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Discussion Starter · #1 · (Edited)
Thinking about the AGM to Lithium upgrade for my 6 year old (but still working OK) 100Ah batteries. All new items from Renogy.

It appears I will not be able to use my Battery Doctor, Powermax RV converter/charger, and batteries.

Plan is for (2) 100Ah LiPo4 (the basic ones, not smart) batteries, and a 40A/20A DC to DC charger (and using the LC input to charge at 20A most of the time). Plus the 2000W PSW inverter/charger.

Questions:

I'm trying to figure out a few last details...

the specs say that LiPo batteries charge up to 14.6 or .7 volts. Being an AGM guy, I'm wondering about how much impact that much voltage (14.7V) will have on all the 12V items that are in the van (TV, Ham Radio, Scanner, Maxxaire, radio, lights, USB sockets, etc.)

They all expect about 13.2V from a standard battery, so 14.7 is about 11% over voltage. Has anyone had any issues?

I'm not thrilled with the size of the 2000W Inverter/Charger. I like the built in transfer switch, but can't seem to get info on the details of this unit, like...

- does the fan run if the batteries are charged and you're on shore power?

- does the (included?) remote switch have to be on in order for the transfer switch to work?

-the optional remote display meter for the Inverter/charger... is it just a copy of the built in display? Does it show SOC, etc...?

If I give up the combo unit and just get the 2000W inverter, I should be able to get their basic 20A charger to charge while on shore power, right? I'd lose the transfer switch but that's not a big deal for my use.

Now, I just get home and plug in to shore power if I'm not using the van for a few days... I don't think about full charging (which I guess is not good for LiPo)... I don't think about anything... it just works. Will I have to spend my diminishing brain cells remembering to check the meters all the time? Now I have a simple volt meter readout... it tells me if I'm fully charged (which is OK with AGMs), or low on charge. Easy...

Thoughts welcome - some items on sale NOW !
 

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Discussion Starter · #2 ·
One other thought.

Instead of the 40A DC to DC charger, If I got the:

DCC50S 12V 50A DC-DC On-Board Battery Charger with MPPT

could I use it as a B2B charger and a shore power charger? Seems like I could set up a 120V to DC power supply instead of solar panels and that would give me B2B and shore power charging...

It doesn't seem to have the 50% charging LC wire, does it?


What would 2 typical 100W solar panels deliver for volts and amps to the MPPT unit? I could easily use a shore powered 25A 12V DC power supply as my (fake) solar panels.

Do-able? Has anyone done it?

No interest in solar panels for my application.
 

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I still stand by my view that there are very few, if any, consumer available, 12 volt x 100 amp-hr batteries that can reliably sustain much more than 600 watts / each, maybe 800 watts max for short periods.

So it kind of depends on if your goal is to have a 2000 watt inverter trying to run an 1800 watt induction load, or really just to have some extra headroom for less intensive uses.

This is especially true for mobile rated applications.

Since you are making so many changes, perhaps consider to build it up as a 24 volt system for the larger power loads. This will help with making it more reliable in heavy power use and obviously more ecological since it will need less copper.

You are a fairly technical individual, so it will help to free up the van community from continuing to be stuck quite so far in the past. (WWII technology vs WWI)
 

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One other thought.

Instead of the 40A DC to DC charger, If I got the:

DCC50S 12V 50A DC-DC On-Board Battery Charger with MPPT

could I use it as a B2B charger and a shore power charger? Seems like I could set up a 120V to DC power supply instead of solar panels and that would give me B2B and shore power charging...

It doesn't seem to have the 50% charging LC wire, does it?


What would 2 typical 100W solar panels deliver for volts and amps to the MPPT unit? I could easily use a shore powered 25A 12V DC power supply as my (fake) solar panels.

Do-able? Has anyone done it?

No interest in solar panels for my application.
Bogart engineering promotes the idea of using a DC - DC converter to boost the 12 volt vehicle voltage to a slightly higher level, and then using their PWM solar charge controller to charge the battery pack.

I have tested this with both 12 and 24 volt systems and it worked fine - at least on a test bench.

Worked with both Lifeline AGM and Battle born battery based systems.

I won't comment on your renogy strategy as I don't use any of their stuff for customer installations.
 
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Discussion Starter · #5 · (Edited)
Perhaps I should have stated my goals more clearly.

Primary goal:
Replace old AGM batteries with batteries that will offer more power (as in more usable amp hours of 12V DC) without lots of day to day management tasks (ie. checking meters, turning stuff on and off, etc.)

Secondary goals:
Allow charging via van alternator and shore power. No solar.
Power my few existing high draw devices... small microwave, keurig, induction cooktop, Engel fridge, plus the usual existing items... tv, radios, USB charging, lighting, etc.
Use equipment that is readily available at an affordable cost. Preferably on sale !
Higher power output per pound.

Non-existent goals:
"Free up the van community from continuing to be stuck quite so far in the past." Almost all commercial and DIY class B vans on the market are 12V based... that's fine with me.
Save copper... not sure what I'd save, given that the van has all of it's wiring in place, except for a few wires that would be replaced to link new system components that are right next to each other.
Use 24 volts... seems like that would require a lot more rebuilding... everything in the van is 12V except for the 120VAC Microwave, Keurig, and cooktop. Seems like getting a 24V system to provide 12V to all of my existing loads would be expensive.

Harry, I appreciate your thoughts, but I think I'd prefer to hear from members that have experience with the products I cited, and the specifics I asked about. If I were starting the build on a new van, I would consider some of your points as more relevant.
 

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I get it.

The bogart solution is similar to what you requested - just proven in case you were curious.

You are replacing the entire inverter + batteries + charging system, so setting it up as 24 vs 12 is zero cost, other than adding a small 24 - 12 volt converter for the minor 12 volt loads.

It is common for people to be concerned about using more modern methods, so I understand why you are using this approach.
 

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Oh, my, so many questions.

The 2kw inverter charger does work and the fan does come on regularly. Download the manual and read it. They didn't have the remote when I purchased mine. Mine just has a remote switch + led for "on" and "error". The transfer switch is automatic, but the inverter has to be "on" before it activates. Annoying but makes sense so that the "charger" part can be active if needed. The inverter is very configurable. For example, I only have a 15A rated shore plug so I configured the inverter to never draw more than 20A (ok, I live on the edge).

My experience is that 2x100ah lithium's will drive the inverter just fine. You can pull 130A out of each before they shut down and the inverter will shut down LONG before that. I have pulled 1.8kw for 10 minutes (boiling water and heating air) with no problem. But then I have no long-duration loads. My typical use is get oatmeal boiling, turn down to simmer, then use the microwave or the coffee maker. No problems. I wish I had gone for 3x batteries, Not for power draw, but power to last two or three days off-grid. Right now I can barely make 2 days without significant solar.

As for 14.6v vs. 13 on ham radio stuff. I have been tracking the service battery and it jumps to well over 14 v when the engine is running. Hard to imagine a proper power supply being so fragile a volt or two will cook it.

The smart batteries/with heaters are kind of pricey, but you get shunts built into each and self-calibrated SOC indicator. The external battery display is all you really need (regardless of my self flagellation with HomeAssistant and plotting out all that data). Makes for a very clean wiring box.

I approve getting a straight inverter and treating shore power as an extension cord to one outlet + separate charger for the battery bank. The combination, for me, since all I do is dry camp, a waste of money, weight and space. It does, however, do exactly what it says it does.

Unless you live somewhere that experiencers temperatures > 30C for extended periods, I would not worry about storing the batteries at 100% SOC. Mine are approaching 24 months old and survived the "heat dome" last spring (40C!) and near zero C (I have plumbing which is the only time I use shore power :) and have lost an (indicated, who knows what is real) .3% capacity (.6ah/200). Storage at 100% is associated with reduced lifespan, but high temperatures (at any SOC) is a much bigger problem.

I went all in with Renogy to simplify my wiring assuming that Renogy would design their components to work well together. I realize that that was probably wishful thinking on my part but my experience, over the last two years is that their stuff works and one doesn't need to micromanage it to be successful. @Lolaeliz had an issue with her inverter/charger - but that sounded like a childhood-failure. Some products just fail early. I guess that is what warrantees are for.
 

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Thinking about the AGM to Lithium upgrade for my 6 year old (but still working OK) 100Ah batteries. All new items from Renogy.

It appears I will not be able to use my Battery Doctor, Powermax RV converter/charger, and batteries.

Plan is for (2) 100Ah LiPo4 (the basic ones, not smart) batteries, and a 40A/20A DC to DC charger (and using the LC input to charge at 20A most of the time). Plus the 2000W PSW inverter/charger.

Questions:

I'm trying to figure out a few last details...

the specs say that LiPo batteries charge up to 14.6 or .7 volts. Being an AGM guy, I'm wondering about how much impact that much voltage (14.7V) will have on all the 12V items that are in the van (TV, Ham Radio, Scanner, Maxxaire, radio, lights, USB sockets, etc.)

They all expect about 13.2V from a standard battery, so 14.7 is about 11% over voltage. Has anyone had any issues?

That high voltage is very brief and occasional. 99% of the time, you will see 13.1-13.3V. We have not had any problems with nominally 12V appliances accepting this. The inverter and AC appliances will love the lack of severe draw-down. No more running the engine to use the microwave.

I'm not thrilled with the size of the 2000W Inverter/Charger. I like the built in transfer switch, but can't seem to get info on the details of this unit, like...

- does the fan run if the batteries are charged and you're on shore power?

- does the (included?) remote switch have to be on in order for the transfer switch to work?

-the optional remote display meter for the Inverter/charger... is it just a copy of the built in display? Does it show SOC, etc...?

If I give up the combo unit and just get the 2000W inverter, I should be able to get their basic 20A charger to charge while on shore power, right? I'd lose the transfer switch but that's not a big deal for my use.

Now, I just get home and plug in to shore power if I'm not using the van for a few days... I don't think about full charging (which I guess is not good for LiPo)... I don't think about anything... it just works. Will I have to spend my diminishing brain cells remembering to check the meters all the time? Now I have a simple volt meter readout... it tells me if I'm fully charged (which is OK with AGMs), or low on charge. Easy...

Just plan to have your batteries somewhere in the 50-80% range when you get home. Turn off the inverter and plug in the van. Your fridge will switch to AC, so with minimum load, the batteries will stay in that sweet range. Numbers will actually matter less.

Thoughts welcome - some items on sale NOW !
 

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I'd stick with the plain 40A DC-DC. The dual DC-DC/MPPT unit doesn't have the D+ and LC inputs that let you to add control switches for On-Off (D+) and half-power (LC). DC-DC is my only Renogy experience. I doubt the IC's remote display includes SOC. Mine doesn't and its amp readings are unreliable. IMHO, you'll need a shunt-based battery monitor for lithium SOC.
 

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@Lolaeliz had an issue with her inverter/charger - but that sounded like a childhood-failure. Some products just fail early. I guess that is what warrantees are for.
Renogy sent me a replacement inverter/charger even before they got the one that was defective.

Were I to do it again, I would buy just the inverter, with the shore power extension chord set up. The inverter charger is a gigantic space-waster. And I would go straight for the DCDC/MPPT combo unit.

@proeddie -- Renogy 10% off Coupon Code: willprowse
 

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Although the DCC30/50S isn't appropriate for @proeddie requirements, with even a modicum of solar input the controller will only draw 1/2 the rated current from the alternator. Since most of my driving with depleted batteries is during the day, my 50a charger is effectively 25a unless the sun is overhead.

One of the odd quirks with their stuff.
 

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Although the DCC30/50S isn't appropriate for @proeddie requirements, with even a modicum of solar input the controller will only draw 1/2 the rated current from the alternator. Since most of my driving with depleted batteries is during the day, my 50a charger is effectively 25a unless the sun is overhead.
One of the odd quirks with their stuff.
It's not just Renogy. Most of the dual units do something similar. They are great if you have severe space or budget constraints, otherwise separate units offer more flexibility and efficiency.
 

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Discussion Starter · #13 ·
Given that the DCC30/50S for shore power charging is not a viable solution,

One more thought:

If I get the 40A B2B unit, could it be connected to a DPDT selector switch...

in one position, it would get its input from the van starter battery, a typical connection.
in the other position, it would get its input from a shore-powered 25A DC power supply (which I already have)

This would allow the B2B unit to be both an alternator or shore power charging source.

Yes / no?

Might be a hypothetical idea, but might be useful too.
 

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2018 159 High Roof gas, BC, Canada
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I'm a nerdy guy so I went with separate components. Renogy 60A MPPT solar charge controller, Renogy 40A DC-DC charger, 50A power converter (charge batteries from shore power). Separate inverter too (and a backup inverter just in case, both can run at the same time).
I'm surprised and happy that it all works.
In fact, to respond to your desire to "I don't think about anything... it just works", my system more or less "just works". I am curious and so I watch my battery monitors and the display on the MPPT SCC, but that's just idle curiosity.

Being a part-timer, I'm quite blase about my batteries being at 100%, which they are now as we are nearing the spring equinox, the sun is fairly strong and I get charging even in overcast skies.
And while I've upgraded my battery bank to 3 x 100Ah batteries and so I don't get low on the batteries, when I was running a single 100Ah battery, I didn't care if I drove it low either. LiFePO4 chemistry is supposed to handle it ok. I didn't have battery monitors in the beginning but theoretically, if the battery got near zero %, the BMS should cut power and it never did.
I know that I'm being hard on the batteries, but I will NEVER get anywhere near the rated 2000 cycles at my rate of camping so I am not the least bit concerned. :)
The one thing with multiple components is all the connections. And a lot of them are fairly high current and so one needs to be careful with having the right gauge ow wire and the crimping, but you @proeddie know that. I have a lot of connections but I didn't mind as I enjoyed building out my electrical system.

I've only had a couple of issues:
1) cheap Chinese 200A breaker for my battery bank "broke" (tripped) at like 70A. At night or in the rain, it made using any of my kitchen appliances not possible without starting up the engine and having the DC-DC charger lend a hand (supply 40A so the battery bank needed to supply only like 30 to 60A). I've replaced the cheap breaker with one that's not as cheap and it seemed to work under a 100+A load (microwave) as a test. I hope it works as I'm setting out on a long trip soon. I brought a spare dumb switch (not a breaker) to swap in just in case it fails too.
2) One of the fans on the Renogy DC-DC charger is getting noisy so I'll have to replace it.
 

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Questions:

I'm trying to figure out a few last details...

the specs say that LiPo batteries charge up to 14.6 or .7 volts. Being an AGM guy, I'm wondering about how much impact that much voltage (14.7V) will have on all the 12V items that are in the van (TV, Ham Radio, Scanner, Maxxaire, radio, lights, USB sockets, etc.)
I am going to just focus on this one, the lithium batteries will never really supply 14.7 volts. As soon as a load is applied you will see close to 13.6 volts. While this is a little higher than what is expected it should not cause an issue. During charging is the only time to be concerned. I have not noted any issues (I do limit my charge voltages to 14.2, as there is really no reason to go higher).
 

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One other thought.

Instead of the 40A DC to DC charger, If I got the:

DCC50S 12V 50A DC-DC On-Board Battery Charger with MPPT

could I use it as a B2B charger and a shore power charger? Seems like I could set up a 120V to DC power supply instead of solar panels and that would give me B2B and shore power charging...

It doesn't seem to have the 50% charging LC wire, does it?


What would 2 typical 100W solar panels deliver for volts and amps to the MPPT unit? I could easily use a shore powered 25A 12V DC power supply as my (fake) solar panels.

Do-able? Has anyone done it?

No interest in solar panels for my application.
Renogy 100w monocrystalline specs:

  • Peak Power (Wp): 100W ± 5%
  • Voltage at maximum power (Vmp): 18.6V
  • Current at maximum power (Imp): 5.38A
  • Open circuit voltage (Voc): 22.3V
  • Short circuit current (Isc): 5.86A
  • Power allowance range: ± 5%
  • Dimensions: 42.4 x 20.0 x 1.38 inches
  • Weight: 14.3 pounds

    The Renogy DCC50S normally only does 25A charging when you have both B2B input and solar input hooked up at the same time. A cutoff switch is needed to get the full 50A, otherwise it automatically limits both inputs to 25A. What you’re suggesting with your power supply won’t work because the MPPT side of the DCC50S requires 15V minimum.

    EDIT: Upon further reading, for shore power, you would want to use a 12v charger, not a power supply, and you would connect it directly to your bus bars or directly to your battery bank. A power supply wouldn’t work because it won’t shut itself off once the batteries were full.


  • I’m in the process of getting my electrical setup figured out. Got some of my parts already, but need to buy more. I’ll be using 200w Renogy solar panels with the DCC50S. For batteries I went with SOK 206AH.
 

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Discussion Starter · #17 · (Edited)
EDIT: Upon further reading, for shore power, you would want to use a 12v charger, not a power supply, and you would connect it directly to your bus bars or directly to your battery bank.

A power supply wouldn’t work because it won’t shut itself off once the batteries were full.
That's my point... if a power supply that's 12V at 20A is connected to the input side of a Renogy 40A B2B, the B2B will act like it's getting its power from the alternator, and should charge the batteries AND shut itself off when the batteries are full...

for example:
Font Rectangle Gas Automotive parking light Circuit component


Seems like that would work. This would be in a no-solar-panel installation.
 

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I've heard that solar panels are all pretty much the same within a particular voltage class and used that to rationalize purchasing the cheapest I could find which, at the time was "rich solar". They looked just like Renogy panels and they also sell MPPT chargers that look just like the Renogy ones with a different overlay.

Also, for some odd reason scanning Amazon, eBay and direct from the OEM could save a fair amount of money. Panels were cheaper from Amazon, electronics from eBay and nothing direct from the manufacturer (at the time). Go figure.
 

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Given that the DCC30/50S for shore power charging is not a viable solution,

One more thought:

If I get the 40A B2B unit, could it be connected to a DPDT selector switch...

in one position, it would get its input from the van starter battery, a typical connection.
in the other position, it would get its input from a shore-powered 25A DC power supply (which I already have)

This would allow the B2B unit to be both an alternator or shore power charging source.

Yes / no?

Might be a hypothetical idea, but might be useful too.
I don't know if the two units (DC-DC and power supply) would get along. I know that Renogy says DC-DC draw can sometimes be 1.5X its rated output. How will the 25A power supply react if the DC-DC tries to draw more than 25A?
 

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Discussion Starter · #20 ·
I was figuring on setting the 40A unit to 20A using the LC wire... I have a bunch of 12V regulated power supplies rated at 25A for ham radio use... seems like it might work.

Just figuring that if it did, it would save $150-$200 for a separate LiPO 20A charger by using the smarts of the B2B unit to manage the charge rates. I thought someone might have tried it...
 
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