LiFePO Batteries ???

[bruceb58]

I am pulling it once the new 50A DC to DC is delivered I just ordered.

Yes...flex panels suck. I tried to talk my brother out of his. Besides life, they also get hot because there is no cooling so their output is reduced. Less of a problem for you since you are near the water

 

[tpenfield]

Here is my other approach . . . It might be a coin toss.
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I'm not getting any usable advice from the DIY Solar forum, but I think I'm in the ballpark with either of these approaches.

 

[tpenfield]

I have an Orion 12-12/30. I am pulling it once the new 50A DC to DC is delivered I just ordered.

Thanks for the offer . . . just a reminder, buy/sell dialog should be conducted in PM's rather than the forum.

 

[tpenfield]

@bruceb58 . . . I may wait it out for the Orion XS, as I believe they have solved the heat/cooling problem and have more output control than the Orion Smart series.

 

[bruceb58]

@bruceb58 . . . I may wait it out for the Orion XS, as I believe they have solved the heat/cooling problem and have more output control than the Orion Smart series.

I certainly would.

It also can take advantage of VE.Network so that it will do remote voltage sensing with a battery monitor which you should really add to your lithium bank even if the battery has a builtin monitor. The battery built in monitors are very innaccuarate.

That's also another reason you should use Victron solar controllers...programmable through your phone.

 

[bruceb58]

Thanks for the offer . . . just a reminder, buy/sell dialog should be conducted in PM's rather than the forum.

Didn't even think about that when I posted it...no problem.

 

[tpenfield]

I have decided to go with the approach of charging the LFP batteries, then let the LFP's the charge the AGM's. Since the LFP's 'rest' at about 0.5-0.8 volt higher than the AGM's, it might be a more effective approach . . . electrons going 'down hill' to my way of thinking. The features of the Dual Input Renogy charger are designed for a mixed battery system with solar and alternator charging, which simplifies things.

Here is my cleaned-up wiring diagram for those who have not fallen asleep yet. . .
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The Renogy charger is said to be butt-simple to set up and has some nice features . . . (Boy-genius Will Prowse has a nice video on the unit)

• Solar input is favored over the alternator input
• The solar input activates when the Panel Voltage (PV) reaches 15V, (so it shuts itself off at night)
• The Renogy unit will take only 1/2 of its rated output from either source (Alt or Solar). So, for the 50 Amp unit it will only take 25 Amps from the alternator.
• When the 'House' battery is fully charged, the unit will trickle charge the starter battery via the second input (Batt/Alt input)

I plan to charge the AGM's (for when the boat is at the mooring) via the Victron Orion XS ( Xtra Smart) charger, which will get its power from the LFP batteries. I am going to set the input threshold on the Orion to about 13.5 volts, so charging of the AGM's will only happen when the LFP's are near 100%. As the LFP's get depleted (go below 13.5 volts) the charging of the AGM's will stop. I'll have to see how this threshold works in real-life

When the engine(s) are running the AGM's will get charged directly from the alternators and the LFP's will get charged as needed from a combination of solar and alternator sources.

Figuring this out has been sort-of-fun, but too much techy stuff for morning pre-coffee thinking.

 

[tpenfield]

One area of the design that has me thinking/re-thinking is when the engines are running the voltage on the output side of the FET Isolator will probably be higher than the input side as per the schematic below . . . Approximate voltages shown at the FET Isolator.
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I'm not sure the FET Isolator will like this. . .

I may need to put a relay in the 'energize' circuit of the isolator to shut it off when the engines are running. A typical automotive relay (which the boat has several already) using the 'normally closed' side should do the trick.

Alternatively I could use the relay to shut off the DC-DC charger when the engines are running.

 

[bruceb58]

One area of the design that has me thinking/re-thinking is when the engines are running the voltage on the output side of the FET Isolator will probably be higher than the input side as per the schematic below .

Shouldn't be an issue. In normal use, there is no voltage at the input and only voltage on the output when the engine is not running.

 

[tpenfield]

Getting ready to spend some money on this next month and will need some new wiring.

The main battery wiring is AWG 2/0 and other wiring looks to be AWG 6. Not sure if I'll need any of the 2/0 since I'll be surplussing some in reducing the number of batteries.

 

[tpenfield]

After several times going back & forth on the design approach, I have decided to go with a dual output controller (rather than the dual input controller) The EPEver controller has a nice feature of providing only a trickle charge on the second output, which is what would be typically needed for the AGM batteries. . . . not that the LFP batteries would need much more than a trickle either . . . but the charging profile will dictate that. Updated diagram below . . .

I've also decided to use a relay to turn off (lock out) solar charging when the engines are running so as not to get voltage/current trying to come from 2 places. We'll see how that all works out.

I better start ordering components so I would change my mind (again)
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[bruceb58]

You don't need to lock out the solar. It is fine to have multiple sources charge your batteries. I do it all the time with my lithium.

 

[tpenfield]

I just ordered about $1K worth of batteries, controllers, converter and related 'stuff' to start my battery / power system upgrade.

The game plan will be to remove the existing batteries this weekend.

I'm going to see how much of the 2/0 AWG cable can be re-purposed for the new system.

 

[cyclops222]

The LIFEPO4 batteries are very safe . What you want on a boat way away from land.
All other chemistries of Lithium Ion DO DO catch fire for no reason.
You will not put out any other Lithium type fires on your boat.

 

[tpenfield]

Despite the pouring rain, I was able to get the 7 (seven) batteries out of the boat.
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I believe one of the house batteries was internally shorted out, so I couldn't run the maintenance charge over the winter, as both the charger and inverter would peg at their maximum amps (80 amps for the inverter charger, and 30 amps for the shore power). The batteries are all pretty much cooked, having sat over the winter. The best battery was sitting at 10 volts and the second best was at 6 volts. Both not worth fussing with.

Anyway . . . my LFP batteries should be here next week and I'll need to get a couple of Lead-Acid starter batteries for the port and starboard engines.

So, 7 batteries came out and 4 batteries will be going back in. I'll need to see about re-purposing some of the 2/0 AWG wire in the new configuration. Not sure If I can, but won't know until I get the extra battery boxes out of the way.

 

[Scott Danforth]

did you fill all the extra screw holes in

 

[airshot]

The LIFEPO4 batteries are very safe . What you want on a boat way away from land.
All other chemistries of Lithium Ion DO DO catch fire for no reason.
You will not put out any other Lithium type fires on your boat.

Very rarely do they catch fire for no reason, but, the smallest mistake can create an intense white hot fire in seconds that water does not put out !! Lifepo4 are much improved and more forgiving !!

 

[tpenfield]

did you fill all the extra screw holes in

Not yet . . . got to take the battery boxes out first.

 

[tpenfield]

The LIFEPO4 batteries are very safe . What you want on a boat way away from land.
All other chemistries of Lithium Ion DO DO catch fire for no reason.
You will not put out any other Lithium type fires on your boat.

and @airshot

Yes, I believe the benefits of LiFePO4 have been discussed in this thread and elsewhere.

I've ordered two 100Ah LiTime LiFEPO4 batteries with cold temperature charging protection to replace the five AGM batteries that served as the house battery bank. They should arrive on/about Wednesday of next week.

I'm going to try to get a couple of decent Lead-acid batteries locally for the engine banks.

 

[tpenfield]

In other news. . . I have found that the port engine still has a persistent coolant leak. Each year I try to fix it, but over the winter it looses about a gallon of coolant.

Probably some cross-over assembly maintenance is in my future, as I believe that is where it is leaking.