Are my batteries on their way out (or Using A Hydrometer)?

[halcyon]

Also bear in mind that the voltage will vary with temperature as well, as the voltage is normally based on sg curve. Come to that with age of battery, as capacity will increase from new, then start to decrease with time.

Brian

 

[Anonymous]

It sounds to me as though your batteries are not being charged. As a liveaboard I know the problems. You need to monitor the battery terminal voltage preferably with a digital voltmeter and the current flowing into them. Take a piece of paper and draw three columns - Time, Volts, Amps Then note the time and voltage, then start the engine, and note the Volts and Amps every 15 or 30 minutes.

I would expect:-

1000 12.125V 0A
1005 12.775 55A
1020 12.850 52A
....... ........ .....
1900 13.885 22A
...... ......... .....
2359 14.40 5.5A

Or something like that. With an alternator booster it will be much, much, faster but it won't be over in just a few hours, not with decent fridges and normal liveaboard stuff unless you have a lot of solar or wind?

 

[AndyTTT]

Just a quick question.... does your hydrometer have any actual numbers on it ?

The specific gravity of the acid (measured by the hydrometer) relates directly to the real voltage/condition of the battery, so if your hydrometer is telling you that the battery is low, the voltage of the battery will also be low.

However, since your voltage reading is high, this will only be a surface charge, and not of much consequence, as soon as you apply a load to it as other have said it will just drop away very quickly.

As for Gel batteries - my opinion on them is that they will last a long time if maintained correctly - and to do this you will have to ensure that the charging systems is correctly set up for them, as some mentioned earlier, they can easily be overcharged. For most uses the best thing would be flooded lead acid batteries meant for deep cycle use as people have mentioned, so they can be checked and topped up as necessary.

I personally wouldn't touch starter batteries for deep cycle applications. The best would be to get types which are specifically built for deep cycle/semi traction applications. (such as the T105 from trojan or other equivalents).

 

[AndyTTT]

ohh... and if you are in turkey.... there is a battery manufacturer there called Mutlu...

www.mutlu.com.tr

They make semi traction/ deep cycle batteries and should be readily available all around turkey.

 

[demonboy]

Hey chaps,

Thanks for your answers and for the general education on batteries. I'm keen to try out Lemain's and Tobble's suggestions. Thanks to the rest of you for your help and to new forum member Andy's comments.

I think this weekend we'll be purchasing some new batteries. Not being able to enjoy a cold beer as the sun goes down on the mountains that have been heated up to 40 degrees through the day is extremely frustrating!