Lithium Batteries (for the rest of us)

[Lagoon4us]

Originally Posted by pbiJim

Does that particular monitor determine state of charge by reading voltage? Or is it some high tech gizmo that measures current flow over time & does a calculation?

DC Systems Monitor (DCSM)

[goboatingnow]

[QUOTE,Originally Posted by skipmac ]Well same here. Methinks the LiFePO batteriies are just not quite ready for prime time. Long ago and far away I was an EE and even with that background the care and feeding of LiFePO batteries seems like a lot of hassle and lot's of potential for screw-ups and trashing a big dollar investment.
[QUOTE]

This is not correct , if anything lifepo4 is easy to maintain then LA, because you don't have all the issues around partial charging and discharging

Cell balancing is definitely not needed in fractional C setups.

In fact if these cells were the price of SAMs LA , we wouldn't have any of this fancy BMS stuff connected. You'd have just the usual voltage meter / amp meter or something All of this concern is purely cause the cells are currently expensive , that will change over time

Dave

[Lagoon4us]

Dave is absolutely correct our installation is working proof.
Frank.

[boom23]

Originally Posted by Maine Sail

There are a number of commercially available BMS products out there. On our bank I am using a Clean Power Auto House BMS and the cell modules. The alt & solar cut can be made from simple Cole Herse DPDT relays and the load cut from a Tyco EV500 contactor. We also have a manual alt cut switch that disconnects the B+ of the MC-614 regulator and a manual on/off for solar. I also wired in a Cell Log 8 to monitor cell level voltage.

I would recommend charging the Winston cells to no more than 14V then dropping back to 13.8V then to 13.5-13.6... Programming the reg for your use with the bank will take the most time...

Be 100% sure you have all battery temp sensing for all charging sources turned off and that the alt reg pos volt sense and neg wire connect directly to the banks posts...

I would strongly urge you to consider a Balmar AT series hairpin wound alternator. These banks will eat wimpy alts for lunch. As it is now our alt is limited to about 110A to stay out of alt temp limiting range. Once you start bouncing in and out of temp sensing the charging performance sucks. I've found the overall charging performance far superior by limiting the alts output by using "belt manager". It may take a while to find the sweet spot where she will run at 190-200f all day long.. She's already physically melted the heat shrink off one alt temp sensor.....

I have exactly the same setup you describe with four 700A Winston cells, Balmar AT 165A alternators with serpentine belts and external 614 regulators, Clean Power Auto BMS and Victron MultiPlus and MPPT (with three 260W panels).

I am very happy with the setup. My electrician left two of the original house bank batteries in place with an automatic switch over if the LiFePo batteries get disconnected due to over/under charge.

Why do you think that the batt temp sensing should be not connected?

Also, we should compare charging settings. It may help to reduce trial and error time...

[Lagoon4us]

I'm thinking that having a lead acid battery as the start battery it gets charged from the OEM Alternator and circuit as per normal BUT by switching our Lithium over to it when warranted, the Alternators regulator senses the LA's resistance and charges accordingly which tops up the Lithium nicely.

We disconnect once we reach 90% leaving other sources to finish topping the Lithium up.
This situation occurs during night runs, cloudy days or when motoring into the sun with the panels not getting full exposure.

We don't let Lithium charge sources charge the LA's.

This by practice has worked very well for last four months.

Thoughts?

[pbiJim]

It might be worth considering setting up a large alternator with a magnetic clutch like an automotive air conditioner compressor uses. That way, when the Lithium batteries get up to the desired max charge level, you con disconnect the mechanical drive to the alternator & not worry about issues with alternators running with no load.

Just an idea.

[Lagoon4us]

Originally Posted by pbiJim

It might be worth considering setting up a large alternator with a magnetic clutch like an automotive air conditioner compressor uses. That way, when the Lithium batteries get up to the desired max charge level, you con disconnect the mechanical drive to the alternator & not worry about issues with alternators running with no load.

Just an idea.

Read my post i have a 400amp pack running now, it's quite adequate and we don't need alternators that jam in huge amounts in a short time, i don't think that's a cruising requirement.
It works for us you really don't need to complicate it or make it expensive with specialised gear.
Cheers

[Maine Sail]

Originally Posted by pbiJim

It might be worth considering setting up a large alternator with a magnetic clutch like an automotive air conditioner compressor uses. That way, when the Lithium batteries get up to the desired max charge level, you con disconnect the mechanical drive to the alternator & not worry about issues with alternators running with no load.

Just an idea.

The easy solution to this is to simply cut the B+ wire to the regulator. No regulator on, no alt output..

Balmar for example prefers to have the B+ wire cut rather than the field wire but both do the same thing. No need for a clutch when a simple manual switch will do. Of course with a well programmed regulator this is pretty much not really necessary. On long runs however we do often turn the alt completely off...

You would not want to cut the B+ (output) of the alt with the regulator still on but cutting the B+ powering the regulator is safe.....

[Maine Sail]

Originally Posted by boom23

Why do you think that the batt temp sensing should be not connected?

Also, we should compare charging settings. It may help to reduce trial and error time...

In an area that can get cold the voltage can get compensated UP and this can cook the cells... No real need for temp compensation at the fractional "C" levels we charge at on boats... Even with a 140A alt on a 400Ah bank I can not even record a .25 degree change in battery cell temps....

Your charge settings will vary based on your use, your average DOD that initiates a charge, your alt etc. etc....

Ours have been adjusted many times to get it just right for our cruising & use. As it is we have way more charging than we need and we often wind up manually turning the alt off. Unfortunately we motored nearly 45 miles today, due to glass like conditions, and the entire time the alt was off...

I try to leave our bank at less than 80% SOC or less when we leave the boat. Solar is also turned off when we are not there.

[b_rodwell]

I am about to set up lithium house batteries for my Lagoon 400. One issue I am not clear on is should I keep the existing lead acid starting batteries? Some of the other parameters of my situation are:

. I am planning for 1000 watts of solar panels
. I do not plan to have a genset
. I do plan to have a Honda eu2000i generator
. I do plan to have an independant starter pack (probably lithium again)
. My context is full time liveaboard cruising mostly on the pick
. I would expect to be monitoring the state of my lithium batteries every day
. I was thinking of 400 amp hours of lithium storage but I have not finalised that value yet.

I know that the lithium batteries could be used for starting. If I have only lithium my set up is simpler. I don't have one charging regime for the lead acid batteries and another for the lithium house batteries.

What do you think?

Brian

[Zanshin]

Brian,

I would keep at least one good-sized lead-acid battery somewhere aboard, preferably as the starting battery. This is just because all Lithium cells/batteries/banks have intelligence built in to prevent damage. This can turn off the battery and render it unusable until reset/recharged and I would like to have an option to accept potentially damaging a battery if I really need to use it - like starting an engine when absoluely required.

[Lagoon4us]

Not sure Zanshin what you mean by intelligience built in? We have no BMS and simply check/manage each day as we do our fuel/water etc..

A BMS is not required for four cells.

A lead acid start bank is a good safe way to go, it's worked well for us all season.

Cheers

[roetter]

Originally Posted by Lagoon4us

Not sure Zanshin what you mean by intelligience built in? We have no BMS and simply check/manage each day as we do our fuel/water etc..

A BMS is not required for four cells.

A lead acid start bank is a good safe way to go, it's worked well for us all season.

Cheers

Zanshin may mean the 'intelligence' that a battery monitor has. I.e. 'knowing' when the batteries are full (low amps going in and over a certain voltage), accumulating the amps going out over time am showing them as Ah out, calculating percentage of charge and estimate time remaining, utilizing Peukert and so on.
That is just a 'simple' battery monitor that everybody, lithium or not must have.

[roetter]

New install:

I just installed 360 Ah Winston cells. More on this adventure later.
My question is regarding alternator not charging. I have a Volvo B2-40 with 105A Mitsubishi alternator.
After install the installing was about 50 Ah down, started the engine at the dock out of gear running about 1200-1400 RpM. From memory the alt started charging at 100 amps going quickly to 90+A. With the voltage coming up and probably temperature protection coming in it dropped to 70-80 A. There it stayed until voltage when to 13.88V. This is where my note begin.
+ 10m 13.99 V 48A
+15m. 14.09V 33A
+25m. 14.20V 10A
+30m. 14.21V 6A

I stopped and know that I should install a high voltage cut off solenoid or switch to prevent long term plating damage.

Next day I went on a trip to test under real condition. Morning about 90 Ah down ( had fridges on high with shore charger off)
Motored about 45 min then sailed for 4-5 hours. Started engine as no wind. After 30 minutes initially at 2200 RPM then at 1800 Rpm I get a battery alarm on the engine control panel. The BMS shows 8 amps flowing out of the battery, Ah's are -5 at 13.3V clears the alt is not producing output. I feared I fried it or the split diode overheated, which I had replaced 2 years ago for the same reason. I had increased my LA capacity from 440 to 710 about 12 months before the split diode died.

Next morning I went to check. Started the engine and the BMS shows 78A going in with about 90Ah down.

My question:
Does the Mitsubishi 105 A alt have a temperature protection that switches it completely off?
Why does it output 'only' 78A and not 100A as it was cold now? It did before. Any change I fried one of the 3 rectifying diodes in the Alt? But that should cut down even more to around 65A.

I am now about 1.5 hours into today's trip running 2200 RPM.
14.1V at 30 A , BMS showing 0.1 A down. It is a Xantrex LinkLite and I have not gone through the parameters to adjust to the different batteries, except for capacity.

[roetter]

Additional information

I left the engine room panel next to the alternator off for more cooling. Unfortunately, I do not have my IR temperature meter with me.

The split diode is a Cole Hearse for 140A alternator. Could it have a heat cut off? I just put me clamp-on amp meter on the cables there in predation to disconnect the house charge cable there in a few minutes. I burned my hand on the housing just touching it briefly.