Bad Battery(s) and Long-Term Storage

[Doodles]

I have two battery banks, one battery for the engine and two for the house. All are AGM. I've just discovered that either one or both of the house batteries has gone bad and needs replacing. The engine battery appears o.k. The problem is I'm leaving to go overseas for 4-6 months and don't have time to replace the batteries before leaving. The boat is in the water at a marina where it is well look after. I do not have an automatic electric bilge pump or anything that would be relying on the DC power. My question is am I doing anything an harm by just leaving things as they are until I get back and can replace the bad battery(s)?

[barnakiel]

If for 4-6 months then you may like to have the batteries fully charged before you leave and left on trickle charger.

b.

[Adelie]

You might consider getting a small solar panel ($30ish) that RVer's use to keep their batteries from self discharging during long storage periods. If they really aren't toast, it might leave you batteries with a full charge and ready to use.

[Doodles]

The problem is the house batteries are toast, they won't hold a charge; however, the engine battery is fine. I'm inclined to just forget about everything until I get back, but I'm wondering about the engine battery that is o.k. Its an AGM, so if it should discharge over the 4-6 months I'm gone just sitting there (will it?), is there any reason it shouldn't just charge back up once I put the battery charger back on?

[Stillraining]

Yes! You want to isolate the bad house battery and disconnect it from the system...so you can keep shore power charging going...depending on whats wrong with the battrie (s) it could be a potential fire hazard just walking away plugged in as is.

Take your good start battery and pair it with the good House battery so you have bilge pumps at least...

IIRC AGM"s have one of the lowest resting discharge rates of all batteries...I should think 5 months sitting if fully charged would do no harm.

I would definitely make arrangements for someone to check on your boat from time to time though..if it springs a leak at the dock a bilge pump will drain the batteries in no time.

FWIW I have not been able to charge my 4 Trogen flodded bats for 9 months now due to my ongoing refit...I was at the boat last week and my link pro still shows 12.13 volts.

[barnakiel]

Disconnect the toasts, save the engine battery.

b

[Doodles]

Originally Posted by barnakiel

Disconnect the toasts, save the engine battery.

b

So, even though they are separate banks, the toast banks (house) will pull down the engine battery? Is that what you're saying?

[barnakiel]

They will not. But by putting the engine one on trickle you make sure it is same condition when you are back.

The house (1+1) might be a good idea to disconnect from each other so that the bad one does not drain the good one. But if you need a big bank you still will have to get two new ones I guess.

b.

[Doodles]

Originally Posted by barnakiel

They will not. But by putting the engine one on trickle you make sure it is same condition when you are back.

The house (1+1) might be a good idea to disconnect from each other so that the bad one does not drain the good one. But if you need a big bank you still will have to get two new ones I guess.

b.

Got it! Thanks.

[hellosailor]

In theory an AGM can sit for six months of self-discharge (NO external drain!) without being harmed, but I'm looking at two that might have gotten permanently insulted by just such a wait. They lost power way faster than expected, and don't seem to be coming all the way back. It will be a few weeks before I know anything more about them, i.e. how much they are or aren't really back again.

If you CAN connect a trickle charger or small solar charger (and most of the small ones are not even rain-proof) to each battery, separately, go for it. If not...disconnect the cables, charge 'em up before you leave, and sort out the collateral damage when you return.

[bobfnbw]

Originally Posted by Doodles

I have two battery banks, one battery for the engine and two for the house. All are AGM. I've just discovered that either one or both of the house batteries has gone bad and needs replacing. The engine battery appears o.k. The problem is I'm leaving to go overseas for 4-6 months and don't have time to replace the batteries before leaving. The boat is in the water at a marina where it is well look after. I do not have an automatic electric bilge pump or anything that would be relying on the DC power. My question is am I doing anything an harm by just leaving things as they are until I get back and can replace the bad battery(s)?

There are several things wrong with this that I can see.
For one, Why would you leave a boat unattended for up to 6 months with no electric bilge pump ? That just sounds crazy to me. Just rain done the mast alone can add up. So you need a bilge pump first, and some batteries to run it 2nd. Everything else on the house load should be ok, just turn it all off.
The start battery should be fine, but I would get one solar to keep it charged up. wouldn't cost much.
But for piece of mind, if you don't have the time to get this stuff done, get her hauled out and put on the hard, and when you come back replace the batteries.
My opinion.
Bob

[Doodles]

Originally Posted by bobfnbw

There are several things wrong with this that I can see.
For one, Why would you leave a boat unattended for up to 6 months with no electric bilge pump ? That just sounds crazy to me. Just rain done the mast alone can add up. So you need a bilge pump first, and some batteries to run it 2nd. Everything else on the house load should be ok, just turn it all off.
The start battery should be fine, but I would get one solar to keep it charged up. wouldn't cost much.
But for piece of mind, if you don't have the time to get this stuff done, get her hauled out and put on the hard, and when you come back replace the batteries.
My opinion.
Bob

The boat was setup and formerly owned by the late Hal Roth, and he did not believe in electric bilge pumps. So far I've been going with his philosophy and not changing too much. I figure if it was good enough for Hal, its good enough for me. And actually, I've had several people whose opinion I respect agreed with him one this issue. The idea is that electric bilge pumps give you a false sense of security and are easily fouled by trash which can quickly run down a battery. Roth had a couple big manual bilge pumps installed since the typical electric one won't keep up with a serious leak. The advice I've been given is to not rely of the electric pump but instead physically check on it or have someone else check on it. The marina I'm at has a very dependable staff that walk the docks twice a day checking for problems. I've lived aboard here for almost two years and I can vouch for this, so I'm comfortable leaving the boat in their hands. i also have friends on the dock (other live aboards) that will keep an eye on it.

Wauquiez's are know for being extremely dry boats. We haven't moved the boat in 6 months and the bilge is still dry, i.e. no leaks, from the mast or otherwise. No worries there.

[bobfnbw]

Well hal roth is wrong IMO. Having had a boat sink at the dock recently, I can attest to what not having a reliable electric bilge pump can do. Its one thing if you are living aboard, quite another if you are away and marina staff are looking out for you. They will watch as your boat sinks.
Sorry, but every boat should have a electric bilge pump aboard, or three. It still might not save your boat but will give you time to find and fix the problem hopefully. A big trash pump on the main engine would be my 2nd choice, and a distant third for the manual pump. You can find any one to advise or support all kinds of assertions, but the truth is, in the end you have to pay the piper for your decisions. I believed my boat was a dry boat as well, and left the pump off while doing some repairs, and the boat not plugged into shore power, and a electrolysis issue ate thru the thru hull and she sank.
50K later and still trying to get it back to where it was.
Its free advice, take it for what you paid for it.

[Doodles]

Originally Posted by bobfnbw

Well hal roth is wrong IMO. Having had a boat sink at the dock recently, I can attest to what not having a reliable electric bilge pump can do. Its one thing if you are living aboard, quite another if you are away and marina staff are looking out for you. They will watch as your boat sinks.
Sorry, but every boat should have a electric bilge pump aboard, or three. It still might not save your boat but will give you time to find and fix the problem hopefully. A big trash pump on the main engine would be my 2nd choice, and a distant third for the manual pump. You can find any one to advise or support all kinds of assertions, but the truth is, in the end you have to pay the piper for your decisions. I believed my boat was a dry boat as well, and left the pump off while doing some repairs, and the boat not plugged into shore power, and a electrolysis issue ate thru the thru hull and she sank.
50K later and still trying to get it back to where it was.
Its free advice, take it for what you paid for it.

I realize most will agree with you and I'm in the minority. As you say, we all have to live by our decisions.

Sorry to hear about your boat, must have been a big leak. Would an electric bilge pump have run long enough and moved enough water to have kept it afloat until you discovered the problem? Not trying to be contrary, just wondering for my own benefit since I'm still not sure what I'm going to do.

Thanks for the input.

[btrayfors]

Originally Posted by Stillraining

......
FWIW I have not been able to charge my 4 Trogen flodded bats for 9 months now due to my ongoing refit...I was at the boat last week and my link pro still shows 12.13 volts.

Tilt! TILT!

Your Trojan's are likely to be toast. Flooded batteries need to be maintained at/near full charge, with periodic "controlled overcharge". Sitting 9 months with no charge is certain to result in significant sulfation, much of which is unlikely to be reversed even with heavy cycling and equalization.

FWIW, 12.1 volts just tells you about the battery's state of charge (SOC)...less than 50% in this case.. It says nothing at all about the battery's capacity to store and delivery energy.

Sorry. Just sayin' :-(

Bill