battery replacement

[irwinsailor]

14 months ago I bought 8- 6volt golf car batteries form Sam's club because they were a good price. It looks like I will be buying 8 more batteries again and need to know what will hold up better. What is a good value for battries?

[Jon D]

Gunnar

That those batteries went bad in 18 months does not sound right. Something caused early failure IMHO.

Did the batteries run dry at any point?

Or did the charger put out too much voltage??

I spent a much higher initial dollar figure and put Rolls on the boat however I'm into year 6 with no performance degredation. I do however watch the batteries to make sure they are being maintained properly.

[GordMay]

I’ve always found Trojan batteries to provide good value in flooded deep cycle batteries.
http://www.trojanbattery.com
As Jon said, 18 month life seems poor service, even for el cheapo batteries.

[irwinsailor]

I took good care of the batteries. I too am surprised that they did not hold up better.

Were they all configured as "one bank"? I was talking with a Rolls dealer at the boat show and he indicated that you dont want to paralell too many batteries. As a matter of fact, you want to minimize the number of batteries set up in paralell if at all possible.

The reason: if one cell on one in one battery in one paralell circuit goes bad it has a tendency to "bring down" the rest of the circuits. This makes some sense as the "bad" circuit could never come up to full voltage thus the whole circuit as well. Could make your battery chargers or alternators work harder trying to charge the system possibly reducing the battery life even more.

Just a thought.

I have four flooded GC batteries in our 28 sloop and once had to replace them sooner than the single 4D battery that was there previously, so I wonder.

-robert

[irwinsailor]

I have 2 banks of 4 batteries each. Both are weak and I can not get them to charge well but one bank is very weak. I have been testing for a bad cell but have been unable to find which cell it could be. The next time I go to the boat I am thinking of removing the 4 weaker batteries and having them load tested. It will be a big job because we have the boat on a mooring.

[Pblais]

Two banks of four each sounds about max for a single bank. My last setup of 3 banks of 2 trojans each worked well for about 7 years. When it finally died I changed it to a starting bettery and one bank of 2 AGM's, but in concept yours should work very well and supply a lot of power.

I'm thinking it may not be the 'batteries' that failed but maybe the charging sytem that was improper or maybe some other probelm that caused the batteries to have weakened so quickly. Failure to fully recharge or to deeply discharge the batteries very low and often would shorten the lifespan greatly. IT's amazing how you can make the batteries die when you discharge them to 10% capcity on a regualr cycle.

On bad cell could cascade to the rest of the bank but not both banks. Something is probably wrong with the system as a whole and not just because the batteries were defective. Testing the batteries would perhaps tell you what killed them but maybe not why.

I just replaced a starting battery caused by a combination of factors wrong with the system including a bad isolator that was brand new and a miss wired bilge pump.

Testing the whole system after you replace the batteries would really make you sleep better. Adding a battery monitor was the best thing I ever did. I found the last problems before I lost 2 group 4 AGM's (at $200 each) though I did lose a top of the line starting battery (it was not monitored). Testing the shore charger, alternator, regulator and all grounds is a good thing to do when your battery banks have problems or you install new batteries. Check the charging voltages. They most always can be adjusted to some small degree that matters in a big way. Over and under charging are equally very bad. Water in the cells is only one indicator and of course something to stay on top of too.

[By Invitation]

Gunner,

I second Paul's suggestion of a good battery monitor - they are excellent. You can really tell what's going on with your batteries and your charger circuit. Sounds to me like it's really not the batteries. I would install the monitor first to see if you can find the problem before spending money on a new bank.

[DeepFrz]

Gunner, have you checked the specific gravity of the electrolyte in each cell? That is the best way to guage the health of each battery cell.

Deep

ps: Surrette (Rolls) has a great battery maintenance section on their web site.

[outislandmike]

"Failure to fully recharge or to deeply discharge the batteries very low and often would shorten the lifespan greatly" Most very likley your problem. Flooded deep cycle batteries take much longer to charge, taking a lower charge rate, and very long curve to FULLY charge. N. Calder says improper charging is the most common reason for failure of this type of battery. You may think it's charged, but probably not. Without a good solar or wind, charging a boat on a mooring is a challenge.

Mike

[irwinsailor]

Charging is not a problem with my genset and 140 amp charger. I took all the batteries home and charged them individualy for about 40 hours each. All of them came back and I could not find anything wrong with them after the long charge. I think much of my problem is that I use much more battery power than I realized.

[Jentine]

Have you equalized the batteries. Perhaps this would bring the batteries back to life.

[Alan Wheeler]

Hey gunner. I am presumeing you have the batteries connected in a series parrellel arrangment? Are you 12V or 24V?
What can happen is if you have managed to deeply discharge the bank at sometime, the banks will recharge at slightly different rates. This equates to a different impedance to the charger and so different current being supplied to individual banks. So some banks may not ever get to be fully charged again. when this happens, the no, of charge cycles enhances the problem and you have a result of some banks not pulling their weight with supply. The only way to ensure you don't have this happen, is to individualy charge as you have done and get everything back to normal again.
Maybe Rick has a better answer to this, but as far as I know, there is no otherway of keeping all batteries equalized in a series parrellel configuration.

[sv_makai]

I would also recommend a load test on each of the battieries saeprately in the bank. We installed new Trojans T105 2 years ago and found less than stellar performace from the bank. Though the battieries were new we ran the load test and found one that was bad. It killed the performace of the overall bank.

We replaced it and have had a bank that has been performing to expectations.

We found that regular equalization on the order of once a month made a huge difference. We would notice longer and longer times for the solar panels to get the batteries to float. Normally we are fully charged bu 10:30 Am. Once the charge goes past noon we equalize and things are back to normal. Many of the manfucatures recommend equalizing flooded batteries. Just one note check your water level often.

[Jon D]

Gunnar it sounds like you do not have a battery monitor on the banks. I would suggest putting a Ahr meter of some type that can monitor all you house banks. You never want to let them go below 50% discharge. i.e. if you have 400 Ahrs in your bank never go below 200. This will help you gauge where you are really at with regard to battery usage and recharging. It is surprising sometimes how much energy the larger boats use.