Lifepo4 upgrade?

[sailingharry]

Originally Posted by Chotu

So many people have converted to these batteries. I can’t believe they’re so difficult to use.

I haven't yet converted, so I am just an armchair quarterback. But your point is exactly what leads to many of the heated discussions on this forum. They are not terribly difficult to use, but they most certainly require attention and carefully managed systems. Once configured properly, they should be nearly set and forget, but they are never truly forget. There is no doubt that there is a significant learning curve!

Where trouble begins is when people drop them in and forget them.

I am fairly convinced that the risks associated with forgetting are only cost risks and not safety risks. You screw up, you buy a new battery. But there are no morgues involved! (Recognizing of course that a suddenly failed battery in a less than ideal location does present collateral risks).

[Chotu]

Originally Posted by sailingharry

I haven't yet converted, so I am just an armchair quarterback. But your point is exactly what leads to many of the heated discussions on this forum. They are not terribly difficult to use, but they most certainly require attention and carefully managed systems. Once configured properly, they should be nearly set and forget, but they are never truly forget. There is no doubt that there is a significant learning curve!

Where trouble begins is when people drop them in and forget them.

I am fairly convinced that the risks associated with forgetting are only cost risks and not safety risks. You screw up, you buy a new battery. But there are no morgues involved! (Recognizing of course that a suddenly failed battery in a less than ideal location does present collateral risks).

I see! I have never read those threads before. I know they are long and winding. But I can see where there would be a lot of controversy. Pros and cons.

I know that when it comes to batteries I am a set it and forget it, water it once a month kind of guy. I’m not going to want to pay attention to my batteries. Especially if it starts getting cold out. I can imagine all of the stress and anxiety I would feel at 40°F. Thinking to myself what if it dips below freezing tonight and I destroy my $1600 battery?

No thank you. That’s definitely not the kind of stress I need in my life.

My boat has been designed from the start to have the most simple systems possible. This is an added layer of complexity I don’t think I’m willing to take on.

[sailingharry]

One other comment about the low temperature end. A proper BMS will monitor the battery temperature and disconnect charging sources at low temperature. Of course, that means you don't get charged. But the important thing is that it is set and forget. The temperature drops to 25 overnight, the charge sources are disconnected, and at 10:00 when the temperature comes up, they start charging.

Of course, this falls apart with a common charge/discharge bus. But even that can be designed out.

[Chotu]

Originally Posted by rslifkin

Perfect! Big upgrades always go better when you have time to figure it out slowly and aren't under the gun to get something working.

Agreed. Keeping the current systems as the lightest approach without switching to LIFEPO4.

And definitely I agree. This is not a good time to be trying to figure out a new system. It’s also always better to just use something for a while and then see how you might want to improve it if at all.

I certainly will have some higher power demands coming as the water maker starts coming online and stuff. But maybe I can just run that during the day.

I did something pretty unique with my electrical system. Different than most people.

To save weight, I kept the battery bank fairly small.

I know my own usage patterns. Running a water maker? That’ll be in the middle of the day. Some microwaving? Middle of the day. Any other chores and tasks that I use battery power? Middle of the day.

At night there is nothing but The LED anchor light, the LED lights to light up the deck a little bit, and a deep freezer. Regular old homestyle freezer. And of course the electronics that run the propane refrigerator. All of that is easily managed overnight for a couple days with my current set up.

And if I get into a deficit from too many clouds, I have generators.

So I guess I will stick with this right now.

[sea1ljs]

you might find this helpful

https://youtu.be/EaiwxDUY9ho

[Maine Sail]

Originally Posted by dlj

Battleborn publishes -4F to 135F. You'd have to see what the specific batteries you're looking into state.

-4 is "use" as in discharging. Charging is 32F and up...Battleborns BMS physically disables charging at 32F..

[PaulCrawhorn]

There is no "temperature compensation" with LFP, as with lead.

Remember you do not want to sit at or even get to 100% Full if you want good longevity

as it is opposite for lead.

Having your pack configured as easily removed sub-packs has many advantages

just take them home in wintertime, let cheap lead remain for the season.

[goboatingnow]

Originally Posted by PaulCrawhorn

There is no "temperature compensation" with LFP, as with lead.

Remember you do not want to sit at or even get to 100% Full if you want good longevity

as it is opposite for lead.

Having your pack configured as easily removed sub-packs has many advantages

just take them home in wintertime, let cheap lead remain for the season.

Why unless you have sustained freezing temps your bms should control charging when the temp is high enough

[Chotu]

Originally Posted by PaulCrawhorn

There is no "temperature compensation" with LFP, as with lead.

Remember you do not want to sit at or even get to 100% Full if you want good longevity

as it is opposite for lead.

Having your pack configured as easily removed sub-packs has many advantages

just take them home in wintertime, let cheap lead remain for the season.

Gotcha. I didn’t know about keeping them not fully charged either. That could be problematic because I have a lot of solar and my batteries sit at full charge all the time.

I don’t have a home. At least any type of building on land to bring these to. I expect my boat to work in all weather.

[Phil_Fr17]

Originally Posted by PaulCrawhorn

No LFP should be charged at all below freezing.

In HOT temps they can be fast charged safely at high current

In sweater weather definitely stay under 0.4C

As you approach 40°F stay well under 0.1C.

Being conservative will extend lifespan.

Taking chances can render scrap, and even increase risk of cells shorting out.

There are dropins with internal heating circuits, but silicone heating pads with built in thermostat cutoffs are not expensive.

If you insulate a box, make sure it can be vented when things get hot again

You talk about LFPs in general in your advice list. And I would tend to think particularly of the LFP batteries sold by Aliexpress or other 'manufacturer' who do not give the internal characteristics of their products.

The Winston manual does not say the same thing about the temperature of use, whether charging or discharging since it speaks of -45°C to +85°C.
Of course, these are extremes, but it gives a comfortable leeway.

[Chotu]

Originally Posted by Phil_Fr17

You talk about LFPs in general in your advice list. And I would tend to think particularly of the LFP batteries sold by Aliexpress or other 'manufacturer' who do not give the internal characteristics of their products.

The Winston manual does not say the same thing about the temperature of use, whether charging or discharging since it speaks of -45°C to +85°C.
Of course, these are extremes, but it gives a comfortable leeway.

This is an interesting development in the thread in general.

I did see some low temperature LFP batteries specially made for industrial purposes.

Does anyone know of a consumer best brand that is reasonable price like these others that works at low temperature? That could change the entire thing.

[GRIT]

There are some interesting posts in this thread. I don't want anyone thinking of changing to Lithium to get turned off by what some folks have said here, so I'm going to give you my opinion too.

We installed CALB Lithium cells a year before launching the boat, and we've been living aboard since she launched in the fall of 2019. Our first winter was spent in Halifax, NS, with temps down to -20C.

We have CALB cells, and a REC Bms, and have installed the "battery" inside the boat's living area, so it experiences the same temps we do.

I don't know if you can install them inside or not, but if there's any chance you'll be in freezing temperatures, I'd suggest that this is the least worrisome place to put them. They don't outgas like Lead does, so we don't worry about them affecting air quality.

I'm not going to get into the nitty gritty about how we have our system set up, but we have not balanced the cells since the installation 4 years ago, and the packs are all within 3 thousands of a volt. ( I checked just now, for this post.) The reason I mention this, is because I've read of many folks using their batteries without a BMS, and for low charging/discharging uses like boat house banks, I can see why this would work. You should still have over/under charge protection, but otherwise I'd not fret too much. That's all our BMS has been doing since we installed it. No balancing, just "monitoring voltage", and acting as a safety fuse for over/under charge.

We don't have a maintenance schedule for our lithium bank. Solar and wind are set to 13.6 volts, then shut down. ( 13.6v is the cell Manufacturer's suggested "float" level). Through testing I found that charging (via solar and wind) to 13.6 volts, brings the cells to roughly 98% fully charged.

Solar charging voltages are regulated by Victron solar regulators, and the wind is turned on/off with a victron 712, but a normal controller set to 13.6v would do the same. That's the same equipment many folks use on their lead banks.

All this to say, lithium isn't a big deal to use, and I haven't done any maintenance to them, other than to check the connections once. Every once in a while I look at the BMS to see what the individual pack voltages are, just to reassure myself that everything is copacetic, but that could be done with cheap digital voltage displays from Amazon too.

We've been pleased with our lithium bank, and mostly because we don't have to think about it.


Cheers.
Paul.

PS
When I say low charging/discharging, I mean normal house bank use. That includes running the vacuum and sander, which takes about 70 amps, and the toaster takes 100 amps. Those are low amperage discharges for lithium (on a 700AH bank), only about 0.1C. Traction use (cars) is a high charge/discharge use. Using Lithium on boats is not a high stress use for this technology, which is why many folks get away with using lithium without a BMS.

[Phil_Fr17]

I agree with GRIT too, CALBs (excellent brand and manufacturer) are an excellent choice, especially in our use.
Calt, CALB, Winston, Synopoli are among the brands whose reputation for seriousness is second to none. The price is higher, but so is the quality and overall comfort, not to mention the use.

If I gave the information of admissible temperatures by the Winston cells, it is only to answer directly the primary question of Chotu concerning the low temperatures, not to say that only these cells are valid.
Indeed, the LFPs are more comfortable in a temperate environment such as under an aft berth and can be placed under these berths without any problem since there is no harmful gas emission or extreme temperatures harmful to the batteries.
The other advantage being not to position them (if possible) in the engine room precisely because of the extreme cold temperatures in the event of wintering without anyone on board and too hot when the engines are in service.
I installed several LFP batteries, so a park on a catamaran that its owner made himself, and for him, I told him right away to house the batteries in the living area, either in the center of the boat, or in the floats under the aft berths for reasons of wintering and high temperatures when the engines are running. It suffices to adapt the diameter of the wiring according to the length of the cable to overcome the distance, the remoteness.


I also agree 100% on the use that we make of these cells or lithium batteries in boating, always at low charge and discharge, which means that if they have been correctly balanced at the start, just before installation , the risk of imbalance is almost nil (which does not prevent you from checking from time to time!).

Based on this observation, the BMS are not useful (I don't have any), and if necessary, if you want to have some, they are there more to avoid a possible deep discharge, and especially in the case of BMS with Bluetooth , to have all the information on your phone, which avoids a dedicated screen, and therefore additional costs.

[dlj]

Originally Posted by Maine Sail

-4 is "use" as in discharging. Charging is 32F and up...Battleborns BMS physically disables charging at 32F..

Thanks for the clarification Rod.

So below -4 you can't even use them? That's good to know...

What happens on the high temp side? Same sort of thing? At what temp do you stop being able to charge them?

dj

[Chotu]

Originally Posted by dlj

Thanks for the clarification Rod.

So below -4 you can't even use them? That's good to know...

What happens on the high temp side? Same sort of thing? At what temp do you stop being able to charge them?

dj

Many of them, it’s 113 Fahrenheit. You can’t charge above that. But that’s OK because you don’t run into that. Not very often.