Change both Batteries or only One?

[Hamin' X]

Most batteries have the "date code" branded into the case. The first two figures are the key. Most begin with a letter that corresponds with the month and the the second is a number for the year. Some manufacturers reverse the order. Example: A7xxx would indicate January of 2007, as would 7Axxx. Some manufacturers skip the letter "i" in the letter sequence to avoid confusion with the number "1".

~Rich

[c130king]

Anybody done this on an M?

Is there a "Born date" on a battery? I understand that if a battery has be sitting to long it will not preform as well.

James,

Several posts on this in the past few months...many by me since I plan to do this to my 2005 as soon as I get back to my boat in the states (which has been delayed unfortunately... ).

Here are a couple of threads:

THREE WAY SWITCH

and

Battery Switch Location (this thread starts off on the location for the battery switch but gets around to your questions).

Also, I plan to use the BatteryMinder as recommended by several on this board to increase my battery life.

I plan to go with 2 x Group 24 in the battery compartment...that should be all I need.

Good Luck,
Jim

[James V]

Thanks Jim. I have these already. I would recommend looking at the series 27 batteries as you have room. The price is not that much differant.

[c130king]

I was told by some others through PM that 2 x Group 27 will not fit in the compartment without modding it somehow...don't really want to do that.

But if I can find 2 that fit then I will do go for it. But in reality, with my planned useage, I think 2 x Group 24 around 75-80ah will work fine.

Jim

[James V]

The West Marine deep cycle bateries series 24 are 65 amp hrs. I do not recomend the starting batteries as they will not come back after a being drawn down to far (below 11 volts ??????)

I have not tried it yet but I think you can just slide one all the way over and be able to put 2 in. West Marine has a great return policy. Get 2 of the plastic series 27 batteries boxes, $ 16 each and work with them. If it does not work, Clean and return.

[c130king]

I am planning wet-cell deep cycle...two of the same kind.

I will check the measurements when I get back to my boat. But I was told that due to the size of the opening even if you slide a Group 27 all the way over there will not be enough room to get the second one in through the opening.

Jim

[March]

I changed both my batteries last year, with Optimas yellow (75 Amps) My electrical setup: the two batteries connected via a Xantrex Pathmaker separator. A 65 W solar panel with a booster is connected to the house battery. In theory, once the house battery is full, the system changes to the engine battery and vice-versa. The most power-hungry device is a Waeco cooler. It draws a lot, but it's designed to work only 5 minutes an hour or so. The average would be about 3 Amps, medium power (I don't really need to make ice on the boat.)

Okay, at first everything worked perfectly: both batteries were chock full at sundown. The cooler would work all night long, plus the cabin lights (LED) and the anchor light when needed. By morning, the engine battery would be full, and the house battery down to less than 50%. But as soon as the sun hit the panel, within a couple of hours, the house battery would recharge.

This year I have experienced problems. The cooler shut itself out 2 hours into the evening, even when I started with a full battery. The display signalled not enough power--and sure enough, the House battery was less than 15% at around 9 o'clock at night. No way would it last me till morning. The other battery is also down to 85% by morning, even though the Xantrex should have kept it separated

Trying to debug the system: it may be the cooler whose computer is on the fritz and it draws much more than 3 AMPS (say, something like 30?) Maybe the the Xantrex separator doesn't "separate" anymore the way it's supposed to?

Or maybe the Hourse battery has a shorted out element and doesn't hold juice?

Both batteries are equal. I had more luck with a bigger house battery. Never had any problem with the KMart smaller engine battery.

I am taking the house battery back to the dealer next week. I'll start debugging from there

[Compromise]

I use a combiner which keeps the batteries seperate buy will charge both batteries at the same time.

Ditto for me, I had the stock battery and a second on my '02 X and recharged more and more before deciding to change them out.

[Hamin' X]

I would suspect your controller. It has to be giving erroneous readouts, because a 65W solar panel will only charge at about 4 amps. You said your 75 amp/hr house battery was at <50%, that means that the panel would have to charge it for 10 hrs in direct sunlight just to bring the one battery up. Ain't gonna happen in a couple of hours.

~Rich

[John Christian]

March, I'm not familar with your combiner but it may be working fine. I suspect that by routinely discharging below 50% you've greatly reduced the life of the battery. At 80% discharge you'll cut the life in half vs. 50% . Still I'm surprised that your having problems after only 1 year. I'd think that even with that high of discharge you'd still get 2 -3 years.

let us know what you find out,

JC

[March]

Hamin X
You're right--my mistake. I guess it's wishful thinking. It used to be fully charged by late afternoon. II was still able to start off the evening with both batteries chock full.

The controller is a Sun 2000 controller that is supposed to boost the current flow--when need be. I don't know how effective is that or it's just voodoo electronics. Point is, I used to have a larger house battery (had to pad up the place with styrofoam when I switched to the Oprima wich is smaller) and I can honestly say that I spent weeks on the lake, no engine, fridge running continuously, with no problems whatsoever.

I never used the cooler full blast--maybe it was drawing even less than three. Don't have the specs here, but 3 Amps are stuck in my mind.

John Christian. You're right, but this is a famous optima deep cycle, 14 months old. To my recollection, I only drained it once--over the winter when I did not disconnect the battery cables (Optima, right?). Even that seemed kinda weird for I had no consumers on line at all

Could there be a short somewhere? But on the other hand, I redid the electrical system myself, marine grade wire. Every connection has been carefully soldered, crimped, and insulated with shrinking plastic tubes. Each circuit has AT LEAST one appropriate fuse (sometimes two: one at the appliance, one at the main bus)

To my mind, if there's a short somewhere, the fuses will blow first

[James V]

Just a reminder - Solar panals work best with no shade on them, lines, mast, boom, etc...

There is varring degrees of "short". A slow drain can happen. Here is a cheep way to test your system. Take out all fuses and mark if any are different. Cut battery switch off. Disconnect Postive terminal and insulated. you do not want this touching anything as very bad sparks can happen. Get a small watt 12v light and wires. Connect between battery and positive terminal. (do not connect the positive terminal to battery. Turn on battery switch and look at light. You are looking for a dim glow, best done in a dark space. Work your way through putting in each fuse at a time. Do not turn on anything.

Good luck, I think your main problem is not enough charging. My Merc charges the most when the batteries are down the most. So I use the motor to charge the batteries at above 2000 rpms for about an hr before the sun gets very high. My next upgrde is the Honda 1000w Gen.

Does anybody have the chart for battery voltage and how down the batteries are? How long should you wait after charging to check vlotage?
Is it different for Deep cycle or Gel?

[March]

James: good suggestion--I can see how that would work.

I don't think that the issue is voltage though. It's amperage--a horse of a different color. I also disagree with the fact that the issue is charging: like I said, at some point in the past the system worked just fine--for years on end.

The panel is Unisolar. They pride themselves on making it work even when partially shaded and it does. True, solar panels tend to lose their ability to charge overtime. When they're spanking new, they will charge more. Give them a couple of years, they tend to charge less. The difference is a matter of a fraction of an Amp: op to 0.5, I would guess

But if the problem is charging, then the batteries will no longer get full--because they don't get enough juice from the pannel, right? That is not the case. The issue here seems different. They do get full but they don't hold enough juice to carry the cooler overnight. So either the cooler draws more amps, faster than it's supposed to, or amps somehow get drained due to a partial short--or maybe even at the Xantrex separator (it's an electrical-mechanic device)

Or: the battery doesn't start with 75 Amps when it is full. Or it loses the amps due to an internal short of one of the elements

[Hamin' X]

Lead-Acid batteries (wet-cell, AGM, Gel, etc.) begin a process called sulfation, when not at full charge. When a battery is constantly charged to only partial capacity, it will soon loose the ability to reach the original rated capacity and begin a downward spiral of losing capacity, as long as there is insufficient charge to reach 100%. The reduced capacity due to sulfation, becomes the new 100% level.

It is incorrect to think that it is not a matter of voltage. If the voltage is low, it makes no difference how much capacity (Amps) your charging system has, the battery will not reach full charge. It will just reach a lower level quicker. If your controller is reading your battery voltage incorrectly, it will reduce the voltage of the charge too early and not allow the battery to reach full charge, even though it's read-out will indicate 100%.

Again, I think that you have suffered battery damage due to insufficient charge level. As I stated before, a 65W panel will require at least 10 hrs. to provide the 40 amp/hr recharge capacity needed for your battery. This is under ideal conditions, and assuming that you are not using the battery to power anything during the charging cycle and also assuming that the original read-out of capacity was correct..

~Rich

[March]

Rich:
You're right, I was thinking that the controller might be the culprit too. The problems is so iffy because there are so many variables and the health of the electrical system depends on each and every one of them.

Something weird happened to my Sun 2000 controller three years ago. When I pulled the boat out of the storage and tested it, it would not charge, even though the panel provided plenty of power. The controller's display showed 0.00. Called the Sun people and they advised me to move a jumper within the controller itself. I did that and presto! the controller was as good as new, or so it seemed.

Now how on earth could that jumper slide into the other position? The controller was mounted on the wall and nobody removed it over the winter. Used to work just fine in the fall...

But then again, the system seemed to work again after I reset the jumper. And it kept on working just fine or two more years.

I see your point concerning the voltage. Like I said, my odd little gauge shows percentages... so it obviously measures the amps. A battery whose voltage is down to 10 percent would register 1.2 volts. (Of course, I measured the voltage of the battery with a cheap-o voltmeter and it still showed a little below 12 V when my gaude showed only 10% full. That's what made me believe that it's the amps.)

I guess the flip side of the coin would be, you can have all the 12 Volts you want (eight AA batteries of 1.5 V each would do the trick) but if you don't have the necessary amps, it's all for naught