Lithium house battery charging

[Travelling Westerly]

Morning all

Looking into replacing my standard lead acid house battery with a 216ah lithium battery. I notice that I need a B2B charger in order to charge it whilst under motor.

I've had a look at Sterling and Victron chargers but can't quite figure out how to wire it up to my set up.

My set up is alternator to 3 way Victron Argo Fet isolator. 1 output to house batt, 1 output to engine start and 1 output to bow thruster battery.

The wiring diagrams only seem to show a 2 battery system set up. Anybody have any good ideas on how to best wire it up.

 

[Caladh]

Morning all

Looking into replacing my standard lead acid house battery with a 216ah lithium battery. I notice that I need a B2B charger in order to charge it whilst under motor.

I've had a look at Sterling and Victron chargers but can't quite figure out how to wire it up to my set up.

My set up is alternator to 3 way Victron Argo Fet isolator. 1 output to house batt, 1 output to engine start and 1 output to bow thruster battery.

The wiring diagrams only seem to show a 2 battery system set up. Anybody have any good ideas on how to best wire it up.

I’d advise you to investigate Lithium batteries/charging/requirements/safety more thoroughly. Plenty of info out on the web.

 

[halcyon]

I’d advise you to investigate Lithium batteries/charging/requirements/safety more thoroughly. Plenty of info out on the web.

There's a large tread
270ah DIY LiFePO4 build

.

Brian

 

[Poey50]

There's a more important question to ask first - what happens when the BMS suddenly takes the battery offline into a non-communicative state? I recommend not designing a system until this question is understood and answered satisfactorily. Those marketing drop-in LFP batteries for the marine market tend to dodge it. The opening post in this long thread will take you to some key reading.

270ah DIY LiFePO4 build

 

[Travelling Westerly]

I’d advise you to investigate Lithium batteries/charging/requirements/safety more thoroughly. Plenty of info out on the web.

It looked quite straightforward from what I've read.
Buy a drop in Sterling or Victron Lipo, already have a Sterling Pro mains charger to look after that side of mains charging just had to look after charging it whilst under engine and that's where the B2B comes in.
What have I missed?
I just want to know where to connect the B2B as I can't seem to find a wiring diagram showing a 3 way battery charging split.
I'm quite happy with the charging requirements hence wanting a B2B with lipo charge ability. Safety I'm also happy with.
What more do I need to know? Not being difficult here but it seems straight forward to me.?

 

[Kelpie]

It looked quite straightforward from what I've read.
Buy a drop in Sterling or Victron Lipo, already have a Sterling Pro mains charger to look after that side of mains charging just had to look after charging it whilst under engine and that's where the B2B comes in.
What have I missed?
I just want to know where to connect the B2B as I can't seem to find a wiring diagram showing a 3 way battery charging split.

I'm not familiar with the drop-ins you are thinking of, but usually with drop-ins you need to consider whether shutting off power to any of the loads will cause problems. E.g. autopilot, cabin lights.

 

[Travelling Westerly]

There's a large tread
270ah DIY LiFePO4 build

.

Brian

Thanks . I did start reading that thread when it first began but realised that a drop in 216 ah was available from some well known manufacturers so decided to buy a drop in unit and not build one.
I already have the mains charger side covered via a Sterling Pro with Lipo charge profile. I wanted a similar lipo charger whilst under alternator charging hence the B2B .

 

[PaulRainbow]

Morning all

Looking into replacing my standard lead acid house battery with a 216ah lithium battery. I notice that I need a B2B charger in order to charge it whilst under motor.

I've had a look at Sterling and Victron chargers but can't quite figure out how to wire it up to my set up.

My set up is alternator to 3 way Victron Argo Fet isolator. 1 output to house batt, 1 output to engine start and 1 output to bow thruster battery.

The wiring diagrams only seem to show a 2 battery system set up. Anybody have any good ideas on how to best wire it up.

You don't need a 3 output B2B, there isn't any such thing. You disconnect the domestic battery from the Argofet and connect the B2B between the engine battery and the lithium battery.

That said, i'd respectfully suggest that with such a limited understanding that you would do well to heed the advice for more research before proceeding.

One of the key benefits if fitting Lithium is the ability to charge them fast. So the better approach is to set all charging arrangements up for the Lithiums, then use a B2B to charge the engine and thruster batteries.

If you are not going to take advantage of the benefits of Lithium, you may as well stay with SLA

 

[Travelling Westerly]

I'm not familiar with the drop-ins you are thinking of, but usually with drop-ins you need to consider whether shutting off power to any of the loads will cause problems. E.g. autopilot, cabin lights.

You're right the inbuilt BMS has a set of safety limits that if operated outside of those set points it will shut down. I would loose autopilot etc but considering these drop in units are now made by names I've already got gear from (IE Victron) I hoped their reliability is good...

 

[Poey50]

Thanks . I did start reading that thread when it first began but realised that a drop in 216 ah was available from some well known manufacturers so decided to buy a drop in unit and not build one.
I already have the mains charger side covered via a Sterling Pro with Lipo charge profile. I wanted a similar lipo charger whilst under alternator charging hence the B2B .

The Sterling Pro Charge Ultra isn't suitable despite the claimed LFP profile because the absorption stage is too long. But as said the first issue is a sudden disconnect without warning taking your house battery into a non communicate state. An annoyance if cooking supper in the back of an RV, a danger if crossing a busy shipping lane at night. Do at least read the Marine How To paper in the opening post of my link above. The quality of wiring and electronics in drop-ins sometimes leaves a lot to be desired.

 

[Poey50]

You're right the inbuilt BMS has a set of safety limits that if operated outside of those set points it will shut down. I would loose autopilot etc but considering these drop in units are now made by names I've already got gear from (IE Victron) I hoped their reliability is good...

A good BMS inside a quality drop in should certainly protect your battery. It has no concern for you or your boat. People go the DIY route not just to save money but to create a safer system. Very good integrated systems such as Victron's are well thought out and safe but are costly. You can't buy just the Victron batteries and assume they are drop-ins as they don't have a BMS.

 

[Travelling Westerly]

You don't need a 3 output B2B, there isn't any such thing. You disconnect the domestic battery from the Argofet and connect the B2B between the engine battery and the lithium battery.

That said, i'd respectfully suggest that with such a limited understanding that you would do well to heed the advice for more research before proceeding.

One of the key benefits if fitting Lithium is the ability to charge them fast. So the better approach is to set all charging arrangements up for the Lithiums, then use a B2B to charge the engine and thruster batteries.

If you are not going to take advantage of the benefits of Lithium, you may as well stay with SLA

Thanks Paul, always appreciate your input.
Not sure where you got I wanted a 3 way B2B from though? I know they don't exist and didn't ask for one.
You know my set up as you helped with my BT install which is the reason I'm asking this question in the first place. As you know I now have 3 battery's (as you suggested) and that's where the confusion/request for help is coming from. All the wiring diagrams I can find only show a 2 battery set up for installing the B2b charger - wired between start battery and house. That bit is straight forward but my alternator goes to the 3 way Argo Fet splitter. Should I take the output from the Argo that goes to the current house battery and put the B2B between that 3rd output and the house battery?

 

[Kelpie]

You're right the inbuilt BMS has a set of safety limits that if operated outside of those set points it will shut down. I would loose autopilot etc but considering these drop in units are now made by names I've already got gear from (IE Victron) I hoped their reliability is good...

It's not really a question of reliability, it's overall system design. If you're going to power a critical system from LFP then you need to either accept that it could suddenly switch off, or you need to engineer a fairly sophisticated way of ensuring another power source can step in.

I'm taking a blunter approach to this. Since my boat already has a perfectly good lead-acid battery system, I'm keeping that exactly as it is to handle engine charging and to power critical loads (nav instruments and autopilot, plus a handful of cabin lights). The new LFP is for fridges, laptop chargers, etc etc.

 

[PaulRainbow]

Thanks Paul, always appreciate your input.
Not sure where you got I wanted a 3 way B2B from though? I know they don't exist and didn't ask for one.
You know my set up as you helped with my BT install which is the reason I'm asking this question in the first place. As you know I now have 3 battery's (as you suggested) and that's where the confusion/request for help is coming from. All the wiring diagrams I can find only show a 2 battery set up for installing the B2b charger - wired between start battery and house. That bit is straight forward but my alternator goes to the 3 way Argo Fet splitter. Should I take the output from the Argo that goes to the current house battery and put the B2B between that 3rd output and the house battery?

No. It's a battery to battery charger, so it connects between two batteries, the engine and domestic batteries.

So, You disconnect the domestic battery from the Argofet and connect the B2B between the engine battery and the lithium battery.

 

[Travelling Westerly]

A good BMS inside a quality drop in should certainly protect your battery. It has no concern for you or your boat. People go the DIY route not just to save money but to create a safer system. Very good integrated systems such as Victron's are well thought out and safe but are costly. You can't buy just the Victron batteries.

I know you are trying to help me and I do appreciate that so don't take this the wrong way please, more a question of your advice as I'm sure you know what you're talking about...

I can buy the batteries, this is just a quick copy and paste
Victron Energy LiFePO4 Battery 12.8V 200Ah Smart - BAT512120610 – Battery Megastore

Not Victron but similar Sterling Power AMPS 12V 100Ah LiFePO4 Lithium Leisure Battery

Victron Smart Lithium LiFePO4 12.8V 100Ah Battery | eBay
I have also seen them elsewhere available.

As for the Sterling charge profile being not suitable I find that difficult to accept. I brought that charger with a view to utilising the Lipo function. Sterling told me it was good to use. Are you saying Sterling have it wrong and are selling equipment not fit for purpose?

 

[Travelling Westerly]

No. It's a battery to battery charger, so it connects between two batteries, the engine and domestic batteries.

So, You disconnect the domestic battery from the Argofet and connect the B2B between the engine battery and the lithium battery.

That's great, exactly what I wanted, thanks Paul.

 

[Poey50]

I know you are trying to help me and I do appreciate that so don't take this the wrong way please, more a question of your advice as I'm sure you know what you're talking about...

I can buy the batteries, this is just a quick copy and paste
Victron Smart Lithium LiFePO4 12.8V 100Ah Battery | eBay
I have also seen them elsewhere available.

As for the Sterling charge profile being not suitable I find that difficult to accept. I brought that charger with a view to utilising the Lipo function. Sterling told me it was good to use. Are you saying Sterling have it wrong and are selling equipment not fit for purpose?

If you check further down the advert you will see that the Victrons are not drop in batteries, they have no BMS and are designed to be one component in the excellent and costly Victron LFP system. The Sterling is a drop-in but as I and others have said you need to take a whole-system approach.

I know the problem with your charger since I bought one assuming it would be suitable. I hadn't done enough research. I bought a Victron 30 amp one with fully user-configuable features instead. Sterling also used to market their A2B chargers as suitable for LFP and they still come with a lithium pre-set. But these days they have a red warning sign on their website warning that they do not limit current.

You can't adjust the absorption time on your mains charger and that is what can overcharge. The length of the absorption stage is automatically matched to the length of the bulk stage. One LFP manufacturer has specifically warned against using this charger with its LFP batteries. LFP ideally just needs to be taken to a target voltage and the charging stopped ... no or little absorption, no temperature compensation, no equalisation and no float. The multi-stage chargers are brilliant for lead acid but LFP is different. There is a possible work-around by using a custom setting of 13.6v for bulk and lower for float but even Rod Collins - the closest thing to a marine LFP expert - wasn't sure it would work.

 

[halcyon]

The Sterling Pro Charge Ultra isn't suitable despite the claimed LFP profile because the absorption stage is too long. But as said the first issue is a sudden disconnect without warning taking your house battery into a non communicate state. An annoyance if cooking supper in the back of an RV, a danger if crossing a busy shipping lane at night. Do at least read the Marine How To paper in the opening post of my link above. The quality of wiring and electronics in drop-ins sometimes leaves a lot to be desired.

It seems they are selling voltage controlled chargers, yet from what I read on the drop in battery manufactures you need constant current then constant voltage, also recommended charge charge rate of 0.2C. The funny thing is the charger we made in 1985 fitted this criteria, even had low battery load shedding, they call it progress

Brian

 

[Travelling Westerly]

If you check further down the advert you will see that the Victrons are not drop in batteries , they have no BMS and are designed to be one component in the excellent and costly Victron LFP system. The Sterling is a drop-in but as I and others have said you need to take a whole-system approach.

I know the problem with your charger since I bought one assuming it would be suitable. I hadn't done enough research. I bought a Victron 30 amp one with fully user-configuable features instead. Sterling also used to market their A2B chargers as suitable for LFP and they still come with a lithium pre-set. But these days they have a red warning sign on their website warning that they do not limit current.

You can't adjust the absorption time on your mains charger and that is what can overcharge. The length of the absorption stage is automatically matched to the length of the bulk stage. One LFP manufacturer has specifically warned against using this charger with its LFP batteries. LFP ideally just needs to be taken to a target voltage and the charging stopped ... no or little absorption, no temperature compensation, no equalisation and no float. The multi-stage chargers are brilliant for lead acid but LFP is different. There is a possible work-around by using a custom setting of 13.6v for bulk and lower for float but even Rod Collins - the closest thing to an LFP expert - wasn't sure it would work.

I see what you mean with the Victrons requiring a separate BMS so good point but the batteries do seem available to buy if I go that way.
I was thinking the Sterling was a better way to go considering both chargers are Sterling and their battery has built in BMS. I thought the main components being from the same manufacturer meant they would be matched to work in harmony but I'm guessing from what you said that's not the case ?

 

[Poey50]

It seems they are selling voltage controlled chargers, yet from what I read on the drop in battery manufactures you need constant current then constant voltage, also recommended charge charge rate of 0.2C. The funny thing is the charger we made in 1985 fitted this criteria, even had low battery load shedding, they call it progress

Brian

Or preferably constant current until the absorption voltage is reached then stop or maybe a short constant voltage (absorption) phase if the battery needs regular top balancing like Battleborns do. Yes sophisticated lead chargers are too complicated for LFP. Some people have tried using gell pre-sets on their chargers since the absorption voltage is lower and kinder not realising that there may be a very long absorption phase at that constant lower voltage.