Ideal Drop-in Lifepo4 Battery Purchase Strategy

[ThereAndBack]

This thread is a circus. I don't even know what is going on in here.

[SOLAR SUPPORT]

Since the subject I am trying to explain is scattered, I will try to collect it.

There are unnecessary spaces in the drop-in Lifepo4 batteries, which are manufactured in LA standard sizes. I explained this with the information I have given below. If your boat is not very big and the volume occupied by the batteries is important to you, pay attention to this issue.

200 Ah LA-Lifepo4 std. battery volume is 27.2 liters.
Dimensions: 522x240x219 mm.
Occupy: 200/27.2=7.35 Ah/lt

100 AH LA-Lifepo4 std. battery volume is 12.14 liters.
Dimensions: 330x172x214 mm.
Occupy: 100/12.14=8.23 Ah/lt

300 Ah diy Lifepo4 battery volume is 16.1 liters.
Dimensions: 346x180x245 mm.
Occupy: 300/16.1=18.63 Ah/lt

[pcmm]

Originally Posted by Baronkrak

Or in my word, non-sense.

You might say non-sense but so is stamping your feet and claiming the sky is green. Keep discharging your FLA's to almost 100% and see how many seasons you get out of them.

I see it all the time people at the marina and club complaining that their batteries only last a couple of seasons. But these are the same ones that pull their batteries down to 10v (ish) before switching to battery 2 (yes people still do that)

[Baronkrak]

Originally Posted by pcmm

how many seasons you get out of them.

More than 5 years.

Originally Posted by pcmm

only last a couple of seasons.

The warranty is 24 months from date of purchase.

[pcmm]

Originally Posted by Baronkrak

More than 5 years.



The warranty is 24 months from date of purchase.

On some batteries, not all. Warranties vary a lot for batteries Some are 12 months, some 2, 3, 5 years.

I'm gonna call BS on you draining your batteries fully down to 10.5v regularly and still getting 5 years out of them. You have miracle batteries!

[Baronkrak]

Originally Posted by pcmm

You have miracle batteries!

No, just good quality batteries and care to use them appropriately.

I get 100Ah of a 100Ah battery and some time more.

[pcmm]

Originally Posted by Baronkrak

No, just good quality batteries and care to use them appropriately.

I get 100Ah of a 100Ah battery and some time more.

What brand of Batteries do you have??... I want some. I have yet to see FLA's that can do this... And I was in the Industry

[s/v Jedi]

Originally Posted by Baronkrak

No, just good quality batteries and care to use them appropriately.

I get 100Ah of a 100Ah battery and some time more.

[Baronkrak]

Originally Posted by pcmm

What brand of Batteries do you have??... I want some.

The brand is unimportant but the specifications provided by the battery manufacturer are.
For example the specifications given for a T 105 Deep-Cycle Flooded battery are.

Capacity Minutes
@25 Amps 447
@75 Amps 115

Capacity Amp-Hours
5-Hr Rate 185
10-Hr Rate 207
20-Hr Rate 225
100-Hr Rate 250

[Chotu]

Originally Posted by Baronkrak

The brand is unimportant but the specifications provided by the battery manufacturer are.
For example the specifications given for a T 105 Deep-Cycle Flooded battery are.

Capacity Minutes
@25 Amps 447
@75 Amps 115

Capacity Amp-Hours
5-Hr Rate 185
10-Hr Rate 207
20-Hr Rate 225
100-Hr Rate 250

As a long time user of Trojan T105, that’s at 6 V. Each individual battery.

But are you really claiming to get approximately 220 amp hours out of a Trojan T105 at any voltage pairing?

[Baronkrak]

Originally Posted by Chotu

As a long time user of Trojan T105, that’s at 6 V. Each individual battery.

But are you really claiming to get approximately 220 amp hours out of a Trojan T105 at any voltage pairing?

Manufacturer specification:
Capacity Amp-Hours
20-Hr Rate 225

Define: “voltage pairing".

[pcmm]

Originally Posted by Baronkrak

Manufacturer specification:
Capacity Amp-Hours
20-Hr Rate 225

Define: “voltage pairing".

You do realize that is from fully charged to fully dead to get that ah. and even Trojan warns not to go past 80% or reduced life will be the result (AKA damage)

[s/v Jedi]

Originally Posted by pcmm

You do realize that is from fully charged to fully dead to get that ah. and even Trojan warns not to go past 80% or reduced life will be the result (AKA damage)

It’s called Dunning-Kruger effect, not much can be done.

[Captain Bill]

Originally Posted by pcmm

This is of course incorrect. a 100ah FLA battery can safely only provide at max 50ah. You can actually get 100ah out of a typical LifePO4 battery ( though its really best to take 80-90ah out of it. Regularly getting 100ah out of a FLA is how you end up with users complaining their FLA's only last them a couple of seasons.

The big disadvantage I see with some of the dropin LifePO4 batteries is the BMS's. The cheaper ones often have charging limits half of their discharge. Often you will see a 100amp BMS only having recharge of 50amps. that's not much in a 400ah pack. Plus I think 100Amps is pretty low for most cruisers. Just running your windlass can easily pull 100amps when its working hard.

What is really to be determined is if these LifePO4's really last as long as they say. Which you need in order to get the value out of them for the price.

I really don't see the 50amp charging rate as much of a problem. Since I have three batteries in my house bank they can easily accept 150 amps of charging. Most of the time my charging is done by solar and it's unusual for me to get more than 40 amps going into all three batteries anyway. In fact my batteries are pretty close to fully charged by the time the sun is high enough to generate 40 amps out of my 640w of solar panels. Would you really only have one battery in your house bank so that you are limited to 100amps of draw? Given that drop in LifePO4s depend on an active electronic system (BMS) the idea of having a single battery in a house bank is not a very wise idea. The Chin batteries I have are indeed limited to 100amps continuous, but 285 amps for 5 seconds. Since I have a 300 amp fuse on the bank drawing 855 amps is definitely going to blow the fuse. How long do you run your windlass? I can haul in my entire 200ft of chain in about 3 minutes. Even if it was drawing 100amps the whole time it would only be using about five to 6 amp hours. With LiFePO4 that is lost in the noise. It's not like LA when it takes a long time to get that last 5 amp hours back into the batteries. I don't know how long these batteries will last, but even with buying a new solar controller and a dc-dc charger they broke even with Lifeline AGMs and I get the convenience of LiFePO4. Worrying about getting the AGMs to 100% when in Northern latitudes is a thing of the past. When in Maine last summer it was really nice not to have to run the genset for hours once a week just to top the AGMs. If you are just comparing value based on purchase price then you have a hard time justifying anything over flooded LA. The Value in LiFePO4 is in the convenience and ease of management, not to mention fuel savings and wear and tear on the genset.

[Baronkrak]

Originally Posted by pcmm

You do realize that is from fully charged to fully dead to get that ah. and even Trojan warns not to go past 80% or reduced life will be the result (AKA damage)

Fully dead?
So they are making a false claim?