Fried battery

[captcoho]

:cussing:Heres one for you electric experts. I have a 1984 Hunter 31. I have two battery banks, with a pair of main batteries and a starter battery. The batteries are all Costco marine wet cell batteries, and are about two years old. My setup is as Maine Sail set up, with my main bank consisting of two batteries in series, hooked up to a True Charge 20 ( quite old) and a Blue Seas ACR link between banks. Everything worked really well, until on my last trip, I noticed the main bank was not holding any charge. On examination, the entire anode assembly of one of the batteries had eroded and broken off, as in the picture below. The second battery looks ok, but is dead.
Is my charger causing this? Cannot think of any other reason. How can I test that, or should I just replace with the batteries? I had a problem with hot batteries two years ago, which is why they all had to be replaced.
I was considering going solar (sail in S Cal). If I did that instead, is there any point buying a new charger?

I hope the two batteries were in parallel not series

 

[IanJ]

Thanks guys, especially Maine, Steve and Stu, whose opinions I always have a lot of respect for. As always, the mention of a cold beer seems to distract somewhat from the original problem, but I appreciate everyone's input all the same

 

[Benny17441]

Consider running the refrigerator from a 120V to 12V step down transformer while attached to shorepower. We pre-cool the refrigerator for a couple of days prior to going on a trip but when daysailing we just take a cooler with ice. We keep the charger on the batteries 24/7 but with no loads the charger seems to do a good job of maintaining them.

 

[IanJ]

Maine Sail, I have now installed a Pro Charge U battery charger as you suggested, as well as two new batteries for my main bank (1). I have my whole setup as you suggested in an earlier muse, with a main bank (1), with a Blue Seas ACR link charging my reserve battery (2). I have a couple of questions though;
1) Do I leave my system as is, with new charger, so charger solely charging main bank, and not the reserve?
2) In the Pro Charge manual, it says "Any outputs not being used should be linked across to one that is... to spread loads" As I am only using one, do I really need to hook Output 1 to 2 and 3?
3) Do I hook the charger up to the battery shunt, and not a single battery? I have the same setup as your photo on 1/BOTH/2/OFF Switches Thoughts & Musings posted 1/31/12
Thanks

 

[Gunni]

If leaving a fridge running you should ideally have a charger that will allow for a forced manual "float" setting or a custom program that will allow you to program for only a float voltage. When you leave the boat the charger should be in a float only mode to avoid issue like this. This type of failure can lead to a burned boat and potentially a marina fire..

This is really interesting, I have almost the exact opposite problem. After drawing down 90 Ah's on my 400 Ah house battery bank (2 x 4D) I can power up my genset, switch on my OEM Sentry 120vac 40 amp battery charger and it will trickle maybe 12 amps into the system (as measured by my xantrex Link monitor). It is like it is stuck in float mode. Then if I fire up my auxilary my engine mounted Hitachi 85 amp alternator will show a +25 amp charge. Ideally, I would want my 120vac to dump big amps into the bank and minimize my generator run time. Should I upgrade my charger?

Yes, my DC reefer runs 24/7 all summer long here in swampland - drawing ~7 amps (compressor and fan). There WILL be cold beer! And my boat remains plugged up because I need all 28,000 BTU's of de-humidification!

 

[Bill Roosa]

Gunni, are both genset and battery charger connectedto the bank?
if so the battery charger is probably seeing the alternator voltage and thinks the batteries are charged.
Also, I leave the reefer (5-10 amps depending on temp) on all the time and the battery charger just cycles from float to absorbe. been doing that for a few years now and never had a problem.

 

[Gunni]

Bill; engine not running while genset is running. Independent observed charge rates.
thx,
G

 

[IanJ]

I think you have your answer...

While the terminals are corroded this is likely from over-charging & off gassing the batteries. This over-gassing likely boiled the batteries dry and lead to an internal short which then melted down the positive post.

Keep in mind that chargers don't and can't determine the difference between a battery load and a system load. This can force many small chargers to maintain an absorption voltage every time the fridge or DC system loads run. This is BAD.......

If leaving a fridge running you should ideally have a charger that will allow for a forced manual "float" setting or a custom program that will allow you to program for only a float voltage. When you leave the boat the charger should be in a float only mode to avoid issue like this. This type of failure can lead to a burned boat and potentially a marina fire..

The Sterling Pro-Charge Ultra or ProMariner Pro-Nautic P (same charger) are two chargers that allow a custom program to be created..

Maine Sail, I have now installed a Pro Charge U battery charger as you suggested, as well as two new batteries for my main bank (1). I have my whole setup as you suggested in an earlier muse, with a main bank (1), with a Blue Seas ACR link charging my reserve battery (2). I have a couple of questions though;
1) Do I leave my system as is, with new charger, so charger solely charging main bank, and not the reserve?
2) In the Pro Charge manual, it says "Any outputs not being used should be linked across to one that is... to spread loads" As I am only using one, do I really need to hook Output 1 to 2 and 3?
3) nIs there a way to set this charger on Float, or will it do it automatically when fully charged?
I have copied the setup as your photo on 1/BOTH/2/OFF Switches Thoughts & Musings posted 1/31/12
Thanks

 

[Maine Sail]

Maine Sail, I have now installed a Pro Charge U battery charger as you suggested, as well as two new batteries for my main bank (1). I have my whole setup as you suggested in an earlier muse, with a main bank (1), with a Blue Seas ACR link charging my reserve battery (2). I have a couple of questions though;
1) Do I leave my system as is, with new charger, so charger solely charging main bank, and not the reserve?

Yes with the ACR you will be using it as a single output charger. The ACR will take care of the start/aux battery.

2) In the Pro Charge manual, it says "Any outputs not being used should be linked across to one that is... to spread loads" As I am only using one, do I really need to hook Output 1 to 2 and 3?

Yes any unused output should be bused together to evenly load the output channels..

3) nIs there a way to set this charger on Float, or will it do it automatically when fully charged?

It will do it automatically but you can also create a custom program if you wish that will only be programmed for a float voltage.

 

[IanJ]

Thanks Maine Sail. I really appreciate your advice here. Will not mess with charger unless very easy to program, especially as I am not exactly sure what a "Float Charge" means

 

[Bill Roosa]

G
I was considering the genset's battery charging alternator that may be tied into the rest of the 12volt circuits not the boat engine alternator.
anything making voltage in the same circuit (solar panels??, wind, genset .... anything) is going to confuse your battery charger.