Lifepo4 and led acid hybrid system

[CarpeDiem 430]

1 hour ago, harrytom said:

simple answer NO there is a risk to battery supplying high amps in a short burst,just asked the boy,his field.

BMW have had Li-ion start batteries in their production vehicles since 2014.

That's about the same time that the AS/NZS standard came out saying we couldn't have Li-ion start batteries on our boats...

Hmmm...

[CarpeDiem 430]

2 hours ago, K4309 said:

I'm sorry but isn't this comparison chart a nonsense?

For life cycles, they are assessing FLA, AGM and Gel to 80% DoD, but for Li they say "70% capacity remaining", which is 30%DOD, isn't it?

Then they use those numbers to present the 'Real Cost per cycle @80% DoD' as more than half as much for Li.

Accept it's not 80% DoD, its 30%. If you run any of those other battery technologies to 30% DoD they will last for ages as well. It makes the comparison a complete nonsense.

No.

It says that after 7100 cycles to 70% DOD - the battery will be good for 70% of it's original capacity.

So if you had a 100Ah LFP battery and you pulled 70Ah out of it every single day for 19 years then after 19 years you would have a 70Ah battery.

[K4309 257]

1 hour ago, Guest said:

No, ALL types of batteries are being assessed at 80/50%; it just gives the remaining % of Original capacity for LiFePO4, which it doesnt for LA. So we have to speculate on that. What it illustrates is the ratshit cycles of LA lower than 50% DOD.

 

I don't understand this.

How can it have 70% capacity remaining if it has been discharged to 80% DoD?

Are they measuring DoD as a percentage of full charged voltage o discharged voltage, and DoD as a % of amphr capacity?

Edit, posted at the same time as CD's post.

[CarpeDiem 430]

Hmm.. yeah OK, - I don't think that is the best table

Back to my heat exchanger ...

[CarpeDiem 430]

6 hours ago, Guest said:

Is it thermal runaway on the inrush out of battery or BMS fets crapping them selves that they are worried about?

Manufacturer Specs on my batteries cells  is 1C = 230A In parallel  then would be ~ 460A

Inrush for Yanmar 3GM30 say 6xrun A ~700A (50ms)

So 700/2 = 350A . So 200A FETS in BMS maynot tolerate? Rated 350A for 1sec?

Emergency only or jumper and bypass the bms?

Not really expecting an answer on such how long is a piece of string drift.

Your cells are designed for energy storage. They meet a different design profile.  Just like some Lead AGMs are designed for starting and some are designed for deep cycle. 

There are LFP cells that will discharge at 180C pulse, 90C for 2 seconds and 45C continuous...  A 10Ah battery made with those cells would start a 3GM30

Instead of FETs a starter battery bms would use an automotive grade relay found in electric vehicles. 

[K4309 257]

1 hour ago, CarpeDiem said:

Your cells are designed for energy storage. They meet a different design profile.  Just like some Lead AGMs are designed for starting and some are designed for deep cycle. 

There are LFP cells that will discharge at 180C pulse, 90C for 2 seconds and 45C continuous...  A 10Ah battery made with those cells would start a 3GM30

Instead of FETs a starter battery bms would use an automotive grade relay found in electric vehicles. 

Is the inference then that if you try starting the donk with a standard LiFePo house battery, say by paralleling it with the start, you could fry the FET in the BMS and be a bit buggered?

I've fried FET's in my autopilot. Didn't have to try very hard, just a fairly innocuous system malfunction and then the the whole thing was buggered.

[CarpeDiem 430]

9 minutes ago, K4309 said:

Is the inference then that if you try starting the donk with a standard LiFePo house battery, say by paralleling it with the start, you could fry the FET in the BMS and be a bit buggered?

I've fried FET's in my autopilot. Didn't have to try very hard, just a fairly innocuous system malfunction and then the the whole thing was buggered.

Depends. MOSFETs limit current so if you have one rated for 10amp it will never do more than 10amp.  It's not like a piece of 10amp wire that you can push 30amps through and watch it glow red. They just won't do it. 

A massive inrush could destroy it.  It would depend on the design of the associated circuitry...

 

[Frank 157]

Reading this thread was the first time I'd heard of  lithium-titanium-oxide (LTO) batteries. The interweb says they charge much faster than other lithium ion types however the  energy density is low and the cost is high, I'm curious then as to why they would be considered an option ? 

[Ex Machina 366]

I read this before swapping from VRLAs to lifepo4 for our offgrid bank at home . Very informative info after several years of accelerated testing on different brands and chemistries .  We ended up getting powerplus lifepo4s based on price and a local seller down the road had them on the shelf .

https://arena.gov.au/knowledge-bank/itp-battery-test-centre-reports/

[Ex Machina 366]

30 minutes ago, Guest said:

Wow! A lot of failures.

Criteria for defining extent of failure /definition not clear on first skim.

Good resource for dated overview, but at speed industry is developing hard to apply.

Yeah bought the lifepo4s 18 months ago so it was handy back then . Hopefully they do another round of tests with new tech and chemistries , it takes some of the withcraft out of choosing new batteries 

[Pecco 10]

On 2/12/2023 at 9:19 AM, CarpeDiem said:

This doesn't sound right... Can you maybe post a photo of the "aparatus"?

What do you want to achieve? What's the outcome you are looking for?

Ok, I should try and explain my self better given I may have led to some confusing. Sorry, it is obviously and area that I barelly grasp so, i ll try my best. I am trying to make do with what I have without having to change/spend too much.

 

After starting this thred, and reading the posts following, i settled to replace the existing LA house battery with a 200amp CL. No lifepo4 hybrid system

This would be charged by a 330watts pannel through an mppt controller.

The LA starting battery is charged by the alternator. Whith a voltage cut off controller

I would like to use the alternator as a back up to charge the house battery in case of solar panel faliaure. 

 

 

 

[CarpeDiem 430]

6 minutes ago, prince rupert said:

The LA starting battery is charged by the alternator. Whith a voltage cut off controller

Can you elaborate on what this is? Part number, model? 

[Frank 157]

3 hours ago, Guest said:

It’s been awhile since I read about them. I though they were used in light planes and were very safe so would consider. At 14yro for the sla’s , probably just repeat as I have a dcdc charger now as opposed the LFP profile from alternator. 
l am curious, how do you power your windlass?

On the yacht we still use FLA to power all systems but when due for replacement I will consider going to LiFpo after gaining confidence and knowledge with the van installation.

[Frank 157]

15 minutes ago, prince rupert said:

Ok, I should try and explain my self better given I may have led to some confusing. Sorry, it is obviously and area that I barelly grasp so, i ll try my best. I am trying to make do with what I have without having to change/spend too much.

 

After starting this thred, and reading the posts following, i settled to replace the existing LA house battery with a 200amp CL. No lifepo4 hybrid system

This would be charged by a 330watts pannel through an mppt controller.

The LA starting battery is charged by the alternator. Whith a voltage cut off controller

I would like to use the alternator as a back up to charge the house battery in case of solar panel faliaure. 

 

 

 

I think you just need to get a DC to DC charger 

[Island Time 1,235]

On 30/11/2023 at 7:36 PM, CarpeDiem said:

Thanks. I find it strange that 2008 is the only version referenced in the regulations.

Section 3 of the Electrical Safety Regulations 2010, which is the legal instrument that gives authority to the as/nzs standard states that:

the regulations do not apply to pleasure vessels unless they have connectable installations. 

connectable installation is one that is designed or intended for, or is capable of, connection to an external power supply that operates at a nominal voltage between 90 and 250 volts AC at standard low voltage.

The above clauses in the regulations indicate to me, that if you don't have AC, (or AC self generation including inverters), then the regulations do not apply to a pleasure vessel. 

 

Unfortunately, that is NOT the current standard. See here https://www.standards.govt.nz/search/doSearch?Search=3004 and you can see the 2014 version is the current one, and if you click on the "Cited" bit, you get a list of court citings.

And this one has modified that clause to say "1 This Standard is not intended to apply to small boats equipped with a battery supplying circuits for engine starting and navigation lighting only that is recharged from an inboard or outboard engine driven alternator."

So the "connectable" clause has gone...

[CarpeDiem 430]

3 hours ago, Island Time said:

Unfortunately, that is NOT the current standard. See here https://www.standards.govt.nz/search/doSearch?Search=3004 and you can see the 2014 version is the current one, and if you click on the "Cited" bit, you get a list of court citings.

And this one has modified that clause to say "1 This Standard is not intended to apply to small boats equipped with a battery supplying circuits for engine starting and navigation lighting only that is recharged from an inboard or outboard engine driven alternator."

So the "connectable" clause has gone...

Hi IT, sorry I did not explain myself clearly - my bad.

You are referring to the standard - I am referring to the legislation that gives legal force to the standard.

Without legislation, (or a private body**), that requires the standard be followed, the standard has no effect. 

Per the link you provided, AS/NZS3004:2014 is only legislated by the Maritime Act and Maritime Rule 40E - this rule does not apply to private sailing vessels.  It applies to commercial sailing vessels that are in survey.

The standards.govt.nz site does not list any legislation that gives force to AS/NZS3004:2014 on private sailing vessels.

There is legislation that gives force to the standards predecessor, AS/NZS3004:2008 - this is the Electricity Safety Regulations 2010.  That legislation, legally requires, that ships connected to shore power, (or with self generation), must comply with the 2008 standard.  But not the 2014 standard.

In 2019 there was a MBIE working group which found that the reference to the 2008 standard in the legislation should be updated to the 2014 standard - but that has not occurred yet - the legislation has not been amended.

** any private body, is of course, allowed to say that they only will accept the 2014 standard.

Eg, as an electrician in business you are perfectly entitled to say "I will only do work that meets the 2014 standard".

We have discussed many times on this forum the same thing with the gas standard.  The Gas Standard says that it does not apply to installations before that standard was produced.  But good luck finding a gas fitter that will sign off on your installation being compliant to the previous standard... I doubt you will find one...

As of today I cannot find any legal requirement to comply with AS/NZS3004:2014 on pleasure craft.  It may become a requirement in the future if the legislation is ever amended.

Even if one were just to assume that v2014 automatically trumps the v2008 reference (which I think would be a reasonable assumption) in the regulations, the regulations still do not apply to pleasure vessels without AC.

[Pecco 10]

5 hours ago, CarpeDiem said:

Can you elaborate on what this is? Part number, model? 

Yes sure! I think it is a vsr but, i ll need to go to the boat for part number ect...

 

It is not to protect the alternator.

 

i d be happy if the system would work just by changing the vsr part of the system. (Cabling or adifferent vsr)

 

I ll try to go to the boat asap. As I  normally do.... then I can be more specific.

Thank you for baring with me, i feel this is really gonna work.

Cheers

[CarpeDiem 430]

1 minute ago, prince rupert said:

Yes sure! I think it is a vsr but, i ll need to go to the boat for part number ect...

 

It is not to protect the alternator.

 

i d be happy if the system would work just by changing the vsr part of the system. (Cabling or adifferent vsr)

 

I ll try to go to the boat asap. As I  normally do.... then I can be more specific.

Thank you for baring with me, i feel this is really gonna work.

Cheers

OK.  That makes a lot more sense.  I will reply to your previous message.

[CarpeDiem 430]

7 hours ago, prince rupert said:

Ok, I should try and explain my self better given I may have led to some confusing. Sorry, it is obviously and area that I barelly grasp so, i ll try my best. I am trying to make do with what I have without having to change/spend too much.

After starting this thred, and reading the posts following, i settled to replace the existing LA house battery with a 200amp CL. No lifepo4 hybrid system

This would be charged by a 330watts pannel through an mppt controller.

The LA starting battery is charged by the alternator. Whith a voltage cut off controller

I would like to use the alternator as a back up to charge the house battery in case of solar panel faliaure. 

OK, the voltage cutoff controller you mention is actually a pretty standard voltage cut-on controller, known as a VSR.  The way you explained it that could of been an external regulator.

When you start the engine, the VSR detects the alternator and joins both batteries together so that the charge goes to both the house battery and the start battery.

This is not suitable for dedicated LiFePO4 as, even at 13.8v, you risk over charge.

While the parallel solution would work, I recommend steering well clear of it because it's not really set and forget - and is not really beginner friendly.

Because you want Solar and Alternator charging, the system becomes more complicated if you have separate components.

You could look at replacing the VSR with a DC/DC charger with solar and alternator built in like the CTEK D250SE (with or without the 120S).  I have not used it for LFP so cannot comment, but have used it for AGM with great success.

[Pecco 10]

2 hours ago, CarpeDiem said:

OK, the voltage cutoff controller you mention is actually a pretty standard voltage cut-on controller, known as a VSR.  The way you explained it that could of been an external regulator.

When you start the engine, the VSR detects the alternator and joins both batteries together so that the charge goes to both the house battery and the start battery.

This is not suitable for dedicated LiFePO4 as, even at 13.8v, you risk over charge.

While the parallel solution would work, I recommend steering well clear of it because it's not really set and forget - and is not really beginner friendly.

Because you want Solar and Alternator charging, the system becomes more complicated if you have separate components.

You could look at replacing the VSR with a DC/DC charger with solar and alternator built in like the CTEK D250SE (with or without the 120S).  I have not used it for LFP so cannot comment, but have used it for AGM with great success.

CD thank you a lot for all the explaining, it took a lot of dedication on your side🙂

Happy to shout some beers if you are ever around the BOI!