Lifepo4 Batteries

[Midnightsun]

Starting to take shape.

Made a wood battery tray from Russian birch, stained it black with 3 coats of varnish. Both batteries fit into a 21' x 21" space. Figured I can setup up everything at home and then just screw the battery tray in place and slide everything on. Got all the logistics worked out and now just need to crawl into ridiculous places to install everything.

600 usable AH of Lipo.

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[vineyardgray]

Can't wait to see the project take shape!

[Helmsman]

Any updates on your project?

I haven’t been keeping up lately. I did see that you had 60 amps total charge from two alternators. Are the DC to DC units going to manage the demand from the lithium? With a 600 amp hours bank, it would seem that the much larger accepted charge rate of the batteries could burn your alternators up.

One workaround is an external regulator with a temperature sensor, and in your case you might need a centerfielder since you have them both connected to the bank.

Just some thoughts.

[Midnightsun]

Boat is wrapped up for the winter so probably not until early April before any additional updates. The charge will be handled not by the alternators which can produce up to 135a each, instead I opted for dual 30a DC to DC chargers which will give a total of 60a directly to the lithium bank from both port and starboard wet cell banks which are charged via the alternators while under way. This ensures no problems with the integration of the lithium bank when it comes to charging while under way.

Having a unit on each bank ensures the lithium bank will be charged even if an alternator were to fail albeit at a reduced rate of 30a. In fact these DC to DC chargers seem to be the preferred method over ACRs, combiners and isolators when it comes to lithium integration. Will probably become the new norm if you ask me.

Have 2 of these in my garage https://www.victronenergy.com/dc-dc-con ... n-isolated

An explanation of the DC to DC charging principle. https://www.renogy.com/blog/what-does-a ... %20driving.

[Helmsman]

Source of the post Boat is wrapped up for the winter so probably not until early April before any additional updates. The charge will be handled not by the alternators which can produce up to 135a each, instead I opted for dual 30a DC to DC chargers which will give a total of 60a directly to the lithium bank from both port and starboard wet cell banks which are charged via the alternators while under way. This ensures no problems with the integration of the lithium bank when it comes to charging while under way.

Having a unit on each bank ensures the lithium bank will be charged even if an alternator were to fail albeit at a reduced rate of 30a. In fact these DC to DC chargers seem to be the preferred method over ACRs, combiners and isolators when it comes to lithium integration. Will probably become the new norm if you ask me.

Have 2 of these in my garage https://www.victronenergy.com/dc-dc-con ... n-isolated

An explanation of the DC to DC charging principle. https://www.renogy.com/blog/what-does-a ... %20driving.

Sorry, I misunderstood your post. I like the approach that you are using. DC to DC chargers through the start or other batteries seem to be the best way to go, based upon everything I have read on the subject. There is one gotcha when you first connect lead acid through to LifePO. I was cautioned by the guy who wrote the articles I originally linked, that you need to make sure the voltages are very close to each other in both banks. Otherwise, the initial in rush of current to the lead acid bank from the lifepo might be too strong for your system.

[Midnightsun]

I was cautioned by the guy who wrote the articles I originally linked, that you need to make sure the voltages are very close to each other in both banks. Otherwise, the initial in rush of current to the lead acid bank from the lifepo might be too strong for your system.

The lead acid and lithium are not connected and never will be. I cannot combine batteries via a 1/2/both switch as there are none installed on my Carver. The only time I would say they are combined is via the DC to DC charger however this is completely controlled and as indicated, max out at a 30a output for each unit therefor no possibility of large in rush of current from other batteries regardless of their state of charge differences. These DC to DC chargers work basically the same as a 30a shore power charger but instead of getting 110v power from shore to run the charger they get it from a 12v battery bank. Hope that clears things up.

[Helmsman]

Source of the post

I was cautioned by the guy who wrote the articles I originally linked, that you need to make sure the voltages are very close to each other in both banks. Otherwise, the initial in rush of current to the lead acid bank from the lifepo might be too strong for your system.

The lead acid and lithium are not connected and never will be. I cannot combine batteries via a 1/2/both switch as there are none installed on my Carver. The only time I would say they are combined is via the DC to DC charger however this is completely controlled and as indicated, max out at a 30a output for each unit therefor no possibility of large in rush of current from other batteries regardless of their state of charge differences. These DC to DC chargers work basically the same as a 30a shore power charger but instead of getting 110v power from shore to run the charger they get it from a 12v battery bank. Hope that clears things up.

Yes, it does. Thank you. I went back and re-read the thread. I mangled your clear description of your set up magnificently! Thanks for helping me get there. Merry Christmas!

[Midnightsun]

Here are some pics of the install.

We are on our 3rd week on the boat, the Lithium setup with inverter and solar is what it should have been from the getgo. Tons of juice available all the time and charging is very fast. Very pleased with everything, now let's hope these batteries last 10+ years like they say they will.

Everything is under the galley floor. That would be this hole as can bee seen below. The batteries and most of the other stuff is located under the cabinets. Wiring is attached to the underside of the floor which is plywood and aluminum frame. Depth of the hole under the floor is about 28". Yes I do have the battery positive post insulators, just have not installed them yet.

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Here you can see the batteries, DC to DC chargers screwed to the rear wall as well as the dedicated 80a lithium charger to the right on the back wall as well as the dedicated 20a outlet for the charger.

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Here you can see the dc to dc chargers and the positive and negative bus bars, sorry, tight spot and bad lighting.

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This photo shows wiring running underneath the galley floor secured to the underside, one can see the shunt and the 2 breakers are for the DC to DC chargers.

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Here you can see the overall from farther away, shows also my inverter screwed to the underside of the floor. Also one can see the water filters for the potable water supply and a NOCO charger which gets used when on the hard only as there is no way of powering the boat unless 220v is available.

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[bud37]

Hans...looks like a very nice well thought thru instal as usual.......good choice on the Victron.....kudos....

[Midnightsun]

The dedicated lithium charger combined with solar is giving me pretty amazing charging results. This morning at anchor we are down to 66% capacity of useable house bank power. Started the generator for breakfast and am getting a charge rate of over 106A amps.

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