Lithium Battery Combinations

[Chotu]

Originally Posted by Winf

Thx all for the replies so far. Clearly need to do more study.

RE why lithium - I'm with Rod Collins on this one, "lead is dead."

We've had no major issues from our AGM bank. It is due to be replaced though and cost benefit over the longer term sits with Li from what I can determine.

It allows getting out of the "lead acid mindset" - to somewhat ignore battery status instead of constantly monitoring state of charge. I don't see ability to have greater charging capacity as the primary benefit of Li. Our aim aboard is to minimise charging via generator or engine, solar as much as possible.

I looked at my lithium bank/solar (the batt monitor) many times in the first few weeks since I was still stuck in the lead acid mindset.

After that, I looked at the battery monitor only twice this year. If it’s raining for 3 days and nights in a row, I need to look and potentially use some backup charging. I experienced that last week for the first time this year.

Otherwise, batteries are full by around noon each day and actually catch up from a couple days of rain in one sunny day.

It’s truly amazing to leave the lead mindset. Feels like a house on land. No more managing power.

Running:

Household refrigerator
Deep chest freezer
Autopilot
Chart plotter
Computers and phones
DVD movies
Lights, etc

[jimellifritt]

Originally Posted by Winf

Hi all

Starting to pull together a lithium system to our replace existing AGM house bank.

Looking for how to configure new house bank. i.e. number and sizing of the individual batteries.

Current AGM bank is 4 x 105AH 12V Fullriver DC105's. i.e. 420AH theoretical

The four existing 105AH's fit comfortably into the battery box.

Cruising energy usage approx 150-175AH/day.

500W of solar with programable TriStar MPPT solar regulator.

100W of solar via non programable PWM regulator - plan is to change regulator to fully programable MPPT

55A standard alternator and standard lead acid start battery - will connect to house bank via a DC/DC charger.

60A fully programable Stirling battery charger with generator

Will use Victron - Smart Batteries, MPPT, BMS and DC/DC.

No planned increase in electrical demand.

Battery Bank options considered:

4 x 100AH batteries in parallel

2 x 200AH batteries in parallel

2 x 160AH batteries in parallel - favouring this option

1 x 300AH battery

1 x 330AH battery

Suggestions, recommendations, experiences please?


Thx in advance.

Check with your insurance first. You may disqualify a claim unless installed by certified electrician. Victron is a big player but in a 2 week period 3 boats arrived in Panama with broken victron equipment, in the 3 boat all were instaltions in fall 2022. 4 bad batteries in one boat, one bad inverter charger in another, boat 3 bad inverter charger, one bad battery, one bad balmor external regulator. Their batteries are made in China and QA QC was poor. May have been a bad season. Made me choose to stay with AGM.

[wholybee]

Originally Posted by smac999

whats your reason for going to lithuim? with a tiny 50a charger and alt you are not going to gain many if any benifits of using lithuim vrs agm.

He has enough solar to almost never need to charge with the alternator or shore charger.

LFP charge rates don't drop off as they charge like AGM, so it is easy to get to full charge by noon, where it is difficult with AGM. Which makes the whole system work better.

[wholybee]

Originally Posted by Winf

...
Will use Victron - Smart Batteries, MPPT, BMS and DC/DC.

No planned increase in electrical demand.

Battery Bank options considered:

4 x 100AH batteries in parallel

2 x 200AH batteries in parallel

2 x 160AH batteries in parallel - favouring this option

1 x 300AH battery

1 x 330AH battery

Suggestions, recommendations, experiences please?


Thx in advance.

Back to your question. People will argue over DIY vs. Drop in, and how to parallel them to get the capacity you need. The real world difference is negligible. A well planned installation, whether DIY, drop-in, FET BMS, several in paralell or not, or contactor BMS, will all perform very well.

More important is going to be the source of components and the brand. People sometimes source cheap parts (either cells or drop in batteries) from Alibaba or Aliexpress, and often have problems. Ebay and Amazon are slightly better, but often sellers on those marketplaces are sourcing from Alixxx themselves.

Victron, Epoch, Kilovault, Dakota, Battleborn, Winston, Calb, and a few others are brands that are top of class. If you buy any of those from a reputable retailer, then your parallel configuration won't matter.

It is also important not to make design errors. People will argue over FET vs. contactor and BMS having direct control of the system vs being a failsafe. Again, it doesn't matter. But, there are some common design errors and a few things that need to be dealt with. (Your including a DCDC charger, if connected properly, will address some of those issues). It would be a good idea to have your drawing reviewed before you order anything.

You will also hear people argue over what charging parameters to use. If you browse manufacture recommendations, they all mostly agree, with only a couple tenths of a volt difference, if not exactly the same settings. So, start there. Many people use settings that are completely different to try and extend the life of the cells. That is fine, but be careful, as adjusting the voltages too low can bring some issues also. And be mindful that without adjusting from the manufactures settings you can expect 15 years or more of life.

[Nepidae]

My only comment would be that whatever you plan for now will probably NOT be what you have a year or 2 down the river, so plan for twice as much as you need today.

[Wandering]

Originally Posted by Chotu

I looked at my lithium bank/solar (the batt monitor) many times in the first few weeks since I was still stuck in the lead acid mindset.

After that, I looked at the battery monitor only twice this year. If it’s raining for 3 days and nights in a row, I need to look and potentially use some backup charging. I experienced that last week for the first time this year.

Otherwise, batteries are full by around noon each day and actually catch up from a couple days of rain in one sunny day.

It’s truly amazing to leave the lead mindset. Feels like a house on land. No more managing power.

Running:

Household refrigerator
Deep chest freezer
Autopilot
Chart plotter
Computers and phones
DVD movies
Lights, etc

We have lithium, but I do look at the charge status, several times a day. We have all the loads you have but we also do electric cooking, we make all our hot water and we run our 220v watermaker from the lithium. Out daily average load pulled from the batteries is 214Ah@24v. This doesn't include the direct loads during the day when the solar just goes straight to the load and not into the batteries. We have 920w of solar

[The Sun King]

Lithium batteries in parallel can behave rather oddly, making a single large battery better from the standpoint of peace. However, I like the redundancey of parallel, ignoring the squabbling.
In addition to redundancy, if you have access to the battery BMS units, say through a phone app, you can set the dropout points differently so they don't all quit at the same time, destroying the alternator or leaving you in the dark.
Oh, and make them LFP, not Li.

[BoatBumm]

I own a Pacific Seacraft Crealock 34. Prior to lithium, it was equipped with three 105 amp hour AGM batteries for the house batteries. Charging was from the engine alternator, a Balmar 105 amp unit, and two 120 W solar panels. I wanted to add lithium, but the risk of damaging the alternator if the battery’s BMS cut off charging, and trying to figure out how to charge it in general was a bit daunting. I considered a DC to DC charger, and many people have used that solution. But the locker that the DC to DC charger would be best mounted in was already warm because of an expansion tank for the engine and the hot water heater being in the same locker. The DC DC charger has good size cooling fins, and I anticipated having to rig up some sort of ducted computer fan to keep it cool when it was running.

Then on YouTube I saw the Bank Manager from www.emilyandclarksadventure.com and was interested. I ended up buying it. The installation is fairly simple. The manual is complete. It’s a relatively small box roughly 4 x 5 x 1“, that controls a very large relay that links the lithium battery directly to the AGM systems in parallel. All tho usual charging systems stay the same - charging the AGM‘s and the smart box decides when it can close the relay and transfer the charge or load to the lithium battery. It also basically eliminates the risk of overcharging the lithium battery and having the BMS suddenly shut off, damaging the alternator. The installation was straightforward. I just spent the summer cruising on the boat, and it worked absolutely flawlessly. I cannot say enough about how pleased I am with it. The box is smart enough to draw the load off the lithium battery before it draws off the AGM‘s, but if you’re really stuck for a long period of time with no solar input, and not wanted to run the engine, it’ll eventually draw off the AGMs. When I did start the engine to charge you can specify a maximum charging current based on your alternator’s rating and the lithium battery specs for a charge current. My lithium battery specifies the maximum charge at 50 A and that’s where I set it. The hundred amp Balmar alternator had no trouble doing that, and it was amazing how quickly the batteries were back up to full charge within a short distance of motoring since the lithium battery will easily accept a high charging current until it’s full. The Bank Manager then tapered off the charge to the lithium before the BMS cut off, so the alternator stayed happy.

In my case this summer I got enough solar and/or engine charging that the 206Ah SOK lithium battery handled 100% of the daily loads. But it was nice to know the AGMs were there and fully charged as a backup.

I have no financial interest in the company. I’m just a very satisfied customer, and I highly recommend it. It really solves the problem of easily and effectively integrating a lithium battery into an existing AGM system.

[Nicholson58]

My lithium supplier, tech resource was Hank George with Blue Heron.

hank@starboardlanding.com

He helped configure the system, evaluated my loads and needs and found patch cords, dongles and links to updates I needed to install. He was excellent help throughout.

Don’t re-invent the wheel

[barryglewis]

We bought our 400 A/hrs Winston lithium batteries from Drive by Nature, in Queensland, who were price competitive then. Installed in 2014 and have over 50,000 miles so far, so a bit early to tell long term life...
We have no problem with windlass, hydraulic 3 ton keel lift, or starting 20hp Beta.

Alternator has external regulator, and temp sensor. 660 Watt solar has 2 Victron controllers, SailGen is also lithium aware. Active balancer (Deligreen), cell logger, and Victron low voltage cut out.

[Wandering]

Originally Posted by barryglewis

We bought our 400 A/hrs Winston lithium batteries from Drive by Nature, in Queensland, who were price competitive then. Installed in 2014 and have over 50,000 miles so far, so a bit early to tell long term life...
We have no problem with windlass, hydraulic 3 ton keel lift, or starting 20hp Beta.

Alternator has external regulator, and temp sensor. 660 Watt solar has 2 Victron controllers, SailGen is also lithium aware. Active balancer (Deligreen), cell logger, and Victron low voltage cut out.

How many cycles have the batteries done?. We are doing 100 cycles per year. What BMS? Mosfet or relay based?

[CaptainRivet]

Originally Posted by flightlead404

I have 3x 200 Ahr "Plus" from LiTime, very happy. If you put them in your cart then wait a couple days they will email you with an additional 5% off.

I invested in MRBF for each CABLE going to a positive battery terminal. I added this to my start battery as well.

For the 1st and second house batteries in the string that required a "fuse bar" with two positions, so there's one fuse dedicated to each cable.

I found the best prices at rs-online.com, they are made by Eaton-Bussman and way cheaper than the relabeled Blue Sea.

CFBAR2-M8XSP for the 2 position holder
CFBRAR-M8XSP for the 1 position holder
MRBF-300 for the 300A fuse

Well MRBF check the short curcuit current, if your 200AH LFP has a shortend cell the MRBF will be arced = bypassed. Thats why you need class T or NH fuses as main battery fuse.

[CaptainRivet]

Originally Posted by Wandering

How many cycles have the batteries done?. We are doing 100 cycles per year. What BMS? Mosfet or relay based?

How do you know you done 100 cycles per year?
Every BMS i know except of Tao BMS starts by default a new cycle every day and you cannot change that.

[CaptainRivet]

Originally Posted by barryglewis

We bought our 400 A/hrs Winston lithium batteries from Drive by Nature, in Queensland, who were price competitive then. Installed in 2014 and have over 50,000 miles so far, so a bit early to tell long term life...
We have no problem with windlass, hydraulic 3 ton keel lift, or starting 20hp Beta.

Alternator has external regulator, and temp sensor. 660 Watt solar has 2 Victron controllers, SailGen is also lithium aware. Active balancer (Deligreen), cell logger, and Victron low voltage cut out.

9 years is very good to tell about longlivity. Suggest to make a capacity test and you exactly know how they hold up. Which BMS do you use?

[barryglewis]

We don't have a separate BMS.
Sorry, have no idea how many cycles.

How do I make a capacity test?

In 2020, in the Atlantic heading for Jamaica from Morocco, the cell logger alarm went off as one cell was 0.15v lower than the rest. I used our battery selector switch to use the standby LA battery to power the 3.6v charger via the inverter , to bring the low cell up.
The standby battery is trickle charged by a separate baby solar panel. It died in 2021, replaced with similar.