My Lithium Upgrade

[Treker20]

Opps, that last response was an answer to Booster comment about the white paper.

[booster]

Originally Posted by Treker20

Booster, this goes to show a little bit of knowledge can be dangerous. to me it looked like a great answer.

I think that it it always wise to take most all of the "reviews" or "education" videos that are by the manufacturers or so called independent reviewers that are doing them to make money of links or site advertising.



The Battleborn video is pretty typical of how manufacturers will cherry pick specs to test and set the test parameters to best show off their products. Often they can be very deceptive and misleading.



When you see careful product placement of what reviewers are testing so that they stand out for the camera to see, that is another clue, as is if they got the battery for free or got paid to review it.


How many times do we see reviews by independent reviewers that contain lots of links to the products on specific sales sites that pay for referrals from link contacts.


As in life "trust but verify" before putting down your hard earned money.


That said, if the Renogy gave good information on the heater function, that is a good thing an likely believable as it is not the kind of spec the general public would be interested in or even know existed. Most buyers are on/off/volume types, I think, so the comparisons that push the "ours last longer type" things sell better. Those of us in the lunatic nerd fringe check every little thing in comparison and have need to know why and how it all works.

[Treker20]

I agree, i gave the link so explain the heat function. Renogy's site does not say much about the heat function, and as you say the majority of people won't care about it. There installation guide only says the heat function begins operating when charge amps are above 4. I am going to call them tomorrow for more info on that and some other questions.

I am struggling to find room to install the added equipment i need, like the dc-dc charger and possibly the inverter /charger. Everything is really tight. Then finding ways to get wiring that i need from inside the van to the outside batteries. It will be a challange for sure. I know i am going to have lots of questions once i start, probably after first of the year. T

This forum is so helpful, thanks to everyone that contributes. such a wealth of information.

[jakegw2]

I built a heater system for my LiPo Battleborn batteries earlier this year (you can read the details here: https://www.classbforum.com/forums/f...kit-12103.html).

I actually want my system to operate differently from the way Avanti proposed because I want the ability to control the details of how it works. In my system I can turn the heating function on and off manually. When it is on it is controlled by a small thermostat that then tries to keep the setpoint temperature I have it set for. When it is on it draws about 2.7A of power. It still hasn't gotten consistently cold enough for me to get the type of real-world measurements I want to see regarding duty cycle and such, but one two-day cold snap gave me a data point to consider. Wth the contribution of my solar and outdoor temps in the low 30's, nighttime temps in the low 20s I was able to keep the battery temperature at 42 degrees continuously at the cost of about 20AH of power over about 48 hours of time. As long as I provide shore power to restore the batteries at least once every 10-20 days I can keep the batteries above-freezing and ready to go at a moment's notice.

Of course this was for testing purposes. I can drop the setpoint lower when it gets colder, but still intend to keep the batteries above freezing since I don't want to be in a position of trying to use the heater to warm them up to operating temperature. It would probably work, but why bother when I have shore power right next to the storage location anyway?

If I wanted to do so I could set it for something like 5 degrees and just plan on plugging it in if the temperature was going to be lower than that for more than a few days. Since we seldom get extended cold snaps where I live this would be a protective and maintenance-free option for most winters. To use it I would then need to bump the temperature up to above 25 degrees and keep it powered either by driving or shore power until the batteries warmed up enough to take a charge.

[avanti]

@jakegw2's setup got me thinking of another scenario that will be important to me and which my "dirt simple" proposal doesn't cover:

The scenario is this:
--DW and I are enjoying a mid-winter stay at the beach in Tahiti.
--Back home, an ultra-polar-vortex (whatever that is) is about to send the temperatures at our sleeping van to below the safe storage temperature of the batteries (this should be very rare, but it still needs to be addressed).
--The van has remote telemetry, so I can see the temperature and SOC of the batteries, and have the ability to remotely start the engine.

So, short of hopping on a plane, what should I do?

Well, I can start the engine, which (in my scheme) would start the battery heater in preparation for charging, but that doesn't help much -- I can't run the engine for days at a time.

What I REALLY want in this case is to use the battery to keep itself warm as long as possible (which @jakegw2's data suggests could be a long time). Only if the SOC is getting low would I have to start the van and recharge the batteries.

It appears that the ideal system requires two different ways to use the battery heater:
1) Use charger power when it is chilly.
2) Use the battery's own charge when it is really frigid.

I guess both of these can be automated without too much trouble, but it would require two different temperature set points. It might be tricky to do with internal heaters, unless they can be triggered externally. The extra credit point would be earned by having the system text me when in mode 2 and the SOC gets dangerously low.

Make sense?

[rowiebowie]

Originally Posted by avanti

@jakegw2's setup got me thinking of another scenario that will be important to me and which my "dirt simple" proposal doesn't cover:

The scenario is this:
--DW and I are enjoying a mid-winter stay at the beach in Tahiti.
--Back home, an ultra-polar-vortex (whatever that is) is about to send the temperatures at our sleeping van to below the safe storage temperature of the batteries (this should be very rare, but it still needs to be addressed).
--The van has remote telemetry, so I can see the temperature and SOC of the batteries, and have the ability to remotely start the engine.

So, short of hopping on a plane, what should I do?

Well, I can start the engine, which (in my scheme) would start the battery heater in preparation for charging, but that doesn't help much -- I can't run the engine for days at a time.

What I REALLY want in this case is to use the battery to keep itself warm as long as possible (which @jakegw2's data suggests could be a long time). Only if the SOC is getting low would I have to start the van and recharge the batteries.

It appears that the ideal system requires two different ways to use the battery heater:
1) Use charger power when it is chilly.
2) Use the battery's own charge when it is really frigid.

I guess both of these can be automated without too much trouble, but it would require two different temperature set points. It might be tricky to do with internal heaters, unless they can be triggered externally. The extra credit point would be earned by having the system text me when in mode 2 and the SOC gets dangerously low.

Make sense?

I can't think of anything after Tahiti.

Hard to care about Winter storms imagining my toes in the warm sand and my hands on a cold beer.

[Davydd]

Oh for cripes sake if you want to enjoy the advantages of lithium ion batteries in a Class B for 3/4 of a year in prime RVing conditions connect to shore power with a BMS that can keep batteries above 41F with an external or internal heating system, remove and put your batteries in a conditioned space, find or build a heated storage garage or move south or winter south. It’s just common sense. Do you really want to remote monitor and worrying about batteries when on a tropical vacation and can’t do anything if it goes south? Pardon the pun.

[GeorgeRa]

Originally Posted by avanti

@jakegw2's setup got me thinking of another scenario that will be important to me and which my "dirt simple" proposal doesn't cover:

The scenario is this:
--DW and I are enjoying a mid-winter stay at the beach in Tahiti.
--Back home, an ultra-polar-vortex (whatever that is) is about to send the temperatures at our sleeping van to below the safe storage temperature of the batteries (this should be very rare, but it still needs to be addressed).
--The van has remote telemetry, so I can see the temperature and SOC of the batteries, and have the ability to remotely start the engine.

So, short of hopping on a plane, what should I do?

Well, I can start the engine, which (in my scheme) would start the battery heater in preparation for charging, but that doesn't help much -- I can't run the engine for days at a time.

What I REALLY want in this case is to use the battery to keep itself warm as long as possible (which @jakegw2's data suggests could be a long time). Only if the SOC is getting low would I have to start the van and recharge the batteries.

It appears that the ideal system requires two different ways to use the battery heater:
1) Use charger power when it is chilly.
2) Use the battery's own charge when it is really frigid.

I guess both of these can be automated without too much trouble, but it would require two different temperature set points. It might be tricky to do with internal heaters, unless they can be triggered externally. The extra credit point would be earned by having the system text me when in mode 2 and the SOC gets dangerously low.

Make sense?

How about a temporary almost vertically mounted ~50-100W solar panel aimed south with sufficient size AGM battery with automatic heater. It could be attached with magnets to the side of the van.

[avanti]

Originally Posted by Davydd

Oh for cripes sake if you want to enjoy the advantages of lithium ion batteries in a Class B for 3/4 of a year in prime RVing conditions connect to shore power with a BMS that can keep batteries above 41F with an external or internal heating system, remove and put your batteries in a conditioned space, find or build a heated storage garage or move south or winter south. It’s just common sense. Do you really want to remote monitor and worrying about batteries when on a tropical vacation and can’t do anything if it goes south? Pardon the pun.

Yes, I do.

We routinely camp year around. "Prime RVing conditions" is in the eye of the beholder. I don't know any other way to explain that it is not convenient for me to have to store our rig only in locations with access to power. Common sense or not, that is my goal.

There will be plenty of self-contained energy available in our rig to accomplish this goal. I am simply figuring out how to deploy that energy in a way such that lithium batteries will be as practical and hassle-free as our current AGM batteries. That is a high bar--AGMs are very, very robust and convenient. I believe that I can accomplish this. I would have thought that this would make you happy.

[Davydd]

I don’t know how big you want your lithium battery bank but I can assume over 400ah or you would be wasting your time. If 12V self heating off the batteries you would probably have to have 5a of heating. That’s about as much as I had in a 12V electric heating pad for 400ah and 10a for 800ah. Just a guess. In freezing temperatures I observed cycling on and off and probably off half the time but in -4F it might be on continuously. But just say half or 2.5ah x 24 = 60ah a day. That would be a total depletion of a 400ah battery bank in 7 days. That’s not counting the power needed to monitor the system or leaving your batteries live and not disconnected with all the other parasitic draws. That’s why I say shore power or disconnect and put them in a conditioned space.

[jakegw2]

GeorgeRA - this is entirely feasible. My camper is parked in a spot that is shaded almost all day long, so my total daily AH production on my 340W solar system is around 6-8AH per day max, less for cloudy days.

If I had an unshaded area to park it I could realistically expect 40-50AH on a sunny winter day (the panels are flat on the roof and the sun is low on the horizon during the winter). If parked in an unshaded area I could depend on solar to extend the batteries enough to last through any deep cold snap that my area ever sees. Cold snaps in my area are often accompanied by sunny weather

At 100% duty cycle the heater would use 60AH, but I seriously doubt I would use anything more than 60% duty cycle in most realistic situations. I'll have a better estimate when we get some weather that is consistently in the 20s.

Note that to use solar I need the batteries to be actively accepting a charge, that means I have to keep them up closer to 30 degrees, not 5 degrees for withdraw only. This will increase the duty cycle in very cold environments. TBD on how much for sub -5 degree temps.

Also, I didn't mention this earlier, but when the battery heater kicks off the total parasitic draw of all items in my camper (including the heat controller) is about 0.4A.

[avanti]

Originally Posted by Davydd

I don’t know how big you want your lithium battery bank but I can assume over 400ah or you would be wasting your time.

Agree. If I were aiming at 400 (which is what I have now), I would stick with AGM. You have convinced me to go big. Probably 700ah.

If 12V self heating off the batteries you would probably have to have 5a of heating. That’s about as much as I had in a 12V electric heating pad for 400ah and 10a for 800ah. Just a guess. In freezing temperatures I observed cycling on and off and probably off half the time but in -4F it might be on continuously.

Yes, but remember that we are talking about having the heaters powered from the batteries, not shore power, so there will be a self-heating effect that will further reduce the run time of the heaters.

But just say half or 2.5ah x 24 = 60ah a day. That would be a total depletion of a 400ah battery bank in 7 days.

Even if this is correct, 7 days is plenty (except maybe in MN). Remember, we are only talking about weathering a spell cold enough to damage an unheated battery. And, in my story, I have the option to remote start the engine for a few hours once a week. This meets my expectations.

That’s not counting the power needed to monitor the system or leaving your batteries live and not disconnected with all the other parasitic draws.

As @jakegw2 said, with a properly-designed system, this power is trivial.

[avanti]

Lithonics has a battery heating setup that involves an internal heater pad (which they say is much more efficient than an external one--probably true), but with an external controller:

https://lithionicsbattery.com/wp-con...Kit-Option.pdf

On at 35F and off at 40F. They say a typical duty cycle is 55W, max 80W.

[avanti]

And another: Relion also has automatic internal heaters (I am following a thread on the Transit Forum):

https://relionbattery.com/blog/relio...ture-lt-models

The linked article points out that such a heater can confuse a shunt-based SOC meter, which hadn't occurred to me. This might tip the balance to the externally-powered internal heater approach.

[avanti]

...and:
Lifeblue

https://www.lifebluebattery.com/home/index.html

They claim to have a special BMS that permits safe charging directly from the alternator, without a B2B.

[avanti]

...apparently becoming a common feature:

Lithiumhub

https://lithiumhub.com/product/12v-3...cycle-battery/

[Davydd]

My illustration was assuming heating coming from the batteries, not shore power. Self heating of the batteries connected up was factored in my real life observations of how much power from the batteries would be needed whether internal or external heat source. Also, when your batteries are actively connected in your van and you have the ability to remotely monitor them I think you are discounting to much the passive and parasitic power consumption with your other stated goals. Regardless of calculations the 7 day illustration was actually 6.66 days, just keeping them above freezing not preventing going below -4F, not factoring in the unknown connected battery parasitic loss and if you want to keep them above 20% SOC universally recommended or a cushion of 30% SOC your days away go down dramatically.

When you talk about charging from the alternator, I hope you aren’t thinking of remote starting unattended and away from your van while you are on vacation. If so, I hope no one can see or hear your van or you may have unattended consequences by people or mechanical failure. I can think of a much cheaper solution. Install a 120 VAC 15W electrical outlet outdoors next to your van for simple shore power you say you don’t have.

Hey, but what the heck, I don’t know anything having lithium ion batteries for seven years with the ability to analyze their use and not guessing or surmising. So if you want to dismiss my observations because they were in Minnesota, then remember it never got down to -4F last two years long enough to damage my batteries in my much colder climate with their natural internal heat. So why worry in your supposedly warmer climate. Just don’t worry or don’t drive below freezing until you warm the batteries up. That’s what Winnebago Revel advises and I hope your design has them inside the cabin. That’s the trend learned from experience by upfitters.

[Davydd]

BTW, I can monitor my batteries down to the individual cell with 5 different Silverleaf screens of information. There are four batteries and each battery has four cells. The last screen was the internal battery temperatures when the ambient temperature was 57F. As you can see they are higher than ambient when connected and the van was on shore power.

[avanti]

Originally Posted by Davydd

[W]hen your batteries are actively connected in your van and you have the ability to remotely monitor them I think you are discounting to much the passive and parasitic power consumption with your other stated goals.

Regardless of calculations the 7 day illustration was actually 6.66 days, just keeping them above freezing not preventing going below -4F, not factoring in the unknown connected battery parasitic loss and if you want to keep them above 20% SOC universally recommended or a cushion of 30% SOC your days away go down dramatically.

Except that:

a) It would be absurd to set up such a system in a way that required it to be connected to the van in order to monitor it. This is nothing like your centralized SilverLeaf system (assuming ARV is still using them). There will be a dedicated and very tiny sensor and processor directly connected to the battery.

b) The parasitic load is not "unknown". As I said, it is negligible. To wit:
ESPpower.jpg
That little board at the right is a complete sensor system. It is connected to the Internet via WiFi and is monitoring two different temperature sensors, sending the values to a server once a second. As you can see, it is consuming 0.07A @ 5VDC. At 12VDC that is .029A. That is sending every second. In practice, once an hour would suffice, so you can divide by at least 100, but let's stick with .025A. If you didn't have WiFi, you would need a cell modem, but the power consumption for that would be on the same order. So, if I had, say, 500Ah of battery, I could monitor the temperatures for well over 2 years. As I said, negligible.

c) Since you report that the temperature has never gone below -4F in two years, it seems unlikely that it will ever stay below -4F for a week at a time. Meets my expectations.

When you talk about charging from the alternator, I hope you aren’t thinking of remote starting unattended and away from your van while you are on vacation. If so, I hope no one can see or hear your van or you may have unattended consequences by people or mechanical failure.

I would have agreed with this a few years ago, but a large percentage of vehicles now have this capability built into their remote telematics systems. People are used to it. This isn't the same as the old hacked-on self-start systems. Perfectly safe. As you say, it is unlikely to ever be needed. But I desire to have the possibility covered.

I can think of a much cheaper solution. Install a 120 VAC 15W electrical outlet outdoors next to your van for simple shore power you say you don’t have.

Actually, this will be quite a bit cheaper than installing a 15A outlet, even if that met my needs. That little board costs $10.
More importantly if I am not allowed to stipulate my own needs given my situation, then I give up. I will not pursue this point further. Pointless.

[Davydd]

Since my condo Garage 9 miles away from my house now has internet all my numerous Silverleaf functions can be monitored and controlled remotely with an app on my iPhone and WiFi Ranger with an internal WiFi network connected with Silverleaf. So I would be able to remote start but would not want to or need to for the reasons I mentioned. Just because it is universal and more in use now it just makes it more accessible to go wrong. Unattended running engines attract curiosity.

ARVs are programmable to remote start at any percentage of SOC and how many minutes you want to run up to about 2 hrs or sooner if fully charged independently without monitoring. It can be also done remotely with the app. But like I said, the KISS method is shore power for long term or unattended storage because the Silverleaf charges from shore power, charger shuts when batteries are fully charged and the charger doesn’t turn on until the SOC drops to a programmed SOC. Keeps batteries warm without needing to monitor too just above 41F.

If you bought a vintage van for cheapo bucks none of this would interest one, but this day and age where a fully decked out Class B seemingly of your desires is going to cost $150,000 to astronomical ARV prices. Most every single family house built post WWII per National Electric Code has an exterior 120 VAC 15A outlet. Extension cords are cheap. It is short sighted not to consider this first for an inexpensive investment if you don’t already have it.