Lithium house battery charging

Cornishwesterly said:
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 ?
Click to expand...

Yes, I hadn't meant to imply that you couldn't buy a Victron battery only that you have to buy it as part of a complete Victron system. I've edited my post as it was inadvertently misleading on that point.

Sterling really can't compete with Victron in terms of integration. Their alternator protect device is widely used in LFP systems otherwise people tend to look elsewhere for charging. Their B2B is fine because of the user profiles (where you can independently adjust absorption) but the Victron Orion is neater and, with Bluetooth, more user-friendly.
 
Last edited:
Poey50 said:
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.
Click to expand...

That's the cycle we did back then :)

Brian
 
Poey50 said:
Yes, I hadn't meant to imply that you couldn't buy a Victron battery only that you have to buy it as part of a complete Victron system. I've edited my post as it was inadvertently misleading on that point.

Sterling really can't compete with Victron in terms of integration. Their alternator protect device is widely used in LFP systems otherwise people tend to look elsewhere for charging. Their B2B is fine because of the user profiles (where you can independently adjust absorption) but the Victron Orion is neater and, with Bluetooth, more user-friendly.
Click to expand...
The Marine how to article does seem to suggest the Sterling B2B will protect the alternator from a BMS dump. Does the Victron Orion do the same?
If starting from scratch with a drop in do you recommend staying with a full Victron set up (Ie dump my current Sterling Pro)?
 
Cornishwesterly said:
The Marine how to article does seem to suggest the Sterling B2B will protect the alternator from a BMS dump. Does the Victron Orion do the same?
If starting from scratch with a drop in do you recommend staying with a full Victron set up (Ie dump my current Sterling Pro)?
Click to expand...

I haven't seen the Victron Orion tested in the way that Collins (author of the article) tested the Sterling Pro Batt Ultra. I'd be surprised if that was a problem. However a Sterling Alternator Protect is a relatively inexpensive, easy to fit, back-up against a voltage spike.

I started out with Sterling chargers bought on clearance. I now have all Victron Bluetooth kit (other than the alternator protect). One of the less obvious features of Bluetooth is how much easier it is to update with the latest firmware - essential for a still-developing knowledge base like LFP charging. That plus the integration between devices and wide range of user configuration makes Victron a hands-down winner in my view.

One solution to the problem of sudden disconnect of LFP (not the best solution) is offered by including a Victron BMV 712 monitor in your system. I have mine set up to sound alarms if any disconnect parameters are getting near. I also have a loud external alarm connected to the 712's relay when parameters get even closer. It's not ideal as you need to ensure the monitor is properly synchronised to the battery pack but better than no warning system at all.

In place of the Sterling Pro I have a Victron BlueSmart 12 / 30 mains charger. Plenty for my setup, reasonably priced and 1/3 of the size.
 
Last edited:
If you use your 'engine' battery as an intermediary between the alternator and the B2B charger, does it meaningfully fill the racing requirement of 'battery kept solely for starting the engine'?

Fair enough, a lot of people don't race, and others don't care if they meet the intent of the rules, but from a safety (and avoidance of embarrassment ) point of view., I think there is some merit in the start battery not being used for anything else.

Will it see a lot of cycling and have a short life?

What exactly does one gain from all this complication?
 
TernVI said:
If you use your 'engine' battery as an intermediary between the alternator and the B2B charger, does it meaningfully fill the racing requirement of 'battery kept solely for starting the engine'?

Fair enough, a lot of people don't race, and others don't care if they meet the intent of the rules, but from a safety (and avoidance of embarrassment ) point of view., I think there is some merit in the start battery not being used for anything else.

Will it see a lot of cycling and have a short life?

What exactly does one gain from all this complication?
Click to expand...

I am far from an expert but my understanding is that the starter battery would have to be pretty much full before the B2B would start sending any power across to the lithium bank. This is because the starter battery operates at a lower voltage, so no meaningful charging will occur until it is close to full. This should ensure a nice long life for the starter battery.

At least I hope that's how it works, because that is how I plan to wire up my own boat. There might be something very clever going on involving buck/boost transformers in the B2B which means I've got this all wrong...
 
TernVI said:
If you use your 'engine' battery as an intermediary between the alternator and the B2B charger, does it meaningfully fill the racing requirement of 'battery kept solely for starting the engine'?

Fair enough, a lot of people don't race, and others don't care if they meet the intent of the rules, but from a safety (and avoidance of embarrassment ) point of view., I think there is some merit in the start battery not being used for anything else.

Will it see a lot of cycling and have a short life?

What exactly does one gain from all this complication?
Click to expand...

Unless set up incorrectly the B2B only draws from the start battery when the engine is running and the start battery is above a threshold voltage.
 
Last edited:
Poey50 said:
Unless set up incorrectly the B2B only draws from the start battery when the engine is running and the start battery is above a threshold voltage.
Click to expand...

The more I read the less I like the system.

A low engine battery will never be charged, system runs around 13.3 volt alternator, to low to charge engine battery unless flat and then only to a low level. The LiFePo4 drop in battery manufactures ask for constant current of 0.2C to a voltage point, then constant voltage till current down to 0.02C, reading the spec B2B it is constant voltage / constant voltage. The bare alternator output is closer to the requirement on it's own.

Brian
 
halcyon said:
The more I read the less I like the system.

A low engine battery will never be charged, system runs around 13.3 volt alternator, to low to charge engine battery unless flat and then only to a low level. The LiFePo4 drop in battery manufactures ask for constant current of 0.2C to a voltage point, then constant voltage till current down to 0.02C, reading the spec B2B it is constant voltage / constant voltage. The bare alternator output is closer to the requirement on it's own.

Brian
Click to expand...

I'll let someone who uses the system answer your specific concerns. It's quite a common setup with no downside to the start battery that I'm aware of. But I don't favour the system either for different reasons, and don't use it, as it gives up one of the great advantages of LFP which is the ability to take on charge quickly. My LFP pack is charged from an alternator with external regulator. A B2B then charges the start battery from the LFP. I keep the start battery in permanent float.

Charging LFP via a B2B appeals to those with plenty of solar, which is fine for those who understand their system, and also appeals to those who have been told that LFP is very straightforward - not fine.
 
Last edited:
Poey50 said:
I'll let someone who uses the system answer your specific concerns. It's quite a common setup with no downside to the start battery that I'm aware of. But I don't favour the system either for different reasons, and don't use it, as it gives up one of the great advantages of LFP which is the ability to take on charge quickly. My LFP pack is charged from an alternator with external regulator. A B2B then charges the start battery from the LFP. I keep the start battery in permanent float.

Charging LFP via a B2B appeals to those with plenty of solar, which is fine for those who understand their system, and also appeals to those who have been told that LFP is very straightforward - not fine.
Click to expand...

It's not a concern, more a design function, not something I would design or sell, at least in that configuration.

Brian
 
Cornishwesterly said:
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 ?
Click to expand...
Precisely my point about fully understanding installation of Lithium batteries on boats. You have already got some very good feedback from people who have been there and done it. Tread carefully.
 
Poey50 said:
I'll let someone who uses the system answer your specific concerns. It's quite a common setup with no downside to the start battery that I'm aware of. But I don't favour the system either for different reasons, and don't use it, as it gives up one of the great advantages of LFP which is the ability to take on charge quickly. My LFP pack is charged from an alternator with external regulator. A B2B then charges the start battery from the LFP. I keep the start battery in permanent float.

Charging LFP via a B2B appeals to those with plenty of solar, which is fine for those who understand their system, and also appeals to those who have been told that LFP is very straightforward - not fine.
Click to expand...

That was one of my points in post #8. I'd configure all charging sources to charge the Lithiums, even solar, the a B2B to look after the engine battery, which takes very little looking after anyway.
 
We’ve gone for a setup of Sterling Ultra (shore charger) and Epever MPPT controllers both charging a Sterling lithium house bank, with the thruster / windlass battery being charged via B2B charger (straight from the lithium). Our engine start battery is completely separate to this setup.

Anyone have a recommendation on B2B chargers? I see Sterling does one (12v/30a) that should drop in nicely for about £175...

n
 
ausnp84 said:
We’ve gone for a setup of Sterling Ultra (shore charger) and Epever MPPT controllers both charging a Sterling lithium house bank, with the thruster / windlass battery being charged via B2B charger (straight from the lithium). Our engine start battery is completely separate to this setup.

Anyone have a recommendation on B2B chargers? I see Sterling does one (12v/30a) that should drop in nicely for about £175...
Click to expand...

That mains charger isn't really suitable. See my post #10 in this thread. The Sterling B2B will do it but I think the Victron Orion B2B is better featured and smaller.

At the risk of boring even myself I suggest again that anyone considering changing to LFP asks themselves these three questions about BMS disconnect.

1. How will I know if it is about to happen?
2. What will the effects be?
3. How do I mitigate the effects?

For anyone not able to answer these or not sure why they are being asked you need to do more research.
 
Last edited:
  • Like
Reactions: vas
I think it's safe to say if you want LFP NOW, you pay big bucks and get a fully integrated system from Victron (fe), else you either wait or go learning ...

IOW, LFP is not yet ready for prime time!
 
You must log in or register to reply here.

Share this page

Top