Charging a DIY battery from EV charger

[Freep]

I've been looking for information on how to charge a DIY battery bank(LiFePo4) from a type 2 EV charger and I'm coming up empty.

Do any of you have any ideas where I could look to learn about this?

The ultimate application is a portable powerwall in my snowmobile trailer for my electric snowmobile.

 

[Dzl]

Maybe a DIY EV community would be a good place to start. I would imagine many in those circles would have similar desires

 

[eXodus]

Just getting regular 240V split phase from a Type 2 EV Charger is possible. No option for 120V since the Type 2 only have 3 wires - HOT HOT and ground. No neutral.

The j1772 standard is pretty low end. There is practically only a communication pin (PWM signal) which tells the charger in the vehicle how much current the box at the wall can supply.

DC fast charging is not available, since this requires extensive communication between charger and vehicle.

Look in the J1772 documentation.

https://www.reddit.com/r/solarracing/comments/9sp8mh

 

[eXodus]

type 2 EV charger

Type 2 are actually not chargers, they are only providing 240V power - the charger always sits in the EV.

Most people think they installed "a charger in my garage" while in reality you only installed a fancy extension cord which negotiates power with your EV.

 

[Freep]

DC fast charging is not available, since this requires extensive communication between charger and vehicle.

Ultimately what I'd prefer is DC fast charging from a charging station to my battery bank. I'd like to be able to pull up to a charging station and charge the snow mobile and then charge the 48v battery bank in a short amount of time.


I was hoping there would be some off the shelf hardware that would be fairly easy to install but it seems like we're not there yet.

 

[curiouscarbon]

Maybe a DIY EV community would be a good place to start. I would imagine many in those circles would have similar desires

https://www.endless-sphere.com/forums/

that said, if OP or anyone finds something interesting, please do feel free to link or share it here so we may all learn

 

[curiouscarbon]

Just getting regular 240V split phase from a Type 2 EV Charger is possible. No option for 120V since the Type 2 only have 3 wires - HOT HOT and ground. No neutral.

The j1772 standard is pretty low end. There is practically only a communication pin (PWM signal) which tells the charger in the vehicle how much current the box at the wall can supply.

DC fast charging is not available, since this requires extensive communication between charger and vehicle.

Look in the J1772 documentation.

https://www.reddit.com/r/solarracing/comments/9sp8mh

from the thread

We implemented support for J1772 charging in MS XII using the ELCON 3.3 kW UHF charger. When we did some research, it seemed like they were re-branded versions of chargers available off AliExpress at similar costs, but as a Californian company, we suspected that we could get more support from them if we really needed it.

Not sure if you have anything specific you have questions about, but here's a general overview of the process.

Basically the J1772 spec dictates that 1-kHz, ±12-V PWM pilot signals are transmitted to a vehicle from the charging station as part of the handshaking. In a nutshell, the handshaking process looks something like:

1. Plug car into charge station. At this point there's no AC output
2. Charge station signals 12 V on pilot signal to allow the car to detect that this is a charge station
3. Car drops pilot signal to 9 V to allow the charge station to detect a car
4. Charge station starts to PWM the pilot signal, where the duty cycle indicates the maximum current it can supply
5. Car reads this and basically takes the minimum of what the charge station can supply, and what the car can safely charge at
6. Car drops the pilot signal to 6 V to start charging
7. The charge station begins AC output
8. Charging "ends" when the plug is removed

The ELCON charger handles the AC-DC conversion, so all we really needed to do is handle the signalling to determine when to start charging (ie. steps 2-6).

Once the charging current is negotiated, you can just tell the ELCON charger to start charging, which happens over CAN. We have the ELCON charger sit on a separate CAN bus, and then have an interface board that spoofs the nodes that the ELCON charger expects to talk to. This gateway node performs all the signalling and communicates with the BMS (and Power Distribution) in order to determine when it is safe to close contactors and begin charging.

You'll probably also want to add a J1772 female connector to your vehicle (chargeport) in order to make plugging it in seamless.

Note: Take this advice with a grain of salt, since we didn't have the chance to finish testing before ASC 2018... So this setup is technically not completely validated (although we did use the ELCON charger at campsites using RV plug-ins, albeit without any J1772 signalling, and are hoping to finish validating this soon).

 

[Ampster]

The EV market is the best source. Thunderstruck motors sells a charger that will communicate with a J1772 plug.

Chargers

EV Battery Chargers

www.thunderstruck-ev.com

 

[Ozark Tinkering]

Look up Jehu Garcia on youtube he does some wild stuff with ev batteries. https://www.youtube.com/c/jehugarcia

 

[Ampster]

Ultimately what I'd prefer is DC fast charging from a charging station to my battery bank

I don't know if the DC fast charging protocols go as low as 48 volts, so that might be a limit as well as your battery capacity.
Level 2 is the equivalent of 100 Amps at 48 volts. That size charger is going to be expensive. How many Amps at 48 volts can your batteries accept?

 

[eXodus]

Ultimately what I'd prefer is DC fast charging from a charging station to my battery bank. I'd like to be able to pull up to a charging station and charge the snow mobile and then charge the 48v battery bank in a short amount of time.


I was hoping there would be some off the shelf hardware that would be fairly easy to install but it seems like we're not there yet.

Level 2 allows up to 19kw - usually around 6-11kw

That should be adequate for a snow mobile? I'm assuming you don't have a 100kwh in there?

 

[Freep]

I don't know if the DC fast charging protocols go as low as 48 volts, so that might be a limit as well as your battery capacity.
Level 2 is the equivalent of 100 Amps at 48 volts. That size charger is going to be expensive. How many Amps at 48 volts can your batteries accept?

I haven't built the battery bank yet. I'm still in the research and planning stage and I've got until late fall to get this done. I could build a 96 volt pack if I need to.

It's looking like the best resources are going to be EV conversion forums and sites. Basically, I'm building an EV with just the battery and charging port.

 

[Ampster]

I could build a 96 volt pack if I need to.

I think you are going to get better performance from the motor if you use higher voltage. I learned that a long time ago on an ebike. The advantage is the Amps are less for the same kW of power and the wiring and parts are more available.
For starters, I would recommend an AC three phase motor with a Curtis controller or similar. Don't worry so much about horsepower as it is the flat torque curve that will give you performance. More expensive permanent magnet motors will also give you a nice steady torque curve. Less expensive golf cart motors are all DC based often with brushed commutators that require maintenance.
The pack gets more dangerous above 48 to 60 volts but my EV conversion was at 112 volts and I am still around. I now drive two EVs whose pack voltage is over 400 volts but I let the manufacturer and the service center worry about dealing with that.

 

[curiouscarbon]

tesla is 96S,

4.20 V * 96S = 403.2 V MAX

the DC fast charging is done with 400V range, applied with contactors that directly connect the EV battery, instead of accepting AC input to an onboard charger. when DC fast charging, the **station** is technically the charger



personally i'm not even building 16S LFP packs because the voltage range of 48-58.4V intimidates me because of air and skin resistance, and so far 12V and 24V can service my small scale experiment needs for now

good luck and wear magid gloves made in the last 6 months

 

[eXodus]

when DC fast charging, the **station** is technically the charger

correct.

Level 1 Charging = 120v charger in the car
Level 2 Charging = 240V charger in the car
DC Fast Charging = charger in the station/box/pedestal

I remember the the more common DC Faster chargers can go down to about 200V and up to 480V

Depending on the manufacturer they can go down to about 100V and the newer ones up to 900V for 800V batteries.

How DC fast charging really works and an intro to charging curves | ChargePoint

www.chargepoint.com

The DC fast charger are communicating over Power Line Communication PLC with the vehicle.
"PLC communication, which is digital communication via powerline. In this case, powerline means the control pilot / ground circuit, not the high voltage power lines. The CCS combo standard adopted the HomePlug Green Phy standard (for in-home smart grid powerline communications) as the communication protocol."

Introducing DC fast charging - EVcreate

Multiple DC fast charging protocols exist: Tesla, CHAdeMO, GB/T and CCS Combo. Learn more about them, V2G, standardization and possibilities in DIY projects.

www.evcreate.nl

 

[Freep]

I think you are going to get better performance from the motor if you use higher voltage. I learned that a long time ago on an ebike. The advantage is the Amps are less for the same kW of power and the wiring and parts are more available.
For starters, I would recommend an AC three phase motor with a Curtis controller or similar. Don't worry so much about horsepower as it is the flat torque curve that will give you performance. More expensive permanent magnet motors will also give you a nice steady torque curve. Less expensive golf cart motors are all DC based often with brushed commutators that require maintenance.
The pack gets more dangerous above 48 to 60 volts but my EV conversion was at 112 volts and I am still around. I now drive two EVs whose pack voltage is over 400 volts but I let the manufacturer and the service center worry about dealing with that.

There will be no motor, you are misunderstanding the project. I am planning to build a battery bank in my snowmobile trailer for charging my electric snowmobile. What I want to be able to do is charge the battery bank from an EV charging station.

 

[DJSmiley]

EV Type2 is just plain 240V, either single or 3 phase, AC charging. DC charging is a whole different game (And a lot more difficult to DIY)

Here in NL, those EV charging poles are available about everywhere. I think there are about 80.000 or so installed, not counting private ones and ones on eg businesses.

It's just a matter of connecting some wires to similate an EV car, and the relay in the charger kicks in and provides power. (Just some resistors and a diode)

There are also premade extension cables available so you just get a basic Schuko socket from an EV charger.

Verloop / adapter Type 2 naar Schuko contrastekker - Laadkabelfabriek

Renault Twizy laden aan oplaadpaal. Ook toepasbaar voor laden van elektrische scooters, fietsen, segways en andere elektrische voertuigen.

www.laadkabelfabriek.nl

It just provides a Schuko socket of 240V, up to 16A (3.7kW)
You can use that to charge a battery bank, but to speed things up you want to have a decent charger.. Charging a 280Ah 12V bank at only 20A takes a while...


I've recently build something similar for a customer (4S 280Ah bank) and I installed a Meanwell RPB-1600 charger in that build, allowing to charge the 12V bank at 100 amps.


An type2 charger is NO charger. It's just some wires and a relay. The cable is terminated with a resitor, telling the car the max available amps (up to 32A/phase). By adjusting the resistance the 'charger' knows 'vehicle connected' and 'start charging', where as the last one enables the relay thus providing AC to the car.
The actual charger is in the car, NOT in the 'charging station'. Thats just a fancy relay-based controller with measurement and RFID authentication for billing purposes.

 

[Ampster]

What I want to be able to do is charge the battery bank from an EV charging station

Then back to my earlier suggestion for Thunderstruck Motors for J1772. Do you have the pack to snowmobile charging figured out? Does the snowmobile have built in charger? What voltage?

 

[Ericdhvac]

I've been looking for information on how to charge a DIY battery bank(LiFePo4) from a type 2 EV charger and I'm coming up empty.

Do any of you have any ideas where I could look to learn about this?

The ultimate application is a portable powerwall in my snowmobile trailer for my electric snowmobile.

I was looking for the same thing as another method of charging the batteries in my Sprinter van build, I already have a Victron setup with 630ah of Lion Energy batts paralleled and was thinking that I could get a 220v to 24v or 48v power supply to feed another MPPT to them.

 

[Freep]

Then back to my earlier suggestion for Thunderstruck Motors for J1772. Do you have the pack to snowmobile charging figured out? Does the snowmobile have built in charger? What voltage?

Yeah that's the easy part. Charging the snowmobile from the battery will be done overnight with AC type 1 charging. That's just a matter of adding an inverter that can handle the load.