GIGATT wrote: ↑
May 09 2019 10:47pm
I made a rather bootleg charger out of two laptop chargers
They are 19ish volts each.
What is the highest amperage that you would charge 10 of these packs?
Per the cell specification, about 20 amps ( 2 amps per pack, 1 amp per cell) would be the max I'd charge that pack - since long service life is important to me. But you could double that if you were willing to shorten the service life of the cells a bit. For instance, maybe mostly you charge at the lower rate, but on a long distance tour you charge at a higher rate at stops for convenience.
As it is, I charge at around 1 amp per pack which is about half the standard rate simply because high rate chargers tend to be expensive and heavy. The Meanwell HLG-320H-42A that I use weighs in at 4.2 lbs - which is actually heavier than I'd like for a charger that is always attached to the bike. But it is robust and fast enough for my needs. It is also adjustable to different charge rates and different maximum voltages and because the electronics are potted is well suited to staying attached to the bike. BTW, it isn't a charger per se, but is an LED power supply. It usually costs about $80. Well worth it for me.
BTW, charging to 39 volts probably isn't hurting anything by itself. My concern would be that because you aren't getting very close to a full charge you may run them closer to empty more often. But maybe not if you are running 10 in parallel. If you max charge to 41 volts and don't run them low, they could last a very long time. I charge to 42 volts, but never leave them at that level for more than a few minutes. My understanding is that the 42 volts alone isn't the problem. What matters most is how long the batteries sit at that voltage. I partially charge at night and then top off the batteries before I head out to work. But given my reduced capacity needs of late, I may change my charge voltage to 41 volts just in case that helps longevity a bit more. I'll probably do that this weekend.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
8 x 36v 4.3ah 10s 2P battery packs - 1500W 30A DC Boost Converter delivers 54v and about 1000 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats