Orion jr (48V) Wiring Manual docx
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- Bu səhifədəki naviqasiya:
- Fuses on voltage tap wires
- , the internal BMS fuses do not protect
- Some applications will require the use of fuses on the cell taps. It is the sole responsibility of the integrator to
- Physical routing and installation of wires
- It is strongly recommended to use the validation tool before plugging the harness into the Orion Jr. BMS as it is very easy to make an error wiring the
- Care must be taken not to short any pins with the multimeter. Personal safety equipment including protective eye-wear and gloves and arc-flash resistant clothing
- If errors are found or if cell voltages are not matching properly, do not leave the
- What causes the fuses to blow
- Reason: Accidental contact to cell tap
Orion Jr. BMS Manual – Rev. 2
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Internal Isolation The Orion Jr. has nominal isolation between cell voltage tap sensors and the control electronics and between cell groups 1 and 2 for functional purposes only.
Fuses on voltage tap wires The Orion Jr. BMS has internal fuses on each of the positive cell tap wires. While these fuses protect the BMS, guard against excessive current flowing through the internal protection diodes, and are designed to blow if the maximum voltages are exceeded, the internal BMS fuses do not protect against two tap wires that short together outside the BMS, against shorts at the connector on the BMS, or against excessively high cell tap voltages. While many major OEM vehicle manufacturers have carefully calculated and rely upon the fusing characteristics of the cell tap wires, fuses are strongly recommended as this technique requires much testing and engineering. Some applications will require the use of fuses on the cell taps. It is the sole responsibility of the integrator to determine if these external fuses are needed.
If external fuses are used, they should be kept as low resistance as possible with reason and rated no larger than 3A. Fuses must always be rated for the maximum possible DC working voltage with a suitable DC interrupting current rating. Certain electrical codes or regulations may dictate the maximum fuse size, and it may be smaller than 3A depending on wire gauge and other considerations. Fuses sometimes have relatively high resistance, and the additional resistance can reduce the accuracy of monitoring the cells. Additionally, fuses may be necessary on thermistors to protect against a possible short between a thermistor and a terminal of a battery. It is the sole responsibility of the integrator to determine if fuses are necessary on the cell tap wires.
Physical routing and installation of wires The integrator is solely responsible for designing proper external wire routing, including the selection of suitable wire types and selection of other external components including wire types and wire conduits.
For safety reasons, all external wires must be adequately protected from damage including abrasion from rubbing, vibration, or sharp objects. The integrator must consider all possible environmental aspects including, but not limited to, corrosion or loosening of joints or screws, galvanic reactions, expansion and contraction of wires, busbars, and interconnects due to temperature, condensation, etc. The integrator must also ensure the separation of components and wires from flammable materials. The integrator is solely responsible for ensuring that the application complies with any applicable codes, regulations, and standards.
Orion Jr. BMS Manual – Rev. 2
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Verifying Cell Voltage Tap Wiring
The wiring must be verified prior to connecting any of the wiring harnesses to the Orion Jr. BMS. Improper wiring can cause damage to the BMS unit, catastrophic failure, or even personal safety risks depending on the extent of the wiring mistake.
The most important connector to verify is the cell voltage tap harness, which includes the current sensor wires. There are two methods for doing this:
The first is the tap validation tool which is available for rental or purchase. The tool can be connected to the wiring harness already connected to the battery pack and will verify that cells are wired in the correct order and can detect most wiring mistakes. The validation tool is designed to withstand incorrectly wired harnesses without damage.
information on proper testing. While the tester can catch most wiring faults, it cannot detect all intermittent and high impedance faults.
Wiring can also be verified by carefully using a multimeter, but the use of the tap validation tool is the recommended method. Care must be taken not to short any pins with the multimeter. Personal safety equipment including protective eye-wear and gloves and arc-flash resistant clothing should be worn for protection in the event of an arc flash. In order to avoid two probes on the connector, the negative probe should be attached to the negative most terminal of the negative most cell in the pack rather than on the connector. Then, being careful not to short pins or touch the probe, carefully measure each of the pins on the connector starting with the current sensor - and + wires and the pin for 1-. The current sensor -, +, and the 1- pin should all read 0V since the negative probe of the multimeter is connected to the same potential. Pin 1+ should read the voltage of the first cell (3.3V for example), pin 2 should read the sum of the first two cells (6.6V for example), and so forth. The connection for cell 12 and 13- should read the same voltage since they are connected to the same potential.
When connecting the harness to the BMS for the first time, (after verifying correct wiring), first adjust the cell population settings in the BMS software so the BMS is aware which cells it should be expecting to see. Once you have uploaded the profile to the BMS (see the software manual for more information on this), use the live cell voltages screen to verify that all cell voltages are reading correctly. Then verify on the diagn ostic trouble code screen that no “open wire faults , ” “wiring faults , ” or “low cell” faults are present on the BMS. Open wire or wiring faults indicate that the BMS has detected a problem with the cell tap wiring. If errors are found or if cell voltages are not matching properly, do not leave the BMS connected to the pack for long periods of time as it may drain cells and cause damage to them. If the BMS begins to rapidly flash the red LED (Rev C units only), immediately disconnect the cell tap harness as this indicates that the BMS may be getting damaged by incorrect wiring. Note that the absence of a rapidly flashing red LED does not necessarily indicate correct wiring Orion Jr. BMS Manual – Rev. 2
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Why Orion Jr. BMS Internal Fuses Blow
The Orion Jr. BMS has an internal fuse for each of the cell voltage tap wires. These fuses are designed to blow in over-voltage and reverse-voltage conditions. Sufficient current to blow the fuses will only flow through the tap wires during an over-voltage or reverse-voltage condition.
Below is a diagram showing a sample 48 cell battery pack connected to an Orion Jr. BMS unit. While this example is a higher voltage than the Orion Jr. BMS can handle, the same principal applies. The internal fuses and protection diodes inside the unit are depicted below. In the diagram, all cell tap voltages are within 0 – 5 volts with respect to the next lower cell. As a result, none of the zener diodes conduct and no significant current is flowing through the BMS. Since no current is flowing, all fuses remain in a closed state.
The only time the internal fuses on the tap wires will open is from an over-voltage or reverse-voltage condition. When an over-voltage or reverse-voltage condition occurs, the zener diodes will begin to conduct, causing current to flow through the tap wires and causing the fuses on the taps to blow. This is necessary in order to protect the voltage measurement electronics from damage. Over-voltage and reverse-voltage conditions are both with respect to the adjacent lower cell tap and the adjacent higher cell tap. There are many situations that can lead to over-voltage and reverse-voltage occurring, some of which may be unexpected. While the following few pages are not an exhaustive list, they cover the most common causes.
Orion Jr. BMS Manual – Rev. 2
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Reason: Altering wiring with the BMS connected (or loose busbar) By far, the most common cause of blown fuses and/or more serious damage to the Orion Jr. BMS is when battery pack wiring is altered with the Orion Jr. BMS still connected. While it may seem counter- intuitive, removing a busbar with the BMS cell tap wires connected can result in the voltage of the entire battery pack across two adjacent cell tap wires due to capacitors in a battery charger, resistance from a connected load (motor controller, DC:DC converter, lighting, etc.), stray capacitance, a breakdown in isolation within the battery pack, or other such causes. Since these voltages are well beyond the maximum rated voltage between two cell taps, damage to the unit is likely to occur.
It is very important, both for safety and for the health of the BMS, that all cell tap wires are always disconnected before any modifications are made to the wiring of the battery pack. We recommend designing the battery box enclosure to require the cell taps to be disconnected before the battery wiring can be modified or applying warning stickers throughout the battery pack indicating that the BMS must be disconnected before the battery pack is serviced.
The below example shows a 13.2 volt battery pack. A volt meter is measuring 3.3v from cell tap #1 to #2 in the example.
The next diagram shows what happens when the busbar is disconnected. As the busbar is now open, battery voltage is no longer present at the battery charger, but the internal capacitors in the charger are still charged at the pack voltage (13.2 volts) and have no place to discharge. Because of this, the full battery voltage is present across cell tap #1 and #2 (the multimeter leads in the diagram). Because the voltage is now the full battery voltage, the zeners inside the BMS break down and conduct, causing the fuses inside the BMS to blow. Orion Jr. BMS Manual – Rev. 2
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In the above example, the total pack voltage is only 13.2 volts, which may not cause damage on an Orion Jr. BMS. However, if this same scenario were to occur on a higher voltage battery pack, internal fuses may blow. The below electrical diagram shows the same situation, but with a larger 158v battery pack (Note: the maximum voltage for the Orion Jr. BMS is 60v). When the voltage between the cell taps rises rapidly, the zener diodes inside the BMS begin to conduct, discharging the battery charger's capacitors, resulting in blown fuses. In this case, it is possible to blow all fuses within a particular cell group. Typically current will first flow through the two closest cell taps as it is the path of least resistance (black line in the following diagram) and then seek alternative paths as fuses blow (light purple line.)
It is important to note that a battery charger or load does not need to be connected to the battery pack to cause high voltages between cell taps when a busbar is removed. Isolation faults, built up charge against the chassis (stray capacitance), or capacitors on snubber circuits can all be enough to cause damage. Damage from this can be prevented by ensuring that the cell tap harnesses are fully disconnected from the BMS before any wiring is altered on the battery pack. Additionally, this can be caused by intentional re-wiring of the battery pack or by loose busbars (which also pose a fire risk from arcing.)
Orion Jr. BMS Manual – Rev. 2
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While this diagram shows a 158v battery pack, please note that the maximum voltage for the Orion Jr. BMS is 60v. However, the same principles apply.
The Orion Jr. BMS is designed to survive a single tap wire reversed for short periods of time, but the unit may not survive for longer times or if multiple wires are crossed. Never leave a BMS unit connected with reversed tap wires. Even though the BMS may survive, this condition will the drain attached cells.
Orion Jr. BMS Manual – Rev. 2
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In the above schematic, cell taps 2 and 3 are reversed. This leads to 6.6v between cell taps 1 and 2 and 3 and 4 with a reverse voltage between taps 2 and 3. In this case, 4 of the zener diodes will conduct and current will flow through the tap wires. This condition leads to up to 4 fuses blown (but may be as few as 2 fuses depending on the order that they blow.) In this situation, fuses will generally reset to their normal state once the above fault is fixed.
If a cell tap wire accidentally comes into contact with a different voltage cell while the harness is plugged into the BMS unit, significant voltage may be present. This can also happen if a tap wire is cut or abrades and shorts to another wire or another terminal. Cell tap wiring must not be altered with the BMS connected both for safety reasons and to prevent damage to the BMS. Care must also be taken to route the cabling in such a way that it cannot abrade or be cut by objects.
Transients may also cause fuses to blow inside the BMS. Transients are very rapid voltage spikes that can occur as a result of switching loads, rapid changes in current or other causes. Small transients occur regularly due to loads switching on and off, and the BMS is designed to withstand these common transients. Very large transients, typically caused by shorts within a battery pack or by hard switching very large loads, can be very high voltage and can cause damage, not only to the BMS, but also to lithium-ion cells.
Orion Jr. BMS Manual – Rev. 2
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Reason: Extremely weak cell, internal cell failure (fairly rare) When current is flowing through the battery pack, high resistance connections within the battery pack can cause “voltage drop” that will cause higher or lower voltages at certain cell taps. This most commonly occurs with extremely weak cells or faulty cells which have become internally open. This failure is fairly rare. If cells have become over-discharged or over-charged, the cell impedance will become very high. The BMS will not allow charge or discharge if it detects a seriously under-charged or over-charged cell. However, if the user ignores the BMS and continues to charge or discharge, the cell can cause significant voltage drop (or in some cases reverse voltages) that can cause fuses to blow.
The Orion Jr. BMS contains standard fuses, but also contains additional resettable fuses which protect against certain kinds of temporary lower voltage wiring faults. In most cases where the over voltage or reverse voltage conditions are less than 24 volts for less than 10 minutes, the resettable fuses will reset to normal after the fault is cleared. In situations where faults result in higher voltages across two cell taps, the standard fuses are designed to blow. If this occurs, the BMS must be returned for service. Yüklə 321,11 Kb. Dostları ilə paylaş:
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