Can anyone recommend a battery charger that would allow me to see how much the battery is charged rather than just a red/green light saying that it's 100%? I've got a 48V 10.4 battery on a 500W motor. Thank you
Thanks a lot! I never knew they existedPut one of these in your charge lead, then you'll know precisely - much cheaper than a new charger
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Basically I agree. One detail: I think (but you may well be able to correct me) that the Bosch system has a similar device built in; and that the system does know the state of charge quite accurately. The silly remaining range estimate is based on charge remaining (fairly accurate) and rate of use (rubbish). The stupid result is because the way it computes rate of use is based on much too short a history.It's very accurate, not like those stupid estimating systems you get with Bosch type systems.
I was going to say exactly that, which makes it even more stupid, but I didn't feel like typing it all out. Thanks for saving me.Basically I agree. One detail: I think (but you may well be able to correct me) that the Bosch system has a similar device built in; and that the system does know the state of charge quite accurately. The silly remaining range estimate is based on charge remaining (fairly accurate) and rate of use (rubbish). The stupid result is because the way it computes rate of use is based on much too short a history.
It could give a sensible remaining charge if it were more sensibly programmed.
Minimum voltage.As an asside here...I've got one of these Watt Meters. Is the "Vm" value the mean voltage value used to calculate the number of Watt hours?
Voltage is not a good measure of capacity because it doesn't go down linearly, and it also varies with current.As it knows the actual voltage at any time it should use that to calculate watt hours. It will vary with time as does current; the voltage variation won't be nearly as much as the current one.
Are you sure about that? I used to think it was minimum voltage, but I've often seen the voltage dip under load below the stated value "Vm" given at the end of the ride.Minimum voltage.
These things are made for the RC hobby, where they use lipos. The minimum voltage is important. Show which one you have.Are you sure about that? I used to think it was minimum voltage, but I've often seen the voltage dip under load below the stated value "Vm" given at the end of the ride.
Indeed, voltage isn't a good measure of capacity, but it is needed for correct calculation of wH provided by the battery.Voltage is not a good measure of capacity because it doesn't go down linearly, and it also varies with current.
That's not right. I think you have the right idea, but it's the wrong way round. Watt-hours are a measure of how much charge is in the battery. Watt-hours are a constant size. You can take them out quickly or slowly. If you have a 400Wh battery and take out 350Wh, you have 50Wh left, regardless of how fast or slow you took them. It's amp-hours that are not precise because you can have big ones or small ones. The energy in an amp-hour at the start of your ride at say a constant 5 amps would be 40x5 =200Wh, but at the end of your ride, it would be 35x5 =175Wh.Indeed, voltage isn't a good measure of capacity, but it is needed for correct calculation of wH provided by the battery.
Because of voltage drop etc I suspect that aH used is better for measuring remaining capacity than wH. Someone with better knowledge of batteries can clarify; but ??? if you use a battery under heavy load then light load the aH used will be similar in each case, but the wH will be quite a bit lower in the heavy load case???