My digital scoreboard project has been working great (thanks to a lot of help here, btw!). I am currently running it with a 4S LIPO battery which supplies abt 14.8V (the LEDS need 12). LIPOs require a delicate touch, and it is kind of a pain to remove them each time I need to charge them. I was wondering if I could go to a more friendly charging option? For instance, something like a laptop battery I think should have enough voltage but I have no idea how to build a charging circuit. But I would love to just have a jack on the side where I could just plug in a charging cable (and I do have some spare Dell laptop chargers around that I could use).
I will need a battery that can supply something greater than 12V at about 2A (I need to double-check that) for about three or four hours.
Recognize also that the Dell Laptop chargers are basically just a power supply - the charger "smarts" is in the laptop itself and controls the charging in a (usually) safe manner. You would need to add a smart charger circuit to your scoreboard to allow you to just plug in a laptop charger. Not unreasonable, just something to be aware of - the laptop chargers provide a voltage source at a nominal current, but it is up to the laptop to handle the battery correctly.
So if removing/charging your batteries is a bit of a hassle, will it be easier to use some easy connections on the battery holder so you can swap out the whole battery assembly and swap in a charged one?
Some good ideas here. Thanks. @Robin2, as for using a lead acid, yeah it would be heavy, but that's not a problem. It would still need to be removed to be charged. That's the problem.
@gpsmikey, I'd like to know how much "not unreasonable" it would be to add a charger circuit. I think that for the use case where I just have to plug in a charging cable, that would be ideal.
@liudr, I do like the idea of swappable batteries. Right now I only have the one LIPO. Having a second would help a little. I especially like the idea of making the connections easier. Right now I am using deans connectors and I have to fish around a bunch of wires to manipulate the connection. I need to fix that for sure.
I'm not sure just what the cost would be but it seems I have seen a number of available chargers out there advertised for those batteries (search the forum here too - I think I have seen other posts about chargers for them). I have not worked with those batteries so I don't have any more information.
MrGibbage:
. @Robin2, as for using a lead acid, yeah it would be heavy, but that's not a problem. It would still need to be removed to be charged.
Why?
The usual reason for removing LiPos for charging is so they can be balance-charged. But I suspect that can be done in situ. I'm just not going to offer advice as I am not an expert and I don't wish to be blamed for a fire.
Well, yeah, I guess you are right. I could charge the battery in place, but I still have to disconnect the battery and connect the charger. My goal is to just be able to plug in a charging cable and for the battery to charge. You know, just like your phone and laptop.
In many environments (look at the automotive situation), lead acid batteries are charged at the same time as they are being used. Typically, they charge with a limited current until they hit the desired charge voltage then hold the constant charge voltage. Your environment should be even easier than the automotive one since I assume your scoreboard is in a much more temperature controlled environment (charge voltage is a function of battery temperature).