Hello Forum Users - I just completed my 2nd “Independent” In-Depth film on upgrading an RV to Lithium Power and wanted to share it with the forum. On my most recent film, I designed two different systems for RV’s titled; "Lithium Lite" and "Lithium Super". The “Lithium Lite” system is based on a 300 amp hour system with 3,800 watts of capacity which essentially replaces and doubles the power of most RV’s AGM batteries. This system is ideal for smaller RV’s such as B, B+ and Class C RV’s. The "Lithium Super” is a Powerhouse System which uses a 625 amp hour battery with 8,064 watts hour capacity which allows the entire coach to be run totally on lithium power, to even include the roof air conditioner for up to 8-10 hrs at a 50% cycle. This system also offers expansion to 1250 amp hours. My design includes moving the house batteries (now lithium) from their past “open air” compartment, where the batteries were exposed to extreme temperatures, road dust, water & salt spray, to the opposite side of the coach, to a larger sealed compartment which is temperature controlled. This compartment also houses the inverter, BMS, solar controller and battery isolator, to allow very short cable runs for near zero loss. This unique design captures “Free Heat” generated from the inverter and a neighboring AquaHot compartment to supplement the lithium batteries internal self-heating system to provider power saving and uninterrupted operation during freezing temperatures. I hope you enjoy the film - Mike MasPlease click on the link below for the videohttps://www.youtube.com/watch?v=k2RilLqYE5c&feature=youtu.beSeems if the link is not active - please copy and paste either links above or below - Thanks!https://youtu.be/k2RilLqYE5c

Idle up,I'll have 7200 watt-hours of SiO2 batteries by the summer, and can use them at -40.

Idle-Up wrote:Hello Forum Users - I just completed my 2nd “Independent” In-Depth film on upgrading an RV to Lithium Power and wanted to share it with the forum. On my most recent film, I designed two different systems for RV’s titled; "Lithium Lite" and "Lithium Super". The “Lithium Lite” system is based on a 300 amp hour system with 3,800 watts of capacity which essentially replaces and doubles the power of most RV’s AGM batteries. This system is ideal for smaller RV’s such as B, B+ and Class C RV’s. The "Lithium Super” is a Powerhouse System which uses a 625 amp hour battery with 8,064 watts hour capacity which allows the entire coach to be run totally on lithium power, to even include the roof air conditioner for up to 8-10 hrs at a 50% cycle. This system also offers expansion to 1250 amp hours. My design includes moving the house batteries (now lithium) from their past “open air” compartment, where the batteries were exposed to extreme temperatures, road dust, water & salt spray, to the opposite side of the coach, to a larger sealed compartment which is temperature controlled. This compartment also houses the inverter, BMS, solar controller and battery isolator, to allow very short cable runs for near zero loss. This unique design captures “Free Heat” generated from the inverter and a neighboring AquaHot compartment to supplement the lithium batteries internal self-heating system to provider power saving and uninterrupted operation during freezing temperatures. I hope you enjoy the film - Mike MasPlease click on the link below for the videohttps://www.youtube.com/watch?v=k2RilLqYE5c&feature=youtu.beSeems if the link is not active - please copy and paste either links above or below - Thanks!https://youtu.be/k2RilLqYE5cIf your information and efforts have anything to do with use of the common Group27/31 size 100AH lithium batteries in an RV, you might want to consider doubling of capacity ... without doubling of the area where the batteries are kept ... through use of these Group 31 200AH lithium batteries instead:https://www.lithiumion-batteries.com/products/12-volt-lithium-batteries/group-31-12v-200ah-lithium-ion-battery.php

Phil,Nice find. I'm considering 270 amp-hour SiO2--but they might be pretty heavy, so it may be best to stay with 100 amp-hour jars.Li doesn't have that sort of weight constraint, which is a feature I had not thought of before.

pianotuna wrote:Phil,Nice find. I'm considering 270 amp-hour SiO2--but they might be pretty heavy, so it may be best to stay with 100 amp-hour jars.Li doesn't have that sort of weight constraint, which is a feature I had not thought of before.Don,Also note down aways on the page in the link I gave ... that their 200 AH Group 31 lithium battery still has about 70% of it's capacity at -4 degrees F. I wonder how they pulled that off? Internal heating?

Retaining capacity in LiFePo4 batteries isn't the issue, it's restoring the charge, that's where you'd need some kind of heating setup to maintain core temp. You can safely discharge at high efficiency in cold weather (I believe it's efficiency is substantially higher than wet cell).

RV Lithium Lite & Lithium Super Upgrade Systems - Mike Mas

pianotuna
Nomad III
Sep 18, 2021
time2roll,

I could not agree more with exciting times. Being generator free is the holy grail of off grid.
time2roll
Nomad
Sep 18, 2021
That expanded "Super" at 1250 amp/hours would seem more of a starting point. My 1200 is getting built and installed over the next couple weeks. These are exciting times for off-grid RVing.
HTElectrical
Explorer
Sep 18, 2021
RV Lithium Lite & Lithium Super

Fixed it for you.
pianotuna
Nomad III
Sep 18, 2021
My understanding is that dendrites are the problem with cold weather charging of Li.

The battery management system for Li has to be designed with "hard" limits.
pianotuna
Nomad III
Sep 18, 2021
Idle-Up,

My plan is for 700 amp-hours of SiO2. They have none of the fussy problems of LiFePo4. If it will fit, I'll use another as the starting battery.

I can't imagine an Li (except for the Titinate chemistry) being suitable in temperatures of below -30. Even if the bank is in the heated area of the RV, unless the use is full time.

Getting from cold soaked to operating temperatures would take a fair bit of time--and where would the power come from to operate the furnace?

The link to the video is not clickable.
Idle-Up
Explorer
Sep 18, 2021
pianotuna wrote:
phemens,

The reading I've done (which may be incorrect) suggest low slow charging may be possible at -20 c (-4 f)

Tonight it will be -33c here.

Thanks for the reply - charging at freezing temperatures is incorrect as it will cause immediate un-repairable damage to the cells. If you plan on using your coach during winter, I suggest you only buy a lithium battery with an "Internal" heater. While heat- blankets will let you get by, they do not heat the cells equally which changes the capacity of the cells differently. Here's a little video I did on lithium heating:

Stay Safe Mike

https://www.youtube.com/watch?v=smCms94wH88

https://youtu.be/smCms94wH88
phemens
Explorer
Feb 06, 2021
pianotuna wrote:
phemens,

The reading I've done (which may be incorrect) suggest low slow charging may be possible at -20 c (-4 f)

Tonight it will be -33c here.

Yes, I've heard that as well. My use case is really on the borderline of the threshold for regular charging (getting down to below 0c occasionally, with risk of battery core temp falling into that 'danger zone'), and that's for a couple of weeks at the end of the season (maybe longer is we start extending). Since we're not there to make adjustments during the week, the safest option for me is the waste tank heater running all the time. At 6a/hr, I only really get a drawdown after the sun doesn't send enough juice to the solar panels, so maybe 14 hrs which is 84 ah to recover, which is more than acceptable given my battery reserves. While we're away apart from the heater, there's the residential fridge and usual parasitic draws, so the system keeps up without breaking a sweat.
pianotuna
Nomad III
Feb 05, 2021
phemens,

The reading I've done (which may be incorrect) suggest low slow charging may be possible at -20 c (-4 f)

Tonight it will be -33c here.
phemens
Explorer
Feb 05, 2021
Retaining capacity in LiFePo4 batteries isn't the issue, it's restoring the charge, that's where you'd need some kind of heating setup to maintain core temp. You can safely discharge at high efficiency in cold weather (I believe it's efficiency is substantially higher than wet cell).
pnichols
Explorer II
Feb 05, 2021
pianotuna wrote:
Phil,
Nice find. I'm considering 270 amp-hour SiO2--but they might be pretty heavy, so it may be best to stay with 100 amp-hour jars.

Li doesn't have that sort of weight constraint, which is a feature I had not thought of before.

Don,

Also note down aways on the page in the link I gave ... that their 200 AH Group 31 lithium battery still has about 70% of it's capacity at -4 degrees F. I wonder how they pulled that off? Internal heating?

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RV Lithium Lite & Lithium Super Upgrade Systems - Mike Mas

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