Problem with Battery.

[6volt]

Hi, can someone help explain the problem.

I have just replaced my 2 Trojon GC2-105 ,6 volt flooded lead acid Golf cart batteries with a different brand. The Trojans lasted 8 years and were kaput. I couldn't source Trojans locally.

They are wired correctly as was the previous working installation, in series for a 12 volt output.

After two days of solar charging when I would expect them to be at full charge I
check the cells with a hydometer and find that one battery is fully charged and measures 7.6 volts. the other battery is dead flat and measures 6.4 volts.

They are correctly wired. The charged one is warm and gurgling, the flat one is cold and lifeless.

Why is this so?

Have I been sold a DUD?

Thanks in advance.

At 30 KG s' each I'm not looking forward to returning them.

[skipmac]

Hi 6V and welcome to the forum.

First thought, I wouldn't call 6.4V dead flat but the difference between the two batteries is odd, possibly indicating a problem.

If you're measuring SOC (state of charge) by voltage you need to specify the conditions under which you measured the voltage. A battery just off a charger will show higher voltage for some time before dropping to a stable voltage at full charge. For standard FLA batteries 6.4V would be the stable, at rest voltage of a fully charged 6V rated battery like the Trojan.

Some say you should wait many hours to get an exactly correct voltage reading but my experience, waiting an hour or two will get you very close.

All that being said, two batteries in series, if identical in type and condition should show very close to the same voltage. Perhaps one of the new pair was lower charge when you got them and is taking a longer time to charge up? I would try a couple of charge/discharge cycles before makeing a final determination. Keep a close eye on them just in case one has a problem and starts overheating. After a couple of cycles let them sit for a while off any charge or any load and then measure the voltage.

[6volt]

Thankyou skipmac.

I wasn't very clear. I tested all the cells with a hydrometer.

The battery that measured 7.6 volts showed readings way up in the green zone for fully charged. sg.130

The battery that measure 6.4 volts was way down in the lifeless Red zone on the hydrometer. sg.120

The charged battery cells all had the same sg.
The poorly battery cells all had the same low sg reading.

does that make sense?

Basically since installing them 2 days ago one batterys' SG has risen markedly the other has decreased markedly.

[GordMay]

Greetings and welcome aboard the CF, 6volt.

[john61ct]

Yes they should match. Assuming it isn't a problem with your install, bad connection or wiring. . .

Try to replace both if possible, ideally get your money back and buy elsewhere.

Are you overseas?

It would be worth going to a fair bit of trouble to get a known-good quality brand.

Did you use a credit card?

[john61ct]

dupe, min characters

[boatbod]

Sounds like a bad battery, or at least one that is much older and having a hard time accepting a charge.

[sailinglegend]

I suggest you might just have connected the 12v solar output across the 6v battery that is hot and gurgling at 7.6v. The other has been getting no charge at all.

[6volt]

Thankyou all for your replys.

The wiring/connections and polarity have been checked, its very difficult to get wrong with only a positive, negative and the jumper between the two.

I have rung the supplier and are returning them in the morning.

30 kgs each, up out of the locker, down into the dingy, ashore , and up in to taxi and then repeat.

Cruising is so much fun

[DeepFrz]

When you have them out check the date of manufacture. The dealer may have tried to pawn off an old battery on you.

[CaptJamesCook]

Try changing the position they are connected. Put battery 1 where battery 2 is. Then reconnect and see what happens.
If no change off load the bad battery into dingy.....

[sailorboy1]

stop screwing around, take the bad battery back!!!

[6volt]

Originally Posted by skipmac

Perhaps one of the new pair was lower charge when you got them and is taking a longer time to charge up?

Today I lugged the batteries back to the retailer and gave them the once over.

Skipmac, you are a genius.

The load tester showed both batteries in good condition. One was fully charged and one was at a very LOW state of charge.

Basically it appears as though they were delivered in this condition and being in such hurry to install them and cool the beer, I didn't give them a thorough once over.

The flat one would have taken days / weeks to charge in this set up because the highest voltage drop in a series installation is across the fully charged battery. Apparently? The solar regulator had already decided something was charged and was going into float.

So I now have 2 fully charged batteries installed.

Pretty slack to deliver a flat battery to a customer. But beggars can't be choosers, and with no competition and not another delivery into town for a
week, from the closest supplier over 2000 miles away, I collected the replacements and made a mental note for next time.

But as they say, "experience is something you acquire when you no longer have a use for it" or summin like that.

Thanks to all.

[skipmac]

Originally Posted by 6volt

Today I lugged the batteries back to the retailer and gave them the once over.

Skipmac, you are a genius.

The load tester showed both batteries in good condition. One was fully charged and one was at a very LOW state of charge.

Basically it appears as though they were delivered in this condition and being in such hurry to install them and cool the beer, I didn't give them a thorough once over.

The flat one would have taken days / weeks to charge in this set up because the highest voltage drop in a series installation is across the fully charged battery. Apparently? The solar regulator had already decided something was charged and was going into float.

So I now have 2 fully charged batteries installed.

Pretty slack to deliver a flat battery to a customer. But beggars can't be choosers, and with no competition and not another delivery into town for a
week, from the closest supplier over 2000 miles away, I collected the replacements and made a mental note for next time.

But as they say, "experience is something you acquire when you no longer have a use for it" or summin like that.

Thanks to all.

Genius?

As many posts and "helpful suggestions" as I've made on this forum I have to get lucky once in a while.

I would still keep an eye on the batteries and see how they do before taking off.

[Zil]

Yes be careful and keep your eye on that battery. They do not like to be at a very low state of charge. You may have to replace them sooner than you like. If you get back States find Duracell EGC2 at Batteries plus Bulbs or Sam's Club.