Lithium Battery Combinations

[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.

[CaptainRivet]

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.

Victron smart batteries are not that smart, the BMS sucks. They have Winston cells inside so i would simply get 4x300Ah or 400AH cells Winston and a REC BMS or if it must be Victron use Lynx BMS, lynx Shunt and lynx distributor. Cheaper and better BMS.
Think you manage to build a box where the 4x300Ah or 400AH Winston go into. Much simpler install.
Would get the 400AH cells

[Winf]

Ok thx.

Hadn't really contemplated building my own battery from individual cells.

Can however see potential $ saving. In $AUD looking at $5800 for 2x200AH 12V Victrons. 4x400AH Winstons $3600.

Complexity is more daunting for me though. My understanding of the technology is better than it was a month ago but still not fully confident.

The physical box I can handle. Understanding of the electricals - getting better but not there yet. Things am unclear on -

- issues with anchor winch inrush current. Winch is a Maxwell 1500 with working load current of 160-200A.

- charge source disconnect and load disconnect - not clear if this is automatic from the bms or how to make it so.

- programming and correct settings for the Tristar solar reg and the Stirling ultra charger.

- what to do with existing automatic charge relay between house and start. Currently have a Blue Seas ML-ACR 500A. Think this becomes redundant.

-

[HankOnthewater]

Hi Winf, last year I installed in a campervan 8x160 Ah Calb batteries (2p4s), with a Daly BMS. Works well, giving 320 Ah at 12 volt
I am now installing 4x400 Ah Winston in my bigger campervan, and 4x700 Ah in my boat. I plan to use for both a REC BMS.
You can buy Winston direct from China, or via a Perth company EV Works, approx $800 more, but local and a good company.
In Oz you can buy REC BMS via Solar4rvs

[HankOnthewater]

Originally Posted by Winf

Ok thx.

Hadn't really contemplated building my own battery from individual cells.

Can however see potential $ saving. In $AUD looking at $5800 for 2x200AH 12V Victrons. 4x400AH Winstons $3600.

Complexity is more daunting for me though. My understanding of the technology is better than it was a month ago but still not fully confident.

The physical box I can handle. Understanding of the electricals - getting better but not there yet. Things am unclear on -

- issues with anchor winch inrush current. Winch is a Maxwell 1500 with working load current of 160-200A.

- charge source disconnect and load disconnect - not clear if this is automatic from the bms or how to make it so.

- programming and correct settings for the Tristar solar reg and the Stirling ultra charger.

- what to do with existing automatic charge relay between house and start. Currently have a Blue Seas ML-ACR 500A. Think this becomes redundant.

-

In-rush of large electric motors.... it not a problem for lithium batteries in the capacity we are discussing here, but a BMS can be the limiting factor. For my campervan I have a 8 ton winch, and when the winch stalls, I expect a current of 500-600 amps, not an issue with REC BMS. The anchor winch on my boat is 1500 Watt, and when that stalls, amps would be less than 500 Amp I would think.

For answers on your other questions, I have a fair idea, but I am not an expert in LFP, but still working through all the details as we speak

[CaptainRivet]

Great tips for Aussi.

With your location i would look at TAO BMS, Phil the owner will help you with the rest of your questions.https://www.taoperf.com
He is from next door island new Zealand :-)

A BMS specifically build for boats by an new zealand sailor.

Building your own from cells is not so much about the savings but a) having access to the terminal of each cell to be able to act eg disconnect to top balance a cell that got out of range b) you build it yourself so you know whats in it and your system so out at the ocean can help yourself compared to a blackbox you have no glue whats inside and how it works.

With a high quality BMS and proper casing you won't save much by the way if you use winston+TAO BMS but you get much more functionality, safety and you know your system as said above.

For your whole setup i recommend to look at Jedi's reference diagrams (search or send him a PN), that helps a lot to understand how to set all up and what you need.

[CarlF]

Fewer people are building their own batteries because of a weaker warranty. My “drop in” lithium batteries have a 7 year non-prorated full replacement warranty.

I’m not sure what the Victron warranty is but I expect similar.

Assuming it would fit in your box, I’d go with two 200AH. More than two batteries in parallel creates some challenges to see that they charge and discharge equally. I’ve never known anyone to complain that they had too much battery.

I’d suggest you get a licensed electrician do at least part of the job. Many insurance companies do not like owner installed lithium batteries. My insurance company asked for the name and phone number of the installer.

Do you plan to have your alternator charge the house bank? If so, there are several things you have to do or you could damage your LFP batteries and/or the alternator. This often involves installing a DC-DC charger and removing the relay. But there are several options.

Of course all chargers will have to be set to the voltages provided by the manufacturer. Turn off temperature compensation.

The start battery should not be lithium. You also should install a Class T fuse on the house bank. Check the battery maximum discharge rate. If you have two batteries, double that and make sure the windlass is less.

[CaptainRivet]

@CarlIF: have a close look at the warranty documentation, mostly they are ridiculous and not even worth the paper they are written on as nearly everything is excluded.

The problem with the drop in BMS is that they are really just protection devices and not been able to streer/control external devices which is needed in proper system designs. Yes you can get around with work arounds but problem is all is done on total voltage and not on cell level voltages.

Insurances don't like owner installed systems because they cannot pull the liability to the installer. But if you are out on the ocean what do you do if its professionally installed and for you its an unknown black box? Better you installed yourself and know whats going on and can help yourself.

[Chotu]

I had the Trojan T-105s (maybe a similar footprint with the 105?)

I went with 2x200AH drop ins. They fit perfectly into my 4x Trojan t-105 space with no modification at all.

One big battery is scary. If something goes wrong you’re done.

At least with 2 of them, you can run on the good battery.

[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.

[flightlead404]

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.

Disagree

Three immediate benefits, and I'm challenged to determine (for my particular use) which is the bigger benefit:

-Ability to deplete well below 50% SOC
-Linear charge profile
-No damage by repeatedly not charging to 100% SOC

[CaptainRivet]

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.

Additional safety:
AGMs can run dry and catch fire, worst chemistry for me on a boat, especially the older they get the more dangerous they get...a faulty regulator is enough that this happens.

With LFP the BMS just shuts it down due to HVC.
With proper install lifespan of 15 years minimum.

[SV Confianza]

I am now fully in the camp of getting cheaper batteries like LiTime or Redodo for the capacity, and use the significant savings to upgrade the charging sources like alternators, regulators, and solar. If you’re paranoid about the quality of the batteries add a class T fuse on mid chain on the parallel in case of a battery short to keep your wires from melting. Add class t fuses before bank on charging sources.

The $500/battery savings gives you a lot of upgrades to charging sources.

We have used a mix of battleborn and LiTime/Redodo/zooms for years now. Good class t fuses have saved us from multiple failures (like when I didn’t realize my bats were live and accidentally shorted a cable to my alternator case ground…would have probably welded the cable to my alternator otherwise).

[flightlead404]

Originally Posted by SV Confianza

I am now fully in the camp of getting cheaper batteries like LiTime or Redodo for the capacity, and use the significant savings to upgrade the charging sources like alternators, regulators, and solar. If you’re paranoid about the quality of the batteries add a class T fuse on mid chain on the parallel in case of a battery short to keep your wires from melting. Add class t fuses before bank on charging sources.

The $500/battery savings gives you a lot of upgrades to charging sources.

We have used a mix of battleborn and LiTime/Redodo/zooms for years now. Good class t fuses have saved us from multiple failures (like when I didn’t realize my bats were live and accidentally shorted a cable to my alternator case ground…would have probably welded the cable to my alternator otherwise).

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

[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.