Batteries and Solar

[SusieC]

I’m interested in the hive minds thoughts about batteries; live aboard, adding 900w of solar, currently have 4x663 100ah batteries, 5 year old sterling inverter charger. The 663’s I know are “technically” for starting cars, but they have done well for 5 years, don’t have budget for lithium, battery box hard to access so not keen on maintaining wet cells.

what would you do?

[LadyG]

1 hour ago, SusieC said:

I’m interested in the hive minds thoughts about batteries; live aboard, adding 900w of solar, currently have 4x663 100ah batteries, 5 year old sterling inverter charger. The 663’s I know are “technically” for starting cars, but they have done well for 5 years, don’t have budget for lithium, battery box hard to access so not keen on maintaining wet cells.

what would you do?

I have three battery banks, one is the starter, so standard starter, I installed a 90 ah, essentially cost little more than the 65 which had been on the boat.

I have replaced the other two banks (5 agm deep cycle batteries) over three years of ownership, giving me nominal 600 ah with two X  275w solar panels. It all works fine in summer.

I tried to tell myself that modern agm deep cycle would be as good as fla, but I don't really know. 

I had the batteries fitted by people who insisted on buying and installing the batteries, so I just hope they are the correct ones, obviously being a mere woman, like myself, your electrical guys will not expect or welcome any technical input from you 

someone will be along soon to advise. They will want you to do an energy audit.

personally I try to stick to 12 volt appliances, in fact pretty much no appliances (long story).

THe fridge is the biggest consumer, they come in 12v (expensive), or standard household 240v, which need to be fed power via an inverter, these two items have to be matched.

Edited June 14, 2022 by LadyG

[Tony Brooks]

To try to illuminate what LadyG said. Technically AGM batteries can charge a bit faster and give a high rate of discharge than flooded cell lead acids, they also have better supported plates that may shed less, given a longer life, but they are far more difficult for an ordinary boater to test and diagnose unless they have battery monitoring and regularly (each day) take readings and note, so you can recognize when things begin to alter. Any sealed battery, be it AGM, Gel, or sealed lead acid will have their life reduced if the charging voltage regularly exceeds the manufacturer's recommendation.

 

You can't simply compare AGM and flooded cell lead acid batteries because there is/was more than one AGM technology and several designs of FLAs  A top line FLA battery with plates inside glass fibre pockets and deep sediment traps will last longer than ones with shallower sediment traps and non-pocketed plates. Lead calcium batteries can be charged at a higher voltage than lead antinomy ones so are less prone to gassing.  Deep cycle FLA with pocketed plates will last longer than duel purpose FLAs without pocketed plates.

 

Basically for any one type the heavier it is, the better and the more expensive the more likely it s to have a longer life BUT always check the manufacturer's spec. to compare the cyclic life and depth of discharge. The greater the cyclic life and the deeper the depth of discharge the longer it should last.

 

Remember that the longer and deeper you leave batteries discharge the more they will sulphate and the shorter their life. This applies across the board.

 

To answer the OP's question. I would fit battery monitoring, so I could keep them as well charged as possible and then keep the 633s until they show signs of loss of capacity or cell failure. Then I would fit a good quality deep cycle lead calcium battery bank. I would not worry too much about sealed or open cell because with the majority of standard charging system they will not need topping up until either the charging voltage control fails, a cell shorts, or the plates sulphate. Remember batteries really are consumable items and over 4 years or so life for any that most people will buy is  good.

[MtB]

3 hours ago, Tony Brooks said:

Remember that the longer and deeper you leave batteries discharge the more they will sulphate and the shorter their life. This applies across the board.

 

 

Only within the lead acid genre.

 

Once you get a grip on LiFeP04 then all that changes. 

 

 

[Tony Brooks]

6 hours ago, MtB said:

 

 

Only within the lead acid genre.

 

Once you get a grip on LiFeP04 then all that changes. 

 

 

 

Totally agree. If you properly understand and provide the charge control required plus it's affordable there is absolutely no question this is now the case. However, LadyG was comparing FLAs and AGMs