Lifepo4 upgrade?

[Chotu]

Thanks for the input, Grit. I have always hoped you avoid respond to this one because if anybody’s an expert on doing temperature sensitive things in the cold it’s you. Ha ha.

I guess if I do upgrade eventually to the lithium, I will have to move them inside. Maybe I will take that into account when putting together my electrical control panel locker. I will leave a spot for a lithium battery to go.

[Chotu]

Well, the decision is now made. I’m getting these LIFEPO4 batteries.

The reason being that I do have to run more electrical things now and I would have to buy a couple extra Trojan batteries anyway. For the price difference, a fresh lithium bank would be smarter.

For cold-weather? Screw it. I will mount them inside as has been suggested. I will just change the design of the boat a little bit.

[PaulCrawhorn]

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.

Chemistry is chemistry.

Winston's products are fantastic, but from the beginning Winston Chung Hing Ka touted his addition of Yttrium to the cathode material as if it radically changed the nature of his cells (Thundersky at the time / Sinopoly now, also a great maker )

All those I trust have always been skeptical of those claims.

Treat them all the same as you would CALB, CATL, A123, etc

I agree lots of shoddy crap out there too, but the need to slow/stop charging as the cells get cold does not change with greater QA

[PaulCrawhorn]

Originally Posted by dlj

So below -4 you can't even use them?

Discharging is not a problem just efficiency / capacity falls as resistance rises.

It's only during charging that the cell internals must be warm to avoid actual damage.

[Phil_Fr17]

Maybe, but there is research (apart from Winston) done on yttrium and its effect on the lithium battery that is not trivial. Only Winston has the 'recipe' and he keeps it for the moment, which is normal, but the research labs are trying to understand the why and how of adding this rare earth in lithium chemistry.
Nobody knows exactly what Winston Chung did or in what proportion or what state or process he uses Yttrium, that's what other researchers are trying to figure out.
Personally, I have cells of this brand, I have never taken precautions about the temperature in winter, often negative temperatures, the wintering being done at a load varying between 50 and 70% of SOC.
I'm also not saying that these cells are perfect, that doesn't exist, but looking at the characteristics of other manufacturers, there is a difference in the temperature of use.
However, I also advise CALB, CALT and a few others to avoid any price-only purchase on Alibaba (for example).

[goboatingnow]

Originally Posted by Phil_Fr17

Maybe, but there is research (apart from Winston) done on yttrium and its effect on the lithium battery that is not trivial. Only Winston has the 'recipe' and he keeps it for the moment, which is normal, but the research labs are trying to understand the why and how of adding this rare earth in lithium chemistry.
Nobody knows exactly what Winston Chung did or in what proportion or what state or process he uses Yttrium, that's what other researchers are trying to figure out.
Personally, I have cells of this brand, I have never taken precautions about the temperature in winter, often negative temperatures, the wintering being done at a load varying between 50 and 70% of SOC.
I'm also not saying that these cells are perfect, that doesn't exist, but looking at the characteristics of other manufacturers, there is a difference in the temperature of use.
However, I also advise CALB, CALT and a few others to avoid any price-only purchase on Alibaba (for example).

There’s huge amounts of research going on on newer electrolytes etc and specific anode and cathode configuration. The Yttrium debate has moved well forward

[Chotu]

Question. I have been looking at a single lithium battery with 400 amp hours at capacity. That’s not a good idea is it? I should break it down into two smaller ones shouldn’t I? In case one goes bad?

Is anyone else running one single lithium battery?

[PaulCrawhorn]

Do not use Drop-ins is my reco, you want to be able to get to individual cells for testing / monitoring / maintenance, also replacing the BMS when needed.

Plus having more of a say in the quality / longevity of your cells.

There are plenty of rigs using 300+Ah cells.

Going much bigger in a mobile context, some say susceptible to damage from shock, boats get slammed by waves.

Yes redundancy can be a good idea if cruising to more primitive locations, so 2P at least

[PaulCrawhorn]

The only issue here is CHARGING near or below freezing, and at what C-rate?

Originally Posted by Phil_Fr17

Personally, I have cells of this brand, I have never taken precautions about the temperature in winter, often negative temperatures, the wintering being done at a load varying between 50 and 70% of SOC.
I'm also not saying that these cells are perfect

Again Winston cells are indeed top notch, that is not disputed.

> there is a difference in the temperature of use

Says who?

The only "evidence" that Winston cells can be charged at higher C-rates, or at all at a lower sub-zero temp

without reducing longevity, or even rendering scrap

is words according to Winston, printed on their data sheet.

AFAIC that is not sufficient for me to risk treating them any differently from other quality LFP cells.

But you do you, just don't claim what they say is objectively true!

"Extraordinary claims require extraordinary evidence"

[SV-Viento]

Originally Posted by PaulCrawhorn

Do not use Drop-ins is my reco, you want to be able to get to individual cells for testing / monitoring / maintenance, also replacing the BMS when needed.

This appears to be consensus thought on CF but it appears to me its generally in the context of lower quality drop in options. What about higher end drop ins from eg Mastervolt? They have what appears to me to be a well thought out system approach that includes “drop in” units.

[Chotu]

Originally Posted by PaulCrawhorn

Do not use Drop-ins is my reco, you want to be able to get to individual cells for testing / monitoring / maintenance, also replacing the BMS when needed.

Plus having more of a say in the quality / longevity of your cells.

There are plenty of rigs using 300+Ah cells.

Going much bigger in a mobile context, some say susceptible to damage from shock, boats get slammed by waves.

Yes redundancy can be a good idea if cruising to more primitive locations, so 2P at least

OK. But if I have to have some complicated external battery management system, I won’t be doing this. Drop ins are basically the only way I’m going to do it. Just my personal preference. I don’t have tire time to fuss with anything complicated.

I don’t think I’m going to worry too much if it doesn’t last 15 years. If it doesn’t, I’ll just get a new one.

So I will get a pair of 200 amp our lithium batteries then. Instead of the single 400. Just in case something goes wrong. Don’t want to be caught with no power whatsoever.

And yes. I enjoy going to very remote places.

[PaulCrawhorn]

Originally Posted by SV-Viento

What about higher end drop ins from eg Mastervolt?

These are complete systems, the likes of Lithionics and Victron also, you pay for integration / design advice, not just order a single unit from Amazon / Ali / eBay.

The term Drop-in does not apply to these at all afaic.

To the extent the drop-in vendors start adding connections to outside devices for monitoring & control at the per-cell voltage level, allow for replacing the BMS or using other balancing tools etc

We will need an additional qualifier, like "smart drop-in" or something.

Dropin by itself means a closed system.

[Chotu]

Another kind of stupid question I guess. I have a pair of 60 amp outback MPPT charge controllers. If I get a pair of batteries with internal BMS, is that going to be an issue? I would hook them in parallel, and then hook both chargers together onto both batteries in parallel also? Everything in parallel?

Would I get twice as much power on a cloudy day if I have both controllers going at the same time? I understand this in terms of lead acid batteries, but I really don’t get it when it comes to feeding power to a battery management system that then charges the batteries.


To be clear, these are drop in batteries. Black box. Internal BMS, internal everything. From the outside they will feel just like lead acid batteries. But with better performance.

[Phil_Fr17]

@Paul, I wrote above : "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."


But I NEVER believe a commercial publication not verified by tests and reliable sources.
I can't put my batteries in the freezer either, and anyway, my freezer can't go down to -45°C, so... I consider that from the operating temperature range they give, my -10°C reached in winter are in the zone of comfort and use.
We're not going to spend our time cutting ass hairs in four either...


Again, and here I'm addressing Chotu, using quality cells (not pre-made or "drop-in" 12 volt batteries, - I'm not sure with the correct word, I'm french -) would be the best thing to do.
200Ah cells, for example, for weight and transport reasons, and put in parallel to have a cell equivalent to 400Ah.

[PaulCrawhorn]

Originally Posted by Chotu

Drop ins are basically the only way I’m going to do it

Get the details from the vendor or maker first

as to how many of their multi-cell units they allow to be paralleled.

And most especially if you are going to higher voltages and want to serial them, IMO a very bad idea.