CL77 Charging system seems to boil off electrolyte

Snakeoil · Post by **Snakeoil** » Sun Oct 30, 2011 6:44 pm

Today, as I was putting my bikes away for the winter, I noticed that the battery on my '67 CL77 was way down in electrolyte. I did not put many miles on the bike this year. Rode it in the spring and fall motogiros (maybe 500 miles) and some minor rides over the summer. Maybe put 1000 to 1500 miles on it this summer.

I know that the charging system is not regulated. I always ride with the lights on. All I've read is the system can barely keep the battery charged. But based on my electrolyte level (3 other bikes were all fine, one with an identical battery) I get the feeling that the system is causing the battery to offgas a lot while riding.

Is this common? Would a Tympanium or similar solid state regulator correct this. Or do I perhaps have something else going on here?

Thanks,
Rob

Jethro · Post by **Jethro** » Sun Oct 30, 2011 9:25 pm

I know as a lead/acid battery discharges, some of the electrolyte is absorbed into the lead plates and the fluid drops. That's why they say that a battery should be charged before adding distilled water to the cells. (Although I usually make sure there is enough fluid that the plates are submerged before I charge a battery.) So you might throw it on a charger and see if the fluid comes up at all. Then go from there if a discharged battery is not the problem.

Jethro

G-Man · Post by **G-Man** » Mon Oct 31, 2011 2:55 am

Rob

I think that the bike switches in more charging coils when the lights are on so having them on will not reduce the charge to the battery.

Using a solid state rectifier will make things worse as that will just provide more charge available to the battery. I think that you just need to keep the battery maintained as running it with low electrolyte will cause the problem to escalate.

G

brewsky · Post by **brewsky** » Mon Oct 31, 2011 5:37 am

Rob,
Have you checked the battery voltage with the engine running, lights on, and rpm 3000-5000?

If you have > 14V under those conditions you are probably cooking the acid off.

Are your HL and TL bulbs stock wattage? Coils stock?

Snakeoil · Post by **Snakeoil** » Mon Oct 31, 2011 1:27 pm

Thanks for the replies, guys. Yes, everything on the bike is stock, even the HT leads. Only upgrade was a solid state silicone rectifier.

I thought I read here that in the higher RPM ranges, the alternator on these bikes is much higher than 12 vdc. I'm aware of the lighting coil coming into the circuit with the lights on to maintain battery charge. But all I've read say that these charging systems are marginal at best.

I too prefer to have the plates covered before I put a charger on a battery. I made a couple of overflow trays from plastic laundry detergent bottles yesterday and my std bike batteries are in those. Honda battery is on the charger and should be done. Need to go down and check. I did check the voltage before I added any water and it was at 12.52 vdc. I realize that the voltage does not tell you the condition of the battery, but it is an indication of its health.

I just went down to check the battery. Charger indicated fully charged and on float. (Deltran Battery Tender plus). Electrolyte level was right where I set it yesterday when I added water. Voltage is a steady 13.62 disconnected from the charger.

In all my years of riding Jap bikes, going back to the early 70's, I've never had a battery electrolyte level go this low with so few miles.

regards,
Rob