Converting to Lithium

[Stephen_Albers]

Those temperature limitations are not very limiting for winter operations except for -4F storage, which is a constant worry for NY winter operations where a cold snap could be harmful. Arizona is a fairly reasonable solution, though it can get very cold in the desert too. True 4-season capability needs an operating range of -20F to +120F to cover 98% of weather conditions in the USA, Canada and Mexico.

[Jon Vermilye]

Originally Posted by Stephen_Albers

Those temperature limitations are not very limiting for winter operations except for -4F storage, which is a constant worry for NY winter operations where a cold snap could be harmful. Arizona is a fairly reasonable solution, though it can get very cold in the desert too. True 4-season capability needs an operating range of -20F to +120F to cover 98% of weather conditions in the USA, Canada and Mexico.

True, but now that I'm retired, I am perfectly comfortable narrowing that range down to what is comfortable. I'm a firm believer in attempting to stay in the 70's year round. Here in the desert the winter nights do get cool, but the coldest so far this winter has been 28°F, and the average is in the high 30's - low 40's. 60's - 70's during the day.

[Stephen_Albers]

Then your research has located an ideal product for your application.

[Air Doug]

I just learned a bunch more about temperature ranges and best storage temperatures and state of charge for the Battle Born batteries from an interview with the CEO. He recommends long-term storage of the battery at room temperature with a fair amount of leeway around that. Lots more info in the interview. But the range is clearly smaller than what ours are encountering outside in the trailer in Maryland. Last year we kept the trailer slightly heated, like 40 degrees, but not this year. I will have to think about a solution.

One thing I didn't know is that BB now sells a thermostatically controlled 12V battery heater with adhesive designed just for the BB batteries. It is $220. Per battery! Yikes!

And they are coming out with an internally heated battery this quarter. Very interesting. They are clearly thinking and acting on the needs of folks who don't keep their batteries inside a heated RV.

I posted the link in a new thread but here it is too:

https://www.youtube.com/watch?v=ywn-vBjKblI

[Air Doug]

By the way, Jon, great thread. Thanks for sharing all you have learned doing the conversion.

[redbarron55]

Yikes!! is right!
You can add a lot of lead acid batteries for just the cost of the heaters!

[Stephen_Albers]

The temperature limitations of Fe Lithium are very serious for anyone contemplating anything close to 4 season operation or locating outside the deep south. You should press the manufacturer for specific test data in cold weather and carefully assess its impact. Are batteries permanently damaged by short term exposure to outsize temperature as the published operating specifications suggest? If so, then your major investment in batteries is constantly at risk for temperature damage. There are two different situations to consider: Underway and storage. Your batteries are likely more at risk when you are not using your trailer and it is just being stored than they are while underway.

Many snowbirds plan only operations in moderate temperatures. But temporary temperature swings exceeding 40 degrees are quite common, which average temperature data miss completely. And attractive opportunities for unforeseen operation in more extreme temperatures will likely present themselves in the real world. Planning for worst-case is appropriate if you don't want to become a babysitter for your battery.

[Jane P.]

Originally Posted by Jon Vermilye

I agree with Douglas. Again, talking with Battleborn, it is important that you charge at at least 14.4V for the absorption phase. That is when the battery balancing system does its thing. While you can charge up to 14.6V, they prefer 14.4V.

As to charging via tow vehicle, I have had no problems running a Victron 9 amp DC to DC controller set at 14.4V. I could go with a higher current version, but with my typical 4 hour drive between campsites, @ 9 amps I'm putting 36 amp hours into the batteries. With 320 watts of rooftop solar, between the two sources, I have never ended up at a campsite with less than 100% full batteries.

Hi Jon,
I dropped a new BB 100v lithium last week, along with a Pacific Dynamics replacement to my controller’s lower section. After reading the various posts to this thread, I decided to locate the battery in the cabin, under the front dinette seat. I belatedly learned that the trailer’s built-in monitor will not work with a lithium, and after researching various BVMs, I’m getting Victron 712.

While In the process of buying even more expensive goodies to support the BB Li, I need clarification for your recommendation re a DC-DC isolation power supply. I discussed this issue with Battle Born, and they did not think this would be of help. They suggested that I’d have to accept the fact that the battery would not be fully charged by the TV.

As with you, I do travel from one off grid camping area. The drive can be anywhere from 2 - 4 hours. It is not unusual for me to travel at night. If I read your post correctly, you depend on your rooftop solar panels to work in conjunction with your DC-DC Isolation converter, to fully charge the Li battery.

So my question is, what does your Victron controller, as a stand-alone, add to the process of recharging under tow? How does it coordinate with rooftop solar?
I really want to understand how this all comes together, as I prefer to purchase any additional needed items and install them at the same time.

Thanks in advance for your prompt response.

[Jon Vermilye]

Originally Posted by Jane P.

Hi Jon,
I dropped a new BB 100v lithium last week, along with a Pacific Dynamics replacement to my controller’s lower section. After reading the various posts to this thread, I decided to locate the battery in the cabin, under the front dinette seat. I belatedly learned that the trailer’s built-in monitor will not work with a lithium, and after researching various BVMs, I’m getting Victron 712.

While In the process of buying even more expensive goodies to support the BB Li, I need clarification for your recommendation re a DC-DC isolation power supply. I discussed this issue with Battle Born, and they did not think this would be of help. They suggested that I’d have to accept the fact that the battery would not be fully charged by the TV.

As with you, I do travel from one off grid camping area. The drive can be anywhere from 2 - 4 hours. It is not unusual for me to travel at night. If I read your post correctly, you depend on your rooftop solar panels to work in conjunction with your DC-DC Isolation converter, to fully charge the Li battery.

So my question is, what does your Victron controller, as a stand-alone, add to the process of recharging under tow? How does it coordinate with rooftop solar?
I really want to understand how this all comes together, as I prefer to purchase any additional needed items and install them at the same time.

Thanks in advance for your prompt response.

The Victron DC to DC converter can be set for any output voltage you desire. Mine is in the trailer set for 14.4V. I have measured the current it supplies to the batteries with the truck at idle, and it is the rated current, 9 amps. While it is possible that the tow vehicle wiring is so small that it can't supply 9 amps, that is unlikely, particularly at driving RPMs. If you want more charging amps, Victron makes larger DC to DC converters, as do others.

Whether this will fully charge your batteries during a nighttime drive depends on how far down they are &, of course, how long you drive. The lithium batteries will accept the full output of the 9 amp converter until 98% full, so you can use 9 amps times the drive time to determine what you are going to put in the batteries.

The rooftop controller, a Victron 100/30 provides the full output of the panels, again until the batteries reach 98% full. At that point it switches to absorption at 14.4V for anywhere from 10 - 20 minutes. I have it set for adaptive absorption, although some (including Battleborn) suggest setting it manually for 1/2 hour per 100 amp hours of battery capacity. After absorption, it switches to float, which I have set at 13.6V.

Hope this helps.

Jon

[k0wtz]

What are you planning to do what will be your camping style. We just returned from Quartzite 2 weeks boondocking with a small 12v car battery.

We are not electronic users such as tv. We have a small portable radio runs on 2a batteries. We have a hand pump for water no bathroom.

oh we returned we still had plenty of battery power left.

you need to think through I guess your must haves in 12v power remember more batteries is more weight!

When we camp the luxuries are left at home but up to you!


good luck

bob

[k0wtz]

Steve you nailed it!

bob

Originally Posted by Stephen_Albers

The temperature limitations of Fe Lithium are very serious for anyone contemplating anything close to 4 season operation or locating outside the deep south. You should press the manufacturer for specific test data in cold weather and carefully assess its impact. Are batteries permanently damaged by short term exposure to outsize temperature as the published operating specifications suggest? If so, then your major investment in batteries is constantly at risk for temperature damage. There are two different situations to consider: Underway and storage. Your batteries are likely more at risk when you are not using your trailer and it is just being stored than they are while underway.

Many snowbirds plan only operations in moderate temperatures. But temporary temperature swings exceeding 40 degrees are quite common, which average temperature data miss completely. And attractive opportunities for unforeseen operation in more extreme temperatures will likely present themselves in the real world. Planning for worst-case is appropriate if you don't want to become a babysitter for your battery.

[JonRaw]

Originally Posted by Jane P.

Hi Jon,
I dropped a new BB 100v lithium last week, along with a Pacific Dynamics replacement to my controller’s lower section. After reading the various posts to this thread, I decided to locate the battery in the cabin, under the front dinette seat. I belatedly learned that the trailer’s built-in monitor will not work with a lithium, and after researching various BVMs, I’m getting Victron 712.

While In the process of buying even more expensive goodies to support the BB Li, I need clarification for your recommendation re a DC-DC isolation power supply. I discussed this issue with Battle Born, and they did not think this would be of help. They suggested that I’d have to accept the fact that the battery would not be fully charged by the TV.

As with you, I do travel from one off grid camping area. The drive can be anywhere from 2 - 4 hours. It is not unusual for me to travel at night. If I read your post correctly, you depend on your rooftop solar panels to work in conjunction with your DC-DC Isolation converter, to fully charge the Li battery.

So my question is, what does your Victron controller, as a stand-alone, add to the process of recharging under tow? How does it coordinate with rooftop solar?
I really want to understand how this all comes together, as I prefer to purchase any additional needed items and install them at the same time.

Thanks in advance for your prompt response.

Originally Posted by Jon Vermilye

The Victron DC to DC converter can be set for any output voltage you desire. Mine is in the trailer set for 14.4V. I have measured the current it supplies to the batteries with the truck at idle, and it is the rated current, 9 amps. While it is possible that the tow vehicle wiring is so small that it can't supply 9 amps, that is unlikely, particularly at driving RPMs. If you want more charging amps, Victron makes larger DC to DC converters, as do others.

Whether this will fully charge your batteries during a nighttime drive depends on how far down they are &, of course, how long you drive. The lithium batteries will accept the full output of the 9 amp converter until 98% full, so you can use 9 amps times the drive time to determine what you are going to put in the batteries.

The rooftop controller, a Victron 100/30 provides the full output of the panels, again until the batteries reach 98% full. At that point it switches to absorption at 14.4V for anywhere from 10 - 20 minutes. I have it set for adaptive absorption, although some (including Battleborn) suggest setting it manually for 1/2 hour per 100 amp hours of battery capacity. After absorption, it switches to float, which I have set at 13.6V.

Hope this helps.

Jon

Jane, No disrespect for Jon Vermilye's opinion at all, but my suggestion is to get the Victron 712 installed and set up. It's a pretty simple installation. Once you are able to see your voltage (and more importantly, current/amperage) in real time you will get a better idea if you need a DC/DC converter. After talking with Battle Born they suggested that it won't really help my situation. So far what I'm seeing matches that recommendation, but my testing has been limited.

[Jane P.]

Originally Posted by Jon Vermilye

The Victron DC to DC converter can be set for any output voltage you desire. Mine is in the trailer set for 14.4V. I have measured the current it supplies to the batteries with the truck at idle, and it is the rated current, 9 amps. While it is possible that the tow vehicle wiring is so small that it can't supply 9 amps, that is unlikely, particularly at driving RPMs. If you want more charging amps, Victron makes larger DC to DC converters, as do others.

Whether this will fully charge your batteries during a nighttime drive depends on how far down they are &, of course, how long you drive. The lithium batteries will accept the full output of the 9 amp converter until 98% full, so you can use 9 amps times the drive time to determine what you are going to put in the batteries.

The rooftop controller, a Victron 100/30 provides the full output of the panels, again until the batteries reach 98% full. At that point it switches to absorption at 14.4V for anywhere from 10 - 20 minutes. I have it set for adaptive absorption, although some (including Battleborn) suggest setting it manually for 1/2 hour per 100 amp hours of battery capacity. After absorption, it switches to float, which I have set at 13.6V.

Hope this helps.

Jon

Thanks Jon,
This is very helpful.

I'm learning about Lithium Batteries as I go along. I naively assumed that, given enough drive time, I would arrive at a new camp site with a fully charged battery. Not so with a Lithium.

At this point, I will hold off on adding a DC-DC Isolating Convertor until I add solar, later this year. This will give me an opportunity to road test my new Lithium.

Additionally, I am seriously contemplating a 2000 Inverter backup generator. That would essentially mitigate the trickle charging issue.

Thank for your excellent response.

[Jon Vermilye]

Originally Posted by Jane P.

Thanks Jon,
This is very helpful.

I'm learning about Lithium Batteries as I go along. I naively assumed that, given enough drive time, I would arrive at a new camp site with a fully charged battery. Not so with a Lithium.

At this point, I will hold off on adding a DC-DC Isolating Convertor until I add solar, later this year. This will give me an opportunity to road test my new Lithium.

Additionally, I am seriously contemplating a 2000 Inverter backup generator. That would essentially mitigate the trickle charging issue.

Thank for your excellent response.

As Jon (JonRaw) noted, you do not "need" a DC to DC converter to charge from the tow vehicle, but it does take 14.4V to fully charge & balance the individual cells in the battery. If your tow vehicle holds 13.6V or more at the trailer batteries, you will eventually get close to a full charge. I've watched my Victron solar controller, and it gets the batteries to 98% at 13.6V or so before switching to absorption and 14.4V for the last 2% and cell balancing. 98% is pretty near full!

You may find your solar does all the topping off necessary.

[Defenestrator]

It's even better than that - alternator voltage can run higher than 13.6V on a lot of vehicles. Sometimes up to 14.5V, and maybe higher in some cases. The voltage drop from the long thin wiring running from the alternator all the way back through the tow connector may limit how much actual charge you get, but I've definitely seen on the order of 4-5A charging lithium batteries from a 2016 Silverado.

So, it might be slow because of the smaller voltage delta but it'll generally get it up to a full charge eventually. Even when it doesn't, it'll be really close because of the sharp voltage "knee" on LFP batteries (voltage vs charge is relatively flat until around 90-95% where int climbs rapidly).

[k0wtz]

Originally Posted by Defenestrator

It's even better than that - alternator voltage can run higher than 13.6V on a lot of vehicles. Sometimes up to 14.5V, and maybe higher in some cases. The voltage drop from the long thin wiring running from the alternator all the way back through the tow connector may limit how much actual charge you get, but I've definitely seen on the order of 4-5A charging lithium batteries from a 2016 Silverado.

So, it might be slow because of the smaller voltage delta but it'll generally get it up to a full charge eventually. Even when it doesn't, it'll be really close because of the sharp voltage "knee" on LFP batteries (voltage vs charge is relatively flat until around 90-95% where int climbs rapidly).

After 4 alternators on my 98 Volkswagon Beetle tdi in 20k my mechanic and I have discussed what could be destroying my alternators very expensive to remove by the way!

Here is what he thinks. The VW has some sort of a hidden draw if that car sets for a month the battery will be completely wiped out. I use my jumpers to start the car since the battery is completely drained he thinks its killing the alternator. He says this one is not engineered to be a battery charger but a maintainer.

I have owned a few cars in my 78 years but I think he is on to something!

bob

[CarlD]

A couple considerations regarding a DC-DC isolator.

1. The voltage drop in the wires of the tv and trailer are the biggest limitations to charging while driving with any type of battery. An isolated DC-DC converter eliminates this issue for the most part. Your input voltage to the DC-DC converter may drop to 10 volts, however the output will remain at the setpoint voltage. The current draw from the tv will be considerably higher than the current to the battery (power out = power in * efficiency) you can do the math.

2. The DC-DC isolator can fully charge the battery.

3. A DC-DC isolator prevents the LFP battery from back charging into the tv if the ignition switch is left on and the engine not running. Most likely not an real issue.

4. The Victron DC-DC isolator is easy to install. (put it near the battery).

5. And it is really not a lot of money.

6. My Victron 9 amp DC-DC converter works well with my Renogy 20 amp MPPT solar controller.

[Defenestrator]

Yeah, that can definitely be a problem. It's safer for travel trailers because the wiring from alternator to batteries is so long and thin that it limits charging current, but boats that switch to large Lithium banks can burn out alternators.

[Raspy]

I just installed a 50 amp Anderson plug on the rear of my Ram, and wired it with two #6 wires from the battery. There is a 60 amp circuit breaker on the plus lead close to the truck battery.

My trailer came wired with an Anderson plug on a pigtail on the tongue, wired to it's batteries with a pair of #6 wires.

So, now when I hook up and plug in the seven pin , I also plug in the Anderson pigtail from the trailer.

I'm now running my fridge on DC when towing, instead of propane, and arriving with my trailer batteries at around 13.5 volts, fully charged. We are almost home from a 900 mile trip to Valley of Fire, and I haven't actually measured the amps being sent. The truck also has a factory smart charging alternator that starts out above 14 volts and drops to about 13 when everything is charged, so I may not need any further regulating of the charge current. In the next few days I'll have more accurate voltages and delivered amp readings.

I've been wondering why someone with a conventional alternator couldn't use a PWM solar controller to charge the trailer batteries from the trucks alternator. Just connect the alternator output to the solar controller collector input. Be careful to match the delivered amps to the solar control rating.

The advantages would be that the controller would act as a smart charger while driving, and a disconnect when stopped. PWM controllers are also ver cheap. Most vehicles have a constant 14.1 to 14.5 volt output to their battery anytime the engine is running. With the controller, every startup would be interpreted as a new solar day, and a smart charge program would manage the charging. MPPT would give no benefit and PWMs are cheap, so PWM would be the way to go.

[k0wtz]

I did this once to run a large amplifier for my ham radio set-up. Nr 6 wire to another battery in the trunk to the amplifier.

I could run massive amperage draw and never run the car battery down. Makes sense to me and I can light my propane on the fridge but it will be blown out when I arrive.

Probably safer anyway to do what you are doing!

bob