EMW SmartCharge-25000HV
V12 QUICK START GUIDE
(For a Fully Built Unit, PFC)
PLEASE read this quick guide in its entirety BEFORE powering up anything!
WARNING: This document describes circuitry that is directly connected to the AC
mains, and contact with any part of the circuit may result in death or serious injury. By
reading past this point, you explicitly accept all responsibility for any such death or injury,
and hold Electric Motor Werks, Inc. harmless against litigation or prosecution even if
errors or omissions in this warning or the document itself contribute in any way to death
or injury. All mains wiring should be performed by suitably qualified persons, and it may
be an offence in your country to perform such wiring unless so qualified
1. This charger will work ONLY on High-Voltage packs with resting voltage of at least 310V and CV point
of at least 340V (all numbers assume 240VAC input). Attempting to use this unit with lower voltage
battery will damage the charger and may result in a fire. Quick specs:
a. Input voltage: 85-260VAC
b. Output voltage: 310-400VDC
c. Output power: 20-25kW (depending on version)
d. Micro-controlled, BMS-aware, serial remote control, multiple overheat protections, fully
programmable in field, open source
2. Inspect unit for possible damage in transit. If you see any signs of damage, do not power up. Contact us at
charger@emotorwerks.com for further instructions. It is very helpful to have photos of the damage when
you contact us.
3. Place unit so that the fan inlets and outlets are on the sides (i.e. not on top and bottom). This is a preferred
orientation for thermal management
4. [OPTIONAL] Connect BMS to the unit. There is a 5-pin connector broken out from the box. It normally
has a jumper installed between the first 2 positions. In your actual system, if you want to use BMS, you
would remove that jumper and connect a normally closed BMS loop (such as CleanPowerAuto’s
miniBMS system) between those 2 terminals
5. Connect DC wiring to the unit (STOP and read the entire instruction set for this step before doing
anything!)
a. As always with HV wiring, observe necessary precautions
i. Wear protective goggles & rubber sole shoes
ii. Try not to use both hands at the same time (to reduce the possibility to run any currents
through your body)
iii. Treat every HV terminal / wire as live even if you ‘know’ it’s not energized.
b. OBSERVE POLARITY on battery connection! Wrong polarity will result in extensive damage to
the charger and significant fire hazard.
c. VERY IMPORTANT: on your first battery connection, use the included inrush resistors in
series to reduce the initial inrush current to charge the caps inside the charger.
i. There will still be a visible spark on the first connection – be prepared for it.
ii. If you fail to use inrush resistors on the first connection, the spark will be much more
dramatic and the inrush current can easily blow up the internal capacitors in the unit
iii. After a few seconds, disconnect the battery, remove inrush resistors, and reconnect the
battery back to the charger. Make sure you do all this in <30 seconds to not allow the
internal caps to discharge too much
d. If your charger will be mounted in the vehicle and always connected to the battery, you do not
need to do anything else.
e. If the charger will be disconnected and re-connected to the battery often, you will either need to
perform the above procedure every time or install an optional pre-charge circuit on the output. The
simplest precharge circuit would consist of the same pair of precharge resistors with a relay (rated
for the output current of the charger) across them. The relay will have to be driven by D5-HC
output on the control board. This will ensure relay closes as the charge starts and thereby bypasses
the inrush resistors.
6. Connect AC wiring to the unit – observe markings on the unit. Incorrect connection WILL damage the
charger.
7. Plug in the AC wiring into mains. In a few seconds, the fans should spin up. If they don’t, we advise you
to NOT PROCEED
8. If you have already configured the charger (see appropriate step below), you can let it time out (5
seconds). Similarly, if you have already set the charger power in one of the previous runs, you can let the
next screen time out, as well (10 sec). Essentially, once your charger is fully configured, you do not need
to do anything on the next power-up – after 20 sec timeout, the charger will proceed with the parameters
from the last run (stored in non-volatile EEPROM).
9. [To be performed ONLY ONCE for a given battery pack] The first thing you will see on each power-up is
an EMW greeting on the screen. If this is the first time you run the charger, press any button during the 5-
second countdown to set up your battery parameters. The series of screens will follow, allowing you to set
up (one of the buttons is used to cycle through values, another – to confirm selections):
a. Battery type (LiFePo4 and NiCd/NiMH charging profiles are currently implemented. You can use
the charger with Lead Acid battery by ‘faking’ the CV and # of cells settings below to match your
float charge voltage)
b. CV cutoff (only for LiFePo4, can ignore this parameter for Nickel-based batteries). You can enter
the number from 000 to 399. The actual CV voltage used will be your entered number divided by
100. So, to set CV to 3.5V (EMW recommended setup for CALB batteries), enter 350.
c. Number of cells – from 000 to 399
d. Capacity of cells – from 000 to 399. This parameter used to determine CV cutoff current (set in
the code to 0.05C – standard for TS and CALB batteries)
e. Calibration of the sensors:
i. In our 12kW units, there are separate steps for Zero-point Voltage Sensor Calibration and
Voltage Sensitivity Calibration. These are not yet implemented in 25kW units.
ii. IMPORTANT: please ignore ‘Short the output’ prompt if the charger asks for it –
shorting the output of the charger while powered from AC mains will result in AC
mains short and will likely damage the charger.
iii. The charger will come pre-calibrated – if you need to change the calibration, you will
need to do that in firmware. Contact charger@emotorwerks.com for instructions
10. Once you are done with the setup, the charger will enter the runtime countdown (10 sec). If this is the first
time you are running the charger, press any button to program output power. You will enter into the
runtime configuration menu. Press left (normally red) button to cycle through menu options (‘run’, ‘pwr’,
‘timer’), confirm selections with right (normally green/black) button:
a. Enter input current. The charger will not allow you to exceed its ratings (20-25kW depending on
charger version) so entering anything beyond ~100A for the input current will result in charger
using 100A limit. WARNING: ensure proper fusing / breaker on your mains power line.
b. Enter output current. Maximum possible output current is limited to 50-70A (depending on
charger version), and your settings will be capped to that maximum.
c. Once power level (if needed) & timeout (if needed) are set, navigate to ‘Run’ menu item and
confirm. The charger will display the settings of the charging step for 5 sec and will start. It will
stop automatically when the charging is complete, displaying AH delivered. WARNING: to
achieve max rated power, ensure adequate access to [reasonably] cool air to the charger’s fans (i.e.
do not mount charger near your motor or in open sunlight, etc). Upon completion, the charger will
set End-of-Charge wire on BMS dongle to TTL “LOW”.
d. You can terminate the charge at any time by setting BMS input to TTL “LOW”. You can also
terminate the charge by disconnecting input power. EMW chargers are protected from both AC
mains and battery disconnection during charging
11. Finally, you can now (as of V12 firmware after September 20, 2013) control the charger remotely via a
Serial TTL line.
a. You can connect the charger with the standard FTDI programming cable to your PC and issue
commands via the terminal application such as TeraTerm.
b. Alternatively, you can control the charger directly from another microcontroller with UART TTL
serial line – such as another Arduino (UNO, Due, etc). Soon, we will be posting some Arduino
Sketches showing how it’s done.
c. In either way, you would connect the control cable to the header on top of the small blue arduino
board inside the charger (you will have to open the charger box). Set the baud rate to 9600
d. You will also need to disconnect the LCD by depressing the black round button on the bottom
right from the LCD. You need to do this before powering up the charger – the firmware checks for
LCD presence and defaults into Serial control ONLY if it does not detect LCD
e. The current set of commands is as follows (for important applications please verify against the
firmware posted at ):
i. Commands are contextual, with response depending on which state the charger is in right
now. Every command is an ASCII string starting with symbols 'M,' and ending with ',E'.
ii. If the charger is in 'waiting for command' mode (signified by 1Hz 'READY' message
transmitted by the charger), the main command is 'M,ccc,vvv,E', where ccc is the CC
current and vvv is the CV voltage.
iii. In the charging state, the charger will send an ASCII string with major parameters every
second. Format: 'M,D0,C965,V334,T-68,O1,R0,E' - [D]uty 0%, output [C]urrent 96.5A,
output [V]oltage 334V, heatsink [T]emp -68C, [O]utput charge 0.1AH, [R]untime 0
minutes.
iv. In 'charging' state, the charger will accept a 'STOP' command. If issued once, the charger
pauses. If issued twice, the charger stops. If, after the first STOP command, a START
command is issued, the charger resumes. This is the same behavior as charger's response
to manual button inputs in the manual mode. In fact, same functions are used... RED
button is emulated by 'M,001,000,E' command, GREEN - by 'M,000,001,E'.
v. This set obviously is a 'Minimally Viable' set that allows for automatic control of the unit.
Feedback welcome.
Thank you again for purchasing an EMW SmartCharge-25000HV intelligent open-source charger! We hope you
will enjoy the freedom of open source and will contribute to the community by sharing your adjustments to the
charger firmware.
Please let us know if you have any questions / suggestions / comments by emailing to charger@emotorwerks.com
Thank you,
Valery Miftakhov
Founder, Electric Motor Werks
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