[paulp]

Finally found where a whirling almost bubbling computer noise was coming from on my sons CF500HO, After a long ride down a mountain hearing it, then pulling the seat asap its coming from the battery!
Its a zero maint Yuesa, I don't see any voltage or error lights going on at all even when its "boiling" or making that noise.
Anyone know the cause? or correction or even if its an issue or not..?
Is weird to say the least.
Thnx

 

[NMKawierider]

Battery acid bubbles because of two reasons, it's being exposed to heat or...the main reason..its being over charged. Check the voltage just sitting there not running then start it and check it at around 3000 RPMs. Should be around 12.7 and not over about 14.5 running. If it is higher, the rectifier/regulator would be my first guess. Bad stators usually make lower voltages unless phase-shorted. Lower voltages won't boil batteries and won't charge them making a voltage error show up.
Of course there may be a problem with the battery...but if it shows 12.6-13.2 static I wouldn't think so.

[paulp]

Thanks, on it tonight to see!

[paulp]

Results are in,
so while they , I have 2 of the same atv's, were on the trailer, i conducted the same to each to compare.
1st unit with boiling noise: 12.5v -static-when turned key on, not running. When running at standstill fluctuates between 14.4-14.8. at 3k Rpm it stays at same range as well.
2st unit -no issue-: 12.8v -static-when turned key on, not running, and fluctuates between 14.2-14.7 when running, Rpm same range at 3k rpm.
Its the 2nd time this noise was heard after a long ride...
They're the decent Yuesa Batteries on all.
Thanks again..
P

[doug80638]

14.8V is the upper limit and  OK for an AGM battery.

There is no shortage of reports of AGM batteries making this noise so don't be too concerned.

If the battery passes a load test, and there is no visible damage to the case, keep using it.

[NMKawierider]

Yeah but I didn't think they put AGM (Absorbed Glass Mat) batteries in these. Mine is just a standard lead-acid not a AGM. Still, the numbers are in range although I would have thought the noisy one's should have been closer to the quiet one. How about heat? where do they put these batteries? Anywhere over the top of a heat source...that's missing a heat shield maybe...which CFM is known for?

[doug80638]

I thought Yuasa batteries were AGM, and could not be serviced.

All lead acid batteries bubble to some degree during charging and that's normal.

A sealed battery making noise means the pressure exceeds the over-pressure valve resistance. That could mean a marginal valve or overcharged battery. 

If you can hear it, you might be losing water. The sealed caps can usually be pried off and distilled water can be added and the caps reinstalled. I've done this with my lawn mower battery but not (yet) the ATV battery.

Is there any moisture or signs of leakage on the top or sides of the battery?

[NMKawierider]

I thought Yuasa batteries were AGM, and could not be serviced.

All lead acid batteries bubble to some degree during charging and that's normal.

A sealed battery making noise means the pressure exceeds the over-pressure valve resistance. That could mean a marginal valve or overcharged battery. 

If you can hear it, you might be losing water. The sealed caps can usually be pried off and distilled water can be added and the caps reinstalled. I've done this with my lawn mower battery but not (yet) the ATV battery.

Is there any moisture or signs of leakage on the top or sides of the battery?

At least on mine I replaced the Factory with the exact same. Came with the acid pac that had to go in and sealed. I removed the seal on the old battery. Almost bone dry I refilled with distilled water, put it on a smart charger for a week and it came back. Tossed it anyway cause the plates were damaged but I could have used it for another year or so I believe. Think I'll check this new one after 2-years and refill it. Maybe get more then 4 years out of it.

[paulp]

Thanks all,
once we use it again I'm going to check the heat on the battery.   I have a second unit right next to it and itentical minus the color and its fine when talking about where the battery is placed on the frame, ie..works for one so should be ok for the other.
I'll pull it to check the level is great advice to go to next, including is it AGM or liquid, I'll check that as well!
Thanks, stay tuned...