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    Algorithm to estimate given battery chemistry and capacity

    Dear All,

    I would like to know if there any techniques for estimating the battery chemistry as well as its capacity in AH so that appropriate charging current can be decided. Thanks.

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    Re: Algorithm to estimate given battery chemistry and capacity

    I have not heard of a smart charger which is able to detect Amp-hour capacity of a random cell.

    It's a bad idea to charge a cell unless you know how well it tolerates mistakes. You ought to know what is the type of battery, and its final voltage at end of charge.

    One useful reading is temperature. When a cell is full, it no longer converts charge current to replenish electro-chemical storage. Instead it heats up to a greater degree than it did during bulk charge.

    You'll need to experiment with batteries you're already familiar with, to watch how they behave during all stages of charging. Example, start charging at a very low rate (small Nicad is 70mA). Keep track of Amp-hours. Monitor temperature for 5 minutes. If the cell stays cool then increase the rate 50 percent. Go another 5 minutes. When you reach a rate which is high enough to warm the cell just a few degrees, stop charging. Do a slow discharge, and see if it yields back the same amount of Amp-hours (or nearly the same) as you gave it. As you can guess, numerous trials are necessary, at various charge rates, and temperatures, and timeframes, in order to evaluate the condition of a single battery.


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    Re: Algorithm to estimate given battery chemistry and capacity

    Dear BradtheRad,
    Thanks for the reply. How is it there are charging stations which can charge vehicles from different manufacturers having different battery capacities. Is it that the fast chargers are able to detect the type of battery or they have some built in database.
    Thanks.



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    Re: Algorithm to estimate given battery chemistry and capacity

    Vehicle charges, even most mobile phone chargers, have a communication path to the battery management system. They can tell the requirements by asking the management system what it needs and adapt the charging rate accordingly.

    Brian.
    PLEASE - no friends requests or private emails, I simply don't have time to reply to them all.
    It's better to share your questions and answers on Edaboard so we can all benefit from each others experiences.



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