ABYC and ISO Li reference diagram

[newhaul]

Originally Posted by s/v Jedi

There are plenty boats with 100Ah or 200Ah LiFePO4 batteries. I have a much bigger battery as well, but I don’t see the need to ridicule thise with smaller batteries! Many cruisers don’t want to have much electric at all.

Anyway, I tried my best to help and actually put an hour of my time into it. I wonder why I bothered.

Well I for one say thank you for posting your charts and schematics.

Now I know I'm 250ah lfp ( not much more than 150ah cells factory direct calb cells) I could easily do it with a mere 100ah bank
Now without my fridge and don't need heat I only use about 15ah per day underway.
With the refrigerator I use about 35ah in summer. My 200 watts solar does good and I don't really want any more on the boat . In winter it's my 400 watt wind turbine . And yes it's quiet and produces about 10amps average . Which means 240ah potential in a day.
And running the furnace I use 40ah at anchor .
Yes all LED lighting.

[noelex 77]

Originally Posted by goboatingnow

Hence the load isn’t parasitic it’s serving a function

The energy needed to engage a relay is a parasitic load.

Comparing a parasitic load with a useful load such as the energy used charging a phone or tablet is not appropriate.

[goboatingnow]

Originally Posted by noelex 77

If it does not transfer any energy it is a “parasitic load”. The energy needed to engage a relay is a parasitic load.

Sorry but you are wrong as any simple google search will reveal

“With regard to electrical appliances, it represents the power consumed even when the appliance is shut off, that is standby power.”

A parasitic load or current would be a current flowing when the device is nominally considered “ off”

The relay mentioned draws zero current when “ off” hence it is not a parasitic load.

The nearest correct term is quiescent

“The definition of quiescent is “a state or period of inactivity or dormancy.” In electronics, quiescent current is the current flowing into a system in standby mode with a light or no load.”

The relay consumes 7A while changing state. That’s it’s load current. It then enters one or two “ dormant “ states and hence its current can be characterised as “ quiescent. “

It’s very certainly not “parasitic. “

[goboatingnow]

To return to the elegance of the switching in the RGleason proposal

Clearly it’s solely an emergency switch and would be labelled so , it could even be mechanically locked with a padlock

Firstly the two way switch achieves several functions.

Off is normal operation
1: bypasses the bms contactor. ( note it doesn’t depower it see later )
2. The SLA is coupled in and the Li feed is disconnected

Now to assure the BMS contactor is never powers on while the SLA is in circuit the AFD contacts via a small relay ensure the contactor is forced off.

This functionality is not duplicated in a ML series latched relay.

The second switch is a emergency Li ( and one is one the SLA too) battery disconnect. This is for maintenance , last ditch safety and anything else, it was added later to allow forced disconnect of the batterie like is present today on virtually every boat.

[noelex 77]

Originally Posted by goboatingnow

The relay mentioned draws zero current when “ off” hence it is not a parasitic load.

The relay needs to be “on” except in a fault condition.

Substitute a latching relay or a simple switch for the relay and you will save energy.

[s/v Jedi]

Originally Posted by newhaul

Well I for one say thank you for posting your charts and schematics.

Now I know I'm 250ah lfp ( not much more than 150ah cells factory direct calb cells) I could easily do it with a mere 100ah bank
Now without my fridge and don't need heat I only use about 15ah per day underway.
With the refrigerator I use about 35ah in summer. My 200 watts solar does good and I don't really want any more on the boat . In winter it's my 400 watt wind turbine . And yes it's quiet and produces about 10amps average . Which means 240ah potential in a day.
And running the furnace I use 40ah at anchor .
Yes all LED lighting.

Thank you, I need to be remembered I’m not just feeding the trolls now and then.

Arguing over lost power being called parasitic or not, admitting the daily loss of the solenoid alone equals 1% of battery capacity even with the much bigger cells… it all is so unrealistic.

And it’s always just words: no pictures of things built, no measurements, nothing. I never saw the pictures of their solar arrays, lfp batteries, BMS’s, electrical installations etc. For all we know it doesn’t even exist.

[wholybee]

Originally Posted by goboatingnow

There are two switches , one is a two way switch which doubles as a bms bypass the second position switched in the SLA

Secondly that switch uses it AFD contacts to trigger a relay to electrically interlock the bms contactor from ever being powered up while the SLA is switched in.

Hence its a very simple and elegant design

<snip>

I don't think that solution is simple or elegant. If it were simple and elegant, it wouldn't require a second page on the drawing just to explain how it works. And, IMHO, it is clumsy because it requires a second interlock circuit to work, and because the disconnect is via a relay and not a manually operated switch

To me, the simple solution, what I proposed a long time ago, is a simple 1-off-2 switch to select between the house and starting batteries. The off position is a disconnect, it gives a normal and emergency positions, and doesn't require a clumsy interlock to prevent both from paralleling together.

If you then wanted to add a second switch to bypass the BMS relay, that is a separate issue but could easily be done.

The only thing your more complex solution offers is to combine the BMS bypass switch with the normal/emergency switch. I could see this is you were very limited in space to mount a second switch, but is seems a poorer solution in every other way.

[goboatingnow]

Originally Posted by noelex 77

The relay needs to be “on” except in a fault condition.

Substitute a latching relay or a simple switch for the relay and you will save energy.

I never argued this

A latching relay can never be completely fail safe. For me 3Ah is well worth it for that feature.

[goboatingnow]

Originally Posted by wholybee

I don't think that solution is simple or elegant. If it were simple and elegant, it wouldn't require a second page on the drawing just to explain how it works. And, IMHO, it is clumsy because it requires a second interlock circuit to work, and because the disconnect is via a relay and not a manually operated switch



To me, the simple solution, what I proposed a long time ago, is a simple 1-off-2 switch to select between the house and starting batteries. The off position is a disconnect, it gives a normal and emergency positions, and doesn't require a clumsy interlock to prevent both from paralleling together.



If you then wanted to add a second switch to bypass the BMS relay, that is a separate issue but could easily be done.



The only thing your more complex solution offers is to combine the BMS bypass switch with the normal/emergency switch. I could see this is you were very limited in space to mount a second switch, but is seems a poorer solution in every other way.

The original RGleason proposal was two switches.

The thinking developed that if the bms contactor reengaged while the SLA was switched in this was bad. Hence the desire to interlock the SLA with the contactor.

Of course this could be done via two switches but you still needed a relay interlock of some sort or a custom battery switch.

So if you use your 1-off-2 you still run the risk that the bms could reengage whilst the SLA is in circuit.

The elegance of the interlock prevents this by inverting the AFD logic

You really needed to participate in the long thought processes on diysolarforum to see how the thinking evolved , there were many iterations of that diagram.

[newhaul]

Originally Posted by s/v Jedi

Thank you, I need to be remembered I’m not just feeding the trolls now and then.

Arguing over lost power being called parasitic or not, admitting the daily loss of the solenoid alone equals 1% of battery capacity even with the much bigger cells… it all is so unrealistic.

And it’s always just words: no pictures of things built, no measurements, nothing. I never saw the pictures of their solar arrays, lfp batteries, BMS’s, electrical installations etc. For all we know it doesn’t even exist.

Yep agreed. BTW for all interested there are actually pictures of most of my stuff in one stage of install or another on my refit page .
Somewhere in the dpages of this https://www.cruisersforum.com/forums...-a-187721.html
A few links to YouTube vids of it as well .
Money where mouth and all that .
Again thanks jedi for all the help along the way these many years of my lfp experiment.

[newhaul]

Originally Posted by wholybee

I don't think that solution is simple or elegant. If it were simple and elegant, it wouldn't require a second page on the drawing just to explain how it works. And, IMHO, it is clumsy because it requires a second interlock circuit to work, and because the disconnect is via a relay and not a manually operated switch

To me, the simple solution, what I proposed a long time ago, is a simple 1-off-2 switch to select between the house and starting batteries. The off position is a disconnect, it gives a normal and emergency positions, and doesn't require a clumsy interlock to prevent both from paralleling together.

If you then wanted to add a second switch to bypass the BMS relay, that is a separate issue but could easily be done.

The only thing your more complex solution offers is to combine the BMS bypass switch with the normal/emergency switch. I could see this is you were very limited in space to mount a second switch, but is seems a poorer solution in every other way.

My question still unanswered in all this is why can't I parallel a FLA with my LFP Bank? What will happen? Please be specific.

[noelex 77]

Originally Posted by goboatingnow

For me 3Ah is well worth it for that feature.

So when you turn off all systems there is still a 3Ahr consumption from the relay but this is not a parasitic load?

[goboatingnow]

Originally Posted by s/v Jedi

Thank you, I need to be remembered I’m not just feeding the trolls now and then.



Arguing over lost power being called parasitic or not, admitting the daily loss of the solenoid alone equals 1% of battery capacity even with the much bigger cells… it all is so unrealistic.



And it’s always just words: no pictures of things built, no measurements, nothing. I never saw the pictures of their solar arrays, lfp batteries, BMS’s, electrical installations etc. For all we know it doesn’t even exist.

It doesn’t exist because it’s a design exercise. The design evolved over several weeks of discussions on a long thread on diysolarforum with inputs from several people but equally driven by RGlesons own priorities and desires.

The use of the TE relay was discussed several times.

I made the point that for me , complete fail safe operation is important. Important enough to consume 3Ah daily.

Others may reach other conclusions neither Is “ best “ they are just different priorities. If for example saving every Ah possible is important because your battery capacity is on the limits , then of course you may choose other solutions. They may be less or more safe too.

I find the constant arguing on CF that ( like sea cocks ) that there’s one “best “ solution often from a man with a huge big boat with hugely expensive and complex systems is bizarre

There is never one “ best “ solution

Sometimes I too feel others are just trolling , but I persist , I started this thread merely for information. But some people can’t seemingly accept others may have different ideas to them.

[goboatingnow]

I have a boat with possibly more complex command and control solutions then virtually anyone possibly here. I have full SMD build capacity and a complete electronics design workshop.

However I feel no interest or desire to post data or pictures just to “ show off “ I merely contribute my expertise in areas I can. People can take from it what they want.

I’m not denigrating other solutions merely defending my own. My solution might be different but I beleive I can put forward Cogent engineering arguments as to why my solution meets the inherent compromises.

Some people however seem to think their personal solution is the only one “ best “ and then spend pages trying to convince others that the ideas that they didn’t think up are wrong.

By all means present your arguments in your Own thread. But stop trying to dogmatically prevent others from expressing what they feel is “ best “ for them.

( aka I’m more then personally happy to expend 3Ah to achieve full fail safe contactor operation , you may think
otherwise that’s fine. But it doesn’t invalidate my perspective )

[zurk]

correct - a lot of people dont understand flow thru system design for lifepo4 or modern systems for boats which have power to spare. a design for 100Ah is completely different than one for 2000Ah and burning 10-20Ah on a 2000Ah setup is nothing as ive tried to point out to people.