750 SF charging numbers?

TeddyG

TeddyG

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Location
Portland Oregon
Greetings,

My 750SF2 always starts immediately, the Odyssey battery it came with seems to hold a charge and recharges very fast when stored, but at idle I'm seeing @12.5 volts and up to 13.5 at 3-4K RPM. Just wondering if these are normal numbers. The Bosch regulator appears to be fairly new or was replaced judging from its clean and shiny appearance, the coils are original, and all the main wires have been replaced.
Thanks for your input once again.
 
No charge coming from the dynamo at idle and until the reg Gen light goes out, so 12.5 will be your battery volts. Once you're into some revs 13.5 would be a healthy voltage. So all looks good to me and my basic electrizical skillz.
 
If your Bosch reg is the original mechanical type you can adjust it. What are the figures at 3000rpm with the headlight on? Bosch gen usually puts out heaps, there are a few threads on here when I was sorting out my sf2 which was overcharging. I ended up running the modern VW reg, which the original Bosch part supercedes to
 
13.5v across the battery terminals is a bit low for me but not a real worry. Ideal is low 14 numbers. The new Bosch electronic replacement regulator is far better than the old original vibrating contact type. There are numerous tests available for the genny and reg if you do a search, but maybe an idea to wait and see if the battery stays ok with the bike in use.
 
I know I'm a cracked record but an Odyssey battery needs 14.5v to fully recharge. So you will need to use a battery charger to maintain full capacity. Otherwise the rated battery capacity will become reduced.
 
Rob said:
I know I'm a cracked record but an Odyssey battery needs 14.5v to fully recharge. So you will need to use a battery charger to maintain full capacity. Otherwise the rated battery capacity will become reduced.
Click to expand...
I used an Odyssey for years on my SFC without problems, including various long road trips and the bike staying outdoors.
And it has electronic ignition as well.
No charging from an outside source.
Paul
 
I do too Paul, and the solid state Bosch regulator holds volts at 14.35. Enough to maintain ~80% of rated capacity over time. I just choose to protect my investment with an occasional boost from a Ctek charger on its AGM setting.
PC 680 now around GBP 134 😳
 
FWIW, lower charge volts at say 13,8V is within a suitable charge for a battery that is in very good condition, as a guide

The problem starts when the 6 individual cell compartments do not have the same state of capacity condition. In time this lower 13,8V does not allow any under undercharged cell reaching correct SG reading, your true indicator of charge ( talking flooded cell for demonstration purpose ), ie other cells voltage rise faster and rob the under performing cell of recovery, the oft read "Equalize" over voltage charge, usually 2,25-2,27V per cell now requires 2,4V per cell, for a limited time application. Battery self heating an issue for EQ charge profile.

AGM batteries have an alternate plate chemistry which is not well disclosed from my researches. PR blurb is useless.

Summary, you can live with lower charge voltage operation, in time the battery will fail short of its design life cycle. A Few here have the inside story sorted. HTH j
 
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