Adding Lithium capacity to our existing setup

[paulbrown22]

Can't answer those questions without knowing exactly what you have and how it can be configured.

I need to check what "smart" regular I have (nothing that smart as it's probably 20 years old). But beyond that I have nothing yet, just starting to think ahead on what I might want to do in the future and similar to the OP thinking about upgrading to some modern Victron charging/solar/inverter/monitoring gear as a first step and then swapping out to Lithium house batteries later on!

 

[chris-s]

Okay interesting. I thought the charge would flow via the DC-DC charger to the domestic bank, discharging the engine battery which would then get topped up again by the mains charger. Are you saying connect the mains charger to the domestic bank?

The dc-dc charger will start charging the house batteries at 13.2v. It seems to work fine with the victron shore power charger just on the engine battery. This is how we maintain our lithiums over the winter, tho we do let them rundown a bit rather than maintain them at 100%.

Chris

 

[PaulRainbow]

The dc-dc charger will start charging the house batteries at 13.2v.

When the input battery is at 13.2V ?

It seems to work fine with the victron shore power charger just on the engine battery. This is how we maintain our lithiums over the winter, tho we do let them rundown a bit rather than maintain them at 100%.

Chris

What are your settings for the DC-DC charger and the shore power charger ?

 

[Sea Change]

I'm going to slightly hijack this discussion with a question of my own.
We've been experiencing some exceptionally dull and rainy weather today, so I've been thinking about digging out my unused DC-DC charger.
I don't really want to use it for engine charging, I'm far too tight fisted to burn diesel just to top up my batteries.
But I do have a Silentwind 400 sitting doing almost nothing, keeping the engine and windlass lead acid batteries topped up.

If I hook up the DC-DC so that the lead acids can charge the lithiums, will this work with just the wind gen running? I'm worried that it won't reach a high enough voltage to work.

 

[geem]

I'm going to slightly hijack this discussion with a question of my own.
We've been experiencing some exceptionally dull and rainy weather today, so I've been thinking about digging out my unused DC-DC charger.
I don't really want to use it for engine charging, I'm far too tight fisted to burn diesel just to top up my batteries.
But I do have a Silentwind 400 sitting doing almost nothing, keeping the engine and windlass lead acid batteries topped up.

If I hook up the DC-DC so that the lead acids can charge the lithiums, will this work with just the wind gen running? I'm worried that it won't reach a high enough voltage to work.

Yes it will work but you will likely find that it repeatedly switches in and out. As the voltage rises high enough to switch on the DC/DC, the drain to the lithium bank will be such that the lead battery will deplete quickly until it switches the charger off. I am not sure how long the DC/DC will last constantly switching in and out. If the DC/DC is small enough and the wind turbine is powerful enough to make more than the DC/DC can transfer between batteries, , then you are good to go

 

[ianabc]

For running fridges etc at anchor, personally I would start by adding more solar ahead of more battery.
Appreciate that space is tight on a Fulmar, but 30w is very small these days. Surely you could find space for at least 100w - perhaps in a couple of semi flexible panels (ours are on the sprayhood). And perhaps another one or two moveable semi flexible panels able to be set up when at anchor?

We have a Danfoss co.pressor running our fridge 4 Amps when running.



We have a 5 x 100 Amp hr lithium battery bank.

 

[Sea Change]

Yes it will work but you will likely find that it repeatedly switches in and out. As the voltage rises high enough to switch on the DC/DC, the drain to the lithium bank will be such that the lead battery will deplete quickly until it switches the charger off. I am not sure how long the DC/DC will last constantly switching in and out. If the DC/DC is small enough and the wind turbine is powerful enough to make more than the DC/DC can transfer between batteries, , then you are good to go

It's only an 18A DC-DC, but I think you're right that in practice it would cycle on and off which wouldn't be ideal.

 

[mrming]

Perhaps just fit a Victron solar controller for now and leave the existing mains charger as it is. When you go Lithium fit a Victron DC-DC charger and a new mains charger.

Checking back in on this. We fitted 2 x 50W Renogy solar panels, on the stern pulpit meaning they can be angled in one axis through around 180 degrees. We fitted the Victron MPPT controller as recommended by @PaulRainbow (SmartSolar MPPT 75V 15 amp). Just finishing up our annual boat holiday. We’ve been blessed with very sunny weather and we’ve just spent 5 days away from shore power, running the fridge, 5G router and charging the kids’ myriad of devices with no power problems. Success!