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How to charge a battery

Posted: Wed Feb 18, 2009 5:31 pm
by thackers
I thought i posted this yesterday but must have forgot to press the submit button :roll: :roll:
Could some kind person give me simple instructions how to wire up to charge a battery? I have a regulator with the extra outlet so presume it can be done, and no it's not to power a rack full of lights :o

Re: How to charge a battery

Posted: Wed Feb 18, 2009 6:20 pm
by dapper
Dave, I always thought it was from the B+ extra terminal on the regulator to the positive of the battery and then earth the negative terminal of the battery to chassis/frame

MTS

Re: How to charge a battery

Posted: Wed Feb 18, 2009 11:10 pm
by thackers
O.K simple enough, but how do you then go on to wire up from the battery? Is there some kind of trickery in between battery and component? :?

Re: How to charge a battery

Posted: Thu Feb 19, 2009 12:46 am
by coaster
Yes there will be thackers, what is it you are hoping to power?

Re: How to charge a battery

Posted: Thu Feb 19, 2009 10:01 am
by thackers
I'm hoping to power from the battery a clock that sits on top of the legshield toolbox on my Vega :idea: . At present i just charge up the battey when flat, but thought this would be bad for battery life. The regulator would provide 12v lighting as in the simple upgrade on L.C.G.B and i presumed this would also charge a small 12v battery then operate the clock. :?:

Re: How to charge a battery

Posted: Thu Feb 19, 2009 2:09 pm
by coaster
Wiring a clock to an on board battery would be VERY simple, just make sure you insert an in line fuse in the feed wire to the clock.

Just to clear mup a misconception though, small re-chargeable cells (e.g. AA. AAA etc) do actually benefit from being fully discharged before re-charging. These type of cells can become 'memory mapped' if put back on charge when only partially discharged on a regular basis.

Always a good idea to rewgularly run your laptop and mobile batteries flat ;)

Re: How to charge a battery

Posted: Thu Feb 19, 2009 11:17 pm
by rog60
For what it's worth, I've used the LCGB site to fit a charging circuit on my Indian GP. I also fitted a junction box and ran the charging(red) wire via this to the battery and connected the two small spotlights I had to the other terminal on the junction box, but I found that the battery discharged quickly and realised that the original rectifier stopped this discharge to earth due to a diode being fitted. I have now fitted a 2-way switch between the battery and charging regulator to prevent this.

Re: How to charge a battery

Posted: Fri Feb 20, 2009 2:33 pm
by coaster
rog60 wrote:For what it's worth, I've used the LCGB site to fit a charging circuit on my Indian GP. I also fitted a junction box and ran the charging(red) wire via this to the battery and connected the two small spotlights I had to the other terminal on the junction box, but I found that the battery discharged quickly and realised that the original rectifier stopped this discharge to earth due to a diode being fitted. I have now fitted a 2-way switch between the battery and charging regulator to prevent this.
It would be better to substitute the switch for a diode then you wouldn't need to remember to operate the switch all the time :roll:

Re: How to charge a battery

Posted: Fri Feb 20, 2009 10:02 pm
by rog60
DOH!!!! of course, any ideas on possible sources?

Re: How to charge a battery

Posted: Fri Feb 20, 2009 11:37 pm
by J1MS
It is possible to wire up the std 12volt ac regulator to a mini bridge rectifier wired in paralell, to then charge a battery which you can then use for your dc supply, I have done this on about 30 or more Lambrettas and a couple of small frame vespas. Using a mini bridge rectifier, the ac connections on the rectifier (mini bridge) are not used.

The negative connection of the mini bridge is wired to the regulator (from the same connection that feeds the loom with power).
The positive from the mini bridge terminal is connected to the battery's positive connection, then the battery's negative is connected through a fuse to earth.
This will give the battery a charging current of about 2 amp hour, under normal use. From what would be termed a "half wave rectified supply". I use this set up as its very cheep reliable and simple, as the ac is already regulated to about 14.6 volts all thats needed is a circuit that turns the ac supply into a dc current, which the rectifier (mini bridge rectifier) does.

Mini bridge rectifiers are available from about £5, and claim to handle current up 35 amps. and up to 400 volts. signified by markings on the side 35/400 these are available from Maplins, and this is the one I use and have used on my GP for the last 11 years, I must admit I have managed to boil the battery when on a Euro rally due to too many revs for too long, over charging the battery. This is not the fault of the rectifier but more the ac regulator supplying too high a voltage at prolonged high revs. I also run this system on my SX and the battery is now 7 years old and still working, but this is a 12volt 7amp sealed battery, much better quality than the Lambretta Item. I hope this little bit of info is of some help to anyone looking for some dc power from standard 12 volt ac system as fitted to all Indian electronic SIL systems.... 8-) 8-)