450 watt alternator conversion kit

[cjleroux]

Is it worth buying and installing a 450 watt alternator conversion kit (as sold by motorworks.co.uk) for my '81 R65?

i do mostly short trips with my bike, so the battery runs flat every 6 weeks or so. BMW checked my alternator and said it's fine, and the battery is new.

[Bob_Roller]

Just get a float charger and  plug it in when you park the bike in the garage .

A lot cheaper in the long run !

[MrRiden]

I employ Bobs method. Other options might include looking into a higher output or an adjustable regulator. jumping the ALT light with a resistor [might not make any improvement] or going the clean every connection route.

[Barry]

If the battery runs flat it may be faulty and if it isn't it soon will be they don't like to be fully discharged.

It might not be extra watts you need unless you have lots of accessories like heated grips etc.  An adjustable voltage regular like the police spec item might do it.

I'm with Bob though I charge the battery for a few hours once a week. Also I use a 10W halogen pilot bulb as a day time running light.  It's suprisingly bright and uses much less power than the headlight. Next step would be an LED stop tail bulb.

The standard 280 W is a veritable power station compared to Brit bikes of the day. It ought to be enough.

[R65_Mark]

A vote here for specialty battery tender/chargers.

The R65’s electrical system does seem marginal – I’d say more so the battery than the charging system.

I have a bunch of Battery Tender Juniors that I use.  Whether parked at home of at my work/shop, my R65 is plugged in.

Most trips I do are to/from work and around town - often short trips less than five miles and a lot of standing between starts.  I use them on my other toys as well, which tend to sit around a lot longer between outings.  Batteries/state of charge has never had a problem.

Mark

[montmil]

You would only benefit from the 450 watt unit if you have multiple running lights, electric clothing and/or grips (big power eaters) or a ghetto blaster stereo system.

The R65's charging system is inadequate below 3000 rpm. While riding in town for lengthy periods of stop n' go traffic, the engine is dependent on the battery along for ignition power.

A battery tender is lass expensive and keeps you running happily.

Monte

[drewboid]

A couple of tricks are available if you find your battery discharging due to a lot of low RPM riding:

1. Reconnect the ignition wire at the key switch so the bike will run with the parking light on rather than needing to turn on the headlight. I used this trick at the MSF course and when doing low speed practice in the parking lot.

2. Add a diode in series with the ground lead from the voltage regulator. A 10 Amp - 50 volt diode from Radio shack works fine - the end with the white ring on it should be pointed toward the chassis ground. this will increase the charging voltage about 0.7 volts which is particularly good if you are using a sealed battery.

3. Change the alternator to the Enduralast or Omega alternators. I am using the Enduralast and really like it.

So there you have some tricks - #1 free, #2 low cost, and #3 expensive.   YMMV