battery issues

[alex_in_az]

I'm on my 3rd battery since last september, they just seem to suddenly die. the 1st time I thought it was just a crappy chinese battery and replaced it. then the 2nd one died and I wondered if it could be something at fault in the charging circuit. I fitted a new battery last week and hooked up a volt meter to it.
at rest the battery is showing 12.3 and at 4000rpm it is 14.5. does this sound about right? what can I check to tell me any problems I might have in the charging circuit?

[lilgman]

Hey Alex in AZ, I'm new to working on motorcycles, but on cars, charging voltage is usually more in the 13.7 area. 14.5 volts is high and will cause the battery to boil. I hope you'll get some other opinions from people with more experience than I have, but if not I'd look into replacing the regulator.

[ChillRider]

Hmm... my Zonsghen ZS200GY-2 rectifier always seems to produce 14.5 V too, but the truth is that it is kinda harsh on the batteries: I took to regularly check and top up the fluid in mine at least once a month, or after each long-ish ride (anything significantly beyond my normal daily work + leisure commutes of 25-35 km in one go).


Today I replaced it anyway since I had a brand new one sitting around (also cleaning up the relevant cables and area, which were gunked up), and it still gave a rock-solid 14.5V reading on the multimeter, once it has replenished the initial starter's draw.

Several online sources seem to quote that same figure as a maximum value, and a simple "battery + charger health meter" I have (basically, just a bunch of LEDs that light up at different voltages) also reads "14.5V - Charge at MAX".

So I dunno, is the battery supposed to take 14.5V all the time without boiling? Or are these chinese rectifiers simply not sophisticated enough to cut back on some of the voltage? Most home chargers also seem to cap at 14.4V for regular lead-acid batteries and 14.8V for AGM/cold conditions. That 14.5V figure sounds indeed .1V too high, and mind you, it's not like it's temperature-controlled or anything.



Maybe we should switch to a maintenance-free type of battery (e.g. AGM) which can take some more voltage by design?

[duck9191]

14.5v is high but is fine for cyclic use. Does it go any higher when you rev it? Keep an eye on the water level and add as needed. Ideally they would use a cc/cv charger but they don't due to cost.

[ChillRider]

Nope, it stayed at a rock-solid 14.5V from idle all the way up to "give it some gas", with a fully pre-charged battery and only 2-3 seconds of starter action before. It only read a lower voltage while replenishing the starter's draw, which didn't take long at all.


To be noted, I'm running LED headlight and taillight bulbs, so the curent draw even at night is way lower than normal.

[JerryHawk250]

Honda Specs. are 14 to 14.8v @ 5000 rpms.

[alex_in_az]

Originally Posted by JerryHawk250

Honda Specs. are 14 to 14.8v @ 5000 rpms.

thanks, it was over 15v at 5k, I dropped $12 with VMC on a new regulator and now its at 14. that's the cool think about these bikes, nothing is expensive to replace if it goes wrong. I picked up a spare CDI while I was at it, just in case.

[Musictrek]

Originally Posted by alex_in_az

I'm on my 3rd battery since last september, they just seem to suddenly die. the 1st time I thought it was just a crappy chinese battery and replaced it. then the 2nd one died and I wondered if it could be something at fault in the charging circuit. I fitted a new battery last week and hooked up a volt meter to it.
at rest the battery is showing 12.3 and at 4000rpm it is 14.5. does this sound about right? what can I check to tell me any problems I might have in the charging circuit?

14.5 at 4,000rpm sounds high to me. I can get 14 at 1,500rpm