Dead AGM's, need help,

[Sailor647]

Originally Posted by CarlF

I'm afraid you are another victim of the cruiser's AGM scam. They should never be recommend as house batteries for cruisers who don't plug into a slip at night. As others have said, AGM's can die within a year if not fully recharged to 14.4V every day or so. It's called Partial State of Charge (PSOC) sulfation. It sounds like you don't have enough solar and wind to do this.

This is not true. We have had Full River AGMs installed for 6 years now - since July 2015. (It's now April 2021.) We have enough passive equipment to charge them without being tied to a dock. We mostly use solar, but if it's cloudy, we can either run the engine or the Honda Genset. We monitor their state of charge every day and adjust accordingly.

The key is not letting our FR AGMs discharge past 12.4 or 12.3 - which is 75% or 65% respectively. Batteries are different. You don't have to be a battery expert, but you do need to know how to maintain what type of battery bank is on your boat.

[Wotname]

Originally Posted by Mr B

.........

I might just get 3 new x 200 amphrs of FLA batterys and start from scratch,
They dont seem so troublesome as AGM's, Due to charging issues,

Im still not sure whether the Diesel Alternator is killing the AGM's or not,
Its a totally rebuilt very old diesel alternator,
I have also read that the old alternators wont charge AGM's.
Thats totally out of my forte,

..............

Cheers Brian,

Everyone has to start somewhere, no one is born knowing everything about electricity. Join the learning curve!!!!

FLA are certainly more tolerant of low level abuse - just never let them run dry. Keep an eye on the electrolyte level and top up as required with distilled water. And they are cheaper but they can spill and they do need ventilation.

The alternator itself won't kill AGMs, it depends on the regulator fitted to the alternator i.e. the voltage output of the alternator. The principle killer of AGM is NOT fully charging them and then leaving then partially discharged for days / weeks.

It takes hours and hours of charging to get from say 80% to 100% regardless of AGM or FLA. For most of us, this means a good solar setup if choosing AGM.

So for many cruising boats, AGM are a poor choice however they do have a place if you know how to look after them.

[moseriw]

victron 712 250 USD
china product 20 USD

I have the china products for every battery bank V/A and the are doing better then the victron with lots of confusing informations.

[atoll]

you can get a boost controller with a dump load for your wind generator,charge voltage is adjustable for AGM's

https://www.ebay.co.uk/itm/383663782...hoCrMkQAvD_BwE

[Mr B]

Originally Posted by atoll

you can get a boost controller with a dump load for your wind generator,charge voltage is adjustable for AGM's

https://www.ebay.co.uk/itm/383663782...hoCrMkQAvD_BwE

I have been looking at them, But being some where to get it delivered, Our postal services are crap,

[Davo1404]

As others have correctly stated, 600 amperes of deep cycle batteries will struggle to get fully charged with a 50 ampere alternator. Especially so if you don't have a smart regulator hooked to it. My advice would be to down size your house bank to say 400 amps of fla. This will give you more of a chance of keeping them fully charged.

[Boatyarddog]

Originally Posted by Sailor647

This is not true. We have had Full River AGMs installed for 6 years now - since July 2015. (It's now April 2021.) We have enough passive equipment to charge them without being tied to a dock. We mostly use solar, but if it's cloudy, we can either run the engine or the Honda Genset. We monitor their state of charge every day and adjust accordingly.

The key is not letting our FR AGMs discharge past 12.4 or 12.3 - which is 75% or 65% respectively. Batteries are different. You don't have to be a battery expert, but you do need to know how to maintain what type of battery bank is on your boat.

Truth!

[Mr B]

Well I bit the bullet and bought 7 brand new batterys,
They are Super Charge, MRV70, 105 Amphrs, Allrounder, 12 months full replacement,
And a Smart Battery, Start battery Isolater from Redarc,

I got an Auto electrician in to check out the system and set it up,
He verified I had it all set up right,
But he was lacking in knowledge on Parallel Battery banks and set it up wrong,
He only does boats with overnight battery banks, Totally different to my set up.

He put the positives on all the separate batterys making the bank a group of little batterys instead of one big battery,
At 12.30 AM Thursday, my brand new batterys were down to 12.1 volts and Falling Fast in volts,
The start battery was 13.9 Volts at one end with the battery Isolator and the rest were all over the place down to 12.1 Volts,
By Morning, My Brand New Batterys were going to be Dead Flat,
So I pulled all the cables off and started from Scratch,

All the batterys were joined up, Black to Black and Red to Red,
All positives off one terminal at one end,
All negatives off one Terminal at the other end,
The red cable was off the Alternator, So I soldered a new clip on it and put it back on the alternator,
The soldering Iron is 240 volts off the invertor,
All finished about 8-00 AM, I was stuffed from lack off sleep,

The wind generator is going Flat stick, Its pumping power in to the batterys,
My New Elcheapo, Chinese Wind Genny with controller, $165-00 AUD, It works,
The sun is up and the solar panels are whacking power into the batterys, Lots,
I ran the Diesel and alternator for an hour,
Its got 12.32 in all the batterys, Checked individually,
They are gaining in Volts all round,

I am very happy its all working properly and efficiently again,,

I was not looking forward to berthing at Eden again at the mooring wharfe and connecting to the 240 volt outlets to charge my Batterys up,
We got battered at the mooring wharfe, Even with out wind or waves, The surge is over the top,
My little cat races backwards and forwards all night long, Even with 10 mooring lines on it,

Plus my system is set up so I dont need either 240 volt shore power or a generator to make it work, Or to keep the batterys charged,

The 500 watts of solar panels are more than enough to keep all my batterys, Fully charged, All the time with all systems running 24/7.

The wind generator is only a back up when there is no sun for a few days,
Or an hour on the diesel alternator is more than enough to pump the batterys up,

It gives me hot water for a shower, So its not wasted diesel either,
I have a hot water pump on the motors outlet to pump the water thru the motor and heat exchanger on the hot water tank, As its only a bypass on the motor for the hot water tank, Its not very efficient on its own,

I untied from the Quarantine Bay Pier. and moved back to Kiah Inlet on the Towamba River as I now have confidence all my systems are all working again properly,

And to give the batterys a chance to come back up to full charge again,

When I checked the panels for output, The diodes and to see if they had got wet from the huge waves that had crashed down on them in Bass Strait,
I was in 6 metre waves following when a couple of them came up over the whole top of the boat and over the Bimini filling the cockpit from over the transom, and crashed down hard,
They were undamaged and dry inside, Very surprising,

But the panels were upside down and not giving out any power. Hahahaha Hence, I though they were damaged,
But with the sun on them, They are pumping out heaps of power,

Sunday at 10-00 AM, Kiah Inlet, Towamba River entrance,
The Wind is 30KPH, The sun is shining brightly,
Its quite cold here in the wind,
The wind genny is screaming in the wind, Pumping in power,
The solar panels are pumping in power to the batterys,
The 90 litre Freezer is running at Minus 18 Celcius,
The Lowrance 8 inch GPS and Fishfinder was running all night with the anchor alarm set,
The batterys are at 12.42 Volts and rising,

My Full system is now, All 12 Volt,
500 Watts of Solar Panels,
1800 Watt Wind generator, Chinese, (Cough, Cough,) With Controller,
55 amp Diesel alternator,
735 Amphrs of sealed lead acid batterys,

One Battery will be for my anchor windlass, but will still be connected to all the rest in the main bank,
The motor is always running when I lift or drop my anchor,

Thanks all for the help and for the boost to my confidence in myself to do my own work,

FWIW, This boat didnt have Hulls in it or any power or plumbing in it two years ago,
I did at all myself and now have a proven ocean going Blue Water vessel I have every confidence in,
8 Gales so far in Bass Strait, I think certainly proves my boats capabilities,
And No, I dont like being caught out in Gales,

Cheers Brian,

[markcouz]

Note that your meter should be set to DC when testing batteries/panels/chargers etc - if you look at post #1 and your latest post you will see you clamp tester is set to AC and the readings are no good.

[markcouz]

In fact your Aneng MT88a can read AC/DC volts, but only AC amps, not DC amps.

[Paul L]

If you want your new batteries to have a long(er) life you should make sure that the cables that parallel the batteries are all the same length and size. The picture shows different size wires. This will end with the batteries being unbalanced in the bank.

[Mr B]

Originally Posted by Paul L

If you want your new batteries to have a long(er) life you should make sure that the cables that parallel the batteries are all the same length and size. The picture shows different size wires. This will end with the batteries being unbalanced in the bank.

Thanks, I will be doing that, The small wires are the ones the Sparky put on,

But I did it in a hurry, Early in the morning, From 12-30 AM to 7-00 AM, and I couldnt find all my proper sized cables,
I was trying to save my Batterys from going dead Flat,

All the batterys are now exactly the same volts, individually checked,

[BillKny]

MrB,

There is still a LOT wrong with your installation. A LOT. Just looking at mechanical, the batteries are not strapped down in any way. They MUST BE! They look like they are sitting on a plain wood deck. They MUST have some way of safely containing spilled acid. The wood they sit on will likely not last long. These are not VRLA batteries (like your old AGMs), they will dribble small amounts of acid.

I have two suggestions:

• Fire your electrician. He is dangerous working on boats. He knows less than nothing. I am not joking here.
• Read a book. I'd suggest Nigel Calder's Boatowner's Mechanical and Electrical Manual. It will be a tough slog if you are starting from zero knowledge, but I guarantee if you put as much time into it as you have put into posting here, you'll know more than that guy who is (apparently) charging you money to screw up you system. The book will be easier to read through and make good sense of than posts from random strangers on here, and you'll be a better sailor for it.

[mitiempo]

Even if labeled "deep cycle" they are still essentially starting batteries.

[Nate24]

Very interesting discussion. Look up a marine wire gauge distance chart. That will help you determine the proper cable size for your set up. I would ensure the cable size is correct first. Then that the fusing is correct for the cabling and the bank. The last thing you want is a fire.

As suggested previously, ensure that you have the batteries properly secured and in the proper casing. I would put boots on each positive battery connection. Ensure that your charging systems are capable of charging and are set for the type of batteries you are charging.

Your charging systems will feed your batteries based upon the charge acceptance rate of your battery bank (source would be the manufacturer of your batteries) . Charge acceptance rates are different for different battery types, and different for different total amp hours on the bank. That needs to be considered for your cables, your alternator/regulator (which could burn out if not properly regulated, and your fusing.

You are close to getting the system set up. Just make sure that your system is safe. Nigel’s book suggested previously would help you tremendously, particularly with the knowledge you have picked up so far.