Plug charger first into e-bike battery and then wall socket, or vice versa? (or it doesn't matter?)

[Sophie777]

For battery storage at home there are specific bags, glass fiber fireproof, not expensive.... 25€ on AliExpress

Do these bags work?

 

[Plummet]

It's immaterial whether theres a switch at the wall or not. The 'actual' switching takes place within the charger, both on the input and output, and it won't turn on any output to the battery until the charger has sorted itself out power-wise, shaken hands with the battery and done a diagnostic check that the battery isn't too low/high on charge, that there isn't any iffy cells etc etc. If you plug the battery in first it makes no difference to the process - the output of the charger won't allow anything into it anyway because it's switched based on the above.



It won't, for the previous reasons given.

The caveat being any cheap, non branded shite where battery ports are hot and/or there is no comms line to the charger, or input caps aren't protected (switched via mosfet) from 240v surges etc etc. The differences between a Bosch charger and a £20 no-name chinese charger will be immense.

TLDR - for decent systems it makes absolutely no odds how you connect everything up. You have to remember that big manufacturers will design high voltage electrical products that will be utterly infallible even by ham fisted monkeys (most ebikers there then).

But people are of course free to do what they like, follow the manuals etc.

You failed to quote my very last statement where I said plugging in was possible due time the smarts in the charger.

I get all that. But still, I will continue to plug everything in then switch on at the wall. It is good practice to do so on all electronic components.

 

[jonmat]

For most of the well known ebike systems out there (Bosch/Yamaha etc) made in the last 5+ years or so it really doesn't matter. This is one of the joys (and unfortunately, cost) of having a properly engineered system unlike the cheap shite. Decent stuff will not have hot battery ports and everything has to handshake and systems/health be checked/ratified before any charging happens. That said, I always plug the charger in first but only because of habit.

On badly designed stuff (like older e-unicycles that I used to use) you would HAVE to have the charger plugged in first otherwise the hot battery port output (circa 100v) being shoved into an unplugged charger would spark enough to skid your pants.

Absolutely spot on.

 

[cappuccino34]

MOST battery chargers and batteries actually communicate with each other, sometimes via CAN bus, sometimes via UART communication protocols.

An exception is the Spesh SL. The book does say connect before plugging in to the mains, but it seems happy whichever way you do it. I don't think there's much in the way of sophisticated Comms between the charger and battery because there's only three pins in the connector. It just works.

Most of my experience has been with Giant bikes (because I've had the most trouble with them). With those bikes you MUST connect to the bike/battery FIRST, then switch on the mains power. When charging is complete you MUST turn off the mains/unplug before disconnecting the battery/bike.

The reason for doing it in this order is because there's a message sent to say 'go into charge mode', which then turns the battery power output off to prevent the bike from powering up when connected. When the mains is turned off/unplugged, there's a message to say 'exit charge mode', which allows the bike to turn on again.

I know this because I had a load of problems with the Giant bikes that me and the wife had (mostly hers). Giant didn't want to accept that it was a battery firmware problem and said it was a charger problem, but I knew that wasn't the case because I'd been swapping batteries and chargers around and the fault always went with her battery, not her charger. Giant wouldn't have it (probably because a charger is cheaper to replace than a battery). In the end, I sniffed the CAN messages and figured out what was going on. The charger was telling the battery to go into 'running mode' when charging had finished, but the battery was stuck in 'charging mode' because of a firmware bug, which eventually got fixed with a firmware update.

 

[Oldfella]

MOST battery chargers and batteries actually communicate with each other, sometimes via CAN bus, sometimes via UART communication protocols.

An exception is the Spesh SL. The book does say connect before plugging in to the mains, but it seems happy whichever way you do it. I don't think there's much in the way of sophisticated Comms between the charger and battery because there's only three pins in the connector. It just works.

Most of my experience has been with Giant bikes (because I've had the most trouble with them). With those bikes you MUST connect to the bike/battery FIRST, then switch on the mains power. When charging is complete you MUST turn off the mains/unplug before disconnecting the battery/bike.

The reason for doing it in this order is because there's a message sent to say 'go into charge mode', which then turns the battery power output off to prevent the bike from powering up when connected. When the mains is turned off/unplugged, there's a message to say 'exit charge mode', which allows the bike to turn on again.

I know this because I had a load of problems with the Giant bikes that me and the wife had (mostly hers). Giant didn't want to accept that it was a battery firmware problem and said it was a charger problem, but I knew that wasn't the case because I'd been swapping batteries and chargers around and the fault always went with her battery, not her charger. Giant wouldn't have it (probably because a charger is cheaper to replace than a battery). In the end, I sniffed the CAN messages and figured out what was going on. The charger was telling the battery to go into 'running mode' when charging had finished, but the battery was stuck in 'charging mode' because of a firmware bug, which eventually got fixed with a firmware update.

Regarding Giant chargers. Mine failed so I took it in and the first thing the shop asked me if had I used an inverter to charge the bike. I have just installed a big system on my camper just so I can charge off grid. Seems the Giant chargers don't like inverters as the owner of the shop also found out and he is charging from his house he has had solar installed in. My Trek doesn't have any issues with charging just seems to be the Giants. There is some small print in the manual that just states you must charge from a 240v outlet.I received a new charger but that doesn't solve the problem of how I am suppose to charge when I'm on the road.

 

[Bender]

For most of the well known ebike systems out there (Bosch/Yamaha etc) made in the last 5+ years or so it really doesn't matter. This is one of the joys (and unfortunately, cost) of having a properly engineered system unlike the cheap shite. Decent stuff will not have hot battery ports and everything has to handshake and systems/health be checked/ratified before any charging happens. That said, I always plug the charger in first but only because of habit.

On badly designed stuff (like older e-unicycles that I used to use) you would HAVE to have the charger plugged in first otherwise the hot battery port output (circa 100v) being shoved into an unplugged charger would spark enough to skid your pants.

This answer makes all the sense. I've seen all kinds of replies here with concerns about arcing and plug this or that first. In reality, given the complexity of these systems, I'd venture there's no live voltage in the leads until the charger negotiates with the bike. It shouldn't matter which one goes first (in a properly engineered system).

I need to measure if the leads are alive without negotiation, but it's my assumption.

 

[Hotrod]

I've always plugged into the battery port first then the wall socket. However, I now use a surge and fuse protected power strip with a switch on it so I just flip off the switch and then the connection order doesn't matter.

 

[Ark]

Do these bags work?

I wouldn't trust them, from the research I did the majority are useless.
any from known brands well work, like the brands who specialise in fire proof lipo bags for the radio controlled car/heli/plane market.

but I don't know if they do them big enough to fit a bike battery.

don't trust the cheap Chinese ones

If your battery is UL certified like Bosch it should have almost 0 chance of a failure causing a fire anyway.
One of the requirements for the battery under UL cert is that it shouldn't spread any flames when it fails.

I'd imagine all the big brands are doing UL certification, some American states like NY banned the sale of all ebike stuff thats not certified as below
"An accredited testing laboratory must certify the safety of powered bicycles, powered mobility devices, and storage batteries.

• Powered bicycles must meet Underwriters Laboratories (UL) standard 2849.
• Powered mobility devices must meet Underwriters Laboratories (UL) standard 2272.
• Storage batteries must meet Underwriters Laboratories (UL) standard 2271."

I don't have a switch on my wall socket; would it be okay to connect the Bosch charger to a surge protector - which I can turn on and off?

The reason I ask is that Bosch says in their manuals not to use "extension cords".

You can use extension cords but they have to be rated properly for the load going through them

Bosch etc are probably just worried people will grab any extension cord without knowing better.

All the extension cords that are on a reel, they should come with a warning about fully unwinding them if your pulling over a specified load too

They aren't exactly idiot proof


The fast charger only pulls 6amps, a gaming pc can pull almost 6 amps and they can be plugged into most surge protected extension leads without issue.
the normal Bosch charger is only 2 amps.


Your surge protector should have an AMP rating stated on it somewhere

 

[Sophie777]

I wouldn't trust them, from the research I did the majority are useless.
any from known brands well work, like the brands who specialise in fire proof lipo bags for the radio controlled car/heli/plane market.

but I don't know if they do them big enough to fit a bike battery.

don't trust the cheap Chinese ones

If your battery is UL certified like Bosch it should have almost 0 chance of a failure causing a fire anyway.
One of the requirements for the battery under UL cert is that it shouldn't spread any flames when it fails.

I'd imagine all the big brands are doing UL certification, some American states like NY banned the sale of all ebike stuff thats not certified as below
"An accredited testing laboratory must certify the safety of powered bicycles, powered mobility devices, and storage batteries.

• Powered bicycles must meet Underwriters Laboratories (UL) standard 2849.
• Powered mobility devices must meet Underwriters Laboratories (UL) standard 2272.
• Storage batteries must meet Underwriters Laboratories (UL) standard 2271."

You can use extension cords but they have to be rated properly for the load going through them

Bosch etc are probably just worried people will grab any extension cord without knowing better.

All the extension cords that are on a reel, they should come with a warning about fully unwinding them if your pulling over a specified load too

They aren't exactly idiot proof


The fast charger only pulls 6amps, a gaming pc can pull almost 6 amps and they can be plugged into most surge protected extension leads without issue.
the normal Bosch charger is only 2 amps.


Your surge protector should have an AMP rating stated on it somewhere

Yes, thanks, I checked: my surge protector has a 15 amp rating on it, so I think I'm okay.

 

[Brian VT USA]

The fast charger only pulls 6amps....

This is the problem with rechargeable batteries. Some folks want to recharge them fast and to 100% every time so they have a "full tank" whenever they want to go again.
It's a bad recipe that's asking for big problems.

 

[Ark]

This is the problem with rechargeable batteries. Some folks want to recharge them fast and to 100% every time so they have a "full tank" whenever they want to go again.
It's a bad recipe that's asking for big problems.

I personally wouldn't want a fast charger. I was just showing that 6 amps isn';t a big load for the majority of extension cords.
I think my extension reel is 25metres rated at 25amps with thermal cut off built in so if the extension cord did start to get warm it would shut off.
I think my extension reel states if your pulling more than 7 amps to unwind the whole reel
it's surely not as kind to battery cells as the standard charger and the cells will get warmer having a slightly more volatile chemical reaction when charging obviously, which may shorten the life time of those batteries when it comes to retaining capacity

 

[cappuccino34]

Regarding Giant chargers. Mine failed so I took it in and the first thing the shop asked me if had I used an inverter to charge the bike. I have just installed a big system on my camper just so I can charge off grid. Seems the Giant chargers don't like inverters as the owner of the shop also found out and he is charging from his house he has had solar installed in. My Trek doesn't have any issues with charging just seems to be the Giants. There is some small print in the manual that just states you must charge from a 240v outlet.I received a new charger but that doesn't solve the problem of how I am suppose to charge when I'm on the road.

A 'pure sine wave' inverter rather than a 'modified sine wave' perhaps?

 

[Oldfella]

A 'pure sine wave' inverter rather than a 'modified sine wave' perhaps?

It is a pure sine wave. And you would think a system installed in a house would be latest equipment.

 

[Mikerb]

Having paid attention to what happens when i charge my bike I agree that there is definitely communication that takes place both with the battery and the CAN. I connect everything then switch on the mains. Nothing happens for a bout 3 seconds then the Kiox 300 lights up giving the state of charge and the LED Remote also lights up. When the mains is switched off the LED Remote and Kiox 300 shut down.

(the above is obviously charging the battery whilst in the bike....I virtually never remove the battery so dont know what occurs just charging the battery out of the bike)

 

[cappuccino34]

It is a pure sine wave. And you would think a system installed in a house would be latest equipment.

China's finest sine wave perhaps?
If you've had a charger failure that was seemingly down to an inverter I'd put a scope on it and soon to see how clean the wave looks.

 

[Rotwilder]

Personally, I never ever connect LIVE POWER to anything until all connections are made to what is being supplied.

 

[lovespicyfood]

I feel like this might only apply to a cheap non-mainstream battery / charger...I would hope (and think) that all of the reputable major manufacturers have designed their chargers to not require a sequence that could easily be missed.
I have my Canyon charger (for Shimano e-tube) setup on a smart plug that is turned off but plugged into my bike battery. I setup an automation to turn on this smart plug and thus my charger the morning before I ride to top off. This way I can keep the battery at a 60% storage charge until I know I'm going to ride...

 

[CaptKirk]

Since the e-bike fire on the Toronto subway, I've been concerned about the safety of storing and charging my Bosch Trek Powerfly battery inside my apartment.

One of the causes of e-bike fires according to the Toronto Fire Department is "incorrect charging"; they say to follow "manufacturer instructions".

I always thought for some reason we are supposed to plug the charger into the wall socket first, and then the battery.
Now I am finding contradictory information: some manufacturers say to do the reverse (plug the charger into the battery first).

I checked my Bosch manuals for my charger and battery. Neither are clear about which to do first. However the illustrations in the manual for the charger shows the charger being plugged into the wall socket first; the illustrations in the manual for the battery show the opposite.

Is there a consensus in the interest of maximum safety as to whether the charger should first be plugged into the wall socket or first into the e-bike battery?

From a electrical point of view, the Bike "control board" has a very large capacitior inside, when charging the bike battery these "Caps" have the same voltage potential as what is present in the battery. By plugging the charger in first to the wall socket the voltage in the "Battery Charger" Capacitors is raised to the same potential voltage so when the charger plug is inserted into the bike there will not be a "ARC" or large spark. These sparks/Arcs can cause voltage spikes that can destroy sensitive electronics in the "Bike controller" making it useless. Try to charge batteries when you are home and present to observe the process, or remove the battery and charge it on a fire proof surface (tile,etc.) Never purchase cheap batteries or chargers , unless your insurance policy is blame free and up to date.

Regarding Giant chargers. Mine failed so I took it in and the first thing the shop asked me if had I used an inverter to charge the bike. I have just installed a big system on my camper just so I can charge off grid. Seems the Giant chargers don't like inverters as the owner of the shop also found out and he is charging from his house he has had solar installed in. My Trek doesn't have any issues with charging just seems to be the Giants. There is some small print in the manual that just states you must charge from a 240v outlet.I received a new charger but that doesn't solve the problem of how I am suppose to charge when I'm on the road.

Not all inverters are "Sine" wave generated voltage, some use a modified "Square wave" and depending on the design parameters and components used may cause issues with operation and generated heat damage. Cheap inverters are just that, a cheap way to do something, they do work but are not bullet proof

 

[Sophie777]

From a electrical point of view, the Bike "control board" has a very large capacitior inside, when charging the bike battery these "Caps" have the same voltage potential as what is present in the battery. By plugging the charger in first to the wall socket the voltage in the "Battery Charger" Capacitors is raised to the same potential voltage so when the charger plug is inserted into the bike there will not be a "ARC" or large spark. These sparks/Arcs can cause voltage spikes that can destroy sensitive electronics in the "Bike controller" making it useless.

I have no electrical knowledge, but this explanation seems to make sense to me.
I think I will just continue with my usual practice over my last 4 years of having an e-bike - that is, to plug the charger into the wall socket first, and then to the battery.
Appreciate everybody's input in this thread.

 

[Oldfella]

From a electrical point of view, the Bike "control board" has a very large capacitior inside, when charging the bike battery these "Caps" have the same voltage potential as what is present in the battery. By plugging the charger in first to the wall socket the voltage in the "Battery Charger" Capacitors is raised to the same potential voltage so when the charger plug is inserted into the bike there will not be a "ARC" or large spark. These sparks/Arcs can cause voltage spikes that can destroy sensitive electronics in the "Bike controller" making it useless. Try to charge batteries when you are home and present to observe the process, or remove the battery and charge it on a fire proof surface (tile,etc.) Never purchase cheap batteries or chargers , unless your insurance policy is blame free and up to date.

Not all inverters are "Sine" wave generated voltage, some use a modified "Square wave" and depending on the design parameters and components used may cause issues with operation and generated heat damage. Cheap inverters are just that, a cheap way to do something, they do work but are not bullet proof

Thanks, I am trying to learn as much as I can. I have taken the broken charger to an electronics engineer to see if he can find out what has blown and if it can be prevented.
The inverter I use is not a cheap Chinese one, it Epever and was specifically put in so I could charge e bikes.

 

[CaptKirk]

I wouldn't trust them, from the research I did the majority are useless.
any from known brands well work, like the brands who specialise in fire proof lipo bags for the radio controlled car/heli/plane market.

but I don't know if they do them big enough to fit a bike battery.

don't trust the cheap Chinese ones

If your battery is UL certified like Bosch it should have almost 0 chance of a failure causing a fire anyway.
One of the requirements for the battery under UL cert is that it shouldn't spread any flames when it fails.

I'd imagine all the big brands are doing UL certification, some American states like NY banned the sale of all ebike stuff thats not certified as below
"An accredited testing laboratory must certify the safety of powered bicycles, powered mobility devices, and storage batteries.

• Powered bicycles must meet Underwriters Laboratories (UL) standard 2849.
• Powered mobility devices must meet Underwriters Laboratories (UL) standard 2272.
• Storage batteries must meet Underwriters Laboratories (UL) standard 2271."

You can use extension cords but they have to be rated properly for the load going through them

Bosch etc are probably just worried people will grab any extension cord without knowing better.

All the extension cords that are on a reel, they should come with a warning about fully unwinding them if your pulling over a specified load too

They aren't exactly idiot proof


The fast charger only pulls 6amps, a gaming pc can pull almost 6 amps and they can be plugged into most surge protected extension leads without issue.
the normal Bosch charger is only 2 amps.


Your surge protector should have an AMP rating stated on it somewhere

Just a observation, but Lithium batteries are very different than traditional batteries and cannot take high current when charging. That "18650" lithium cell can put out somewhere around 20-30 amps, charges very well at 2,3,4, and 5 amps from a smart charger. Anything higher could cause excessive heat in the cell which creates internal pressure and venting of the cell, which could lead to a fire. Its okay to go fast on a ebike, but please take your time when charging the batteries.

 

[Brian VT USA]

I bought an aftermarket charger that allows me to charge as low as 1 amp (and that's the setting I usually use).
And It allows me to set it to stop charging at less than 100%. I usually set it to 80%.
This works great for me. I slow charge while I'm working and 80% battery is plenty for rides after work (2-4 hours).

 

[RustyIron]

Is there a consensus in the interest

The facts are based on reality, and not on the consensus of half-baked notions of crackpots. But to be fair, your question needs to be better defined. If you want to know whether it makes any difference when using the chargers and batteries of top tier bike companies, then no, it doesn't make any difference. But if you want to add in all the crappy products that come from skeevy manufacturers in countries with no consumer safety rules, then the sequence of charging should be the least of your concerns.

 

[Brian VT USA]

Blind faith in anything (including "top-tier certifications", etc.) may cause you pain and suffering.
Use the many tools that are available to you before making choices that have potential for serious harm to you and others.

 

[Planemo]

By plugging the charger in first to the wall socket the voltage in the "Battery Charger" Capacitors is raised to the same potential voltage so when the charger plug is inserted into the bike there will not be a "ARC" or large spark.

As I mentioned earlier, there should be no arc or spark whatever way you plug things in because the caps you refer to are switched, either via mosfets or relays (on both input and output) following system handshakes. It makes not one jot of difference however I plug things in with my Bosch system, zero sparks. If things are sparking, it's a crap system, simple as.

 

[Planemo]

Just a observation, but Lithium batteries are very different than traditional batteries and cannot take high current when charging. That "18650" lithium cell can put out somewhere around 20-30 amps, charges very well at 2,3,4, and 5 amps from a smart charger. Anything higher could cause excessive heat in the cell which creates internal pressure and venting of the cell, which could lead to a fire. Its okay to go fast on a ebike, but please take your time when charging the batteries.

You appear to be discounting that ebike batteries are connected in parallels. That could be 2, 3, 4 or more cells, each perfectly capable of taking (in the case of a Sanyo GA for example) 1.67A. It's why my Bosch stock charger is 4A, the optional fast charger is 6A. The max charge current all depends on how many cells are in parallel and to some extent the limitations of the BMS, not the limitations of li-ion per se.

 

[CaptKirk]

You appear to be discounting that ebike batteries are connected in parallels. That could be 2, 3, 4 or more cells, each perfectly capable of taking (in the case of a Sanyo GA for example) 1.67A. It's why my Bosch stock charger is 4A, the optional fast charger is 6A. The max charge current all depends on how many cells are in parallel and to some extent the limitations of the BMS, not the limitations of li-ion per se.

PLANEMO: we were discussing safely charging lithium ion batteries, Please provide your education experiance so we can judge the validity of your claim, The fact that you claim everyone else has junk if it aint Bosch just shows your extremely limited knowledge in this area. . And just so you know, the BMS is the first limitation that MUST be respected. But sure contribute your opinion, but if someone takes what you say as gospel and burns down their house cause they did not get your full intent or meaning please jump back in and re-explain your position.

 

[Planemo]

Wtf are you talking about?

Never claimed anything was junk if it wasnt Bosch. In fact I only have one Bosch system. My 4 other li-ion systems (and far riskier - running 134v on 3600Wh packs) are non branded Chinese.

I then stated my Bosch charger was 4A, the fast one is 6A (which are both facts, not claims).

You were the one that stated a 18650 cant be charged at more than 5A which is true in one sense but I simply pointed out that it its largely irrelevant (utter bollox if I'm honest) as we dont run 1P packs on our bikes.

And where you are going with your BMS quote I have no idea but I suggest you grab a coke and a smile.