Drop in Lithium Charging Question

Howdy Folks!
I’ve recently changed over to single Ruixu 100ah lithium battery in our RV. I have 260 watt’s of solar with a Victron mppt 100/20 controller. I’m wondering if I need or should make any changes to my charging system. The Victron should be good to go set to Lithium. Battery charges with Ford E350 alternator while driving, not sure of charging parameters. If we plug in or start generator the existing WFCO power center charges (Absorption @13.6V., Bulk @ 14.4V & Float @ 13.2V). What do you think. Hate to throw more money at it if not required.
Thx!

I also would like to hear opinions on this. I also have a WFCO it's 68100 Converter/ Charger that has a similar charge profile. Mine charges bulk at 14.6v at 100amps. I am still deciding what direction to go. I typically am on free shore power, so I have a hard time justifying the cost of doing a major upgrade. I did order 8- prismatic LFP 3.2V 200ah cells to replace my 4 house batteries, and am planning on installing some solar.

I don't know of a drop-in battery (of reasonable capacity) on the planet that isn't perfectly happy at a bulk charge of 14.4 and float at 13.2. I think you're good to go with the WFCO for as long as it holds out, so long as it's not throwing too much current at it - most drop-ins like to see .5C or less, so as long as the WFCO isn't charging at 100A you should be fine. Double-check with the Riuxu user manual, of course... given the questionable quality of their BMS, you definitely don't want to run the edge on their charging specs and risk frying the BMS.

Not sure about your alternator charging though, that can get hairy since alternators can throw out 15v or more, particularly if they're older. If it was me, I'd undo the alternator charging connection and put in a B2B charger with a programmable profile instead so that I could be sure of the voltage and current I was throwing at the LFP.

Thanks for the Input!
The WFCO lithium solution charges at Bulk@14.6V & Normal@13.6V, not a big difference but I’m a dummy. Seems like wasted $ Here’s a LINK . Question on the B2B charger. Would that be between the “under hood battery” and House battery. That seem like a good idea. Most of are charging is done while driving. Thanks again! If I can get RV system dailed might move on to our boat ?

@Oneeyedjackass yep, a B2B charger connects to start battery and house bank, and once start battery reaches charging voltage (indicating that your alternator is running) it starts pulling current from the start battery and processing it into an intelligent charging profile through to the house bank. There are a multitude of ways to charge an aux bank from the alternator, but a B2B is definitely the safest and best for your LFP aux bank.
As for that WFCO, looks like it's fine... I mean I wouldn't expect it to last more than a couple of years, the RV forums are full of complaints about WFCOs but I don't see it being necessary to replace it before it dies. If I recall the Riuxo charging specs properly, they do allow up to 14.6v bulk charging and .5C (so 50A for your 100Ah battery) charge current, which is what the WFCO will deliver.

Basically, -1 for reliability but +2 for currently working, so... keep it while it lasts unless you're going to be depending on it for an extended period of time.

Thanks Justin!

Just came across this link re: sterling B2B charger on the battleborn site. LINK

Oneeyedjackass said:

Just came across this link re: sterling B2B charger on the battleborn site. LINK

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Yeah, BB has been selling Sterling units in their kits for a while now... it's a good match, actually, the Sterlings are great -we're the largest stocking Sterling distributor in the US, we should know - but that being said, their user manuals are a terrible PITA to understand, which has always made my job as tech support a real pain too. That's part of why I'm looking forward to the Victron Orion-Tr Smart B2B charger sooooo very much, because the thing is an absolute breeze, especially when compared to the Sterling.

...of course, the Victron unit only comes in a 30A model (in the 12/12 version) while the Sterlings come in at 60A or higher with the waterproof versions, so Sterling will always have a place in the B2B world, but man... I think we're going to be selling a lot more Victrons than Sterlings. At least, for my own sake I hope we do, I'm tired of talking people through setting the Sterlings

Check out wills video on the Renogy DC to DC (BtoB) charger. I just installed one in my tow vehicle and could not be more pleased. And around $160 you just can't beat it for the $$.

Justin Laureltec said:

Yeah, BB has been selling Sterling units in their kits for a while now... it's a good match, actually, the Sterlings are great -we're the largest stocking Sterling distributor in the US, we should know - but that being said, their user manuals are a terrible PITA to understand, which has always made my job as tech support a real pain too. That's part of why I'm looking forward to the Victron Orion-Tr Smart B2B charger sooooo very much, because the thing is an absolute breeze, especially when compared to the Sterling.

...of course, the Victron unit only comes in a 30A model (in the 12/12 version) while the Sterlings come in at 60A or higher with the waterproof versions, so Sterling will always have a place in the B2B world, but man... I think we're going to be selling a lot more Victrons than Sterlings. At least, for my own sake I hope we do, I'm tired of talking people through setting the Sterlings

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But I'm pretty sure you can parallel up the victrons, so problem solved.

Wellydex said:

But I'm pretty sure you can parallel up the victrons, so problem solved.

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Accurate - I mean, you can parallel any charge sources, so that's true regardless. The argument against is that two Victron 30A B2Bs cost more than a single Sterling 60A B2B... but again, the user interface is so much better that I think it's well worth it.

Rbertalotto said:

Check out wills video on the Renogy DC to DC (BtoB) charger. I just installed one in my tow vehicle and could not be more pleased. And around $160 you just can't beat it for the $$.

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I am also planning an RV system based around the Renogy DCC50S ponied up to a Magnum MS-2000 charger/inverter. The DCC50S will manage battery charging from either my solar array or the truck's alternator, and the MS-2000 will manage charging when connected to shore power. Both devices love the LiFePo4 batteries. Oneeyed... you might want to consider this unit if you are going to be spending any money. You also might get a reasonable price for your used Victron MPPT converter on the interweb.

Jimbtv said:

I am also planning an RV system based around the Renogy DCC50S ponied up to a Magnum MS-2000 charger/inverter. The DCC50S will manage battery charging from either my solar array or the truck's alternator, and the MS-2000 will manage charging when connected to shore power. Both devices love the LiFePo4 batteries. Oneeyed... you might want to consider this unit if you are going to be spending any money. You also might get a reasonable price for your used Victron MPPT converter on the interweb.

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Thanks for the idea Rbertalotto. I think I’m going to wait for the Victron B2B unit. I’m already using their solar controller and battery monitor.
I do need to figure out how to install it within the existing emergency start system that’s on RV.

I'm just getting started on my battery bank and charging system plans in my to be converted shorty school bus. After watching Will Prose YouTube videos I was leaning towards 24v but should the Renogy B2B 12v change it from a cost perspective? The Sterling B2B 12v to 24v is quite pricey. Would there be a Victron alternative? Your thoughts? I'm looking at least 2400WH of Lithium (LFP).

BillB said:

I'm just getting started on my battery bank and charging system plans in my to be converted shorty school bus. After watching Will Prose YouTube videos I was leaning towards 24v but should the Renogy B2B 12v change it from a cost perspective? The Sterling B2B 12v to 24v is quite pricey. Would there be a Victron alternative? Your thoughts? I'm looking at least 2400WH of Lithium (LFP).

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Well I'll say here as I've said elsewhere: I personally avoid Renogy like the plague just because they're not a manufacturer, they're a branding company... so when you buy something, you might get a fantastic product at a reasonable price or you might get junk, just depending on which warehouse they recently bought and slapped their name on. It's a crapshoot and I don't like gambling with electrical components.
That being said, Victron's 12 to 24 B2B charger (the Orion-Tr Smart Charger) only delivers 15A of charge current and costs $263.50... you can parallel-connect as many as you want to a battery bank to get the charge current up, but of course the price goes up then too. Are you looking at 200Ah of LFP at 24v, or were you going to get 2 100Ah 12v LFP batteries and series-connect them to reach 24v? That's relevant because that would leave you with 100Ah at 24v , in which case a single 15A charger like the Orion-Tr Smart would be appropriate so long as it wasn't your only charge source; if you're truly looking at ~200Ah at 24v, though, you definitely want a higher charge rate and you'd be looking at 2 or 3 of the Orions in parallel, and you're back to a very expensive proposition.

If you have a 12v native chassis I always strongly recommend that you keep your house bank 12v as well; I know that you (ostensibly) save money in wiring with 24v systems, but up-and-down-converting on voltages almost invariably costs more than you save. It makes sense in an off-grid system, where you don't have any DC loads and you're only ever going to be running an inverter, but in any mobile application it's far better (and fewer components to fail) to keep your house bank at the same voltage as your native chassis voltage.

Thanks for the advice. I don't want to buy low quality junk when it comes to this type of equipment. The Sterling 12v-12v 60A is the same price as the Sterling 12v-24v 70A/35A but worth it I suppose. You bring up a good point on matching the chassis voltage even though I have no 12v devices yet purchased or installed. The cost of wiring is not that much more in a small mobile application as mine? A 3600w LFP 12v bank (300AH) looks very reasonable. For that I would buy (12) 3.2v 100AH cells arranged 4S3P and a good BMS. Do you think 600W of solar and a 50-60w MPPT Controller would be a good match for that battery bank size?

Ordered the Victron Orion smart charger from Bay marine. Might be a bit tricky to install with emergency start function on RV. Thinking I can isolate with a 3-way battery switch. Power from alternator/emergency start cable to Common, bat 1 will go to Victron then on to charge house battery, bat 2 will go directly to house battery to provide “jump” if chassis battery is dead. Is there is a simpler way hook me up. ?

connected up everything seems to work correctly ???

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