Why can i not slow charge a lead acid battery?
ive been trying figure out how can build simple charger 12v 7ah lead acid battery not understand circuits on internet. feel stupid feel there huge gap between people me barely know electronics , people know. explanations of diagrams leave me lost. feel people dont explain enough or cater people not have electronic background , assume know bare basics.
ive been trying pass gap year , im still struggling frustrates me point feel forgetting electronics cause im not clever enough....... =(
anyways have read charge lead acid battery there 3 basic stages. complex me build want charge battery start till end. if correct slow charge @ 10th of batteries ah capacity. 7ah battery charge @ constant current of 7/10 = 700ma?
now think can use lm317 regulate current 700ma using 2ohm resister give me 625ma, ok slower charge then. confuses me this:
1. can this, plug battery in charge @ 625ma 14hours? simple that?
2. voltage must amps at?
if had charge battery in 3 stages must how can u know when 1 stage must finished , next stage must start? measuring battery voltage? how do when battery on charge? not measure charging units voltage? or must first unplug battery charger , measure voltage decide stage should on?
ive been trying pass gap year , im still struggling frustrates me point feel forgetting electronics cause im not clever enough....... =(
anyways have read charge lead acid battery there 3 basic stages. complex me build want charge battery start till end. if correct slow charge @ 10th of batteries ah capacity. 7ah battery charge @ constant current of 7/10 = 700ma?
now think can use lm317 regulate current 700ma using 2ohm resister give me 625ma, ok slower charge then. confuses me this:
1. can this, plug battery in charge @ 625ma 14hours? simple that?
2. voltage must amps at?
if had charge battery in 3 stages must how can u know when 1 stage must finished , next stage must start? measuring battery voltage? how do when battery on charge? not measure charging units voltage? or must first unplug battery charger , measure voltage decide stage should on?
1: yes.
2: whatever battery requires @ moment in time.
with power source 1 of either voltage or current "constant" - i.e., fixed @ specific value supply - other value free wander around whatever connected device requires be. it's voltage fixed, , current determined circuit attached it. constant current source current same, voltage set circuit attached it.
that said, there upper limit supply can give "variable" value, , has taken consideration (i.e., can't draw 40a 1a, 12v power supply or melt). constant current supply have know upper voltage , cater it. 12v battery that's high 15v while charging, plus have factor in 1.25v drop of lm317t. need @ least 17v going in current regulator - better safe , have few volts more. choice old laptop power supply these typically 19v.
however, there 1 more gotcha in this. lm317t liable hot. need big ass™ heat sink on it. go lm338t has mich higher current handling capacity , shouldn't quite hot. you'd still need heat sink though, not quite big.
2: whatever battery requires @ moment in time.
with power source 1 of either voltage or current "constant" - i.e., fixed @ specific value supply - other value free wander around whatever connected device requires be. it's voltage fixed, , current determined circuit attached it. constant current source current same, voltage set circuit attached it.
that said, there upper limit supply can give "variable" value, , has taken consideration (i.e., can't draw 40a 1a, 12v power supply or melt). constant current supply have know upper voltage , cater it. 12v battery that's high 15v while charging, plus have factor in 1.25v drop of lm317t. need @ least 17v going in current regulator - better safe , have few volts more. choice old laptop power supply these typically 19v.
however, there 1 more gotcha in this. lm317t liable hot. need big ass™ heat sink on it. go lm338t has mich higher current handling capacity , shouldn't quite hot. you'd still need heat sink though, not quite big.
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