Lithium Battery charging.

[linklemming]

I use one of these

Load Resistor 6.8

6.8 Ohm 400 Watt Load for Battery Discharge Testing.

ebikes.ca

You can also use a standard electric heater without a fan (several discharge levels available)

https://www.walmart.com/ip/Pelonis-...tings-PSH20Q3ABB-Black/344308112?from=/search

 

[6zfshdb]

I use 60V LED bulbs for a discharge rig. That way, the setup does double duty as a light source during the frequent power outages we get.

I added a twist timer so it's set & forget

For batteries with flat spade terminals, it's easy to make a connector out of an old extension cord. Just cut the plug in half as shown:

 

[PCeBiker]

I use 60V LED bulbs for a discharge rig.

Do you mean 60 Watt LED bulbs?
All my LED bulbs are 120 Volts, most are 60 Watt equivalent and are actually 10 Watts.

Are your bulbs actually 60 Volts?
Will they operate from what I assume is 48 Volt battery?

 

[m@Robertson]

You can also use a standard electric heater without a fan (several discharge levels available)

https://www.walmart.com/ip/Pelonis-...tings-PSH20Q3ABB-Black/344308112?from=/search

Will it then just put out a lesser amount of heat due to the low voltage of the battery?

 

[PCeBiker]

Will it then just put out a lesser amount of heat due to the low voltage of the battery?

That's what I figure.
It's a simple resistive load.
I've got a bunch of old-school incandescent bulbs that I can use in same way.
They just won't draw as much current and I may only see a red glow on the filaments.

That's why I'm curious as to what @6zfshdb has going on.

 

[6zfshdb]

Do you mean 60 Watt LED bulbs?
All my LED bulbs are 120 Volts, most are 60 Watt equivalent and are actually 10 Watts.

Are your bulbs actually 60 Volts?
Will they operate from what I assume is 48 Volt battery?

They are actually rated at 12 to 48V but will operate on 60V as well:

https://www.amazon.com/gp/product/B07XC3N59Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

They are just 15 watts each but I leave them connected for several hours to get the charge level I want. It's easy to do with the twist timer. I have no need for a fast discharge rate and the lower wattage is better for the battery.

 

[PCeBiker]

They are actually rated at 12 to 48V but will operate on 60V as well:

Cool !!
I didn't know know there was such a beast.
That's a great idea !!

Good for people living off grid or running solar/wind power.
You don't have to worry about the voltage being an exact number.

 

[PCeBiker]

I found a 6 pack for $25 CAD

12V Low Voltage LED Light Bulbs - Warm White 7W(Only for 12V), Pack of 6 https://a.co/d/7S2extO


Now I want to buy some, just so I can blow one up in a regular socket.

 

[6zfshdb]

I found a 6 pack for $25 CAD

View attachment 154617View attachment 154618


12V Low Voltage LED Light Bulbs - Warm White 7W(Only for 12V), Pack of 6 https://a.co/d/7S2extO


Now I want to buy some, just so I can blow one up in a regular socket.

Buy 6 of these and you're good to go:

At just 42 watts, it will take some time to do a discharge but what's the hurry?

https://www.amazon.com/gp/product/B000BQRY5M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[m@Robertson]

All very neat ideas. I've heard of the timer+incandescent bulb strip. The fact they were incandescent tells you how long ago I saw it

The load resistor I linked draws at about 7 amps, which sounds like a lot but its about what you'd be using if you were pedaling at about mid-level assist on the BBSHD the battery is hooked up to. So its normal riding discharge speed The one thing I need to think on is a timer. I set a kitchen oven timer... but thats far from perfect. You could easily drain the battery if you took a nap or something.

I absolutely need to do the twist timer, and asap, now that I'm reminded it exists.

 

[PCeBiker]

All very neat ideas. I've heard of the timer+incandescent bulb strip. The fact they were incandescent tells you how long ago I saw it

Yeah, the incandescent bulbs are getting hard to find, but they are still available.
I got mine at the local dollar store.

The one thing I need to think on is a timer. I set a kitchen oven timer... but thats far from perfect. You could easily drain the battery if you took a nap or something.

I just bought a second one of these,..
They work great and can go for 12 hours.

BN-LINK 12 Hour Mechanical Countdown Timer with Grounded Pin - Energy Saving https://a.co/d/5B8sFLn



I also have one of these for my RO filter,..

That wind up timer is completely mechanical including the clock mechanism.
If the power goes off, the timer keeps counting. (The plug in timer has an electric clock)

It has failed on me a couple of times when the clock mechanism wasn't wound enough, and it didn't shut off.
Make sure you hear it ticking away before you leave it.
A full wind, (not just past 10) then back to the setting you want, gives the spring a full wind up.

 

[PCeBiker]

The in wall 12 hour spring wound timers can get really expensive, so you need to consider the ramifications if it fails to shut off.

This is well worth the $15 in my opinion, but you need to use an extension cord.

As far as I figure it, a failure could occur if the switch is switching high power and the contacts of the switch fuse/weld together.
Then it won't turn off.

The surge current of a charger can be HUGE !!

 

[Jeremy McCreary]

I use the BN LINK twist timer. No problems in 25+ charging sessions.

Q1. Ball park, what are the odds of welding the timer open closed with a current surge from a 2A charger?

Q2. Are charging surges avoidable?

An unattended shut-off you can rely on brings a lot of peace of mind. I have a track record on remembering to put the wash in the dryer, and it's not good.

 

[PCeBiker]

I use the BN LINK twist timer. No problems in 25+ charging sessions.

Q1. Ball park, what are the odds of welding the timer open with a current surge from a 2A charger?

Just plug your charger in normally to an outlet and listen/watch for sparking.
Check your plug for black soot and little balls of welded metal on the prongs.

If that happens, you know that all that crap will be going on inside your timer.
The contacts tend to be pretty small (although the contacts themselves are made from a better metal more capable of dealing with arching)

I've burned up wall outlets from high current devices.
Black melted prongs on the plug.

Q2. Are charging surges avoidable?

Yup, just don't ever plug it in.

An unattended shut-off you can rely on brings a lot of peace of mind. I have a track record on remembering to put the wash in the dryer, and it's not good.

What we all want is fail safe.
I expect everything to fail.
I just want it to fail in a safe way.


Can you imagine if a BMS failed to not overcharge a battery ??

 

[PCeBiker]

Ball park, what are the odds of welding the timer open with a current surge

It's not welded open that I'm worried about. It just won't turn on.

It's welded closed that concerns me where it won't shut off.

That's hit and miss, because the contacts tend to be spring loaded.
If the spring isn't strong enough to break the weld, then it won't shut off.

That could happen at any time.

Or maybe never??

 

[PCeBiker]

I use the BN LINK twist timer. No problems in 25+ charging sessions.

You could disassemble your timer and inspect the contacts.
Melted, burnt, black drippy contacts aren't good.

 

[PCeBiker]

I decided to take my new timer/switch apart,..

So, all that possible arching, sparking and potential HUGE surge current is going through this tiny little micro switch.

I dunno ??
Seems a bit under rated for what a battery charger might demand?

It says that it's rated 15 amps, 8 amp tungsten.
Should I trust it ??

 

[rich c]

To be clear, I'm charging using the manufacturers charger but from a solar source., Rather than the grid.

To charge my battery from the grid costs certainly isn't "cents" where I live charging when the sun is out is free.

It's easy to calculate the energy need to charge your battery off the grid. Certainly isn't cents certainly isn't a calculation. Convince me it isn't cheap to charge on battery on the grid. The equipment needed to solar charge certainly isn't free. Here is a link to calculate your grid power used. Even in Hawaii where electricity costs $.38/kwh, the cost to charge a battery is 24 cents. https://electricbikereport.com/how-much-does-it-cost-to-charge-your-electric-bike/

 

[Jeremy McCreary]

a

It's welded closed that concerns me where it won't shut off.

That's hit and miss, because the contacts tend to be spring loaded.
If the spring isn't strong enough to break the weld, then it won't shut off.

That could happen at any time.

Or maybe never??

Sorry, that's I what meant. Thanks for looking inside for us.

Now back to the odds. As a practical matter, if I do the charger input plug test you mentioned, and see no sign of overheated metal, can I safely forget about this potential risk? Just talking about chargers that pass this test, not in general.

 

[PCeBiker]

Now back to the odds. As a practical matter, if I do the charger input plug test you mentioned, and see no sign of overheated metal, can I safely forget about this potential risk? Just talking about chargers that pass this test, not in general.

I dunno?
You're going to have to make that judgment call for yourself.

It's the initial connection that can draw HUGE amps but not blow your time delay fuses/breaker switches.

If you plug and unplug your charger a bunch of times and you get a noisy spark show, that leads to thinking HUGE surge current that a micro switch may not be able to handle.


I was quite surprised plugging in my chargers and hearing the sparks.

I've burnt up plugs on my high power devices and burned out wall outlets.

Check your plug for heat/surge damage..