Victron 165AGM replacements

[Black Diamond]

I'm doing my own research on this, but I'd be interested in what other people would do in a similar situation.

I have a 2 1/2 year old boat that came with 4 Victron 165AH AGM batteries in its house bank. This past fall, I noticed that my monitoring solution (which counts AMPS and has been pretty accurate so far) was not accurately reading state of charge percentage. When the batteries were supposed to be 87% charged, I had a voltage on the bank of 10.8V. I noticed this when my refrigeration stopped working (not good). Further investigation showed that they would read 12.5V right up to the moment when they would ---bang--- drop to 10.8V.

My 30 years of sailing tells me that one or more of the batteries probably has a bad cell in it, and its bringing down the whole bank. I could try to find 3 good batteries in the 4, and just remove the bad one from the bank, but I'm considering just replacing the whole bank.

I'd be interested in what people would put in to replace them. I'm looking at a straight AGM replacement as well as newer technology such as Carbon Foam, LiFeP04, etc. The key criteria here is space. I currently have 4 batteries in a factory made box that measure 485 mm (19.1") long x 172 mm (6.8") wide x 240 mm (9.45") high each. I'd like to get 800-1000AH in this space, and the number of batteries it takes to do that is secondary.

I have a 130AMP Mastervolt Inverter/Charger and 700 watts in 5 Solar panels on the bimini going thru 4 different controllers to charge the batteries. Solar alone can drive 40-50AMPS into the batteries on a nice, clear June day.

If I *HAD TO*, I'd be willing to place extra batteries in different parts of the boat to expand the bank, but I'd like to start with just an upgrade in the same space.

Does anyone know of a 200AH battery that would fit in the same space? These are not 8Ds, more like a 4D in size.

[ranger58sb]

So the original batteries are only 2-1/2 years old? Would have thought you'd get 8-10 years from them... and would guess first that replacing just one bad battery in the existing bank (with another of the same) would be much more cost effective. This time.

The battery box is only 6.8" wide? Can't envision how that'd work for a 4D-like footprint...

-Chris

[Black Diamond]

Yes.. they are only 2 1/2 years old. I usually get at least 6 out of AGM's, but they were LIFELINE, not Victron.

I was always told that if you insert a new battery into a bank of 2 1/2 year old batteries, it will be dragged down to their level. You usually wanted to replace them as a group. Granted, these are not 5-6 years old, but still...

No.. the box isn't 6.8" wide. There are four AGM batteries in the battery box. *EACH* of which is 19.1" long, 6.8" wide and 9.45" high. Put them together and you have something 28-30" long (4 batteries at 7" accounting for gaps) for a box with about 20-21" wide (19.1" doesn't change in that direction), and 10" high (the 9.45")

My next experiment will be to try and desulfate (equalize) the batteries to see if I can get them to come back... Some AGM batteries say you can't while others say you can... I'd rather not have to replace them, but...

[Stu Jackson]

Why "experiment?"


Why not find out whether YOUR batteries can or cannot?


Why not find out if you actually have one bad battery and which one it is?

[Black Diamond]

I am. I will. The issue is that I am 200 miles from my boat at this time. I won't be back there for a few days. I've already eliminated many possible issues. Now I only have a few things to check out...


I'm all for fact based problem solving, but you need the time to do it. Testing the batteries at "rest" and in different combination requires time, as well as equalizing.


I'm 90% sure of what it is (I've seen this movie before), but will obviously get the facts before laying out any money.

[ranger58sb]

Originally Posted by Black Diamond

Yes.. they are only 2 1/2 years old. I usually get at least 6 out of AGM's, but they were LIFELINE, not Victron.

I was always told that if you insert a new battery into a bank of 2 1/2 year old batteries, it will be dragged down to their level. You usually wanted to replace them as a group. Granted, these are not 5-6 years old, but still...

No.. the box isn't 6.8" wide. There are four AGM batteries in the battery box. *EACH* of which is 19.1" long, 6.8" wide and 9.45" high. Put them together and you have something 28-30" long (4 batteries at 7" accounting for gaps) for a box with about 20-21" wide (19.1" doesn't change in that direction), and 10" high (the 9.45")

My next experiment will be to try and desulfate (equalize) the batteries to see if I can get them to come back... Some AGM batteries say you can't while others say you can... I'd rather not have to replace them, but...

Yes, adding one new to an in-service bank isn't usually suggested as optimum. OTOH, 2-1/2 years old isn't ancient... and maybe cost savings (adding only one new Victron battery) would be worth a look.

Ref sizes, got it. Guess I'd just shop on the Lifeline and Odyssey sites for size options of possible alternatives. And Lifeline has 6V AGMs too...

What does Victron say about equalizing their AGMs?

-Chris