How do I know if my batteries are bad

[boudreaux]

I have a 48 volt easy go, with six 8 volt Trojan T875 batteries. I have a digital volt meter that I bought from Scotty B ( which was a great purchase as were the new cables I bought from him).

After this very cold winter, with the cart inside the un-heated, un-insulated garage with single digit temps outside, my batteries will not hold a charge.

Four of the batteries were purchased in 2010 and two were purchased in 2012.

After charging them they read fully charged 51 or what ever fully charged is. As soon as I disconnect the trickle charger, the voltage meter falls to around 41.3volts. I took the batteries to auto zone and they tested them and they told me the batteries were good.

Is this a specific gravity problem? Is there an additive I can put in the water? I have only used distilled water.

Do I need to buy new batteries because these are old? Is there a test that I can do to see if the batteries still work.

I have run the cart just a few feet with the charge reading 41.3 and it felt normal; but I was afraid to do it for an extended time because I have read here that doing that can damage the batteries, but if the batteries are bad so what, but if the batteries were bad I wouldn't be able to run them for an extended period with the gauge reading 41.3 volts.

[Volt_Ampere]

They cannot be good if the voltage is 41.3!!!! One or more is shot and not allowing enough current to flow to run your cart. You need to LOAD TEST them. They may have froze and damaged the plates if they did not crack the case. If they were new in 2010 they are at the end of their life anyway. If you look at the voltage / state of charge charts that are in this forum you will see that your batteries are not good at 41.3V.

[joesam]

At 41.3 it almost sounds like your digital voltmeter is wired with one battery out-of-the-loop. Are you really sure that you connected the meter to the "very outside" pos and neg posts? If you add 8+ volts to that reading, your pack sounds a bit more normal (if not just a bit weak) - either that or you've got some very bad batteries in the batch.

[mymonstertruck]

Batteries should last 5-6 years depending on how good you take care of them.

[boudreaux]

thanks for the replies, I will confirm that the meter is connected correctly. The batteries were tested individually outside of the cart, not still in the cart and connected.

[joesam]

Ahaaa! - the batteries were out for testing - I'm even more convinced that somehow the meter got connected wrong and is missing one battery! That voltage (short by 8+) was just too much of a coincidence.