Replacing RV charger/converter with a Victron charger

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robwolff3 asked Nov 5, '21

Replacing RV charger/converter with a Victron charger

I am thinking about replacing the charger/converter in my RV. It has a WFCO WF-8955LiS and I want to replace it with the Victron Blue Smart IP22 12-Volt 30 Amp charger. My thinking being I want to configure very specific custom charging profiles for my LiFePo4 batteries, 90% SOC before taking off for a trip, 50% SOC for storage and the existing WFCO charger is does not have configurable profiles.

The charger/converter in an RV not only charges the batteries but also acts as a power supply for all of the onboard 12v appliances when the RV is plugged into shore power. I have no doubts that the Blue Smart IP22 30 Amp charger will charge my LiFePo4 batteries to my desired profiles but would it also be able to power the 12v appliances at the same time while charging my batteries? and continue to power my 12v appliances once my batteries are charged? I know this Victron charger has a power supply function but I would have it in charging mode as the first priority is charging the LiFePo4 batteries.

Will this work? Is there a better solution I'm not thinking of?

Some additional notes:

I dont need an inverter so I was not considering the Miltiplus
The 12v appliances include: (They turn on and off as needed.)
- LED lights - 1A
- Fridge - 7A
- Furnace - 7A

battery charging Lithium Battery charger

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kevgermany ♦♦ commented · Nov 06, 2021 at 09:16 AM

Overall you have enough power in the system, and you can assess charging times from the output current to see if it's acceptable.

However you need to check carefully if you can achieve the desired charge profile, I'm not sure you can.

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Answer 1 · 2021-11-06T18:51:36Z

Mike Dorsett answered · Nov 06, 2021 at 06:51 PM

looking at your loads, your peak current is only 15A - leaving worst case 15A to charge batteries. The fridge would likely be at 30% duty cycle, and 'furnace' would probably be a lot less (water heating or air heating?). This should leave plenty of energy for recharging. Depends on your battery capacity, which is not stated.

Also, why drop the Lithiums from 90% to 50%? If 'storage' means you are not using any of the loads or the RV, Litium storage can be anywhere from 50% to 25%; but it's generally not needed to charge the batteries more than once a year if they are disconnected from loads (inc BMS). The charger can then be set to give float charge equivalent to 90% SOC.

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Answer 2 · 2021-11-07T01:01:44Z

xmd answered · Nov 07, 2021 at 01:01 AM

I have a small RV with the IP22 (30 amp / 3 circuit).

First, 50% SOC is very conservative - your LiFePO batteries will probably already last 10x longer than your RV, even if charged to 90% or 100%. Many LFP batteries are good for 2000+ cycles, and if you are storing your RV part of the year, you aren't even doing one cycle per day. You don't have to coddle your LFPs.

Second, note that the multi-battery IP22s do not have independent control of all circuits. I have a 3-channel IP22 (of which I'm using 2: one for house LFP and one for lead acid starting battery) and it seems like it bonds the two together. E.g. you can't have different charge profiles for each battery. If you can find a happy compromise between Lead Acid and Lithhium profiles, the IP22 is great.

I had mine set up to float at 13.2, and vampire loads were causing the LFP house battery SOC to drop to under 80%. Since I think of my RV more as a "emergency vehicle" I wanted it to be at 100% all the time, so I bumped up the float voltage to 13.5.

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kevgermany ♦♦ commented · Nov 07, 2021 at 10:57 AM

I may be wrong, but conventional wisdom is that Lithium batteries suffer stress when higher or lower than 50% and that storing fully charged shortens the service life. I think that's what the OP is working from. My lithium charger has a function to put them into storage mode, which discharges down to 50%.

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