Ok, a small variation to the learning theme here.... I have learnt something but I need you clever people's input to cement the learning further .... here goes.
On our boat we have a 12v system. Not counting or talking about the starter battery but the leisure batteries. 2 iirc 180 amp AGM batteries. total 360 amp hours but only in reality 180 as they should never be taken below 50% state of charge, my ref for that says about 12.06v = 50% ( resting check - no load) - that much we all know - They are about 18 months in to their expected 4-5 year service life.
My learning today is that the Aferiy P210 'solar battery' one of the packs that comes with 2kw/h of lithium, charger MTTP controller and inverter all in one is a decent price but critically they have a 12v 25 amp anderson port output - I've asked and they say its regulated to 13.8 volts. That's me all educated and pleased to be so.....
The Q is I want to add this 13.8v to my boat to the fuse panel in parallel with the lead acids (at their max fully charged rate of 12.8v.) My understanding is the 13.8 v from the lithium will service the loads with a very small dribble back to the lead acids. So if you like a bit like the 'hybrid' system many use as a permanent install but on Percy it would be use only no charge, as the Aferiy would have duty back at home when we are not on the boat a real bonus duel use for out type of boat/cottage living - we'd charge separately ( different topic).
I've tried this with my Ecoflow but that 12v output is regulated to IRC 12.8 and also 10 amps - the water pump and bath pump can get close to that and have tripped it before. Also it is via the cigarette type socket that are not idea as they work loose - so not as useful and under load seems to drop voltage so not good for the fridge.
So I am hoping the 13.8 from an Aferiy would work without issue if connected in parallel with the boats existing 12v system?
Any advice ?
2 comments:
Nev,
In response to your battery question.
There are a variety of opinions whether; or not; it is safe to combine lead-acid and lithium batteries, which I think is what you want to do. I don’t believe you want to combine the two battery types for charging but rather supplement the boat domestic battery bank with the lithium. If this is correct, then any potential safety issues revolve around discharging.
As I see it there are three potential risks
1. The battery types have different discharging characteristics and may not discharge at the same rate. One battery may be over discharged whilst the other is underutilized. This can cause excessive wear on both batteries.
2. Because of their different energy densities and voltage profiles, mixing lithium and lead-acid batteries can lead to poor system performance. The lithium battery might remain at a higher state of charge, while the lead-acid battery could be stressed due to excessive discharge. This uneven performance can cause operational inefficiencies and potential failure in high-demand applications.
3. Lithium batteries are more sensitive to improper charging and discharging conditions. Mixing these with lead-acid batteries without proper monitoring systems in place can increase the risk of overheating, venting, or even fire.
Rather than combine different types of battery you might consider the following options.
1. Separate the two types of batteries by installing a two-way change over switch. You could then use either the AFERIY power station or the domestic battery bank; alternatively
2. Recharge the lead acid batteries using a 240V to 12V lead acid battery charger connected to the AFERIY.
Tom, Thank you so much for taking the time to answer my question in such a comprehensive manner. All of what you write makes a lot of sense and the 1&2 at the end are exactly as I will proceed. Not 100% sure I'll go for the battery but the option of the 25 amp 12v output is very useful with the change over switch to keep both systems separate. Percy is not a high power demand boat... like all boats the fridge is the hungry item. I'll be blogging about a chat I had with a boater the other day who'd made some interesting changes to his boat electric wise. Thank again I hope you are well
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