Kenny'sID wrote:Turber, most of what you mention there on the charger is over my head. Can I just get a Li-on, 36v charger and plug it up, and do them separately? Or is there something more to that? And if I want to do them all at once, say I want to do 8 at a time, do I just buy a 36v li-on charger, one that charges that many amp hours? If we talked about it I forgot how many AH 8 of those packs are?
I'll go try to find one and maybe get you to ok one to be sure, and that should get me well on my way.
And while I have you here, I purchased around a 14 AH or very close to that/48v charger recently, not knowing the AH's were an issue as the firsts charger I got came with the kit so I never paid attention. Can I use that on my 48V 18AH SLA?. I gather I can but just barely, however I want to be sure.
The charger setup I'm using is a bit clumsy, but it is versatile. The main thing I'd recommend from it though is that you don't charge to 42.0 volts, but to 41.0 or even 40.5 volts. By all accounts, this will help your batteries last a longer time. My setup makes switching from 4.1 to 4.2 or to a storage level pretty easy. It also allows me to balance charge each individual pack - which may or may not prove to be useful over time.
The simpler approach would be to get a "regular" charger that doesn't do balancing and open it up and adjust it's output voltage to 41v. Search these forums for info on doing that. I haven't done that, but it is commonly suggested. It is probably best to get an actual charger rather than a simple power supply. Though a simple power supply of the right kind will work. The reason is that Li Ion batteries are ideally charged with varying amounts of current. Proper chargers do that. But apparently some power supplies (Meanwells?) effectively do something similar. Again, search these forums for more specifics.
Each pack is 10s 2P. That's 10 18650 3.7v Li Ion cells in series and 2 in parallel. 20 cells per pack. 2lbs weight per pack. Each cell is a nominal 3.65v and 2150 mAh per the LG spec sheet. So that makes the packs 36.5 volts (10s = times 10) and 4300 mAh (2 * 2150) or 4.3 amp hours per pack.
The spec sheet gives a standard charge rate of 1075mA (.5C for this pack) per cell. They allow a max charge rate of double that. But faster charging probably reduces pack longevity a bit. So for each pack, that's a 2150mA standard charge rate or 4300mA max for a fast charge. For simplicity, let's just call that 2amps and 4amps respectively. So if you wanted to charge 8 packs at the same time, you could charge at up a 16 amp (or 656 watt - 16amps * 4.1v) rate. A fast charge would double that. Because the standard charge is .5C, it should take about two hours to fully charge your packs from a near empty state if you use this standard rate. But you may have to do some searching to find a charger that will charge at that rate. Even the Grin Technologies Cycle Satiator will only deliver 360 watts. To go much
I charge at a much lower rate of 6 amps or about 240 watts because my more complex and fiddly setup has a maximum charge rate of 300 watts. But with the right charger, I should be able to charge at more than double that rate and get much faster charging and not hurt the cells one bit. However, I suspect that one reason my packs have stay so well balanced (all charging to nearly the same exact voltage) is that the slower than allowed charge give the cells more time level each other out. And since I probably use up a little bit more than half of my pack's capacity for a round trip commute, I'm not charging the packs from empty. So charge times aren't horrible even at the relatively low rate I'm using.
Anyway, to sum up. You should look for a 36V charger that can deliver up to 16 amps (656 watts) or a little bit less - assuming pack longevity is a goal. And if it is, you should make sure the charger you buy can be adjusted to different charge voltages, such as 41v. A charger like this one seems to offer a good balance between simplicity, capacity, flexibility and price. https://lunacycle.com/luna-charger-36v- ... e-charger/
Charge the packs in parallel and make it a point to spot check them to make sure none of them are misbehaving.
Note that if you are going to charge an individual pack, you may need a separate, cheaper lower amperage charger.
I have no idea if it is a good idea to use your 48v 14a charger on an SLA.