First Trial of Lithium Battery Upgrade

[Lamokadave]

This is sort of a part 2 to my original thread "Another Solar Thread"
The new equipment includes 3- Renogy 100A 12v w blue tooth batteries, new LI BIM 225, and a new solar port to attach a portable solar panel with controller.
We dry camped at Roosevelt lake in AZ latitude similar to Phoenix with 4 near perfect days for solar use. We started at 100% SOC
We were positioned with unobstructed access to sun for the roof top twin 100w panels. Even so my portable Renogy 100W panel angled and positioned to face the sun produced the same power as the 2 combined stationary panels.
We produced on average approx 80 amps at 13.4v daily.
We used energy for fridge, toilet, under 1 hr of furnace usage ea morning, several hrs of moderate lighting, plus recharging personal electronics. Did run a C-Pap machine 1 night.
I did to run the genny for approx 1 hr ea AM to yield these results.
Results:
Using the battery BT to monitor battery levels both for SOC and charging rate I learned the following
Of the 80 amps produced by solar daily only 30 made it back into the batteries by end of the charging day. The fridge alone plus whatever parasitic loads exist ate the balance.
The stock converter only sends approx 12 - 15 amps into the batteries (surprising few)
With the conditions I described above, we lost a net 15 -20 % SOC daily.
The BIM did cycle as advertised and I observed a couple readings over 100 amps charging current.
Conclusions.
With favorable solar panel weather and exposure we need a minimum of 400w solar.
The stock converter is inadequate to recharge if the sun isn't cooperating.
A 2ndary device to monitor SOC, input vs output would be valuable.
Lithium batteries charge at a relatively low voltage. I expected to see 14.4v on my controllers but the never displayed above 13.5 except with converter charging at 13.7.
I plan to upgrade the power center, just need to decide what to install.
I will add some additional portable solar.

[ducksface]

Are you adding more so you don't have to run the generator/ags ever? You'll Reasonably never have enough solar to run the a.c. or an electric heater for any length of time.

Except as a interesting hobby, I can't find a use for solar(in a vehicle with an engine or generator) other than long term storage parking where solar keeps the batteries from draining and the fridge running.

Maybe I need solar and haven't paid attention enough.

[DavidEM]

I am surprised you are seeing 100 amps of chassis alternator charging with 300 Ahs of lithium batteries. I realize that the Li-BIM 225 cycles on and off every 15 minutes, but 15 minutes at 100 amps could be more than your alternator can stand. Remind us what chassis engine you have. If it is a Sprinter chassis I would be particularly worried about 100 amps.

I would do this test: While idling and with the batteries 50% SOC or less, check the alternator's case temp with an IR gun after about ten minutes. Anything more than 200 F is cause to worry.

The Progressive Dynamics 9180L could be a good solution towards faster converter charging.

David

[16ACE27]

Amps and Amp-Hours are two different measuring units (power and Energy although related, are not the same thing). Using them interchangeably confuses people.

[Chateau_Nomad]

Originally Posted by ducksface

Are you adding more so you don't have to run the generator/ags ever? You'll Reasonably never have enough solar to run the a.c. or an electric heater for any length of time.

Except as a interesting hobby, I can't find a use for solar(in a vehicle with an engine or generator) other than long term storage parking where solar keeps the batteries from draining and the fridge running.

Maybe I need solar and haven't paid attention enough.

Unless you have unlimited roof real estate to mount solar panels, and an unlimited budget... I think it's a frivolous experiment to consider solar as a PRIMARY power source. With today's battery/energy technology, solar is nothing more than a supplemental backup to existing charging sources.

I know there are exotic class B vans that are 100% solar based, BUT they have made many compromises - and are UBER EXPENSIVE compared to legacy motorhomes. There are fan boys who disagree, but realistically the proof is in the numbers.

Here's a typical sample for energy needed to run ALL the RV systems without skimping - what I would call legacy use. Your usage might vary depending on how much you compromise due to conserving energy resources - which is typically needed in those "factory off-grid solar" advertised class Bs.

Let's start with the MOST desired option... running that A/C. So, let's figure a setup that could run your 15,000 BTU A/C for maybe 5 hours. And this is ONLY the A/C running - nothing else.

Add up the cost of 75-100 kWh capacity of battery storage. Then, calculate how many 250 watt panels you would need (at average of 1 kWh per day of electrical power generation) to replenish those kilowatt hours each day. Solar panels cost an average of $1 per watt today. Name brand lithium batteries which can store/supply 12 kWh (100 AH) are about $750 each ($63/kWh).

10 batteries @ $750 = $7,500
75 250 watt panels = $18,750

Let's stop there... 75 solar panels??

And I haven't even considered the additional $$$ charge controller, wiring, inverter, converter, transfer switch, installation charge...

Note that this is about what you'd need for a home solar based charge station for an EV... provided you have relatively sunny conditions.

If you follow technology, there are 12 volt mini-split A/C units starting to show up, which are MUCH more efficient. LED technology has become the norm in RVs, so I'm certain that a surge of A/C unit efficiency will soon become the norm.

I think a trend towards greater efficiency/lower power usage in RVs is the answer - instead of trying to supply power to legacy A/C units, ultra-efficient 12 volt systems are needed. Then install multiple low-power units (4?) in the RV - and only use what is really needed. The initial downside is $$$, but with mass production come lower prices.

Currently, my 200 watts on the roof are all I need, whose sole purpose is to keep my 125AH battery bank topped off. It's merely a convenient "back-up" which supplements shore power and occasional generator usage.

[Lamokadave]

Originally Posted by ducksface

Are you adding more so you don't have to run the generator/ags ever? You'll Reasonably never have enough solar to run the a.c. or an electric heater for any length of time.

Except as a interesting hobby, I can't find a use for solar(in a vehicle with an engine or generator) other than long term storage parking where solar keeps the batteries from draining and the fridge running.

Maybe I need solar and haven't paid attention enough.

Never intend to replace what we could do plugged in with what we do when dry camping. We grew up camping in trailers and never had a genny. We did adapt to solar as our "" improved trailers required basic power to run. We learned to be very content that way and see no reason to change just because we can fire up a genny. My goal is to be able to dry camp as long as the tanks last without depleting the batteries. The lithium make a huge stride toward that but 400w of solar isn't quite there with the residential fridge. I really would have preferred a 10 cu ft propane/electric and then there would be no issue at all.

[Lamokadave]

Originally Posted by DavidEM

I am surprised you are seeing 100 amps of chassis alternator charging with 300 Ahs of lithium batteries. I realize that the Li-BIM 225 cycles on and off every 15 minutes, but 15 minutes at 100 amps could be more than your alternator can stand. Remind us what chassis engine you have. If it is a Sprinter chassis I would be particularly worried about 100 amps.

I would do this test: While idling and with the batteries 50% SOC or less, check the alternator's case temp with an IR gun after about ten minutes. Anything more than 200 F is cause to worry.

The Progressive Dynamics 9180L could be a good solution towards faster converter charging.

David

Its an Omni Super C on the f-550 chassis. Equipped with 2 alternators and 2 batteries. I have no idea if all is somehow linked together or dedicated to house vs cab. I've never seen the Ford specs for what Thor orders, but the basic 550 has a single 332a alternator.
I was very disappointed to see such low current flowing from the converter. I checked the model and believe its a WFCO 8930/50. I need to read the specs for that.
I did see it wired through a 15a breaker and assumed I could expect up to 1800 watts A\C which in DC is a fairly high current.
It's obviously not such a simple concept

[DavidEM]

I am sure that the F550 has a serious alternator and a 332 amp alternator should not be phased by an external load of 100 amps. Just surprised at that high number.

A 15A AC circuit supplying a converter says nothing about the converter's DC amp output. Look inside and at the bottom will be the actual charger. The name plate should give the model number and nominal DC charging output.

David

[Chance]

Originally Posted by Lamokadave

Its an Omni Super C on the f-550 chassis. Equipped with 2 alternators and 2 batteries. I have no idea if all is somehow linked together or dedicated to house vs cab. I've never seen the Ford specs for what Thor orders, but the basic 550 has a single 332a alternator.
I was very disappointed to see such low current flowing from the converter. I checked the model and believe its a WFCO 8930/50. I need to read the specs for that.
I did see it wired through a 15a breaker and assumed I could expect up to 1800 watts A\C which in DC is a fairly high current.
It's obviously not such a simple concept

The base F-550 332 Amp comes from dual alternators and not a single one. They are rated at 175 and 157 Amps for the combined 332 Amps. Given the greater surface area and cooling potential of two alternators I would not worry too much about 100 Amps unless it was extremely hot under the hood.

The 15A converter power is likely designed for no more than 80% of that as maximum steady state, and since converter is much less than 100% efficient, the maximum power that it could supply to a battery bank is probably under 80 Amps. Converters rated at 80 Amps are often meant to be used on 20 Amp circuit. Regardless, the much lower charging rate you are seeing is not being limited by the 15 Amp AC circuit in my opinion.

[Chance]

Originally Posted by Lamokadave

Never intend to replace what we could do plugged in with what we do when dry camping. We grew up camping in trailers and never had a genny. We did adapt to solar as our "" improved trailers required basic power to run. We learned to be very content that way and see no reason to change just because we can fire up a genny. My goal is to be able to dry camp as long as the tanks last without depleting the batteries. The lithium make a huge stride toward that but 400w of solar isn't quite there with the residential fridge. I really would have preferred a 10 cu ft propane/electric and then there would be no issue at all.

Solar has its application for certain.

Arizona is great for solar, but it is no longer summer when energy is easier to collect. If you are making 80 Amp-hours daily, that’s only about 1 kilowatt-hour of energy daily which won’t power most larger residential refrigerators.

I have seen vans (as example) with 400 to 600 Watts (nominal) of solar panel capacity that can power their small compressor refrigerator all day and still have enough surplus for lights, pump, fan, etc. In summer in your area a 600 Watt system could collect up to 3 kWh daily which is quite a bit (provided not trying to power an air conditioner which is a completely different problem/challenge).

Unfortunately, a solar system that can make 3 kWh of energy daily may need more than 300 Amp-hours of battery capacity in order to operate efficiently.

Anyway, excluding air conditioning, solar isn’t that expensive any more and can reduce or eliminate generator or idling requirements (assuming you park in sun) to a large degree, provided roof has enough free area for panels. I personally can’t imagine using portable panels.


P.S. — My comments above and units of measure are for a 12-Volt system, otherwise some don’t make sense.

[Lamokadave]

Regardless, the much lower charging rate you are seeing is not being limited by the 15 Amp AC circuit in my opinion.

What do you believe is limiting the current from the charger? Wire size?

[Chance]

Originally Posted by Lamokadave

What do you believe is limiting the current from the charger? Wire size?

Probably not wire size. If measuring only 12~15 Amps, that’s so much under the converter’s rated capacity, for which the wires should have been sized, that voltage drop in wires shouldn’t be the problem (unless someone really screwed up during installation and that’s doubtful).

The “stock” converter (I assume not for lithium batteries) is likely seeing the higher voltage of lithium batteries and determining they are close to fully charged and therefore limiting charge current.

The suggested test above by others should confirm wire size is adequate; although just looking at wire sizes would be good enough for me.

[DavidEM]

For best charging performance I think that voltage drop between the converter or solar controller should be less than 1/4 volt. Tell us your wire gauge- you can usually find it printed on the side of the cable and the current that you want and I can tell you the proper gauge.

But I agree, a lead acid based converter won't charge very fast into lithium batteries no matter the gauge.

David

David

[Chance]

Originally Posted by Chateau_Nomad

.....cut.....

Let's start with the MOST desired option... running that A/C. So, let's figure a setup that could run your 15,000 BTU A/C for maybe 5 hours. And this is ONLY the A/C running - nothing else.

Add up the cost of 75-100 kWh capacity of battery storage. Then, calculate how many 250 watt panels you would need (at average of 1 kWh per day of electrical power generation) to replenish those kilowatt hours each day. Solar panels cost an average of $1 per watt today. Name brand lithium batteries which can store/supply 12 kWh (100 AH) are about $750 each ($63/kWh).

10 batteries @ $750 = $7,500
75 250 watt panels = $18,750

Let's stop there... 75 solar panels??

......cut......

Yes, please, let’s stop there.

Your math needs a lot of work. Powering an air conditioner 5 hours doesn’t take 75 to 100 kWh of battery capacity, not even close. That’s in range of a Tesla S battery that can now travel 400 miles.

An efficient 15,000 BTU/hour existing-technology RV rooftop air conditioner can operate with +/- 1,500 Watts, so 5 hours of run time is only 7.5 kWh, not 75~100 kWh.

There are many motorhomes today that can power their rooftop air conditioners through the night with 600 Amp-hours of lithium battery, which is about 7.5 kWh of capacity. During the day when it’s warmer and A/C has to run harder and not shut off, it would run fewer hours, but 5 hours is certainly in right range.

Just saying it’s not necessary to inflate energy needs to the point of deception. People who are not technical at all may see a post like yours and conclude there is little hope of doing what is already possible (at least from battery standpoint).

And to be perfectly clear, I’m not saying collecting 7.5 kWh of electricity from solar is easy or even practical. Just saying 75~100 kWh is not needed.

[Bill Johnson]

Originally Posted by Lamokadave

This is sort of a part 2 to my original thread "Another Solar Thread"
The new equipment includes 3- Renogy 100A 12v w blue tooth batteries, new LI BIM 225, and a new solar port to attach a portable solar panel with controller.
We dry camped at Roosevelt lake in AZ latitude similar to Phoenix with 4 near perfect days for solar use. We started at 100% SOC
We were positioned with unobstructed access to sun for the roof top twin 100w panels. Even so my portable Renogy 100W panel angled and positioned to face the sun produced the same power as the 2 combined stationary panels.
We produced on average approx 80 amps at 13.4v daily.
We used energy for fridge, toilet, under 1 hr of furnace usage ea morning, several hrs of moderate lighting, plus recharging personal electronics. Did run a C-Pap machine 1 night.
I did to run the genny for approx 1 hr ea AM to yield these results.
Results:
Using the battery BT to monitor battery levels both for SOC and charging rate I learned the following
Of the 80 amps produced by solar daily only 30 made it back into the batteries by end of the charging day. The fridge alone plus whatever parasitic loads exist ate the balance.
The stock converter only sends approx 12 - 15 amps into the batteries (surprising few)
With the conditions I described above, we lost a net 15 -20 % SOC daily.
The BIM did cycle as advertised and I observed a couple readings over 100 amps charging current.
Conclusions.
With favorable solar panel weather and exposure we need a minimum of 400w solar.
The stock converter is inadequate to recharge if the sun isn't cooperating.
A 2ndary device to monitor SOC, input vs output would be valuable.
Lithium batteries charge at a relatively low voltage. I expected to see 14.4v on my controllers but the never displayed above 13.5 except with converter charging at 13.7.
I plan to upgrade the power center, just need to decide what to install.
I will add some additional portable solar.

They make an awning that is solar 1,000 watts that would help with charging the batteries. It's on camper report

[electric]

Originally Posted by Chateau_Nomad

Let's start with the MOST desired option... running that A/C. So, let's figure a setup that could run your 15,000 BTU A/C for maybe 5 hours. And this is ONLY the A/C running - nothing else.

Add up the cost of 75-100 kWh capacity of battery storage. Then, calculate how many 250 watt panels you would need (at average of 1 kWh per day of electrical power generation) to replenish those kilowatt hours each day. Solar panels cost an average of $1 per watt today. Name brand lithium batteries which can store/supply 12 kWh (100 AH) are about $750 each ($63/kWh).

10 batteries @ $750 = $7,500
75 250 watt panels = $18,750

These are wildly inaccurate numbers. How did you get from 15kBTU / 5hr to 75-100 kWh ? There is no logical connection.
There is much variation due to climate and insulation, but rough numbers for A/C is 2kW when compressor is on, which is typically not 100% duty cycle. Let's say 50% duty for sake of discussion, that makes 5kWh of A/C usage over 5 hrs. Very far from 75-100 kWh.
Check out FitRV channel on Youtube, he has very nerdy video on A/C consumption and how to compare apples to apples.
Many new rigs now come with 4kWh to 8kWh lithium banks and 400W to 800W solar. It's not cheap, but not as crazy as it used to be, it is becoming acceptable for many.

[electric]

Originally Posted by Chance

And to be perfectly clear, I’m not saying collecting 7.5 kWh of electricity from solar is easy or even practical. Just saying 75~100 kWh is not needed.

I'd say that 4kWh from solar is reasonably practical (800W of panels), which is about 50% of 8kWh battery (630AH at 12V). So, 50% from solar and 50% from running engine or generator is much better than 100% from burning fuel. This is the system I'm putting in my Vegas.
Much development is now focused on DC A/C units, with much greater efficiency, so in a few years we can swap A/C for a DC fed unit and get even more runtime before having to run the engine.

[Lamokadave]

Originally Posted by Chance

The base F-550 332 Amp comes from dual alternators and not a single one. They are rated at 175 and 157 Amps for the combined 332 Amps. Given the greater surface area and cooling potential of two alternators I would not worry too much about 100 Amps unless it was extremely hot under the hood.

The 15A converter power is likely designed for no more than 80% of that as maximum steady state, and since converter is much less than 100% efficient, the maximum power that it could supply to a battery bank is probably under 80 Amps. Converters rated at 80 Amps are often meant to be used on 20 Amp circuit. Regardless, the much lower charging rate you are seeing is not being limited by the 15 Amp AC circuit in my opinion.

So I finally had a chance to dig in to this a bit.
The premise here is Im considering a swap out of the WMO 9855 converter non lithium to something that supports lithium.
With some amount of difficulty I was able to pull the current deck mount converter. Im hoping some of you can help me understand what Im looking at.
As stated earlier, the converter circuit in the power center is a 15 amp breaker
The converter actually plugs directly into the back of the power center and has a single 6 awg red and white wire leaving it. I expected 2 of each with one headed toward the batteries and another powering house 12v systems. The white is routed directly to a neutral buss and the red goes back into the power center. In the same place the red enters the PC, another red exits and heads toward a device with a small circuit board and what looks like a couple of fuses. The red leaves that and heads into a very busy distribution device. At least one bundle of wires appears to connect to something labelled Vega so Im assuming part of the firefly system I dont really see any larger qauge wires that might head toward the batteries. So at this point, I dont know how the batteries are being charged. I've had no luck trying to trace things underneath as bundles of wires disappear between the frame members and coach bottom

[AJMike]

Originally Posted by Lamokadave

We dry camped at Roosevelt lake in AZ latitude similar to Phoenix with 4 near perfect days for solar use.

We go there when we can as it is a great place for bondocking and usually sunny enough for us to get the solar we need for recharging.

The place used to be packed a couple of years ago and it was hard to find a space, but recently it has been relatively empty. Drive to the water is a bit rough though.

[Lamokadave]

Originally Posted by Lamokadave

So I finally had a chance to dig in to this a bit.
The premise here is Im considering a swap out of the WMO 9855 converter non lithium to something that supports lithium.
With some amount of difficulty I was able to pull the current deck mount converter. Im hoping some of you can help me understand what Im looking at.
As stated earlier, the converter circuit in the power center is a 15 amp breaker
The converter actually plugs directly into the back of the power center and has a single 6 awg red and white wire leaving it. I expected 2 of each with one headed toward the batteries and another powering house 12v systems. The white is routed directly to a neutral buss and the red goes back into the power center. In the same place the red enters the PC, another red exits and heads toward a device with a small circuit board and what looks like a couple of fuses. The red leaves that and heads into a very busy distribution device. At least one bundle of wires appears to connect to something labelled Vega so Im assuming part of the firefly system I dont really see any larger qauge wires that might head toward the batteries. So at this point, I dont know how the batteries are being charged. I've had no luck trying to trace things underneath as bundles of wires disappear between the frame members and coach bottom

Was hoping I would have had some help with this at this point.
Anyway, I did install the Progressive Dynamics 9160L converter and see the following results.
I now can push 33 to 36 amps into the batteries vs 15 with the WMCO 9855 device. Charging voltage still sits at 13.3 to 13.5 vs the expected 14.6. I'm going to be working with both Renogy and Progressive D to figure this out. I"m not ready to assume wire gauge because even prior to installing the new batteries I used 2 different lithium capable charging devices and noticed charging voltage was in the low 13v range. Also while dry camping and relying on solar, the charge controller only showed 13.3-13.5 volts and that's within 18" of the batteries.Appears that the batteries themselves might somehow limit incoming voltage. I do want to get the charging current close to the rated 60 amps