Repurpose RAD battery as emergency power source

eCouleeRider

New Member
Hi! Checked the forums but have not found definitive answers.

Is it possible to repurpose a standard Rad 48v battery as an emergency power source? Think here of charging a phone or powering a small device.
If so, how? Details appreciated.
Has anyone done this?

Thanks!
 

Ccount

Active Member
You would need an inverter with a 48v input, but yes, it would work just fine. Remember though that you would be very limited to the number of amps available (about 6 A max at 120v)
 

CityExplorer

Well-Known Member
I've seen some devices that specifically target the use of bike batteries. I think it was probable on eBay. are you wanting to power 12VDC, 5VDC? Essentially you can look for a buck converter with suitable input, output, and power ratings for your application If you want to power lower voltage DV devices. You can use them in combination with an inverter to power AC devices (110/`120 VAC), or a separate Boost Converter and an inverter.

You could get a Buck/Boost converter and make a variable power-supply with a good range.

What voltage are you looking for?
 

Ccount

Active Member
Also, the Bolton (and other) displays have a USB port on it, which is more than adequate to charge a cell phone right on your bike! I do it every ride!
 

legsofbeer

Active Member
The stock radpower controller on most of their bikes has a 0.5 amp USB A port underneath the display. Get yourself a small USB battery brick so you can charge that when you're not charging devices directly. And, of course, you can use the bike itself as an emergency light in a power outage. I'd bet the battery could drive the front light for at least a week.
 

Tars Tarkas

Active Member
Search Google or Amazon for 48v to 12v converter. You'll have to find some connectors and/or do some soldering but you'd end up with something you could attach a cigarette lighter kind of receptacle to. Then you could plug in a USB charger or any other 12v-powered device. It would really be pretty easy. I'll let someone else do the Ohm's Law math on how long the battery would last, depending on what you plug into it.

One other potentially big consideration is that using the battery that way would put more charging cycles on it, and more wear and tear in general, thereby lowering its life expectancy. Something to think about at $550 replacement cost, But for emergencies , yeah, sure. It would be a pretty good little thing to make and market as an out of the box solution.

TT
 
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6zfshdb

Well-Known Member
Hi! Checked the forums but have not found definitive answers.

Is it possible to repurpose a standard Rad 48v battery as an emergency power source? Think here of charging a phone or powering a small device.
If so, how? Details appreciated.
Has anyone done this?

Thanks!
I built this rig mainly to discharge my batteries for storage but it can also be used as a portable light source outdoors or inside during a power failure:

P1080656b.jpg P1080652c.jpg


My batteries use a slot type connector which was easy to tap by cutting a cheap extension cord plug in half:

P1080033b.jpg P1080654b.jpg P1080655b.jpg
You would likely have to use a different method for your Rad battery though. My batteries have a built in switch & fuse. Keep in mind these would have to be added for batteries that don't have them.


When not in use, the rig hangs on a wall above the work bench:

P1080657b.jpg


To use household appliances, it would be a simple matter to wire up a 48V DC to 110V AC inverter such as this one:

InverterGraphicQtrViewWeb.png


To charge electronic devices, you could also wire up this 48V DC to USB converter:

71CtLOyoDWL._AC_SL1500_.jpg

 
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eCouleeRider

New Member
Wow! Thank you for all the great replies! This addresses my two main concerns: battery maintenance in the winter and using the battery in an emergency. I am using a Luna charger, so I am able to charge at low amps to a desired level - that should help with "winter maintenance" charging.

Now my only question would be: how to make the actual physical connection with a Rad battery? Is there an off-the shelf component that will fit, and what would positive and negative leads be? I built the plug for the Luna based on a good YouTube video, so that is something I am comfortable with. Is there is a reference I should be looking at, or specific tool I should have in hand?

Thanks!

Report
 

Ccount

Active Member
Wow! Thank you for all the great replies! This addresses my two main concerns: battery maintenance in the winter and using the battery in an emergency. I am using a Luna charger, so I am able to charge at low amps to a desired level - that should help with "winter maintenance" charging.

Now my only question would be: how to make the actual physical connection with a Rad battery? Is there an off-the shelf component that will fit, and what would positive and negative leads be? I built the plug for the Luna based on a good YouTube video, so that is something I am comfortable with. Is there is a reference I should be looking at, or specific tool I should have in hand?

Thanks!
Report
Super simple! Simply purchase one of these on Amazon for a buck (or better yet buy the package), and plug right into the charging port on the battery. I use the port to power some super high intensity LED lights for my night rides on the beach and golf course.

 

6zfshdb

Well-Known Member
This was posted in another thread by member Kyogero:


You might find a connector that will fit. The vendor is in the UK though so shipping could be a problem.
 

eCouleeRider

New Member
Super simple! Simply purchase one of these on Amazon for a buck (or better yet buy the package), and plug right into the charging port on the battery. I use the port to power some super high intensity LED lights for my night rides on the beach and golf course.

So I can draw current back through the charging port? I already built those connectors for charging with the Luna.

Here I was thinking that I had to connect to the leads on the bottom of the battery. Would I still need the 48v to 12v converter - or something else to regulate the rate of discharge? I am thinking here that there may be circuitry or fusing that is on the discharge side and not on the charging side. (BTW - any corrections of how I am thinking about this are welcome!)
 

6zfshdb

Well-Known Member
Super simple! Simply purchase one of these on Amazon for a buck (or better yet buy the package), and plug right into the charging port on the battery. I use the port to power some super high intensity LED lights for my night rides on the beach and golf course.

You have to be careful discharging via the battery charging port. The internal wiring likely involves the BMS and could easily be overloaded if you draw too much current.
 

eCouleeRider

New Member
You have to be careful discharging via the battery charging port. The internal wiring likely involves the BMS and could easily be overloaded if you draw too much current.
Thanks. That was my concern.

Is the BMS in a Rad battery in the battery itself, or in the controller?
 

eCouleeRider

New Member
I built this rig mainly to discharge my batteries for storage but it can also be used as a portable light source outdoors or inside during a power failure:

View attachment 73113 View attachment 73110


My batteries use a slot type connector which was easy to tap by cutting a cheap extension cord plug in half:

View attachment 73115 View attachment 73111 View attachment 73112
You would likely have to use a different method for your Rad battery though. My batteries have a built in switch & fuse. Keep in mind these would have to be added for batteries that don't have them.


When not in use, the rig hangs on a wall above the work bench:

View attachment 73114


To use household appliances, it would be a simple matter to wire up a 48V DC to 110V AC inverter such as this one:

View attachment 73116


To charge electronic devices, you could also wire up this 48V DC to USB converter:

View attachment 73117

This is quite awesome!
 

eCouleeRider

New Member
I've seen some devices that specifically target the use of bike batteries. I think it was probable on eBay. are you wanting to power 12VDC, 5VDC? Essentially you can look for a buck converter with suitable input, output, and power ratings for your application If you want to power lower voltage DV devices. You can use them in combination with an inverter to power AC devices (110/`120 VAC), or a separate Boost Converter and an inverter.

You could get a Buck/Boost converter and make a variable power-supply with a good range.

What voltage are you looking for?
I am thinking 12 vdc
 

eCouleeRider

New Member
The stock radpower controller on most of their bikes has a 0.5 amp USB A port underneath the display. Get yourself a small USB battery brick so you can charge that when you're not charging devices directly. And, of course, you can use the bike itself as an emergency light in a power outage. I'd bet the battery could drive the front light for at least a week.
Thanks. I thought about the USB A port too - would like to make something like that which sits right on the battery itself.
 

eCouleeRider

New Member
I think what I am looking for is called a discharge connector - one specific to the Rad battery. Would be willing to build my own if I could find the correct components!
 

legsofbeer

Active Member
Is the BMS in a Rad battery in the battery itself, or in the controller?
I believe it is in the battery itself, I don't see how it could do cell pack balancing otherwise. FWIW, after installing an aftermarket controller there were no config parameters oriented to the battery, besides the low voltage shutoff (I use 40v) which kills power to the motor but still leaves the lights and controller powered. So I will bet that if I set the controller voltage shutoff to some silly low value (eg 36volts), the battery's BMS would shut things down before reaching that low voltage. Not going to test that though, want to milk this battery for as much useful life as I can get. When the BMS does shut down the battery that battery stays off until charged for a while. Only did that once just to see what would happen.

There are two fuses in the battery, a 40amp and 5 amp; I assume the 40amp is for discharge through the main terminals, and the 5 amp for charging via the barrel plug. I didn't know of the pulling power via charging port trick, I'd be careful about drawing more than 2 amps from that.
 

BKing

Member
How low are some of you discharging your battery for storage? I hope no more than half and do so at a fairly slow rate. Also, loading the charge port is asking for a bad BMS.