Low Battery Level ... in just one cell?

[beRto]

As previously suggested, the best starting point is to have the battery properly tested so that its condition is known.

Just for kicks I measure the voltage across the clips of my battery-tender .. it reads 6.7V ....
is this OK???

was I mistakenly given a battery-tender for 6V batteries???   

here is the unit i purchased:
http://mail.google.com/mail/?shva=1#search/ebay/119e05ad45e1c9bf

anyone else have a similar experience with this?

Sorry, the link you provided did not work for me. I am assuming you are using an actual "Battery Tender". The manufacturer's (Deltran) website gives some information on the charging algorithm:

The Battery Tender Plus battery charger delivers 1.25 amperes during bulk charge mode, holds the battery charge voltage constant at 14.4 VDC during absorption charge mode until the battery charge current drops to 0.1 amperes at which time it then automatically switches to a float charge mode. During float charge mode, the output voltage of the Battery Tender Plus battery charger is 13.2 VDC, which is well below the gassing voltage of a lead acid battery. This keeps the battery topped off, while minimizing any detrimental effects to do [sic] gassing. The Battery Tender Plus battery charger is able to perform these complex switching functions because its electronic circuitry is controlled by an on board microprocessor.

source: http://batterytender.com/faqs.php/#4

To summarize:

• (Step 1) Bulk Charge - constant current (voltage increases as required to provide constant 1.25 A)
• (Step 2) Absorption - constant voltage (14.5 VDC), until the current delivered to the battery drops to 0.1 A
• (Step 3) Float - storage condition, constant voltage (13.2 VDC)

On this basis, you should always see voltages above 13 VDC whenever the Battery Tender is connected to the battery. Because there is no feedback to the device, I'm not sure what the reading would be if the Tender is not connected to a battery. I guess that this should be interpreted as a zero current (0 A) condition, in which case the Tender should be in Float mode and provide 13.2 VDC.

It seemed to me that the readings you provided were with the Tender disconnected. You should try again with the battery connected and see what numbers you get.

Battery Tender Charging Profile

source: http://batterytender.com/battery_basics.php

[905mike]

sorry, this is what i got ...
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=160300955588&ssPageName=ADME:X:AAQ:MOTORS:1123

[beRto]

sorry, this is what i got ...
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=160300955588&ssPageName=ADME:X:AAQ:MOTORS:1123

Hmmm, the advertisement says (emphasis added):

The Float Charger prevents self discharge of the battery, while maintaining and extending the life of rechargeable 12 volt batteries. It maintains battery charge for batteries rated from 5 to 125 amp-hours, by providing constant (min. current) 12.5 VDC regulated output. Other types of chargers provide a strong, rapid charge that can boil out liquids, decay electrodes and reduce overall battery life.

According to the description, this charger should always provide constant voltage of 12.5 VDC. This is a very simplistic approach when compared to the Battery Tender method (described in my previous post).

Because the charger is only providing ~6V, your device sounds defective. I'd return it... and then buy a Battery Tender! 

[Paulcet]

(what is the voltage reading across the clips of YOUR battery tender when it is plugged in but NOT hooked up to your battery???)

I have a Deltran Battery Tender® Jr.  It puts out 14 volts when charging.  When not charging, but still hooked up to the battery, it is at 13.36 volts.  0 volts when it is not connected to a battery.

[905mike]

OK.  Enough of this do-nuthin'-wait-and-see.
I made sure the cell levels were topped up and slapped my new-in-March-2008 battery onto an Optimate4.
(http://www.tecmate.com/optimate4_detail.php)


24 hours later, ... I got all green-lights!! indicating a healthy battery, ... i checked the voltage across the battery with nothing connected to it and it reads 13.15V





Conclusion: my whoas are from usin' a defective battery tender (purchased earlier in the season but never used until storing my bike) which DISCHARGED my battery.

[beRto]

24 hours later, ... I got all green-lights!! indicating a healthy battery, ... i checked the voltage across the battery with nothing connected to it and it reads 13.15V

Good stuff!

Conclusion: my whoas are from usin' a defective battery tender (purchased earlier in the season but never used until storing my bike) which DISCHARGED my battery.

Will you be able to exchange the battery charger?

[905mike]

yes. i will be boxing it up a sending it back to the seller for repair/exchange.
then i'll have a spare battery tender.

[scratch]

Glad the problem was discovered inexpensively.

As far as explaining the fluid loss from just one cell (or even a few cells), it could be evaporation.  Even during the winter or rainy season.  Happens to me often enough, moreso during the summer, though.