lithium batteries or AGM

[alctel]

Again for anyone reading this - don't charge above 14v,
and preferably even lower (mine is set to 13.8)

If you top balance your cells before using them and charge to a reasonable voltage (not above 14) they basically should never go out of balance

Keeping the cells at 14.3 - 14.4 as suggested above is a sure fire way to kill them early

[john61ct]

Yes, boggles my mind someone comes into the one community with actual experts who are getting it right, and starts tossing such harmful misinformation around.

Maybe a shill paid by vendors?

Or just a naïf blindly accepting their advice. . .

I would just block, but feel a responsibility to protect newbies told to come here for LFP advice.

[john61ct]

Active balancing is not only completely unnecessary, but a dangerous violation of KISS.

First thing to do with a packaged "system" is figure out how to disable the cell balancers.

[john61ct]

> If you log the voltage during charge of a LFP battery, they go linearly up nicely until maybe 13.7V for a 4 cell 12.8V nominal pack. But past there they kick upwards, and go nearly vertical in voltage curve for very little extra charge input.

And voila those are the exact "shoulders" that need to be avoided for longevity.

At low charge rates like solar, 13.7-13.8V

High charge rates genny or mains, maybe 13.9V

Nothing good comes from pushing higher.

No need to wait for endAmps either, just stop soon as you hit the voltage.

[CatNewBee]

Well, you can do whatever you think is right for you.

IF it is really so as you describe, just buy un-managed 12V LFP blocks and charge them to 13.6..13.8V only. Why bother about a BMS and balancing at all, they are much cheaper any way... So no need to buy an expensive product with built-in BMS and balancer and then castrate it by disabling the balancing - simply nonsense.

I'll stick to the datasheet, there is a reason why big manufacturer use single cell balancing and BMS systems. The cell's have 2 dangerous points at the top and at the bottom, they can degrade and be damaged even if they appear equalized when charged, so top-balancing alone would not do the trick. An active BMS on both ends is the best possible protection and delivers the highest available energy output out of the battery bank.

[john61ct]

And your vendors will be much happier that they get a repeat customer within ten years, rather than the bank getting passed on in your will.

Obviously LVD and OVD protection is critical.

Does your BMS automatically isolate the charge buss at low temps? I guess with Winstons that is less a concern.

[Pelagic]

Thanks to all.....you have just convinced me to wait at least 8 years before switching to this expensive Technology...
..... Far too many fledgling opinions and not enough solid history within the cruising community to install with certainty.

If I need to read for 2 days to understand a battery, then I'll stick with the tried and true inferior AGMs until history and field experience, can provide me with the Cliff Notes.

[john61ct]

Trying to keep current LFP-specific discussions here rather than derailing other threads.

Originally Posted by kenbo

Not trying to be difficult but could you let me know what alternator controller is designed to handle LiFePO4 batteries. I mean fully designed not just adjustable voltage set points.

I'm aware of Nordkyn's design but not really sure if it's on the market at this time.

No, all that is needed is user-custom setpoints like MC-614.

All gear on the market I've seen touting a canned LFP profile, including from LFP makers, are set way too high at 14+V.

The other major improvements would be NO float, just stop output to the LFP bank, and also the ability to really reduce or eliminate Absorb time.

But all these need to be user-adjustable

Best solution IMO, Sterling DC-DC BB line gives a good charge from any old source.

Originally Posted by kenbo

John,

What you say above is not ideal and doesn't represent a fully designed alternator regulator for LiFePO4 batteries.

It either involves some type of alarm and human intervention to open the field circuit. Or the additional use of external relays to do the same.

My comment, I believe still stands. What off the shelf alternator regulator is fully designed to properly charge LFP without workarounds or operator intervention?

There is none. Nor a mains charger, nor a solar controller.

But what I'm saying is, if one does come on the market I would be willing to bet its pre-programmed settings would need user customization to ensure longevity.

(Other thread http://www.cruisersforum.com/forums/....php?p=2524889 )

[hzcruiser]

Originally Posted by Pelagic

Thanks to all.....you have just convinced me to wait at least 8 years before switching to this expensive Technology...
..... Far too many fledgling opinions and not enough solid history within the cruising community to install with certainty.

Hello Pelagic,

reading your post I was expecting someone to advise you to better not buy any anchor until the "fledgling opinions" have matured

[Pelagic]

Originally Posted by hzcruiser

Hello Pelagic,

reading your post I was expecting someone to advise you to better not buy any anchor until the "fledgling opinions" have matured

LoL.... Anchors I understand as they have been around since before the building of the Pyramids.

I admire and am grateful to all the electrical engineers who are tweaking and experimenting with different battery solutions for cruisers,

However, when reading these threads, it is far more complicated and non linear than an anchor thread (although some sailors would still argue that point)

In this case, I think the disagreements and lack of concensus has more to do with new product ignorance rather than stubbornness..... and that tells me it is a few product generations away from being a safe investment for us less technical types.

We will follow in your footsteps once you are all marching in the same direction and when the prices have come down and the world wide support has gone up!

[john61ct]

Originally Posted by skipmac

Maybe someone has come out with a ready to go, plug and play LiFePO installation. If so I'll bet it is even more expensive.

Yes they have, listed in my summary post above.

And yes, they cost thousands, I figure 7x even quality lead. Plus changing to proper adjustable charge sources.

[john61ct]

Originally Posted by Pelagic

We will follow in your footsteps once you are all marching in the same direction and when the prices have come down and the world wide support has gone up!

#1 is from vendors not publishing charge profiles that maximize longevity. I personally believe Maine Sail & co's hands-on research results will result in 15+ years bank lifetime and possibly double that, so you can imagine why.

People used to following mfg specs will always default to believing them, so these arguments with noobs will not go away.

#2 will not IMO happen until LFP is old hat and the next big thing has ramped up as much as say where AGM is now vs FLA.

Demand will be outstripping supply, which of rare earth minerals is very limited.

#3 Good support is always hard to find, I think we just need to become self-educated as much as possible. Turnkey systems manageable by laymen are available now, but way more expensive than DIY.

But I completely agree being a late adopter does have advantages if you're not the pioneering type.

[Pelagic]

Agreed John61ct.....sorry did not mean to derail your discussion..... Just frustrating that I can't follow....(which is entirely my fault!)

[hzcruiser]

Originally Posted by Pelagic

We will follow in your footsteps once you are all marching in the same direction and when the prices have come down and the world wide support has gone up!

No worries at all, Pelagic. It's just a matter of time until LFPs will be the "standard", at least until the next batt technology comes around, of course.

For myself (and my back) I know I'm not getting any new lead, just dragged several Marathon AGMs at 30kg each (65lb) off the boat and up the hill to the car. Pretty much ruined the collapsible trolley.

[Pelagic]

Originally Posted by hzcruiser

For myself (and my back) I know I'm not getting any new lead, just dragged several Marathon AGMs at 30kg each (65lb) off the boat and up the hill to the car. Pretty much ruined the collapsible trolley.

That is a huge consideration!
In my installation, I have 8 x Fullriver AGMs dc-260ah-12v
for a 24v House bank of 1040ah
Each weighs 77.3kgs so totals
618.4kgs.

What would a 1040AH @ 24v new technology battery package weigh in at?