Abakoo 42V 5A Battery Charger for 36V Lithium Li-ion Battery Pack with DC 5.5 x 2.5mm/5.5 x 2.1mm Plug

27 March 2022:Charger deserves an update! Have used the charger daily for the past 5 days with excellent results; noting that just because my charger has worked well for the past week, that doesn't mean it'll continue to work well nor that other similar chargers will perform the same. I'm simply pleased with the charger up to today, so here's the summary (3 minor issues noted at end of 27 March notes) ...- the fan runs continuously; it's not quiet but not incredibly loud ... just charge up in a separate room if it really bothers you- advertised as 5amp charger ... I haven't put it on my multi-meter yet but the charging times would support that claim- 36v/12ah battery pack: takes a 2amp charger about 12 hours to charge ~50% to ~100%; the 5amp charger took ~3.5 hours to charge from 0% (fully unloaded) to ~98/99% ... very nice charge rate!! (ignored all the EE stuff and just went off the red/green charger led ... so please avoid going all poincare with the math)- size is about 2 maybe 2.5 times larger than the typical 2amp charger ... still compact enough to carry in water-bottle backpack; weight is comparable to a 16oz bottle of water- the battery-plug adapter is very useful to have because not all the battery packs have the same plug diameter ... we happen to have multiple boards with a 50/50 split between the 2.5 and the 2.1 diameter; attached a baggy with velcro to the casing to stash the adapter, but you could simply tape it to the case, or leave it at homeNOTE 1:charger cycles off/on towards the end of the charging cycle until it finally shuts off; the battery is close to 98/99% charged ... that is based on putting my 2amp charger on the battery pack which tops off for another 20-30 minutes; still, for the 5amp charger to go 0% to 98% in 3.5 hours is worth money and size ... the 8amp charger is even faster BUT LOUD and fairly good size/weight to backpack round; i do NOT let the charger cycle off/on at the end of the charging cycle because guessing the constant power surging will eventually break/damage the charger ... analogous to "hard" powering a computer on/off for 5 minutes .. eventually the computer is going to give upNOTE 2:do NOT block the fan vents because it gets very warm at max charge rate ... probably a spark/fire hazard if blocked/clogged ... way bad if you spill liquid on the brick as the fan vents expose all the internal circuitry; you probably won't find a easy-portable charger in the 4-6amp charge rate that doesn't have an internal cooling fan ... if you do find one, it might work but probably not as long as one with a cooling fan ... it'll likely smoke-check and burn itself out before too longNOTE 3:the cable that runs from the "brick" to the battery pack (aka charger pigtail) is encased in rather cheap plastic; guessing that flexing the cable at the "brick" attach point, as well as the battery pack attach point will eventually break/disconnect/short 1 or both of the encased wires ... a short at 42v pushing 5amps would be very nasty; you can reinforce the attach point or simply avoid over-bending/flexing the cable; if the cable does start to get damaged, the case looks pretty simple to open, so (1) i'd likely open it, remove the bad section of wire, then re-solder the wire to the brick paying attention to the original color connections; for the battery pack end, i'd cut off the bad section and solder another plug onto the end (buy plugs from ebay/amazon/etc.) paying attention to the plug polarity (red/black color thing) ... in most plugs, the CENTER PLUG IS POSITIVE/RED but check if not absolutely certain; OR (2) scavenge a working plug from anything useless and cut/connect to the charger pigtail after removing the bad section and paying attention to the wire colors ... unfortunately, NOT ALL WIRING IS CORRECT and sometimes the colors are reversed; i highly recommend against simply taping damaged wires ... 42v at 5amps22 March 2022:Tried to charge my 36V / 12ah battery ... worked about 3 hours ... the fan started to randomly start/stop and the LED shifted from red to green to red to green etc.Plugged in a 2 amp charger and LED indicated RED. Plugged in a 1 amp charger and LED indicated RED.Unplugged the 5 amp charger, let it rest 30 minutes ... same results. So this NEW charger worked about all of about 3 hours and then stopped.Will try it again tomorrow after riding the board a few minutes to see it the 5 amp charger will work ... so far, not impressed with the brick.

So I'm big battery nerd. And for $30 this charger is a great deal. It outputs 5amp at 42 volts. It doesn't run hot It isn't loud. See pics for charger output. In my testing I got 186 watts output 37.97v x 4.90amp. The charger is taking in 200.6watts so that's makes it 92.8% efficient which is really efficient charger especially for $30.I gave it 4 stars because i have only used it 2 times. I'll update this if I have any problems down the road.

Worked well for six months. Now will not charger at all. Save you money and buy higher quality charger. No response on warranty questions.

Got it for my boosted board and it charged it way quicker than original charger

The media could not be loaded.  Knew it was used not 3years old and was taken apart wire cut I didn't know? Lol 🤣 have no way to tell if it charge 5amp like I wanted I have a 2 already works fine

This charger is extremely fast works great.

Been through at least over 10 cycles of battery charges and never been dissatisfied in each full charge. The results are highly customer satisfactory in all aspects of its quality.

Using it to increase charging rate to my house battery - added it's output to the factory charger to double the charging rate.