For Sale: 6V Batteries for Sale?

[yvrdennis]

We are replacing our bank of 6 batteries because one of them is cooked. The electrician load tested them and said that 5 of them were fine and one was dead. They don't recommend replacing one battery only so we are replacing the entire bank.

The old batteries are 3 years old and have a nameplate capacity of 217 Amp Hours. They are Discover Energy EVGC6Gs. The boat is in Vancouver B.C.

I'm wondering whether it is worth trying to sell the old batteries, or should I just have the electrician haul them off.

Is there anyone nearby who might be interested in buying these? Four of them would give you a 12V 400 Amp hour bank. Please let me know if you think it is worth trying to sell these.

Thanks,
Dennis

[socaldmax]

I'd suggest advertising them in the local craigslist for RV use. A lot of RV people use them and 4 is a pretty good number for most RVs.

Good luck!

[Cheechako]

If only 3 years old why not just replace the one bad one... it must have been defective...?

[yvrdennis]

Originally Posted by Cheechako

If only 3 years old why not just replace the one bad one... it must have been defective...?

I don't know much about this stuff, but the electrician doesn't recommend it. Something about the new battery getting damaged because it is trying to produce a higher voltage. If I recall correctly Caldwell talks about the same thing in his book.

[Cheechako]

Yeah, that seems to be the common theme... If you are headed away blu water cruising probably best to do what they say.
OTOH, My 8D marine battery failed in it's first year of service as I entered Mexico. I replaced it with a Mexican HD car battery. the battery bank lasted about 3 years until the boat was sold. Don't know how long it really lasted.
and, My 47 footer had 3 4d gel batteries when I got the boat. One failed about 3 years in and was replaced with a deep cycle wet cell battery. When I sold that boat about 2 years later all still going.
So I'm not sure how the theory lines up with reality. Not that I'm doubting the theory, but sometimes theory is about the final 1% and the real world the other 99%! I guess it's a 5:1 $ roll of the dice! willing to risk $80 to save $480?
Sometimes people who are unwilling to risk the battery issue will by a used boat and never replace the chainplates.... what's the higher risk?

[centerline]

Originally Posted by yvrdennis

We are replacing our bank of 6 batteries because one of them is cooked. The electrician load tested them and said that 5 of them were fine and one was dead. They don't recommend replacing one battery only so we are replacing the entire bank.

The old batteries are 3 years old and have a nameplate capacity of 217 Amp Hours. They are Discover Energy EVGC6Gs. The boat is in Vancouver B.C.

I'm wondering whether it is worth trying to sell the old batteries, or should I just have the electrician haul them off.

Is there anyone nearby who might be interested in buying these? Four of them would give you a 12V 400 Amp hour bank. Please let me know if you think it is worth trying to sell these.

Thanks,
Dennis

"cooked" is kind of a generic term when it comes to a single battery that is damaged in a bank of multiple batteries. a single cell of the battery more than likely shorted within itself and has become lifeless....

the electrician is kind of right that you shouldnt put a new battery next to an old one.
but that definitley is not an absolutely true statment.

if all the batteries were on the downhill side of life, the statement progressivly becomes more true as the batteries get older, BUT... depending on the brand of batteries, if they are excellent quality, three years old isnt really old... the life expenctency of a set of trojans is 10+ years... there have been reports of 12-15 years when the system is in excellent health.

buying a new battery and putting it next to the existing ones, will not harm them, and if the existing batteries are in good, sound condition, they wont harm the new battery.... they will all equalize with one another within a month and the system would be back to normal and you would have a very large savings.... as opposed to replacing them all right now.

you must remember when making these decisions, is that batteries commonly do fail before their full life expectancy is reached, often because of operator error or neglect, but also because they just do, as the one that has gone bad for you.... so what will you do when you replace all of them and in two or three years, one of them is bad again.....

not many people would purchase a used battery, because they dont know what kind of life they have lived, or for how long. but you DO... so if you think the batteries have enough life left in them and would be good enough for someone else to use, why dont you take the savings yourself and get one good battery to replace the cooked one.

everyone sees value in a different way, and i see a lot of value in saving a lot of time, trouble, and money here if the existing batts are good.

[anacapaisland42]

Why not just take one out and run on lower ah with a spare battery
Bill

[yvrdennis]

Thanks guys. Good food for thought on this thread. One of our motivations in replacing this bank is that we also want more capacity. The current plan is that we are going to go to 800 Amp hour. This boat has a lot of electron consuming jewellery and based on our experience last summer a bigger bank will help. We're also upgrading our alternator.

We did consider the option of scrapping two batteries and running with four, but we don't want to try and get by on that capacity. I think many boats without two chart plotters, radar, etc., etc., probably could, but I think it would be kind of painful for this boat.

Originally Posted by centerline

not many people would purchase a used battery, because they dont know what kind of life they have lived, or for how long. but you DO...

Actually, we don't. We bought the boat last spring so we really don't know the history of the batteries. The electrician said the batteries came up "good" on the load test, which he feels equates to 70% or so life, but that is a guess. If I do sell them I'm going to be honest about what I know and let the buyer decide if they want to take the risk. I was originally hoping to get about $100 each, but I think I should reduce that.

Thanks,
Dennis

[skipmac]

Saying always replace the entire bank is pretty black and white statement. Would you replace the entire battery bank if they were all two weeks old and one battery cooked? What about two months, or two years?

7-8-10 years I would say that buying all new would be the preferred option, assuming you were not cruising far from civilization where a new battery costs 5-10 times more than it should.

I would consider the condition of the rest of the batteries. If they have been well cared for IE not discharged too low or too often, never out of water, are reasonably close to rated capacity and good quality batteries to start then maybe buy just one battery.

[sailboatboy]

Hi Dennis:

I am in YVR also and might be able to give you some info as I now use 6v L16 AGM's on my boat. When I was out last, I had a large issue of getting fresh batteries in Chile that would be deep cycle in more than name.

4 AGM L 16 is more than 800 am hours, it is just an issue with height.

David

[kudukuguam]

have you considered two battery banks?

[yvrdennis]

Originally Posted by kudukuguam

have you considered two battery banks?

How would that work? Charge them separately and use an isolator switch?

Regards,
Dennis

[yvrdennis]

Thanks everyone for your thoughts. I had to make a decision so I could get the work done while the contractor is on the boat doing the alternator upgrade, so I have directed them to replace the bank with four new higher capacity batts. I realize that we might well have gotten away with a single replacement, but we found the capacity of the existing bank to be too small, so we wanted to upgrade it anyways.

So, if anyone is interested in buying some batteries of unknown history, please let me know what you think they're worth. They may end up being a great deal, or they might not, I don't know.

Thanks,
Dennis

[leftbrainstuff]

You can replace just one.

If you treat them right and have a good battery management system you can monitor them and get comfortable with their performance.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[kudukuguam]

about the two banks: I have a dual charger for dockside use and use diode isolation while charging from my solar panels. I have one bank for what i consider critical loads (comms, nav, bilge pump, etc) and the other bank for all else. I also have a cross-connect switch so i can hook the banks in parallel should something weird be required for power. I can't really imaging what it would be but like to keep my options open. A disadvantage is having two buss power and ground lines but gives me redundancy.