- Joined
- Jan 13, 2010
- Messages
- 2,516
- Points
- 63
I don't "need" to use it if I use the batteries. However I'd think it would be better if I did use it. The minimum is 28V in
Last edited:
LPF Donation via Stripe | LPF Donation - Other Methods
Links below open in new window
ArcticMyst Security by Avery
Backpack Portable CO2 Build
- Thread starter jeffreythe00
- Start date
I don't "need" to use it if I use the batteries. However I'd think it would be better if I did use it. The minimum is 28V in
benmwv
0
- Joined
- Sep 10, 2010
- Messages
- 1,380
- Points
- 48
I think you will be fine without it. At 28v that is 3.5v per cell. Full charge the voltage will be 33.6v. So once the voltage is too low the batteries will be pretty much dead anyways.
- Joined
- Jan 13, 2010
- Messages
- 2,516
- Points
- 63
Well, I don't want to have these drivers I bought just sitting round. Though they are rated for 12V IN so they will be useful for other projects. Hmm...
Now how would I charge these cells? There any special way? Could I just apply 14.8V and let them go? Or do I need a special charger?
Now how would I charge these cells? There any special way? Could I just apply 14.8V and let them go? Or do I need a special charger?
Meatball
0
- Joined
- Feb 1, 2008
- Messages
- 2,894
- Points
- 0
You need a constant current source to charge them. A charger from the hobby store made for Li-po's should be fine.
- Joined
- Jan 13, 2010
- Messages
- 2,516
- Points
- 63
I have a lambda 20V 6A PSU with constant current that in charge all of my Lithium batteries on. So I'll just use that. I just wasn't sure if it needed some sort of special power supply.
benmwv
0
- Joined
- Sep 10, 2010
- Messages
- 1,380
- Points
- 48
Since its a multi cell pack you need a balancing charger!
Cheapest 4 cell one I saw on hobbyking was $9.
Cheapest 4 cell one I saw on hobbyking was $9.
- Joined
- Jan 13, 2010
- Messages
- 2,516
- Points
- 63
I don't understand? What's different between my PSU and a balancing charger?
Meatball
0
- Joined
- Feb 1, 2008
- Messages
- 2,894
- Points
- 0
A balance charger charges each cell separately to a pre set voltage, then stops. Since no two cell are exactly electrical identical when they are put on the charger, each one needs individual attention. This is mostly only done on Li-po's.
benmwv
0
- Joined
- Sep 10, 2010
- Messages
- 1,380
- Points
- 48
Yeah, it can be dangerous not to use one. A bench psu would essentially just charge until the pack is at 16.8v. If some of the cells have different voltages (because of slightly different capacity) then some can be under charged and others over charged. For example, three of the cells could be at 4.1v and the fourth at 4.5v. It still equals 16.8 so as far as a bench psu knows its fine but really it would be damaged from over charging. Then the next time it would be even worse. Possibly even catch fire.
- Joined
- Jan 13, 2010
- Messages
- 2,516
- Points
- 63
Okay. I thought so. Because this pack is sealed I had assumed that each cell was already balanced. However upon looking at the cells it looks like that ribbon cable is just for that. I do understand about balancing cells. Its one of the reasons why I'm straying away from super caps if I can. Charging them individually is a PITA. I'm still going to do tests with them. However before I go playing with these drivers I want to put them on a scope and see how they perform under load. This way I can be 100% sure nothing bad will happen should I decide to use 12v battery alternatives ect. I have to wait until I can get to mariomasters house to do that since I do not own a scope nor do I know how to properly read/use one.
benmwv
0
- Joined
- Sep 10, 2010
- Messages
- 1,380
- Points
- 48
Yeah, 12v SLA are definitely a viable option. 10AH 12v SLAs arent huge (definitely backpackable) and shouldn't be very expensive. Plus less finicky than lipo, but they are heavier.
- Joined
- Oct 26, 2007
- Messages
- 5,438
- Points
- 83
While other batteries may be more forgiving, all LiPo/LiIon batteries need to be charged with special smart chargers so they don't overheat and/or explode. Don't go cheap on that part of the battery equation.
- Joined
- Jul 4, 2008
- Messages
- 2,499
- Points
- 113
This build sounds like great fun !!
I can't wait to see what creative uses you'll have for a portable CO2 laser!!
Please post your pics!
:beer:
I can't wait to see what creative uses you'll have for a portable CO2 laser!!
Please post your pics!
:beer:
Last edited:
- Joined
- Jan 13, 2010
- Messages
- 2,516
- Points
- 63
^ Everyone at work always asks me about the flux capacitor. Nobody ever uses the Dr.Evil reference 
- Joined
- Dec 29, 2009
- Messages
- 3,136
- Points
- 63
in the mean time, you may be able to charge the individual cells with the balance leads. It will take 4x longer though.
Wish it was easier to turn a laptop battery pack into a balance charger...
Wish it was easier to turn a laptop battery pack into a balance charger...
HitShane
0
- Joined
- Nov 30, 2012
- Messages
- 655
- Points
- 28
Please tell me your going to fit this on a Shark? Make sure the Shark has the proper Laser Goggles for your wavelenth!
