Solid HT white wire data

[etacovda]

thats the reason im going 12v, easier to work with (plus i had existing batteries). Which schem are you talking about, the one i attached? if its that one, it still needs a current/charge regulation circuit added to it, it just rectifies the ac, and outputs it as a smooth 14.5ish volt dc wave. Its needs alteration for use with an SLA battery, the only reason its working for me is that i have a charge regulation circuit from my battery drill charger.

If its the one i linked to, no i wont be making a simple circuit diagram for that one because im not 100% sure it will work for you; someone with more electronics experience needs to chime in on that one.

 

[BoltsMissing]

Is this DIY the next direction we need to take with the charging systems ?
http://www.reuk.co.uk/Zener-Diode-Voltage-Regulator.htm

 

[etacovda]

bolts - i have put that into my circuit already as per my circuit above. What is needed is a voltage sensor which will stop charging the battery once 13.8v or so is reached...

 

[duivendyk]

There are two basic approaches to prevent overcharging,one is to taper down the charge rate as the battery voltage goes above a certain limit,the other is to divert the charging current with a circuit that becomes a load when that happens.Because of the unusual mode of charging (with short intense current pulses) I think the second scheme is preferable, that is less risky.I could design my way out of scheme one but I doubt if you people could,there are some sneaky aspects to it that I can identify which prob. means that there are other unknown unknowns.
I have devised a circuit on paper (not all that complicated),that plays adjustable zener so to speak,the excess power can be disposed of in a resistor, a small lightbulb or some LED's in series.So you could set voltage limit where you want to start tapering off,there could be some use for LED's in daytime,tailight or battery status indicator or combination of these ?.I have a 12 V motorcycle battery and should be able to cobble up something along this line for a look-see.This scheme has the virtue that there is no parasitic power loss when just charging.Important ,because we don't have a lot of power to begin with.Any comments or suggestions?

 

[etacovda]

sounds brilliant to me D - exactly what is required. I can buy a 1.2AH 12v SLA for around $20, id be willing to buy one + build the circuit you come up with for a back up to my own + will draw up a tutorial with photos on the build of the circuit, if you like? Then we could sticky a thread on how to build your own SLA charging circuit, will open a lot more people to using lighting on their bikes, I think.

 

[duivendyk]

OK,I'll mine my parts collection and give this a whirl.

 

[impression]

sounds like a sweet plan

if we could get a 'standard' charging circuit that gives us some protection against overcharging... oh i just drool at the possibilities that the minds of this forum will conjure up

 

[duivendyk]

Does anyone know what current these LED's used as taillights typically draw ?.I know the voltage per LED is about 3.5 V.I have about 12.5 V and 400 mA available in the overcharge prevention, current diversion scheme.I put a breadboard together and it seems to function OK,about 0.3V to dump an extra 400 ma into the pseudo zener.Sofar sogood

 

[etacovda]

no idea, sorry - im using all custom lighting on mine wired from scratch. Hopefully someone else can chime in.

 

[skyl4rk]

I have a LED taillight normally used for truck trailers at nominal 12V. it seems to draw 0.02 A at running light mode and 0.08 A brake light mode, on a source voltage of about 10V (a low battery). There are 10 leds in the sealed unit. I see two resistors in there, perhaps two runs of 5 leds in series?

I wonder if there is a way to store the excess energy in the pulse and release it slowly into the battery. Or perhaps battery chemistry may accept short pulses of overvoltage without damage to the battery?

I would suggest an inductor but I think that an inductor releases energy in the opposite direction (polarity) that it got the energy?