I’ve read plenty of articles and read lots of posts of people who have had serious problems with cheap Chinese chargers and Lithium Batteries on the Internet but I never thought it would actually happen to me. Dealing with Hobby King Lipos was pretty sketchy so I ended up settling on the LifePo4 chemistry for all my ebikes. I plugged in my 18-month-old LifePo4 battery into the dirt cheap Chinese charger yesterday and was staring off to space thinking about going into town and actually trying to make some real money. Suddenly huge plumes of noxious smelling smoke erupted from the charger and I leaped off the couch and unplugged it as quickly as I could. The charger continued to spew out smoke for a while until I finally picked it up and threw it out in the snow to chill out. I cut the AC plug on it so that it would never again be accidently plugged in, and then I took it apart to see what happened.

When I took apart the charger I was horrified to see the way it was built. There was an extra large capacitor just wired in and the top of the capacitor was glued to the transformer. It was the kind of wiring that you would probably never see in an American built charger. I cut the power cord off it and threw it in the pile of junked e-bike stuff that I’ve destroyed throughout the years. I bought the charger along with a large 20Ah LifePo4 ebike pack for only $500 shipped (not legally shipped either). The battery had a bad cell and stopped giving me 20Ah within about 4 months so the ebay user imotorbattery sent me a 25Ah replacement battery that I have actually never even used. Ironically decided to go with the LifePo4 chemistry because it was the least likely to burn my house down. I never expected that the charger would be the point of failure that would threaten to torch my house.

For more videos of capacitors exploding check out this youtube video here. My capacitor was about like the one that explodes at :33 except it made a hell of a lot more foul-smelling smoke than it does in the video. There is no way this charger was UL listed or approved by any sort of circuit board standards except the infamous Chinese ‘throw it together and just make is so cheap that they won’t care if it breaks’. At $35 shipped it was so cheap that I didn’t care that it broke, but I did care about all the noxious smoke that poured out of it when the capacitor blew up and the unit automatically didn’t shut off when it failed.

There has got to be a better way to charge my batteries. Luckily there is.

The Cycle Satiator

So what kind of charger should you get that won’t burn down your house? Right now there are only 2 e-bike chargers that I recommend. One of them is the Cycle Satiator for sale from Grin Tech here and other US dealers for around $295. This e-bike charger will charge any battery chemistry from 24v to 60v DC. This charger is built with the highest quality components, does not have a fan, and will probably not burn your house down. You must ensure that it is set to the right battery voltage, amp and chemistry before you plug it into any battery, but if it is set properly it won’t start on fire. I know, I know, you’re thinking $295 for a charger? Are you nuts Karl? Think about how much it is going to cost to replace your house and all your belongings and tell me how insane I am. I’m insane for leaving my $500 batteries charging on a $30 Chinese charger when I’m not home. There is an excellent review of the Cycle Satitiator written by Eric over on electricbike.com located here. Be warned that if you read this review you will probably want to run out and buy one right away.

You can program this charger with the two buttons next to the display or you can hook it up to a PC and program it. The only problem I’ve heard of with the Satiator is that sometimes the BMS will go into a ‘shut down’ mode if it gets drained to low. If this happens then you will have to set the charger into ‘Jump Start’ mode (see this manual section 5.1) to get it going again. The Satiator will normally not start charging unless is senses voltage on the battery side and some BMS’s in ‘shut down mode’ will not start charging unless voltage on the charger is present. It is unlikely that you’ll ever have to deal with this issue and it can also be corrected by hooking up your ‘shut down’ battery to any generic ‘dumb’ charger which doesn’t try to sense voltage before it starts to charge. That will wake it up then you can switch it over to charge with the Satitiator.

The Lunagizer

So it might have a silly name that sounds like cross between a 1980’s TV series and a new kind of battery-powered toy with a drum beating pink rabbit, but I guarantee that the Lunagizer charger from Lunacycle.com is worthy of your hard-earned dough. Eric ordered several thousand of these chargers (at the same time) and swears that at a not-to-distant point in the future that these chargers are going to be the only ones offered with their battery packs. This charger is available for $99 in 52v for 14S 18650 packs here and also in 48v for 13S 18650 packs here. If you buy the Lunagizer charger bundled with a Lunacycle.com battery pack then it shaves $20 off the price and it is available for only $79. The Lunagizer has a LED voltage display as well as the ability to charge at 3amps or 5amps. I always charge at 3 amps because for many smaller packs charging at 5 amps will shorten the life of your packs. Electricbike.com has an excellent article here on fast charging vs pack life and heat buildup that I was going to write first but Eric beat me to it. As a rule of thumb, if your thumb gets too hot when you touch your pack while discharging it or charging it then you are discharging it or charging it too fast. If your pack is hot then your pack will die faster than it should, heat is the biggest enemy of Lithium Batteries and it can decrease their life significantly.

Another really nice feature of the Lunagizer is that there is a toggle switch that will charge your battery to 80%, 90% or 100% (Toggle switch : up 80%, center 90%, down 100%). If you want to double the number of charges on your e-bike battery then you should only charge to 80%. If you want the wheelie popping torque that the extra few volts seem to give you on the BBSxx then you should do like I do and charge to a full 100%. The battery chemistry will advance so fast that the battery you are using this year is going to seem like a POS next year and you’re going to want another one anyway. If you want to switch the charging power (80/90/100%) you will have to cycle the power on the unit to get it to work with the new setting. It’s a feature. My only complaint on this charger is that there is nothing written on the label telling you how to set it to the different charge modes so I just wrote it on my fancy new charger with a sharpie and instantly made it so no one would ever want to steal it.

The Lunagizer is a ‘dumb’ charger (how about “learning challenged” or “just plain stupid”, dumb is such a harsh word) meaning that it doesn’t read the voltage that your battery is starting at to make sure you’re not hooking up the wrong battery to the wrong charger. If you charge a 48v lithium battery with a 52v charger then you are going to have some really serious problems. The safest thing to do if you have several different voltage batteries is to use different charging connectors for different voltage batteries. I use the Anderson Powerpoles for my 48v batteries and then XT60‘s for my 52v packs and the xt90s for anything over 52v. This means it is physically impossible for anyone to plug the wrong battery into the wrong charger. You can create a system like that for yourself as well to keep your household safe. I have had good luck charging my 16S LifePo4 cells on a 14S (52v) Lithium charger but that is because LifePo4 is totally different chemistry than what you find on 18650 cells and they have a much lower individual cell voltage (3.2v for LifePo4 vs 3.7v for Lithium Ion). That means a 16S LifePo4 pack is going to have a nominal voltage of 51.2v and a 14S Lithium 18650 pack is going to have a nominal voltage of 51.8v. Close enough for government work. Wait, aren’t you doing exactly what you just told us not to do? You are plugging in a battery sold as 48v pack into a 52v charger. That 48v pack is really a 52v pack that is being sold as a 48v pack so the bottom line is, know your chemistry, know your voltage and know your pack configurations before you try to do anything you’re not supposed to do. That, and insure your house for the replacement cost not the market value (free advice).

So what did I learn from this real-life nightmare ?

Don’t buy from no-name ebay vendors with the cheapest price like imotorbattery. Even when they give you a brand new battery to replace your battery that flakes out after 6 months, it’s still not a good deal because houses are expensive to replace and your tenants won’t be happy when all their sh!t burns up in a fire. Don’t leave batteries running on the charger when you are not at your home. Charge them up when present then unplug them. Don’t use crappy ass cheap Chinese chargers, except in other people’s houses. Give them to someone you don’t like (your parents? ex-wife? snarky offspring?) for Christmas, it’s a much better thing to do as long as they don’t live with you. Keep a fire extinguisher nearby when charging Lithium batteries. I’m not kidding. Batteries are always safest when charged outside or inside your oven (with the oven off). That way if they DO explode or catch fire they might not take your house out too. Using the wrong voltage battery with the wrong voltage charger is a recipe for disaster. Don’t do it. At best you’ll destroy your battery, at worst…BOOM!

Have fun, and don’t kill yourself in the process. Sounds like the story of my life.

Ride On.