305 battery and charging

casamere · Post by **casamere** » Thu Dec 17, 2015 5:36 pm

Hi Guys, my CA77 is not charging the battery can someone please tell me what I need to replace. Thanks.

DianneB · Post by **DianneB** » Thu Dec 17, 2015 6:57 pm

Most likely to be the rectifier. The original selenium rectifiers were inefficient to start with and get much worse with age.

casamere · Post by **casamere** » Fri Dec 18, 2015 5:33 am

DianneB wrote:Most likely to be the rectifier. The original selenium rectifiers were inefficient to start with and get much worse with age.

Many thanks for the advise Dianne and the prompt PM reply. First class article btw.

Hamamatsu Nippon · Post by **Hamamatsu Nippon** » Sat Dec 19, 2015 4:17 pm

A quick way to check your charging system is hook up a voltmeter to your battery terminals. Chart your findings.

These measurements below are not intended for your 60's 305, rather they are more indicative of a 1980's and on motorcycle. Our average Honda 305 will show lesser volts. Your own results should however be relative to these figures.

Start with a freshly charged battery and switch your lights on. Post your findings here, it's the best way we can help.

1-Ignition off. Normal 12.7v-12.9v
2- Ignition on, wait 10 seconds. Normal 12.2v-12.5
3- at idle 1500 RPM Normal 12.6v-13.2v
4- at 2500 RPM. Normal 13.5v-14.0v
5- at 5000 RPM. Normal 14.0v-14.8v
6- Ignition off. Normal slightly higher than your first measurement 12.8v-13.0v