Is a new-build without lithiums just plain stupid???

[sunchaser]

How do you guys who have lithium batteries installed getting around the ambient temperature concerns? In other words, are you installing them in engine rooms, lazarette, or in the living space?

Heat doesn't seem to slow down the E cars in AZ. ER heat in most NA boating locations seems manageable if outside air is freely circulated. Location of course is vessel dependent but can easily be dealt with on a new build.

On the near horizon are Lithium Sulfur batteries. Testing and development work to-date has shown a temperature range of -20 to 140F with 3X the energy density. No oxygen molecules are used thus fire concerns nil. But commercial readiness is likely 5+ years off.

 

[Mako]

There’s always some newer and better coming on the horizon. Drives me crazy with my expensive MacBook, and now even my television seems obsolete after a couple of years

 

[sbman]

Another aspect of LiFEPO4 that is not often considered is charge efficiency at higher SOC numbers. If you put Lead Acid of any kind, the 'finishing charge' from 80-100% is as little as only 50% efficient. If you have a large enough bank you operate in the 70-100% range all the time. With LiFEPO4 the charge efficiency is closer to 95% throughout the range of SOC.

If your build includes a heavy dependence on Solar charging, you can nearly double the amount of captured power in the charge process with Lithiums over Lead Acid in the same size panels.

 

[Mako]

@Sbman, I believe that’s about right. One strange limitation about lithium however is that they are best stored long term at 80% or less, but not fully charged.

Not sure what time frame “long term” would be. But let’s say for example it’s one week. So you would need to have a charge controller smart enough to discharge the battery down to that level after sitting for a week. Or when sitting for a month, would need to stop solar acceptance at that set point.

Is such an animal common amongst charge controllers for lithiums?

 

[sbman]

@Sbman, I believe that’s about right. One strange limitation about lithium however is that they are best stored long term at 80% or less, but not fully charged.

Not sure what time frame “long term” would be. But let’s say for example it’s one week. So you would need to have a charge controller smart enough to discharge the battery down to that level after sitting for a week. Or when sitting for a month, would need to stop solar acceptance at that set point.

Is such an animal common amongst charge controllers for lithiums?

I just installed a bank of 200aH 'Drop in' lithiums in a GB42. The original Sterling Pro Charge Ultra wasn't up to this kind of a task, using old school Pb based algorithms with multiple hours of absorb charge even on the 'lithium' setting.

The Sterling was replaced with a Victron Skylla IP-65 charger (70 amps) that has lithium features built in and is tunable for just that purpose. If it detects several days of shore power, it will drop voltage to a 'storage voltage' automatically and get the batts down to the 70-80% that you want them at.

 

[Helmsman]

Heat doesn't seem to slow down the E cars in AZ. ER heat in most NA boating locations seems manageable if outside air is freely circulated. Location of course is vessel dependent but can easily be dealt with on a new build.

On the near horizon are Lithium Sulfur batteries. Testing and development work to-date has shown a temperature range of -20 to 140F with 3X the energy density. No oxygen molecules are used thus fire concerns nil. But commercial readiness is likely 5+ years off.

Battleborn lists their 100 AH deep cycle as operable from -4 F to 135 F, which would seem ok. However in their FAQ’s it is stated that the battery quits accepting a charge at 25 F and starts again at 32 F.

The reason for the question is that many installs posted online show the batteries being installed under settees in the salon, or under beds. That brings up cabling issues with longer runs, etc.

 

[Simi 60]

@Sbman, I believe that’s about right. One strange limitation about lithium however is that they are best stored long term at 80% or less, but not fully charged.

Not sure what time frame “long term” would be. But let’s say for example it’s one week. So you would need to have a charge controller smart enough to discharge the battery down to that level after sitting for a week. Or when sitting for a month, would need to stop solar acceptance at that set point.

Is such an animal common amongst charge controllers for lithiums?

Battleborn say "fully charged" then store

With Battle Born Batteries, the winterization process is simple: fully charge the batteries to 14.4 volts and either disconnect them or engage your disconnect switch within your system to prevent a parasitic load drain during storage.
https://battlebornbatteries.com/faq-how-to-winterize-your-batteries/

But they are cylindrical cells
Prismatic may be different

 

[vancouvertechie]

This is a good topic for discussion. We just purchase our 44' Tolly and I replaced all 8 6V Trojans with 8 6V AGM batteries to keep it simple. They are wired in series and parallel. Our inverter/charge controller has the correct charging parameters for Lithium, but the tech is still new.

I spoke with my surveyor to get his thoughts and with the local boatyard electrician. Both of them suggested to go with AGM and wait a couple of years for the price to go down and the tech to get better.

My plan is to install 800 watt solar panel system with 4 separate charge controllers, so if one panel is shaded the others will not be affected. We plan to either anchor or to be hooked up to a mooring ball for a couple of days at a time.

Either way this is all good stuff!

VT

 

[Art]

This is a good topic for discussion. We just purchase our 44' Tolly and I replaced all 8 6V Trojans with 8 6V AGM batteries to keep it simple. They are wired in series and parallel. Our inverter/charge controller has the correct charging parameters for Lithium, but the tech is still new.

I spoke with my surveyor to get his thoughts and with the local boatyard electrician. Both of them suggested to go with AGM and wait a couple of years for the price to go down and the tech to get better.

My plan is to install 800 watt solar panel system with 4 separate charge controllers, so if one panel is shaded the others will not be affected. We plan to either anchor or to be hooked up to a mooring ball for a couple of days at a time.

Either way this is all good stuff!

VT

VT - Smart move on 4 separate charge controllers. Your 8 batts "... are wired in series and parallel." Can you elaborate?

 

[rslifkin]

VT - Smart move on 4 separate charge controllers. Your 8 batts "... are wired in series and parallel." Can you elaborate?

For 6v batteries in series / parallel to get 12v, you'd typically take pairs of batteries in series to get 12 volts, then parallel the pairs.

 

[Codger2]

For 6v batteries in series / parallel to get 12v, you'd typically take pairs of batteries in series to get 12 volts, then parallel the pairs.

My Duffy comes from the factory with 2 banks of 6 volt batteries. (16 batteries in total.)Each bank of 8-6volt batteries is wired in series then the 2 banks are connected in parallel producing 48 volts.

 

[DDW]

The Sterling was replaced with a Victron Skylla IP-65 charger (70 amps) that has lithium features built in and is tunable for just that purpose. If it detects several days of shore power, it will drop voltage to a 'storage voltage' automatically and get the batts down to the 70-80% that you want them at.

I've not seen that in a charger, and I'm not seeing it in the Skylla manual either. It does drop to a storage voltage but without external loads you will have to wait a long time for them to self discharge to 70 or 80%, so you are effectively storing them fully charged. And then it is bumping them every week. I think longer term you could just set the bulk voltage down, discharge them a bit, and get somewhere below full.

What is really wanted is s true storage mode, which would actively discharge a full battery, then maintain it partially charged. The only one I've seen with this feature is the ePropulsion battery which uses the balancing bypass to discharge the battery to 60% if it hasn't been used in 20 days.

In what studies I have seen, the difference in life storing full vs half full isn't dramatic, but certainly measurable. It is this aspect of current LFP technology that makes them less than ideal for weekend or seasonal use boats.

 

[Art]

For 6v batteries in series / parallel to get 12v, you'd typically take pairs of batteries in series to get 12 volts, then parallel the pairs.

Understood - Thanks!

 

[Mako]

@DDW, if you think about it, the most common scenario would be the refrigerator running while away from the boat, with some solar array providing charging. So the load of the fridge would easily run the bank down to 80% within a week. Then the smart controller would maintain that level.

 

[twistedtree]

The Sterling was replaced with a Victron Skylla IP-65 charger (70 amps) that has lithium features built in and is tunable for just that purpose. If it detects several days of shore power, it will drop voltage to a 'storage voltage' automatically and get the batts down to the 70-80% that you want them at.

That's a nice feature in the Skylla IP-65 (I didn't know it was there), but is not in the Skylla I or Skylla TG.


With less smart chargers the simplest way to handle this is to utilize the float function in the charger, setting the voltage to hold the batteries in the 70% SOC range. The only down side is that when you unplug and untie and depart the dock, you will be doing so with 70% SOC rather than 100% SOC. But in most cases it's no big deal because whatever motoring you do will bring the batteries back up to 100% before you get to an anchorage and need to really use the batteries.

 

[DDW]

@DDW, if you think about it, the most common scenario would be the refrigerator running while away from the boat, with some solar array providing charging. So the load of the fridge would easily run the bank down to 80% within a week. Then the smart controller would maintain that level.

In that scenario you are cycling the batteries so there is no storage issue. My understanding of the chemistry is it has something to do with degradation of the cathodes. Cycling them periodically is supposed to be best, if not cycling then storage in the middle of the envelope somewhere, and worst is long periods fully charged.

For seasonal use you could set the charge voltages down in storage and back up when you get back. For weekend use that's too much trouble, and like TT says you start every weekend at less than full charge. Also you have to end the weekend not at 100% but at 70%, not easy to arrange.

Many of the Victron chargers have the storage feature (my Multiplus does). But if you look at the details of that it doesn't really help the problem.

It must not be that big a concern because adding firmware to a charger or BMS to do this is almost trivial.

 

[twistedtree]

For weekend use that's too much trouble, and like TT says you start every weekend at less than full charge. Also you have to end the weekend not at 100% but at 70%, not easy to arrange.

It's actually quite easy. We arrive back at dock fully charged from alternators, but when shore chargers come on they immediately go to float. It then works as Mako describes with house loads drawing the batteries down until the 70% SOC range, at which point they reach the float voltage and the chargers pick up the loads and maintain things around 70%. It can then stay like that indefinitely.



I say "around 70%" because it's not a precise number since LFP voltage is pretty flat across that SOC zone. In practice mine settle out anywhere in the 55-70% range, which is just fine.

 

[DDW]

So, you leave some loads on, and leave the shore charger set points low?

I'm due to replace the sailboat batteries (15 year old Lifelines now) but this point has me stuck. There are no loads left on at the dock, and it isn't plugged in, but maintained by solar. I could leave some small load on, and set the solar down to the right range. They won't get charged much in a daysail or weekend as the engine gets run only for a few minutes.

 

[Hippocampus]

There are no loads left on at the dock,


Wonder if there’s really “no loads”. Know on my prior boat even with everything on both AC and DC panels shut off there were various parasitic draws. The bilge pumps were directly from the lifelines but wouldn’t think that accounted for the draw as she was a dry boat and they didn’t run. Sure the parasitic draw was very low but sufficient that for the very rare occasions she was on the hard thought it wise to physically disconnected the bank in situations where solar wasn’t able to work like inside a shed. Would try to figure out what your boat draws when “off”. Probably not enough for the Li concern mentioned here.

 

[twistedtree]

So, you leave some loads on, and leave the shore charger set points low?

Yes, exactly. There are always loads. Inverter is always on, fridge, monitoring, cameras, etc.

I'm due to replace the sailboat batteries (15 year old Lifelines now) but this point has me stuck. There are no loads left on at the dock, and it isn't plugged in, but maintained by solar. I could leave some small load on, and set the solar down to the right range. They won't get charged much in a daysail or weekend as the engine gets run only for a few minutes.

That should work. Just be sure the solar can them keep up with whatever load you have or you will end up with a different problem. But it does seem a shame to create an artificial load....

 

[OldDan1943]

Here we go. No shore power. My case, 3X200 amp AGM house. 2X130 amp solar panels. Going to the yard.... bottom job,
The only load is fridge/freezer and bilge pumps. Bilge pumps never cycle.
So long as they dont park me in the shade, I am fine. Park me in the shade for a week, fridge turns sour.
I've gotten use to giving everything in the fridge to the dock crew. They sure do like me. Then taping the doors open.
When the boat is moved back to the slip, the start AGM is fine. Of course, with the thrusters on the house batteries, it is 'back and fill' until the house batteries have some charge.

 

[DDW]

Wonder if there’s really “no loads”. Know on my prior boat even with everything on both AC and DC panels shut off there were various parasitic draws. The bilge pumps were directly from the lifelines but wouldn’t think that accounted for the draw as she was a dry boat and they didn’t run. Sure the parasitic draw was very low but sufficient that for the very rare occasions she was on the hard thought it wise to physically disconnected the bank in situations where solar wasn’t able to work like inside a shed. Would try to figure out what your boat draws when “off”. Probably not enough for the Li concern mentioned here.

I hear ya - on the AT34, there are viper loads and mystery fuses and busses hidden all over the place. The only way to ensure no loads is to disconnect the battery terminal.

Different story on the sailboat, which was built for and by me so I'm pretty familiar with the wiring. There are actually a couple: the solar controller itself is a load, the bilge pumps are left on and the forward one that drains the forecastle occasionally runs for a few seconds (impossible to seal the halyard exits in the mast). So there is a very small parasitic load from the Water Witch pump switches. There is a 24V -> 12V charger for the engine start battery which has a small idle current. There is even a separate panel just for anything designed to be left on - most of which is turned off in its current service. I think under 50 mA draw if no solar.

The solar controller is completely programmable for set points so it shouldn't be a big issue to lower those.

 

[OldDan1943]

The AT34 has a "24 hour" switch..... make everything else dead and the last loads are bilge pumps. Shut the 24 hour switch off, EVERYTHING is totally dead.

 

[DDW]

Mine doesn't. There were hidden or clandestine fuses for CO detector, TV inverter, engine throttle controls, radio keep alive, and a few other things I've forgotten. Only finding and pulling these fuses would eliminate all draw. They are not switched by any switch.

 

[koliver]

The AT34 has a "24 hour" switch..... make everything else dead and the last loads are bilge pumps. Shut the 24 hour switch off, EVERYTHING is totally dead.

Like the "salesman switch" at the door of the Motorhome. If nothing works, check that switch. When leaving one in storage, turn it off.
May be time to put those switches on boats as a matter of course.
Except for the bilge pumps.

 

[OldDan1943]

Like the "salesman switch" at the door of the Motorhome. If nothing works, check that switch. When leaving one in storage, turn it off.
May be time to put those switches on boats as a matter of course.
Except for the bilge pumps.

and the CO detector