Battery charging tips for electric bikes

[Admin]

Hey guys,

If you have any tips for charging electric bike batteries feel free to chime in. Recently I learned that it's best to plug the charger into the bike first and then plug the charger into the wall second.

I think most people (me included) do it the opposite way, leaving the charger plugged into the wall at all times and then connecting the bike whenever it needs a charge. The drawback of this method is that the smart chargers can't get a sense for the charge level of the pack before sending juice. Sometimes this stops charging all together and one of the help tips that ebike support lines provide is to plug the bike in first and then the charger.

I also recently learned that the reason many ebikes don't build chargers directly into the controller unit is that they have to be UL certified. So by separating the charger (or using an off the shelf option) they save time and complexity. I guess a lot of electronics use modular power supplies, one example of an ebike that does not (you can just plug the power cord directly into the bike) is the ebike by EV Global Motors.

 

[Charly Banana]

I found that my Dash charger was getting pretty hot when laying flat on a table on it's rubber feet. So I tried placing the charger on it's side instead to allow the two largest surface areas to be exposed to the surrounding air. After a few minutes the charger appeared to be running cooler.

 

[Ravi Kempaiah]

I found that my Dash charger was getting pretty hot when laying flat on a table on it's rubber feet. So I tried placing the charger on it's side instead to allow the two largest surface areas to be exposed to the surrounding air. After a few minutes the charger appeared to be running cooler.

Nice. Some of the chargers come with inbuilt cooling fan also.

 

[Admin]

Interesting, this makes sense Charly but might impact how the charger works (I'm just guessing here, it might be fine but was probably intended to be right side up by the engineers who made it).

Is there some way that you can think of to keep the charger upright but set it on two bricks or some other non-flammable, flat and sturdy objects? You'd keep the air circulation that way and avoid any unforeseen negatives of positioning the charger in a way that it was not intended.

 

[EddieJ]

Not charging related, but I was recently informed by someone who has been selling all types of batteries almost since year dot, that you should never store a battery on a floor. Apparently over time they discharge. I have no idea how or why, but he certainly wasn't the type of person to make things up.

 

[opimax]

I had heard that about lead acid years ago on cement floors with out any insulation under neath them...but then they didn't have Lithium batteries at that time

Mark

 

[Ravi Kempaiah]

I had heard that about lead acid years ago on cement floors with out any insulation under neath them...but then they didn't have Lithium batteries at that time

Mark

You're right Mark.
Only SLA battery had this problem of discharging and Li-ion doesn't have that problem. However, it will lose its capacity if kept uncharged for long duration.

 

[Admin]

I've heard that storing a computer tower on or near the floor is a bad idea but that's based on more dust getting sucked in. At first I thought that might be the same reason for the battery (like maybe the charger has a fan on it that will get gunked up?) but it sounds like you guys figured it out... thanks for the tip and clarification about which batteries to worry about. Old SLA

 

[Charly Banana]

Nice. Some of the chargers come with inbuilt cooling fan also.

Well, it got up to 95 degrees today. When I began charging the battery after my morning bike ride, I noticed my charger was getting very hot. So, I took Ravi's advice and got out a couple of 12 volt computer fans and a 12 volt power supply and set up the fans blowing on the charger. I was amazed at how fast the charger cooled down and kept cool for the rest of the charge. I just worry about electronic devices running hot and how it can shorten their lifespan. I'm going to keep these fans with the Dash charger throughout the summer, just to be safe.

 

[David1]

I also use a fan Charly, one of those square ones sold at any hardware store plugged into a separate outlet than charger , and is usually over 90 degrees too . Outside with battery removed from bike protected from sun and rain on a fire proof table, one of those metal ones so air can flow freely around charger and battery. I also have a garden hose uncoiled nearby. I keep my smart phone timer on monitoring the process. On my charger when I see the green light start blinking I remove the magnet attachment from battery and then unplug charger from wall outlet . I have seen hardly any heat build up using this system.When installed back ebike reads 100 % . To complete I'm going to have a portable smoke alarm to hang somewhere nearby so If action is needed I'll come a runnin. Just need to build it. I know this alot to do, but I'm use to it now , and better safe than sorry.

 

[Ann M.]

I like everything about your process except it is better to use a surge protector and unplug the charger from the surge protector outlet first, then from the battery. We do the same at our shop and plug into the battery first before starting a charge to prevent any accidental shorting from a misaligned plug.

 

[opimax]

Some bike brands are different though. Stromer ST2 is plug in to the wall first for example, your manual should state what is best for your setup. If it doesnt say and the manufacture doesnt answer I listen the pros(Ann M is one of them )

 

[David1]

Yes thanks Opimax, for that . St2 is what I have.

 

[one4torque]

I've got a stealth bomber coming soon... and my garage gets up to 115-120F in the summer months. I know heat is not kind to my RC Lipo's.... I presume heat is the enemy of my Stealth LiFE battery as well?, do you all rec that I remove the battery and store inside after each ride? Or just leave it in the bike in the HEAT? I really don't want to shorten the life of such a spendy battery.

 

[J.R.]

Always have a functioning fire extinguisher around, preferably near the entry/exit, mounted on the wall waist high. Water won't do for a battery fire.

 

[George S.]

I've got a stealth bomber coming soon... and my garage gets up to 115-120F in the summer months. I know heat is not kind to my RC Lipo's.... I presume heat is the enemy of my Stealth LiFE battery as well?, do you all rec that I remove the battery and store inside after each ride? Or just leave it in the bike in the HEAT? I really don't want to shorten the life of such a spendy battery.

They are tough.

(Link Removed - No Longer Exists)

 

[David1]

I think I've read researching what is needed for ebike. lithium - ion battery fire is water . What your trying to do is cool the battery down it will be spitting sparks and spewing toxic smoke in great amount. Fire exstinguisher will not reach the internal ignition point of battery fire.

 

[David1]

I have the same garage heat in Texas One 4 torque . I always remove the battery from my St2 when bike is in the garage.Have fun with your Stealth , everything I've read is highly favorable.Great company support too.

 

[J.R.]

From Battery University
http://batteryuniversity.com/learn/article/safety_concerns_with_li_ion

"What to do when a battery overheats . . .

If a Li-ion battery overheats, hisses, or bulges, immediately move the device away from flammable materials and place it to a non-combustible surface. If at all possible, remove the battery and put it outdoors to burn out.

A Li-ion fire can be handled like any other combustible fire and for best result use a foam extinguisher, CO2, ABC dry chemical, powdered graphite, copper powder or soda (sodium carbonate).

If the fire occurs in an airplane, the FAA instructs flight attendants to use water or pop soda. Water-based products are most readily available and are appropriate since Li-ion contains very little lithium metal that reacts with water. Water also cools the adjacent area and prevents the fire from spreading. Research laboratories and factories also use water to extinguish Li-ion battery fires.

When encountering a fire with a lithium-metal battery, only use a Class D extinguisher as water reacts with the lithium metal and makes the fire worse. With all battery fires, allow ample of ventilation while the battery burns itself out.

During a thermal runaway, the high heat of the failing cell may propagate to the next cells, causing them to become thermally unstable also. A chain reaction can occur in which each cell disintegrates on its own timetable. A pack can thus be destroyed in a few seconds or over several hours as each cell is being consumed. To increase safety, packs should include dividers to protect the failing cell from spreading to the neighboring one. Figure 1 shows a laptop that was damaged by a faulty Li-ion battery."

 

[Ann M.]

@one4torque, your battery will have a longer life and more charge cycles if you will take it indoors and out of the heat if the bike is parked or stored outdoors. We found that many of our owners' LiIon batteries had significantly shortened lifespans due to constant exposure to Texas high heat, humidity (which prevents heat from dissipating) and hot direct sunlight. Cooler cells charge better. With that said, the different Li-ion chemistries and Lithium polymer based batteries have different tolerances to heat but your garage temp is not optimal for ebike battery storage or charging.