Topic: Bad hydrometer?

[someday]

The other day my bike stalled due to a dying battery.  I know my charging system is faulty.  According to my tests, the rectifier is fried.  I've been using a 1.5 amp charger to top up the battery when the bike is at rest, and it's worked for short rides, but I guess this time I went too far.  Anyway, I pulled the head and taillight fuses and was able to limp the last few blocks home.
I removed the battery from the bike, noticed the electrolyte level was low, so I topped it off with bottled water, (purified, not distilled; mistake?) and charged it up.  When the charger indicator light reads "charged", i disconnect it and the battery reads 12.8v on my meter.  After a few hours not connected to anything, this drops to about 12.3v.  But when I test it with my hydrometer (little eyedropper thingy with floaty balls) all the little balls sink on all six cells, indicating a totally dead battery.  I've had this hydrometer for a few years, and it was a cheap one to start with.  Do they go bad?  Do the little floaty balls lose their magic?
The bike is a '77 CB550F and the battery is a Motocross Xtra (made in USA)
Whaddayathink?

Daniel

[bryanj]

Hydrometers rarely if ever go bad BUT anything other than distilled water will kill a battery

[Bob Wessner]

Also, when you say the electrolyte was low, how low? Were plate surfaces exposed? If so, that didn't help either.

[Bodi]

Purified is OK, reverse osmosis is better, distilled is best. Unless your water is really really bad, it won't kill the battery immediately.
Sounds like your battery is toast. I've never heard of the ball's magic leaking out, I have one of those from around 1970 and it still seems to work fine.
Did the battery ever read correctly? I had one battery brand new that wouldn't hold a charge and would not show the correct SG when charged, I took it back and the shop gave me a new one. I had to wait a day for them to get a new box of acid, they had run out the day before when I had bought the first battery... I guessed that the old box of acid was bad or ran out while filling my battery and somebody just topped it up with water, no prooof though. The new one worked fine.

[my78k]

agreed  on the plates...my tender also claims to desulfate...not sure if it actually works or not though

[someday]

Thanks for the quick replies.  I think some of the plates were partially exposed.  The battery's labeling claims to have some sulfation-preventing quality, but who knows.  I'm sure that riding it around with a bad rectifier, repeatedly discharging and recharging it didn't help.  It's time to put the bike away anyway.  Maybe I'll take the battery back to the store and have them test it.  I might get a new one or a core discount or something.  And over the winter I can fix the charging system.  I like the thread about the DIY reg/rec idea.
I guess I just dont understand how the meter can read >12v and the hydrometer says its kaput.  Physics or some such voodoo.
Thanks again,
Daniel

[Steve F]

Try turning the battery upside down and back again a few times (with the caps on of course) to mix up the water with the electrolyte.  If I'm not mistaken the acid will stay at the bottom and the water will be at the top for the most part.  Check it again after the agitation.

[someday]

Hey Steve F: I tried your suggestion and I think it worked (sort of).  After inverting the battery several times, I got one or two floating balls on three or four of the cells.  Maybe if I keep charging and agitating I can salvage this thing.  Thanks.

[Steve F]

Well, you may still have problems if all you get is one or two to float.  The reason for the agitation is just to get the water you just put in the cells to mix up a bit better with the acid.  Check it again after a good charge, since I don't think any more agitation will really do any more good.

[Bodi]

The way we use our batteries is really not good for them, so expect to replace the thing every 2 years at least. This has certainly been my experience over 35+ years.

I found (here: http://www.batterystuff.com/tutorial_battery.html this info:

Causes of battery sulfation:
- Batteries sit too long between charges. As little as 24 hours in hot weather and several days in cooler weather.
- Battery is stored without some type of energy input.
- "Deep cycling" an engine starting battery. Remember these batteries can't stand deep discharge.
- Undercharging of a battery, to charge a battery (lets say) to 90% of capacity will allow sulfation of the battery using the 10% of battery chemistry not reactivated by the incomplete charging cycle.
- Heat of 100 plus F., increases internal discharge. As temperatures increase so does internal discharge. A new fully charged battery left sitting 24 hours a day at 110 degrees F for 30 days would most likely not start an engine.
- Low electrolyte level - battery plates exposed to air will immediately sulfate.
-Incorrect charging levels and settings. Most cheap battery chargers can do more harm than good.
- Cold weather is also hard on the battery. The chemistry does not make the same amount of energy as a warm battery. A deeply discharged battery can freeze solid in sub zero weather.

So a bike ridden daily, if it has a charging system capable of recharging quickly (after the starting motor drain) and maintaining float voltage would be in pretty good shape, battery-wise.
I don't ride every day. The smaller SOHC4 engines in particular don't have enough alternator power to recharge the battery very quickly after a start, and are incapable of holding above 12.4V below 3000 RPM or so at the best of times. My 400 is discharging pretty much all the time in city riding.
If you use a smart charger when the bike is parked and keep the electrolyte level between the lines all the time, you can probably get your battery to last more than 2 years. I usually have the charger plugged in, but not all the time. I'll try and remember to connect it after riding from now on.