Lithium ion house battery bank disappointment

[Hans Etter]

I was refering to a bank of 5 200 amp batteries as well, that makes 1000 amp. I was told by the manufactur that they purposly underate their batteries and as I stated if you look at the stats they provided it says 3.2 volt nominal and 3.65 volt standard.

[contrail]

Originally Posted by Hans Etter

I was refering to a bank of 5 200 amp batteries as well, that makes 1000 amp. I was told by the manufactur that they purposly underate their batteries and as I stated if you look at the stats they provided it says 3.2 volt nominal and 3.65 volt standard.

Hans, I don't think you understand the math. If you connect in series, then you add all the voltages for your 13.2 volts. If you connect in parallel, you add all the amp hours, and get 800 amp hours, since you are using four at a time....Ok, you have a spare for another 200 amp hours. What you don't get to do is add both voltages and amp hours, to get your 13.2 volts and 800 (or 1000) amp hours. Sorry.

[UFO]

Originally Posted by contrail

Hans, I don't think you understand the math. If you connect in series, then you add all the voltages for your 13.2 volts. If you connect in parallel, you add all the amp hours, and get 800 amp hours, since you are using four at a time....Ok, you have a spare for another 200 amp hours. What you don't get to do is add both voltages and amp hours, to get your 13.2 volts and 800 (or 1000) amp hours. Sorry.

I think you mis-understand what Hans is saying.

I think he has 4S5P

[Hans Etter]

Originally Posted by contrail

Hans, I don't think you understand the math. If you connect in series, then you add all the voltages for your 13.2 volts. If you connect in parallel, you add all the amp hours, and get 800 amp hours, since you are using four at a time....Ok, you have a spare for another 200 amp hours. What you don't get to do is add both voltages and amp hours, to get your 13.2 volts and 800 (or 1000) amp hours. Sorry.

Each cell is 3.2 volt, there are 4 cells in each battery, there are 5 batteries, each battery is the nominal rating of 200 amp, 5 times 200 is 1000 amp. Beside the 5 batteries, I suggested keeping 1 EXTRA cell as a spare. one cell standard amp is 66 amp, max voltage is 3.65 volt for each cell. I can't bother explaining this anymore.

[senormechanico]

Originally Posted by Journeyman

44 & Senor,

Can you two post the AGM-to-LFE "before and after" installations with the battery manufacturer model numbers and number of batteries?

Thanks!
Jman

Before: 4 six volt Trojan flooded in series/parallel. 440 aH @ 12.6 volts.
After: 4 200 aH HiPower 3.2 volt LiFePo4 in series. 200 aH @ 13.2volts.

The difference is amazing in many ways.
Lighter weight (important in a multihull).
No corrosive off gassing or holes in clothing.
More output from the watermaker due to slightly higher voltage and almost no sag as they discharge.
Much faster charging, almost no taper in current. (well, a little when going only to 13.8v).

I would NEVER go back to lead.
I even bought a LiFePo4 start battery for my home's emergency generator.
It holds a charge for a year with no float !
Starts right up when I check it every six months to make sure it's gonna start if I ever need it. No float charger attached.

[daletournier]

I was researching Lithium two nights ago as I planned to do a battery upgrade in South Africa at the end of the year and was considering them.

Woke up yesterday morning and my bank was 10.8v!!!!! Developed a short during the night grrrrrrrr. Thus im installing new batteries today. Just purchased 8 trojans.

I'm completely sold on the advantages of lithium, not sure how anyone can argue against these advantages. But deep cycle trojans and equivalents still have a place. Cheap, very robust and you can have a simple system to built around them. I think the simplicity is important if you are in far and away places. They also take a kicking, I've had solar regs and a balmar reg fail in the past without damage to deep cycle 6v on my previous boat.

Like all batteries owner management is everything, my batteries have died prematurely due to PO not understanding charging regimes, I really should have replaced them earlier.

I expect to get 5-6 years (comfortably) out of this set for a cost of approx $1300usd (900a/hr).

Next time it will be lithium or the equivalent at the time.

[svGenesis]

Originally Posted by Hans Etter

Each cell is 3.2 volt, there are 4 cells in each battery, there are 5 batteries, each battery is the nominal rating of 200 amp, 5 times 200 is 1000 amp. Beside the 5 batteries, I suggested keeping 1 EXTRA cell as a spare. one cell standard amp is 66 amp, max voltage is 3.65 volt for each cell. I can't bother explaining this anymore.

Its because your explanation is confusing!

each cell is 3.2V, 4 cells in each battery, each Battery is 200Ah, 5 batteries!

I think the confusion is you posted 5 cells at 200Ah meaning a 3.2v curcuit and a spare cell, which would be 200Ahs.

[Thalas]

This has been a surreal thread for OP to ask about differences and when people point them out, he just flat out says it’s not true. Yes LiPo4 is more expensive up front. No, it’s not “needed” or for everyone. That said regardless of OPs “facts”...

LiPo4 IS half the weight.
LiPo4 IS double the density.
LiPo4 CAN be discharged 80% vs 50%
LiPo4 DOES have many more cycles making it more reliable and cost effective in the long run.
LiPo4 DOES maximize charging from limited solar as it isn’t more difficult to charge that last 10%.

As a mic drop, here’s a 5.5kwh DIY powerwall running residential AC in about the space of 8 AGM batteries at a lot less weight.

https://m.youtube.com/watch?v=epW0PXm2rq8

[StuM]

Originally Posted by Hans Etter

The spare refers to a cell of 3.2 volt, a battery is made up of 4, 3.2volt cells, the total number of batteries are 5 and besides those 5 that makes 1000 amp. I suggested keeping one extra cell as a spare.

If you don't know the difference between amps and amp hours nor how to calculate amp hours for serial and parallel connections, people here will rightfully take everything you say with a very large grain of salt.

Sure, 5 x 3.2V 200Ah cells wired in parallel will make 1000Ah at 3.2V, but nobody uses 3.2V circuits.

Wired in series to get a nominal 12V circuit. 4 x 3.2V 200Ah batteries will only give you 200 amp hours at 12.8 volts.

[StuM]

Originally Posted by Hans Etter

The float charge is stated for a battery at 13.6 volts float charge. Limited Voltage 3.65, standard current 66 amp, per cell, that comes out to 5 batteries times 4 cell times 66 amp=264amp times 5 batteries= 1320 amp.

That is totally nonsensical. You clearly don't understand what any of your previously quoted specifications mean.

[StuM]

Originally Posted by UFO

I think you mis-understand what Hans is saying.

I think he has 4S5P

Right you are, seems he's actually talking about 20 cells. Took a while to work out what he meant

[hzcruiser]

Originally Posted by Journeyman

Can someone tell me what all the excitement is about using lithium ion batteries as house batteries?

Every time I look at converting from my TPPL AGMs to LFP (or any other Li ion formulation) I come away disappointed.

[...]
We operate our 860Ah AGM bank from 90-30% state of charge which gives a usable 516 Ah. The bank occupies 5,750 cubic inches.

No one wants to force, push or even nudge you into LFPs. If you're happy with your AGMs or LAs just stay with them. It seems you've already made up your mind anyway, or as the saying goes:
"don't trust any statistics you haven't tampered with yourself".

For me, after the Marathon 70 AGMs were shot by the old charge controller I didn't want to lug another set of batts to the boat at 30kg each.

There are many other advantages to LFP, but also disadvantages, as mentioned.
Initial outlay being the foremost one compared to cheaper LAs or AGMs which then only last maybe 5 years (after which time my back won't be much better; so again, weight is an issue when replacing them).

Coming back to "stats", someone somewhere on CF proved that LFPs are then actually cheaper in the overall cost of ownership.

[Pete7]

Originally Posted by hzcruiser

Coming back to "stats", someone somewhere on CF proved that LFPs are then actually cheaper in the overall cost of ownership.

I really struggle with that.

Originally Posted by stormalong

At $7-8K I can replace my flooded lead acid bank six times over. They last at least 5 years so that is 30 years worth of batteries. My present set is eight years old and still going strong. To go Lithium I would need to replace my charge regulators. The weight and space savings are irrevelent on a 12 ton monohull. Why would I want to convert? Perhaps in the future when costs go down and the technology improves but at this point there is no reason to switch.

PS. Air conditioning while under way? Induction cooking? Open the hatches and shade the deck. Cook with propane. A 20 lb tank lasts months.

don't worry, I don't get it either. FLA for me. Cheap and cheerful and easily replaceable if it all goes pear shaped.

Pete

[arsenelupiga]

i dont see how you dont see the benefits of LFP.

Here is calc for australia

480 AH gel replacemet cost = 2600.

400 AH four LFP cost 2,860.

Add BMS to have full insight for $500.

In my case no charger replacement. Reprogram Victrons and add extra switch to disabel alternator charging.

And diy.

Say 3500, which is 900 more
saves you 130kg,
adds 320 AH usable, vs 96AH (as per lagoon manual not to go below 80% charged)
adds extrsa energy as there is no absorbtion.

what is there not to like ?

[valhalla360]

I'm still hung up on 250amp-hr at 12V is claimed to be a lot of power consumption.

Seriously 3hr of air/con at 20% duty cycle? Are you cooling only the bathroom cubical for those 3hr?

On a hot day bringing a 37' boat down from say 95F to 80F is likely going to take at least an hour of continuous run time and unless it's a super insulated boat and after 10am, you just give up on cooling, I would expect a higher ongoing duty cycle once cooled down. It could easily be 3-4 time the amp-hr for very limited air/con usage. If you actually bring the boat down into the 70'sF and run it for 8-10hr per day, that's a whole different ballgame and much more typical.

I would consider 250amp-hr moderate usage at best and arguably light usage. For minimal demand, standard lead-acid batteries do quite well and are cost effective. It's not until you get into high demand situations that you can start to justify the expense and complications of lithium. Also if you motor a lot, the tapering off of charge rates for lead-acid is less of an issue as you have long charge times available.

So, yeah, with low demand, lead-acid are very much still competitive and there isn't a lot of weight and space saving to be gained.