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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Jason on August 08, 2024, 04:24:19 pm

Title: Couple questions on converting house batteries to LiFePO4
Post by: Jason on August 08, 2024, 04:24:19 pm
I want to change the house batteries to lithium as mine are bad. I will do what Tom did for stage 1 Changing flooded lead acid batteries to lithium batteries (https://www.foreforums.com/index.php?topic=47505.0)  and will go with the 12-12/30A Victron Orion-Tr Smart Non-Isolated DC-DC Charger Victron Orion-Tr Smart Non-Isolated DC-DC Chargers (https://baymarinesupply.com/victron-orion-tr-smart-non-isolated-dc-dc-chargers.html)

Question
1- Where can I get the Xantrex setting for changing the battery type?
2- Will the DC-DC charger charge the start batteries on shore power too?
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: craneman on August 08, 2024, 05:00:55 pm
Which Xantrex do you have? The SW 2012 has a custom setting in the menu and you put in the info that the battery manufacturer give you.
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: DaBus on August 08, 2024, 06:36:12 pm
Xantrex gel setting will do just fine with lithium.  It sets float at 13.8 vs 13.67 that a Victron will do.  Your new batteries will do just fine.  Went for 4 years with the old Xantrex ProSine 2500 untill we switched out to a Victron.  1600 AH of lithium are living just fine.  Make sure equalize is OFF.  Your battery BMS is the ultimate arbiter of the charge profile.
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: Jason on August 08, 2024, 06:42:13 pm
Which Xantrex do you have? The SW 2012 has a custom setting in the menu and you put in the info that the battery manufacturer give you.

It's the Prosine 2500.
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: Jason on August 08, 2024, 06:43:09 pm
Xantrex gel setting will do just fine with lithium.  It sets float at 13.8 vs 13.67 that a Victron will do.  Your new batteries will do just fine.  Went for 4 years with the old Xantrex ProSine 2500 untill we switched out to a Victron.  1600 AH of lithium are living just fine.  Make sure equalize is OFF.  Your battery BMS is the ultimate arbiter of the charge profile.

Good to hear, that is the one I have.

Anyone know the answer to question 2?
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: DaBus on August 08, 2024, 06:48:51 pm
The Victron Orion is a alternator  only unit so it will not work for shore power.  You will need some sort of echo charger to go from your inverter/charger (house bank) to your chasis battery.  Or use your boost switch if you have one, though that has some inherent problems if shore power goes out.
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: Realmccoy on August 09, 2024, 09:02:02 pm
I use a second Victron B2B to charge my start batteries (Lithium house to start). It is the smaller B2B Orion 12|12|18 amp. You can set it up for the exact voltages for bulk, absorption and float needed by your conventional start batteries.  All other echo chargers assume your coach batteries are conventional. The AmplStart was capable of lithium to conventional but it went out of business.

Been using it for 19 months no complaints. We boondock enough to make it worthwhile. You can set a low voltage cut off to keep from over draining your house batteries. I installed it in the electronic  area at foot of bed where my transfer switches live. I connected it through a couple breakers so I can isolate it when messing with start batteries or coach batteries.
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: turbojack on August 09, 2024, 10:14:51 pm
Sterling Power makes B2B that are two way. 
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: Dennis H on August 10, 2024, 08:14:08 am
There seems to be trend here to make things more complicated than needed. In reality Lithium batteries are much easier to charge and the built in BMS makes things even easier. Limit charging current t the batteries based on power/current available and set/limit voltage to 14.4 to 14.6 volts, and you are done. The BMS will limit current further. After full charge go to low float voltage 13.2 to 13.6 or better yet stop. No longer needed is the absorption stage or equalization charges. With these voltages a combining relay can be sued to charge the chassis batteries. I have also seen system where an AGM was part of the lithium house battery package to maintain operation when the BMS turned off or to support cold weather or even generator-engine starting.
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: Jason on August 16, 2024, 02:06:06 pm
Another question-

These Power Queens are on sale today for $399 which his $100 off. Amazon.com: Power Queen 12V 200Ah LiFePO4 Battery with Built-in 100A BMS,... (https://www.amazon.com/LiFePO4-Battery-Lithium-Lifespan-Perfect/dp/B09BQVVTHH)

They also have the Plus for $424 which is also about $100 off https://www.amazon.com/LiFePO4-Battery-Lithium-Lifespan-Perfect/dp/B09FSYCXGS

Power Queens get great reviews from what I have researched.

The only difference is the first has a 100A BMS while the Plus has a 200A BMS. I plan on getting 2 or 3 of them. Is the 200A BMS worth it or will the 100A BMS suffice. I don't have solar but would add it down the line.

Thanks.
Title: Re: Couple questions on converting house batteries to LiFePO4 The BMS
Post by: Dennis H on August 16, 2024, 02:42:32 pm
The major difference between the standard and Plus is the BMS. The standard BMS is limited to 100 amp discharge, the plus 200 amp. If using for generator starting or to power an inverter you want the higher capacity BMS.
Look at some of the other brand options. I went with LIPULS.

Amazon.com: LIPULS 12V 280Ah LiFePO4 Lithium Battery, Built-in 200A BMS,... (https://www.amazon.com/LIPULS-LiFePO4-Lithium-Off-Grid-Trolling/dp/B0CSVR3ZGF/ref=b2b_gw_d_simh_d_sccl_1/138-7682835-6986017?pd_rd_w=uP5Nh&content-id=amzn1.sym.cf3b7b6b-c752-47d6-95da-e2ae9547639e&pf_rd_p=cf3b7b6b-c752-47d6-95da-e2ae9547639e&pf_rd_r=ZM35YR6K9X2WTVZPNES6&pd_rd_wg=Z3c7P&pd_rd_r=0b3e028c-a4e9-4896-89cd-b59c00ee12d9&pd_rd_i=B0CSVR3ZGF&psc=1)

Note the favorable dimensions.
Title: Re: Couple questions on converting house batteries to LiFePO4
Post by: Jason on August 16, 2024, 07:45:53 pm
Funny you should mention size, I was thinking about asking a question related to that. A lot of these lithiums seem to be close to an 8D, somewhere in the 20.75 to 20.94" . The Oreilly lead is 20.75 per spec. However, my tray is 19 3/8", so they must take into consideration the handles. Are the base of the lithiums 19 3/8" or less? I don't want to mess with lengthening the tray. The Power Queens are 20.94" so it seems like it would be a gamble if they would fit. Some of these have no return policies on Amazon due to hazmat, so I'd like to get it right the first time.

I also have been looking at Lipuls and like what I see. The concern with those is the posts are on different ends, that won't work for me, I need them on the same end. I don;t want to rerun cable, I am looking for a drop in and connect.