Losing some efficiency to heat and having to use a different EODV will cause the batteries to have lower capacity ratings at different loads. A higher power draw will need a lower end of disconnect voltage to save the batteries from over heating and presenting a threat to device health, over-heated battery danger and other reasons. So when the batteries are placed under a load they lower the voltage that the batteries immediately drop to and the voltage they will drop to when the batteries fail to provide adequate power. The higher power draw also causes more voltage sag. This will cause the batteries to lose some of their energy capacity to heat loss (higher power draw has less efficiency converting the capacity energy to load energy being used). The greater current will cause more heat build up than a lower current. A higher load causes a greater current and wattage per cell. The EODV and the capacity of the battery will vary depending on the load placed on the battery. The reason will become clear in a moment. C Rates are incomplete if you do not specify an End Of Discharge Voltage as well so in reality you need a few tables or a pivot table with CRate and EODV. C Rates tell you the AH capacity of batteries at different loads. C rate's are important because of the peukert constant. Including a new battery vs used battery.ĭifferent manufactrers, chemistries, ages, electrolytes, capacity = bad idea.Īnd if everything is exactly the same? Still not a great idea? Id like to stay on the safe side considering this is a child car.I believe none of the answers above are correct. Nothing of OP info makes this a good idea. I would also like to concur with his evaluations A bad battery and we switch out all batteries in box for same batch. I deal with the marine industry, which uses battery boxes with parallel batteries. Without knowing the details of the charger, it is impossible to know whether it will charge the batteries correctly, whether it will damage the batteries, whether it will leave them less than fully charged, or even possibly damage the charger, although I think that last possibility is rather has provided a useful point of reference regarding the risk associated with using batteries in parallel, and what is considered good practice within his field: How much risk? That is impossible for me to say.Ĭan I also use the built-in charger to charge both at the same time or do I have to modify it somehow? Identical voltage, identical chemistry, identical geometry, identical manufacturers. You are safest if the batteries are identical. If both batteries are fully charged, and they have different characteristics, it is possible that one battery might become overcharged. However, if the batteries have different chemistry, or even different geometry, the charge transferred could be significant. Hopefully, the total charge transferred from one battery to the other will be small. When two batteries with different open circuit voltages are connected together in parallel, current will flow from the battery with higher voltage to the battery with lower voltage, until the batteries are equalized. Two batteries with the same nominal voltage rating, can easily have different open circuit voltages. Can I put these two in parallel? Some sources say that the voltage has to be the same other sources say everything must be exactly the same.
0 Comments
Leave a Reply. |