Domestic batteries replacement

Nina Lucia

Nina Lucia

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We are looking to replace two domestic batteries, currently just sealed lead leisure batteries 110amp that we bought from local chandlery 4 years ago
I was thinking to replace with bigger capacity AGM, which one shall we go for, they are very similar price for two:


TN Power AGM 12V 125Ah Deep Cycle Battery
(TN Power AGM 12V 125Ah Deep Cycle Battery)
or
12v 150ah Expedition Plus Agm Deep Cycle Leisure Battery (EXP12-150)
700 CYCLES, NON SPILL, 4 YR GTEE. (12v 150ah Expedition Plus Agm Deep Cycle Leisure Battery (EXP12-150) | eBay)

Any better options?
Thank you
 
They are just off the bottom end of the price scale and unknown brands. In theory they should be OK, but choice of battery depends very much on your usage pattern charging facilities and life expectations. Not keen on unknown brands myself, but there is a price premium for good brands (like Victron) for the same notional product.
 
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Mind you, your current batteries should have at least another 5 years of life left in them, so why change them now?
 
dukeofted said:
With those prices it is cheaper to go with a lithium now. These are pretty good for the money Lithium Leisure Battery - Fogstar Drift 12v 105Ah

Remember that with lead acid batteries you can only use half the stated capacity so a 105Ah lithium is equivalent to a 210Ah lead acid battery.
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Not really. You can't just drop lithium in to replace lead. When you go lithium you need to change the system not just the battery
 
Bobc said:
Mind you, your current batteries should have at least another 5 years of life left in them, so why change them now?
Click to expand...
I left our automatic bilge pump on for a five days ... small amount of water came in to the bilges trough the mast and ruined both batteries. I have managed to recover them partly but they don't have full capacity any more. They last only couple of hours with only Eberspacher on, then we have to start the engine to top up batteries.
 
Nina Lucia said:
We are looking to replace two domestic batteries, currently just sealed lead leisure batteries 110amp that we bought from local chandlery 4 years ago
I was thinking to replace with bigger capacity AGM, which one shall we go for, they are very similar price for two:


TN Power AGM 12V 125Ah Deep Cycle Battery
(TN Power AGM 12V 125Ah Deep Cycle Battery)
or
12v 150ah Expedition Plus Agm Deep Cycle Leisure Battery (EXP12-150)
700 CYCLES, NON SPILL, 4 YR GTEE. (12v 150ah Expedition Plus Agm Deep Cycle Leisure Battery (EXP12-150) | eBay)

Any better options?
Thank you
Click to expand...

Unless you tell us about your boat, what equipment it has, how you charge the batteries and how you use the boat, no-one can offer any truly useful advise.
 
dukeofted said:
With those prices it is cheaper to go with a lithium now. These are pretty good for the money Lithium Leisure Battery - Fogstar Drift 12v 105Ah

Remember that with lead acid batteries you can only use half the stated capacity so a 105Ah lithium is equivalent to a 210Ah lead acid battery.
Click to expand...
Lithium batteries are quite expensive and cost probably the same to change system, charging, regulating, etc. With AGM is kind of compromise, more capacity than wet lead batteries and straight swap with leads. I suppose we just need to change few parameters on our Victron monitor, charger and MPPT solar controller
 
PaulRainbow said:
Unless you tell us about your boat, what equipment it has, how you charge the batteries and how you use the boat, no-one can offer any truly useful advise.
Click to expand...
Hi Paul,
We have Aphrodite 36, on swinging moorings. We are not spending much time in marinas, if don't have to.
80 amp solar charger on deck, Victon battery monitor, Victron MPPT 100/20 smart charger controller, blue smart charger 12/30/ 3 outputs when we are in marina, Cyrix-ct 12/24V 230A Battery combiner. Volvo 2003T with 70 amp alternator, small fridge that we hardly ever use, Eberspacher 3KW used regularly in the evenings, small plotter, wind, depth, Vesper AIS, auto pilot, all nav lights are LED and cabin light as well.
Starter battery is Varta AGM dull purpose LA105, and two 110 amp wet lead Leisure and Marine Powerplus .
I guess that's all?

Thank you everyone for all the input
 
IMO the big question is of how deeply you discharge your current batteries - how low they get when you use them. In volts or percentage from the battery monitor?

Are you cruising for weekends, or for full weeks at a time?

I have 2 x 165Ah batteries, but they're wired in parallel, so combined they form a single 330Ah battery. I'm not sure if you have a single 220Ah bank, or a switch between them?

I would have thought that 220Ah would be fine for weekend cruising - with 330Ah I start turning the fridge off after a couple of days and try to keep the batteries above 12v (approximately 50%). I added a Smart Shunt during my current refit, so I now possess a quality of battery monitoring I didn't have before.

My main load is the fridge, which is 30W or 40W, and my laptop is of a brand which is quite well known for using little power, so I can run it of a USB-C adaptor in a 12v socket. AIS and chartplotter - even my autopilot, I think - are relatively low loads compared to the fridge. So if you hardly use your fridge then I'd have thought you'd be ok with your current capacity. Not sure how much power an Eberspacher uses though.

You can never have too much battery capacity - are your current 110Ah batteries shagged? Because I'd be running them until they are.

Your proposal is to increase your bank's capacity by 14% or 35% - I'd probably do that once the current batteries are shagged and due for renewal, but not just for the sake of it, to feel good about an "upgrade".

These are pretty cheap batteries, which is fine if you're never going below 80% or 12.5v. Economically, cheap batteries may make more sense than expensive ones even if you're hammering them.

My apologies if you already addressed these questions. It would be typical that I spent several minutes writing an answer because I didn't spend a few seconds reading more carefully. However now I must run before the supermarket closes.
 
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Nina Lucia said:
Hi Paul,
We have Aphrodite 36, on swinging moorings. We are not spending much time in marinas, if don't have to.
80 amp solar charger on deck, Victon battery monitor, Victron MPPT 100/20 smart charger controller, blue smart charger 12/30/ 3 outputs when we are in marina, Cyrix-ct 12/24V 230A Battery combiner. Volvo 2003T with 70 amp alternator, small fridge that we hardly ever use, Eberspacher 3KW used regularly in the evenings, small plotter, wind, depth, Vesper AIS, auto pilot, all nav lights are LED and cabin light as well.
Starter battery is Varta AGM dull purpose LA105, and two 110 amp wet lead Leisure and Marine Powerplus .
I guess that's all?

Thank you everyone for all the input
Click to expand...
Starting point for choosing battery size and type is modelling your usage pattern to identify frequency and depth of discharge then netting off charge from your various sources while on the boat then means of keeping batteries fully charged in between periods of uses.

From what you say so far, a 200Ah+ (100Ah effective) bank would be sufficient for day to day use if you can can keep it fully charged after a period of use. Of course greater capacity gives you greater reserves and if you intend spending longer periods away from shorepower (which is the most effective way of fully charging batteries) this is the first step. Then the choice of actual batteries - type and price depends largely on how many cycles you expect. Basically the higher the price the longer the life and looking at the specs for the cycle will illustrate this. As already suggested, AGMs offer the best compromise for life against cost with the added advantage of higher charge acceptance and lower self discharge. However within the broad church of AGMs there are wide variations in potential cycles, but even the most basic should give a life of 8-10 years in typical "weekend and holiday" usage if they are kept working in the 50-100% SOC range and maintained fully charged when not in use.
 
geem said:
Not really. You can't just drop lithium in to replace lead. When you go lithium you need to change the system not just the battery
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Maybe....but not necessarily. I did drop in lithium , watched it carefully and turns out I did not need to buy anything else.

I suspect the same would be true for many small boat systems adding Lithium - certainly not all but many will work well without any additional kit.
 
Nina Lucia said:
Lithium batteries are quite expensive and cost probably the same to change system, charging, regulating, etc. With AGM is kind of compromise, more capacity than wet lead batteries and straight swap with leads. I suppose we just need to change few parameters on our Victron monitor, charger and MPPT solar controller
Click to expand...
I would not give up on Lithium option without a little more research. I used to think the same as you and kept buying AGM for years because Lithium sounded too complicated. I eventually was confident enough to try last year and it has worked incredibly well, no changes to system apart from some charger settings.....to the point I feel stupid for being scared off doing it ages ago and wasting all that money on AGM. AGM is not really a compromise, Lithium is a step change, simpler, easier, less stressful and cheaper.

Take a look at 12v boating group on Facebook, there is a wealth of info there on how to do it cost effectively, what to watch out for, best suppliers etc
 
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