Merged LiFeYPO4 1000Ah Winston prismatic cells and all electric galley...

[rgleason]

Originally Posted by aybabtme

Apologies for not watching the video, short on time. Couldn't glance exactly what his setup is from the comments, but it seems like they have some circuit to disconnect the lead from the LFP so that both banks get charged to their target voltage independently? If so then I wouldn't see a problem with that. Personally I used battery-to-battery charger to maintain a starter battery from my LFP pack, I didn't want the problem I described before to occur.

Here was a hybrid system FLA/LFP proposal/thought experiment, which I was considering at one time. It became clear that the discharge of the LFP to the FLA was not inconsequential, and the FLA resistance will increase as the FLA battery gets fully charged, thus depleting the LFP faster.

[goboatingnow]

I’ve said it 1000 times , placing LA in parallel with Li simply because you couldn’t be bothered to install field coil switching on your alternator is madness.

Set up your charging from all sources to charge your lithium bank directly , charge other batteries via battery to battery chargers such that each bank type has optimised charging

[Catapault]

@CatNewBee Would you still go with the RECBMS if you were doing your install today ? Or is there something else worth serious considseration.

Especially considering the new ABYC Lithium requirments comming out. (Alarm before cut-off etc)

[Catapault]

Originally Posted by goboatingnow

I’ve said it 1000 times , placing LA in parallel with Li simply because you couldn’t be bothered to install field coil switching on your alternator is madness.

Don't belive anyone mentioned 'not being bothered' or anything to do with Alternators ?

Managing alternators (I have two) seems, to me, to be one (of many) important aspects of a Lithium install.

[Catapault]

Originally Posted by CatNewBee

Do a clean lithium install, not worth it to run zombies in parallel. They will be dead when you need them, you won't notice in advance, as you would use all the time the power from the LFP.

That would be ideal, but the budget may not permit. May need to start small (400AH), and go up from there, after lots of learning !.

[goboatingnow]

Originally Posted by Catapault

Don't belive anyone mentioned 'not being bothered' or anything to do with Alternators ?

Managing alternators (I have two) seems, to me, to be one (of many) important aspects of a Lithium install.

The poster described a system where AGMS where left in circuit to handle BMS disconnect of the alternator. This is back to front thinking

If your alternator is set up to charge your lithium’s it will have a remote disconnect facility , that’s not rocket science. Hence you then charge your starters , other LA batteries using battery to battery chargers from the lithium , no worries about parallel charging issues. Each chemistry has independent charging profiles that suit that chemistry.

[newhaul]

Originally Posted by Catapault

Having just had sticker shock at replacing our 4 x 260 AH Tubular Gel's with equivelent AGM, I'm taking another serious look at Lithium !.

Comming out of winter this year, our (now 4 year old), LEOCH Tubular Gel's have had a massive drop in capacity. Not even lasting overnight with just house loads. (~ 160w) before they crater to 11.4v or so.

So time to give this all another serious look.

Here is a chart Adelie did up a couple years back that will help you decide how to go .

[newhaul]

Originally Posted by goboatingnow

The poster described a system where AGMS where left in circuit to handle BMS disconnect of the alternator. This is back to front thinking

If your alternator is set up to charge your lithium’s it will have a remote disconnect facility , that’s not rocket science. Hence you then charge your starters , other LA batteries using battery to battery chargers from the lithium , no worries about parallel charging issues. Each chemistry has independent charging profiles that suit that chemistry.

I'm setup just the opposite my 75 amp alternator charges my grp24 fla start battery and a 60amp b2b set to charge my lfp 250ah bank. Protects my alternator from potential overheat and sudden disconnect. ( was the best cheapest option for me ) 99% of my lfp charge is from my solar .

[Catapault]

Originally Posted by goboatingnow

The poster described a system where AGMS where left in circuit to handle BMS disconnect of the alternator. This is back to front thinking

If your alternator is set up to charge your lithium’s it will have a remote disconnect facility , that’s not rocket science. Hence you then charge your starters , other LA batteries using battery to battery chargers from the lithium , no worries about parallel charging issues. Each chemistry has independent charging profiles that suit that chemistry.

Still in design phase, but I likely wouldn't do it this way. I'd probably plan for each Alternator to charge its own Starter battery directly, and then charge the LFP bank via a dedicated charger. (Such as a Victron Orion).

This is primairly for redundancy reasons, Can take the engines out of circuit of anything to do with the house bank, and they continue to operate on their own, just fine. Redundancy, and ability to split systems to reduce dependancy is important to me.

Secondary, The alternators needing to charge the lithium will often be the more unusual case. The Solar (existing 3.6kw nominal) will do most of the work there, backed up by the existing 11kva Generator/Charger in the Quattro.

Note: Alternator charging is certainly desired (why waste any power), and keeping things topped up on passage is certainly important. Definitly something I'll integrate, but most likley as a tertiary charging source and one that may often be just left disconnected from the house bank.

[Catapault]

Originally Posted by newhaul

I'm setup just the opposite my 75 amp alternator charges my grp24 fla start battery and a 60amp b2b set to charge my lfp 250ah bank. Protects my alternator from potential overheat and sudden disconnect. ( was the best cheapest option for me ) 99% of my lfp charge is from my solar .

As above, this is the way I'm leaning. (Though I have 2 engines, Catamaran)

[Simi 60]

Originally Posted by newhaul

I'm setup just the opposite my 75 amp alternator charges my grp24 fla start battery and a 60amp b2b set to charge my lfp 250ah bank. Protects my alternator from potential overheat and sudden disconnect. ( was the best cheapest option for me ) 99% of my lfp charge is from my solar .

Given the cost of those B2B chargers I wonder why you bothered if you get 99% from solar

We don't use alt either, tried it once and killed it.
And even though we have a big solar array, we also have big usage so during winter, solar alone struggles.

Still considering running instead a 5kva Mecc Alte generator head "Cruise Gen" wired into the Victron inverter charger for 120amps @ 24v whist underway.
All our cruise miles are at a set rpm range

Next size up from this
Genset supplier here in Oz does them with dual pulley for around $400
https://www.ebay.com/itm/132203171861

[goboatingnow]

Originally Posted by newhaul

I'm setup just the opposite my 75 amp alternator charges my grp24 fla start battery and a 60amp b2b set to charge my lfp 250ah bank. Protects my alternator from potential overheat and sudden disconnect. ( was the best cheapest option for me ) 99% of my lfp charge is from my solar .

From a cost and efficiency perspective your system isn’t optimum , starter batteries require very very little charging and hence can easily be charged by small low cost b2b chargers. Redundancy can be handled by manual overide switches if required

Domestics ( in this case typically the Li battery ) require frequent often considerable charging and its best that all available power sources including alternators are optimised for this. B2B charging from starter to Li ( or worse again , just parallel LA and LI ) needs careful configs to ensure the starter isn’t accidentally run down , or overcharged as the alternator voltage needs to trigger the B2B charging only.

So by not integrating the alternator into the Li system , like all other charge sources , you end up with a less then optimal system , with more inefficiencies and for, high power B2B, Greater expense.

[goboatingnow]

Originally Posted by Catapault

Still in design phase, but I likely wouldn't do it this way. I'd probably plan for each Alternator to charge its own Starter battery directly, and then charge the LFP bank via a dedicated charger. (Such as a Victron Orion).

This is primairly for redundancy reasons, Can take the engines out of circuit of anything to do with the house bank, and they continue to operate on their own, just fine. Redundancy, and ability to split systems to reduce dependancy is important to me.

Secondary, The alternators needing to charge the lithium will often be the more unusual case. The Solar (existing 3.6kw nominal) will do most of the work there, backed up by the existing 11kva Generator/Charger in the Quattro.

Note: Alternator charging is certainly desired (why waste any power), and keeping things topped up on passage is certainly important. Definitly something I'll integrate, but most likley as a tertiary charging source and one that may often be just left disconnected from the house bank.

Fine , clearly you don’t realky need alternators at all but this config is not the norm I suggest. Many people rely on alternator recharging

[Simi 60]

Originally Posted by Simi 60

Given the cost of those B2B chargers I wonder why you bothered if you get 99% from solar

We don't use alt either, tried it once and killed it.
And even though we have a big solar array, we also have big usage so during winter, solar alone struggles.

Still considering running instead a 5kva Mecc Alte generator head "Cruise Gen" wired into the Victron inverter charger for 120amps @ 24v whist underway.
All our cruise miles are at a set rpm range

Next size up from this
Genset supplier here in Oz does them with dual pulley for around $400
https://www.ebay.com/itm/132203171861

We currently have a 7kva Genset which does the charge and 240v hot water system at same time but, the Genset has some years on her and needs money thrown at it at some stage and, the hot water system is way bigger than it need be so at end of life will be replaced with a 25litre model vs the 180 litre we have.
10 minutes of heat up vs 1.5 hours.

[newhaul]

Originally Posted by Simi 60

Given the cost of those B2B chargers I wonder why you bothered if you get 99% from solar

We don't use alt either, tried it once and killed it.
And even though we have a big solar array, we also have big usage so during winter, solar alone struggles.

Still considering running instead a 5kva Mecc Alte generator head "Cruise Gen" wired into the Victron inverter charger for 120amps @ 24v whist underway.
All our cruise miles are at a set rpm range

Next size up from this
Genset supplier here in Oz does them with dual pulley for around $400
https://www.ebay.com/itm/132203171861

Must recall I am an old navy engineer. The 200 bucks for my 60 amp b2b which a lso has an integrated 30 amp mppt so it's a backup just incase. And 200 is cheap insurance.
Also a 1500 watt generator to run my 2512 inverter charger if needed fully adjustable from 1 to 120 amp output and yes voltage is fully adjustable as well.

I am a real proponent of redundancy. Solar / wind/ alternator and generator to run charger.if ever needed. I don't want to be powerless due to any equipment failures.
I like my cold soda and ice cubes.