Our first year with lithium

[Neeves]

Extending my post on 'solar shingles'

I read that balcony solar panels are popular in Germany. If you check this link:

800W Balcony Solar System Set B - OMMO

and scroll down there is an image of the kit, the solar panels, angled toward the sun - which seems so similar to hanging panels off your stanchions (but the balcony application owe nothing to Heath Robinson but look slightly more professional). They fill a niche where you want a temporary installation (unlike most domestic installations that become part of the roof). The balcony installation seem to be sold as a complete kit, possibly including a battery or plugged into the mains. When you move from one rental property to another, and have a different balcony - you can take the kit with you.

There seems no reason to suggest that even small yachts could not have a reasonable solar display ......

...... just think outside the box (or yacht).

Jonathan

 

[Seven Spades]

I have 2 X MMPT controllers. One is connected to 3 X 60W panels in series and the other 2 X 100W in series. The 3 X 60W are mounted on the deck and the 2 X 100W on the sprayhood. They are no in optimal position because it is almost impossible to avoid some shading from the mast or boom. However I never get more than 180-190W of solar. If I leave the boat i tend to tie the boom to one side to maximize the yield. On average in the summer months we will generate over 1kwh per day. It is disappointing but the location is not optimal. But it is enough to keep the fridge and freezer going when we leave the boat for about three weeks in th UK. In the med the yield is higher.

 

[Laser310]

Say a boat had a spot that just held three 100AH AGM batteries.

Isn't it supposed to be the case that lithium batteries store more AH for a given volume?

I was looking for a lithium battery of the same size of a 100AH AGM, but with greater capacity.

It seems like the Lithium batteries that are the size as 100 AH AGM.., are still only 100 AH.

Or am I missing something?

 

[Sea Change]

Say a boat had a spot that just held three 100AH AGM batteries.

Isn't it supposed to be the case that lithium batteries store more AH for a given volume?

I was looking for a lithium battery of the same size of a 100AH AGM, but with greater capacity.

It seems like the Lithium batteries that are theFriends size as 100 AH AGM.., are still only 100 AH.

Or am I missing something?

Depends on the battery.
A friend bought some 300Ah batteries and they were about twice the size of my DIY 280Ah one. I'm not sure what they put in the box.

Also, bear in mind that a 100Ah LFP battery has almost twice the useable capacity of a 100Ah AGM.

 

[Seven Spades]

Your 100aH AGM provide 50aH usable. A 100aH lithium will give 80aH usable. But that is only part of the story, the really big benefit is the efficiency of charging l. So using your engine fir a short time will result in the battery charging really fast whereas with AGM the charge rate drops so it takes a lot of energy to get the battery to float.

 

[Neeves]

Your 100aH AGM provide 50aH usable. A 100aH lithium will give 80aH usable. But that is only part of the story, the really big benefit is the efficiency of charging l. So using your engine fir a short time will result in the battery charging really fast whereas with AGM the charge rate drops so it takes a lot of energy to get the battery to float.

My interpretation is similar but the charging is not quite as immediate as implied.

B2B battery chargers are woefully 'small'. 30/40 amps is not unusual as being part of a Lithium installation. If you have used 80amps of your 100amp Lithium it will still take 3 hours to re-charge (assuming your solar is facing rain), impressively quick compared to Lead - but 3 hours of engine running is still a long time. A 100 amp Lithium bank is not very big, most owners posting here seem to have more than 200 amps.

I stand to be shown I'm totally ignorant and not know what I'm talking about - and thus hopefully learn.

An advantage of Lithium is that the batteries are lighter. We have a 200 amp Lithium that I can lift with ease. We had 2 x 200amp AGMs on Josepheline, each was a bit bigger than the 200 amp Lithium but carrying the 200amp AGMs was a hazard to life (or my back). I could not install the Lead batteries single handed it was simply too hazardous getting them into a tight space. The 2 x 200 amp AGMs were offering the same usable amps as the single 200 amp Lithium at maybe 1/3 of the weight and space.

Jonathan

 

[Seven Spades]

Better to charge at 40a than 10a which is the sort of charge rate you can get when batteries reach 90%. If you upgrade your alternator or fit solar you are really cooking on gas.

 

[Sea Change]

My interpretation is similar but the charging is not quite as immediate as implied.

B2B battery chargers are woefully 'small'. 30/40 amps is not unusual as being part of a Lithium installation. If you have used 80amps of your 100amp Lithium it will still take 3 hours to re-charge (assuming your solar is facing rain), impressively quick compared to Lead - but 3 hours of engine running is still a long time. A 100 amp Lithium bank is not very big, most owners posting here seem to have more than 200 amps.

I stand to be shown I'm totally ignorant and not know what I'm talking about - and thus hopefully learn.

Jonathan

If you expect to rely heavily on engine charging then you'd be much better off fitting a suitable regulator to the alternator (and possibly a new alternator too).

 

[Laser310]

I understand that the Li batteries have more usable capacity.

But it seems that if I have room for AGMs of 300 AH rated capacity.., that will still only be room for 300AH of LI rated capacity.

Correct?

 

[geem]

My interpretation is similar but the charging is not quite as immediate as implied.

B2B battery chargers are woefully 'small'. 30/40 amps is not unusual as being part of a Lithium installation. If you have used 80amps of your 100amp Lithium it will still take 3 hours to re-charge (assuming your solar is facing rain), impressively quick compared to Lead - but 3 hours of engine running is still a long time. A 100 amp Lithium bank is not very big, most owners posting here seem to have more than 200 amps.

I stand to be shown I'm totally ignorant and not know what I'm talking about - and thus hopefully learn.

Jonathan

The new Victron XS B2B charger is fully programmable to give you up to 50A charging if you have a 12v system. You would likely only want to use the full 50A output if you had an 80/100A alternator or you will risk frying the alternator. The XS 50 A B2B will output 50A all day long as long as your alternator can handle the load.
The other thing to remember with lithium is its not essential to charge the battery up to 100% you only need to put in what you need for the day

 

[Neeves]

If you expect to rely heavily on engine charging then you'd be much better off fitting a suitable regulator to the alternator (and possibly a new alternator too).

And then, as some have mentioned, the costs start to sky rocket.

Sydney is enduring what is being described as 'the big wet' - we have been subjected to higher than average very heavy rain (so far for a week), some flooding and a further week to go before the weather turns to sunshine. This is a bit more prolonged than usual but April is commonly the month of heavy rain - and looking at worst case scenarios - you would not want to rely on solar for your power replenishment.

I am aware that you can source combined chargers that offer both solar, MPPT, and alternator, B2B, 'management'. I don't know if this includes the Victron charger that Geem mentions. I accept Geem's comment, you only need to replenish what you need for the next day, say to 60% and you can modify your power usage to better suit the conditions.

Its not the black and white I imply - but needs some thought, before you rush into buying Lithium, the management systems and the solar to replace Lead.


It would be interesting, now that a few Geem, Sea Change, Seven Spades et al have had a year, or more, with a Lithium bank to see summaries of what these owners might do differently now were they to start with a clean slate. If anyone wanted to comment - maybe a new thread?

From playing with my, terrestrially based, 200 amp Lithium power station I would look at, for an Lithium house bank and Lithium galley, at least, 400amps of Lithium, 800 watts of solar (with MPPT controllers to match), a much bigger inverter (currently 1,500 watts). I'd want to buy everything at once - or planned to be one stand alone system. I'd also need an immersion heater (hot showers) (Insulated hot water tank?). I might live with the small B2B charger due to parsimony. Ideally this needs to be installed in a new yacht - so without generating redundant kit.

My ideas - modifying as I learn - still needs lead (or lead plural), engine start, windlass, electric winch(es) - which would support a B2B. I'd be aiming at - no gas. I would take on board Geem's suggestion of 24v rather than 12v.

Jonathan

 

[Laser310]

If you expect to rely heavily on engine charging then you'd be much better off fitting a suitable regulator to the alternator (and possibly a new alternator too).

is the high output alternator usually bigger?

might there be difficulty fitting one?

 

[geem]

And then, as some have mentioned, the costs start to sky rocket.

Not to mention complexity and risk of blowing alternator diodes unless your bms can speak to the external alternator reg

 

[geem]

is the high output alternator usually bigger?

might there be difficulty fitting one?

They are normally physically bigger. They use large frames so they can run larger cooling fans. They often need different belts that can take the increased load so you need pulley changes as well

 

[Sea Change]

And then, as some have mentioned, the costs start to sky rocket.

Yup. I nearly binned the whole lithium project because I was struggling to get my head around the engine charging side of it. So I decided to charge off solar only, which saved me a lot of money and hassle. Works brilliantly.

 

[Sea Change]

I understand that the Li batteries have more usable capacity.

But it seems that if I have room for AGMs of 300 AH rated capacity.., that will still only be room for 300AH of LI rated capacity.

Correct?

If you use drop-ins, possibly.
If you assemble cells in to a battery, it's far more compact.

 

[Sea Change]

Your 100aH AGM provide 50aH usable. A 100aH lithium will give 80aH usable.

I think you're being a bit harsh on the lithium there. 80% is good practice but you could use the whole capacity and it would still outlive the AGM.

 

[vic008]

Why the big drama with lithium? Why cant I go into the store and buy a kit with everything needed? Perhaps I need to decide how big a battery I need.Am told I need a thorough understanding of lithium.

 

[lustyd]

If you expect to rely heavily on engine charging then you'd be much better off fitting a suitable regulator to the alternator (and possibly a new alternator too).

While that would be better, the thing a lot of people forget is that while lithium might take longer to charge, the charge going in is the same as for lead overall so for an hour on the engine you’d have roughly the same usable. Probably less on lead as less comes out than goes in!

But it seems that if I have room for AGMs of 300 AH rated capacity.., that will still only be room for 300AH of LI rated capacity.

I had the same box and installed one Fogstar drift 300Ah and one lead engine start. As said the 300Ah lithium has the capacity of 500Ah lead or more so it’s all good. For the record mine takes 10 hours to fully charge on the B2B but rarely needs it unless we hit the Starlink hard and forget to turn it off.

It would be interesting, now that a few Geem, Sea Change, Seven Spades et al have had a year, or more, with a Lithium bank to see summaries of what these owners might do differently now were they to start with a clean slate. If anyone wanted to comment - maybe a new thread

Personally I’d change nothing. I am considering building a space to increase capacity and fit a watermaker but that’s more to do with moving on board than any issues with the system.

 

[stranded]

I understand that the Li batteries have more usable capacity.

But it seems that if I have room for AGMs of 300 AH rated capacity.., that will still only be room for 300AH of LI rated capacity.

Correct?

I have fitted a Fogstar 460AH LifePo into exactly the same space as one of my two old 200Ah Banner AGMs, so twice the sensibly usable capacity for 1/2 the space and not much more than 1/4 of the weight.

It was explained to me when doing my install that drop in LifePos tend to be built into a small range of standard box sizes so different AH LifePo batteries will go into the same size box.