Battery Voltage drop with no SOC drop?

[PaulRainbow]

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I don't have a bias toward any battery technology, i still fit lots of LA batteries and still advise lots of customers to stick with them. There is no one size all solution, LA is perfect for some, LifePO4 is perfect for others.

Lorries and cars are not boats, they just need something to start the engines. We are still fitting LA batteries on boats to start the engines. We still fit LA on boats with very simple needs or certain usage patterns, but for many boats LifePO4 is a no brainer on many levels.

You are the one with a biased opinion, against anything you don't understand.

 

[PaulRainbow]

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You are biased because you do not understand the subject matter.

It is not progress when you bring out a new technology which needs a BMS just to keep it under control.

The BMS doesn't keep anything under control. A properly installed LifePO4 system will be setup so the chargers don't overcharge, temps are monitored for charging etc etc. The BMS is a final failsafe, in the 12 months since my LifePO4 system was installed the BMS has not had to do anything.

Would you buy a lithium battery with no BMS fitted , Would you buy a lead acid battery with no BMS (i know they do not need one)

I wouldn't fit LifePO4 without a BMS, neither would i fit it without correct cables, isolators, fuses etc.

I equally wouldn't fit LA without appropriate cables, fuses etc. Without any form of management LA can be destroyed by over charging, under charging, over heating etc and can also explode under various fault events.

There are none as blind as them that do not want to see and none as deaf as them that do not want to hear.

Indeed.

 

[lustyd]

I wouldn't fit LifePO4 without a BMS

These days you'd have to go out of your way to do so as drop in batteries are cheaper than lead per capacity and include very good BMS anyway.

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Lead is a dangerous imperfect science, and frankly a terrible solution for the problem. It's low capacity, overly heavy, exceptionally delicate and prone to early failure, short lifespan, produces dangerous gases, contains exceptionally harmful chemicals and is only the incumbent because we didn't have a better solution before.

Now we do have a better solution. You can either put some effort into understanding the better solution, or you can be a luddite and try to stop progress. Either way, Lithium is what the industry has already moved to, so your lead batteries will get increasingly rare and expensive to replace over the coming few years.

 

[Tranona]

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The reason that motor vehicles used FLAs is because they are well matched to that requirement. Some other motorised vehicles such as mototbikes use lithium for the same reason - they better suit the applications. Fortunately the people who design and specify such equipment know and understand far more about the subject than you. In the same vein many here have similar knowledge and understanding so aare able to make up their own minds about what is appropriate technology to use.

Meanwhile you seem to delight in constantly displaying your ignorance on the subject.

 

[MagicalArmchair]

There is the insurance question to cover also, although, I do think about all the dangerous events on the boat, most have involved the LA batteries in some way and the PBO technologist in me can’t help but crave lithium fitted properly and safely.

What I am more minded to do in the short term is get a separate powerstation that is not connected to the boat directly in any way. No insurance complications then I think and no rewiring required. A trusted marine electrician locally, when I quizzed him on switching to Lithium, was pretty strongly against it still also.

The helpful marina manager has arranged for 2 x 190 ah batteries to be delivered (so I lose 60Ahs in total, 30Ahs usable) and for the old batteries to be taken away for me. I’m not looking forward to the cost, but it means I can concentrate on the kids and enjoying the holiday.

@PaulRainbow will running the boat off the starter battery, whilst floated from shore power, do it any harm for today and tonight whilst we wait for the new batteries to be delivered?

Golly, also I didn’t expect battery tech to get people so heated up (pun intended!), perhaps it’s the new anchor thread (lovely stainless Ultra on the Swan next door!).

 

[KompetentKrew]

Thank you all.

So it’s Clear now perhaps?

Yes, "clear" is the setting I use.

You can see where we turned the iron donkey off to sail and we were discharging only at about 6 amps for around an hour. Then the engine goes off when we arrive and we start discharging again at the usual rate. Note the voltage drop like a stone. I didn’t notice when sailing, clearly did when we got in before we hooked up to shore power.

.

Does this chart show two charging sources? Or had it been charging for some hours before 2pm?

On the left hand side, between about 2pm and 3:30, you're charging at only about 1A.

Then, as you say, you discharge at about 6A for 30 minutes, and then you start charging again at 12A. Could be a different amount of current because it's a different charging source or because it's a multistage charger and the battery had been charging for some time at 2pm, so the multistage charger had gone onto the float stage.

But, either way, the batteries are dropping to 11V with very little load, 3A to 6A, which indicates the batteries are knackered.

(Well, hypothetically I guess a the voltage of a 10Ah battery would drop this low under a 6A load, but obviously your battery isn't that small.)

An earlier version of the SmartShunt firmware had only two options here, instead of the current three, and the explanations were absent. I think the names of the options might've been a bit different. It was very easy to make the mistake of choosing the "reset to 100%" option and killing your battery this way. I know because I did it.

The change to the firmware was made a couple of years ago, around the time they added the voltage / current / SoC in the devices list.

 

[lustyd]

What I am more minded to do in the short term is get a separate powerstation that is not connected to the boat directly in any way. No insurance complications then I think and no rewiring required

Make sure it’s LiFePo4, many are not.

What makes you so sure insurance won’t care? Many of those are over the capacity quoted elsewhere so it’s likely the same as far as insurance goes.

 

[lustyd]

Any thing a lithium battery achieves a suitable LA can do, it can do it just as well and safer.

not so. Try discharging to 10%SOC every day with your lead and it’ll be dead in a week. Try leaving it on charge and it’ll boil and produce hydrogen, lithium just stops charging.

 

[PaulRainbow]

All you lithium devotee's go fit this new double available amps, light weight incredible replacement for lead acid to your car. it is such a piece of progress you should be able to slip the LA out and slip the LifePO4 in. Open your eyes. Any thing a lithium battery achieves a suitable LA can do, it can do it just as well and safer. Does that work visa versa.
No one ever answers my questions on here. A bunch of politian's just waffling.

It's hard to believe you are so ignorant of the subject matter, so i suspect you are just trolling.

 

[lustyd]

It's hard to believe you are so ignorant of the subject matter, so i suspect you are just trolling.

There’s a LOT of trolling on this subject right now. No idea what their agenda is and it won’t work anyway as the smart folk are converting in droves where appropriate.

 

[geem]

There are none as blind as them that do not want to see and none as deaf as them that do not want to hear.

You have great self perception

 

[MagicalArmchair]

@PaulRainbow will running the boat off the starter battery, whilst floated from shore power, do it any harm for today and tonight whilst we wait for the new batteries to be delivered?

 

[PaulRainbow]

@PaulRainbow will running the boat off the starter battery, whilst floated from shore power, do it any harm for today and tonight whilst we wait for the new batteries to be delivered?

Not at all

 

[noelex]

The smart shunt counts amps into and out of the battery. A bad battery can drop voltage fast without discharge current. If this occurs, as far as the smart shunt is concerned, the battery can have a high SOC even when the voltage is low.

 

[Tranona]

All you lithium devotee's go fit this new double available amps, light weight incredible replacement for lead acid to your car. it is such a piece of progress you should be able to slip the LA out and slip the LifePO4 in. Open your eyes. Any thing a lithium battery achieves a suitable LA can do, it can do it just as well and safer. Does that work visa versa.
No one ever answers my questions on here. A bunch of politian's just waffling.

Once again demonstrating a complete lack of understanding. It has been explained to you several times why lithium is not suitable for cars and why it is suitable for some applications on boats.

It is your eyes that are closed or your brain is incapable of making sense of relatively simple facts.

 

[PaulRainbow]

There is nothing "simple" about lithium. The simple fact is its very very complex and needs a mass of safety cut outs to keep it safe. and can shut down and be useless if the BMS decides so. . No waffle, is that true of false. It is a farce that a simple 12 volt 100amp battery in the 21st century needs a complex BMS ..thats what you bright educated intelligent people call progress. Children carried away by new faulty 3rd rate technology.

If you are so smart, tell us idiots what a BMS does please ?

 

[Tranona]

There is nothing "simple" about lithium. The simple fact is its very very complex and needs a mass of safety cut outs to keep it safe. and can shut down and be useless if the BMS decides so. . No waffle, is that true of false. It is a farce that a simple 12 volt 100amp battery in the 21st century needs a complex BMS ..thats what you bright educated intelligent people call progress. Children carried away by new faulty 3rd rate technology.

The simple facts I was referring to are related to why different types of batteries are used in different applications. You seem also to have a comprehension problem - reading somehing that is not there. might explain your woeful ignorance on the subject as a whole.

 

[PaulRainbow]

A BMS should save you needing one of these.

See post #18, keep one onboard for your LA batteries. Any smart people who have LFP don't need one.

Still waiting for you to tell all of us idiots what a BMS does ?

 

[VicS]

It is your eyes that are closed or your brain is incapable of making sense of relatively simple facts.

"It is what we think we know that keeps us from learning." Claude Bernard

 

[Caladh]

I think shanemax has left the building ……