Post by mattsedgley on Mar 1, 2009 19:17:59 GMT
There was plenty of talk at racing today about LiPo charging and what is safe and unsafe to do. Part of the friendly banter that we love so much on a sunny Sunday!
Just for your information, and perhaps a refresher to those who've not raced outdoors/over the winter for some time;
Listed below is the 2009 BRCA Electric board Lipo rules for this year, they are provided as a reference for those who may be interested in current LiPo Regulations;
Lithium Based (LiPo) Battery Packs.
The storage, charging and use of Lithium based batteries (LiPo) can give rise to
serious safety implications. The BRCA will publish guidelines for the safe use of
these batteries on the BRCA website. It is imperative that the guidelines are studied
and adhered to.
3.3 Lithium based (LiPo) battery packs must have a hard, protective case that
completely envelopes the cell(s). The case should be made from ABS or a similar
material. The two halves of the case must be factory sealed in a way that any
attempt to open the case will destroy the case. The only opening in the case that is
allowed, is for the exit of wires.
3.4 For 7.4v Packs: The maximum case sizes allowed are as follows: -
Length: 139.0mm.
Width: 47.0mm. (The max. width includes any side exit wires).
Height: 23.5mm. (In addition, chassis location protrusions are allowed)
Saddle-Pack cells are allowed, and must comply with the above width and height
dimensions. Saddle-Pack cells must have a combined length dimension of 139.0mm
max when placed end to end.
For 3.7v Packs: The maximum case sizes allowed are as follows :-
Length: 93.0 mm
Width: 47.0 mm
Height: 20.0 mm
3.5 Individual cells used in the construction of the battery pack shall be rated at 3.7
volts nominal. Individual cells may be wired in parallel.
For 7.4v Packs: The maximum connection ‘In Series’ is two, to give a Final pack
voltage of 7.4v nominal.
For 3.7v Packs: Cells can only be connected in parallel, to give a Final pack voltage
of 3.7v nominal.
3.6 The battery pack shall have leads extending from the case for the positive and
negative electrical connections using wire of adequate size to handle discharge rates
acceptable to racing applications. Alternatively, the case shall have internal
connection points for these wires clearly marked positive and negative so the user
can apply the lead wires. It is strongly advised that the link wire for Saddle Pack cells
utilises a plug which will separate with any undue force.
3.7 The case must have the original suppliers label intact, stating the rated voltage
and the pack capacity. Maximum capacity is 5,500 mah. The Brand name/logo shall
be easily readable.
3.8 All LiPo batteries must be charged with a LiPo-capable charger using the industry
standard CC/CV (Constant Current/Constant Voltage) charge profile.
3.9 LiPo batteries may be charged to a maximum of:-
8.40V for cells/batteries connected in series giving a pack voltage of 7.4v nominal.
4.20V for cells/batteries connected in parallel giving a pack voltage of 3.7v nominal.
Overcharging is a serious safety hazard and will not be tolerated.
3.10 Any competitor found to be charging cells using a charger that is not specifically
designed for LiPo batteries, or using a charge profile other than the industry standard
CC/CV, will be disqualified from the event.
Any competitor found to have charged LiPo batteries to above 8.40V or 4.20V (as
detailed in 3.9) will be disqualified from the event.
Hamworthy - another local club operate a 1C charge ruling where by you can only charge at the capacity of your battery - for example a "Orion 2400Mah" can only be charged at 2.4 Amps (1C)
On the back of the Orion it suggests charging between 1C and 2C - somewhere between 2.4A and 4.8A
The Demon DL4000 pack recommends charging at 5A (1.25C)
The demon DL3800 Pack recommends charging at 5A also (1.32C)
Manufacturers seem to be leaving the "safe charge rate" as a flexible value, which can be a confusion to new drivers and seasoned racers together. Currently SHMCC follows the BRCA's recommendations however, the emphasis being on each individual being responsible for their own equipment and it's safe usage.
May I also take this opportunity to remind all racers that it is important to use a LiPo cut off device to ensure that pack Voltages do not drop below the safe operational voltage.
Matt
Just for your information, and perhaps a refresher to those who've not raced outdoors/over the winter for some time;
Listed below is the 2009 BRCA Electric board Lipo rules for this year, they are provided as a reference for those who may be interested in current LiPo Regulations;
Lithium Based (LiPo) Battery Packs.
The storage, charging and use of Lithium based batteries (LiPo) can give rise to
serious safety implications. The BRCA will publish guidelines for the safe use of
these batteries on the BRCA website. It is imperative that the guidelines are studied
and adhered to.
3.3 Lithium based (LiPo) battery packs must have a hard, protective case that
completely envelopes the cell(s). The case should be made from ABS or a similar
material. The two halves of the case must be factory sealed in a way that any
attempt to open the case will destroy the case. The only opening in the case that is
allowed, is for the exit of wires.
3.4 For 7.4v Packs: The maximum case sizes allowed are as follows: -
Length: 139.0mm.
Width: 47.0mm. (The max. width includes any side exit wires).
Height: 23.5mm. (In addition, chassis location protrusions are allowed)
Saddle-Pack cells are allowed, and must comply with the above width and height
dimensions. Saddle-Pack cells must have a combined length dimension of 139.0mm
max when placed end to end.
For 3.7v Packs: The maximum case sizes allowed are as follows :-
Length: 93.0 mm
Width: 47.0 mm
Height: 20.0 mm
3.5 Individual cells used in the construction of the battery pack shall be rated at 3.7
volts nominal. Individual cells may be wired in parallel.
For 7.4v Packs: The maximum connection ‘In Series’ is two, to give a Final pack
voltage of 7.4v nominal.
For 3.7v Packs: Cells can only be connected in parallel, to give a Final pack voltage
of 3.7v nominal.
3.6 The battery pack shall have leads extending from the case for the positive and
negative electrical connections using wire of adequate size to handle discharge rates
acceptable to racing applications. Alternatively, the case shall have internal
connection points for these wires clearly marked positive and negative so the user
can apply the lead wires. It is strongly advised that the link wire for Saddle Pack cells
utilises a plug which will separate with any undue force.
3.7 The case must have the original suppliers label intact, stating the rated voltage
and the pack capacity. Maximum capacity is 5,500 mah. The Brand name/logo shall
be easily readable.
3.8 All LiPo batteries must be charged with a LiPo-capable charger using the industry
standard CC/CV (Constant Current/Constant Voltage) charge profile.
3.9 LiPo batteries may be charged to a maximum of:-
8.40V for cells/batteries connected in series giving a pack voltage of 7.4v nominal.
4.20V for cells/batteries connected in parallel giving a pack voltage of 3.7v nominal.
Overcharging is a serious safety hazard and will not be tolerated.
3.10 Any competitor found to be charging cells using a charger that is not specifically
designed for LiPo batteries, or using a charge profile other than the industry standard
CC/CV, will be disqualified from the event.
Any competitor found to have charged LiPo batteries to above 8.40V or 4.20V (as
detailed in 3.9) will be disqualified from the event.
Hamworthy - another local club operate a 1C charge ruling where by you can only charge at the capacity of your battery - for example a "Orion 2400Mah" can only be charged at 2.4 Amps (1C)
On the back of the Orion it suggests charging between 1C and 2C - somewhere between 2.4A and 4.8A
The Demon DL4000 pack recommends charging at 5A (1.25C)
The demon DL3800 Pack recommends charging at 5A also (1.32C)
Manufacturers seem to be leaving the "safe charge rate" as a flexible value, which can be a confusion to new drivers and seasoned racers together. Currently SHMCC follows the BRCA's recommendations however, the emphasis being on each individual being responsible for their own equipment and it's safe usage.
May I also take this opportunity to remind all racers that it is important to use a LiPo cut off device to ensure that pack Voltages do not drop below the safe operational voltage.
Matt