dewalt pack and charging will work the same way it's always worked on the o-scope. no need for another charging solution?
Gave up on your Amazon Fire/Lab Nation scope ? For that to be a real winner, you need the 10" version of the Fire $$$ and for LabNation to speed up the sample rate (250-500MS/s) and double or quadruple the stored waveforms
NO ! Forget odd numbers. Cut the batteries apart and solder them back together, 2 at a time in series. That will give you 7.4V. Now take as many if those pairs as will fit into the space of the original LiPo and wire them in parallel.
You can reuse the original charger (controller board).
Will you have a net longer run time time (more power). Maybe. Any marking on the DeWalt cells ? What was the mAh rating of that pack ?
I keep recommending new cells because the Li-Ion battery technology has made HUGE GAINS in the past 5 years or so. Typical 18650 cells have gone from <2000mAh to >3500mAh without significant cost increase.
building the pack isnt the dangerous part??? unless i directly short the pack im assuming.
It's the incorrectly charging part that can cause the damage?
Im sorry i didnt make myself very clear after i read what i wrote.
I already took apart the dewalt pack and yes it has 18650 cells, 10 of them to be exact.
So what your saying is that i can use the electronics from the original battery pack with the 7 18650 cells that i took from the dewalt pack and charging will work the same way it's always worked on the o-scope. no need for another charging solution?
so in theory lets just say i have really crappy 18650 cells that only have 1500mah each 6 of them should net me 9000mah vs the stock 4000mah battery pack. but if i purchased some newer higher capacity 18650 cells i could get 21000mah of capacity?
No, the electronics in the Dewalt pack are meant to charge and balance 10 cells in a certain series/parallel connection. The second you go with a different number of cells or different series parallel connection the electronics will no longer be compatible.
I really want to see someone come in and KICK PICO'S **** !Labnation thinks you only measure voltage or that you want to constantly be trying to do the math of converting the voltage readings to amperage (current clamps produce xxmv = xamp).. I cant imagine it would be very difficult to do since it's just a matter of software changes.
I really want to see someone come in and KICK PICO'S **** !
The Pico Auto Scope uses ancient, slow hardware. Yes the software looks (including ranging for the various inputs) is nice, but not that nice ! And theie probes and add-ons are ridiculous.
LabNation clearly does not see the automotive marketplace.
If you look at the discharge curve, it comes off that 4.2 volt peak charge really quick so they are normally sold as 3.7 volt cells, where the voltage stays through most of the discharge. However it has not stopped tool manufacturers from using it to exaggerate their battery voltage. When I got a Bosch compact impact driver it had a 10.9 volt battery Under pressure from competitors they had to start selling the same battery as 12 volts, like the other guys. In Europe, with stricter regulations, it is still 10.9 volts.You have some misinformation... 18650's are 4.2v full charged, 3.7v @ nominal charge, and the low voltage cutoff is model dependent, but is generally between 2.8v-3.2v. Currently best available capacity in a commercially available cell is 3500 mah.
I agree with you on how dangerous this is. To anyone who is thinking about trying to make a pack on your own, this is very dangerous. You need a properly engineered battery management system to control the charge and dischage rates and provide protection. Failure to do so will most likely result in an extremely dangerous fire with gases violently venting from the cells at 1500+ degrees farenheight.