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Bugenhagen
07-10-2011, 12:14 PM
Hi.Im new here.I hope i'm in the right forum.I just successfully build imhotep bedini fan.And have few question.Here goes: i don't have a proper equipment to measure the spike voltage of the unit.Ang i'm charging a dead 6v4ah battery,how can i distinguish if it's fully charge for safety precaution.Second is it possible to power this bedini with that battery.Lastly can i charge rechargeble lithiun ion battery with this bedini.Thats all for now.Thanks to all for the reply.Good day

Web000x
07-10-2011, 02:22 PM
Hi.Im new here.I hope i'm in the right forum.I just successfully build imhotep bedini fan.And have few question.Here goes: i don't have a proper equipment to measure the spike voltage of the unit.Ang i'm charging a dead 6v4ah battery,how can i distinguish if it's fully charge for safety precaution.Second is it possible to power this bedini with that battery.Lastly can i charge rechargeble lithiun ion battery with this bedini.Thats all for now.Thanks to all for the reply.Good day

You will need to get a voltage meter to measure the battery voltage. Don't exceed the manufacturers max voltage level.

It is possible to power the motor with the battery that you have charged with the bedini fan. However, some people say that using a negatively charged battery is not as efficient for doing this. It will power the fan, but I am not sure at what efficiency it will do this.

Lithium ion batteries usually have a protective circuit similar to a fuse that will break if you try to charge them with high voltage spikes. I have yet to verify that they cannot be charged this way, but take precaution if you do try this.

Dave

Slider2732
07-10-2011, 06:14 PM
I'd agree to only try the li-ion batteries if you can afford to lose them. Li-po's, as used in R/C vehicles are a definite no-no, they can set on fire with incorrect charging methods.

I have recently rejuvenated and recharged several li-ion batteries from an old laptop battery pack. Each cell is of 3.7V capacity and they comfortably charge at about 4.2V over an hour from my similar fan circuits. Those batteries were removed from the laptop pack and any connections (including the small circuit board) were removed.
Each time you recharge them they rise to their full voltage quicker...but that isn't an indicator of charge within them, that is what's called a surface charge. It dissipates over about a day or even less. That's why you need to know the milliamps too, to know how long to charge them and need to meter the batteries as they do charge :)
Ni-Cd's charge in a similar way. Lead acid's seem to be more linear in voltage to current ratio as they charge.
I'm quite new to this myself, but those are my findings.

Bugenhagen
07-11-2011, 02:32 AM
Hey thanks guys,really appreciate it.