Mazda RX-8 Manual page 443

Keep all flames away from the battery, otherwise evaporated gas from the battery fluid may catch fire,
•
and cause serious injury.
Remove the battery filler caps when recharging to prevent battery deformation or damage.
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CAUTION:
Do not quick charge for over 30 min. It will damage the battery.
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1. Remove the battery and then place it in a pan of water.
2. Connect a battery charger to the battery and adjust the charging current as follows.Standard specification
Battery type
Recharge current (A)
(5-h rate)
50D20L (40) 4.05.0
55D23L (48) 4.55.5
75D26L (52) 5.06.0
3. After the battery is recharged, verify that the voltage is within the specification and remains at the same
value for 1 h or more after the recharging was stopped.
If not within the specification, replace the battery.
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Standard voltage
12.4 V or more
o
Quick charge
(A/30 min)
25
30
35
(w) Engine Specifications
Page 206