Sizing lithium "generators" for my rig (fridge) and trailer.

[zimm]

I'm in brainstorming mode and looking at possibly getting 2 different lithium generators. I'm liking Ecoflow but will cross shop Bluetti as well.

Rig- Jeep with an ARB50 qt fridge. It's left me stranded before killing the battery even with the cut off. I want to put a lithium generator and power the fridge off of it. Then run either a DC-DC or some high power current to charge the pack while driving. Not sure of the size I need. From reading the internet, the fridge pulls anywhere from 30-60 watts, but it's not continuous. I drive everyday while on a trip, but I'd like to have 2-3 days capacity just in case.

In the little camper trailer I'm planning- it'll have a 5000BTU air conditioner (410 watt/hr), lights, charge phones, iPad, maybe run a fan, electric blanket if its cold. So I'm thinking something large like an EcoFlow Delta 2. That will let me run the A/C to chill down enough to get to sleep, then turn it off. Or stay warm at night. I plan to run solar on the roof and also run a DC-DC charger from the Jeep back to the trailer just to top off the lithium.

Any thought on this type of set up?

 

[Longshot270]

I'm in brainstorming mode and looking at possibly getting 2 different lithium generators. I'm liking Ecoflow but will cross shop Bluetti as well.

Rig- Jeep with an ARB50 qt fridge. It's left me stranded before killing the battery even with the cut off. I want to put a lithium generator and power the fridge off of it. Then run either a DC-DC or some high power current to charge the pack while driving. Not sure of the size I need. From reading the internet, the fridge pulls anywhere from 30-60 watts, but it's not continuous. I drive everyday while on a trip, but I'd like to have 2-3 days capacity just in case.

In the little camper trailer I'm planning- it'll have a 5000BTU air conditioner (410 watt/hr), lights, charge phones, iPad, maybe run a fan, electric blanket if its cold. So I'm thinking something large like an EcoFlow Delta 2. That will let me run the A/C to chill down enough to get to sleep, then turn it off. Or stay warm at night. I plan to run solar on the roof and also run a DC-DC charger from the Jeep back to the trailer just to top off the lithium.

Any thought on this type of set up?

Since you aren’t running it very long, use the 300hp gas engine with 100+ amp alternator that got you there do the heavy lifting and let batteries carry the light duty fans and chargers. When you pull into camp, plug in the 110v to a big inverter while you set up. Once things are cooled off, plug in a small battery pack to run chargers and fans.

 

[reaver]

If you're already planning on running a DC-DC charger, I fail to see the point of getting an all in one battery pack. Getting a 20A DC-DC charger, and 50Ah litium battery, plus some wires, and tossing in a solar charge controller (or adding it later) will be considerably cheaper. You'd be looking at about 300-350 bucks. A 50Ah battery will run your fridge for a couple of days without a charge, and it's both cheap, and easy to protect it from charging in the cold.

 

[510Steve]

Reaver is spot on with this as this is a similar setup as I have in my 4runner.
However I think the AC unit you have is going to be the deal breaker because you'll need at least a 1500 watt inverter to run it and that dramatically ups the cost.

If you wanted to do just "generators" I would do two separate units as the fridge could run very easily on a small 300wh unit for a day or two. Then for your trailer you have the second larger unit (min 1500 watt inverter) that would be around 1.5 KWH that stays in the trailer while traveling and can be charged through a cigarette lighter when the vehicle is running. This statement holds true for the smaller unit as well. This avoids the need for a DC-DC charger as most generators will only accept around 100 watts charging from the 12V dc source anyway.

One more thing to add is I have had great luck with Bluetti products and I prefer them as they use LifePo4 chemistry vs. NMC cells that Jackery and most others use.

 

[bgenlvtex]

I have 2 friges an Iceco JP42 (roto-molded) in the Jeep and I have this battery pack in line between the truck and the frige when the truck is running it passes thru the battery (charging it in the process), then when I shut down for the day the battery powers the frige/freezer through the night. It is lightweight and very effective, rotomolded frige does a great job holding temperature so little help is needed.

The trailer has an 80L Evacool that runs on the trailer house battery (100ah LifePo)

I don't use any of the "solar generators" because I have no need for 115v, converting 12v to 115v is inefficient and un-necessary . If you are starting from scratch I would encourage you to avoid 115v as much as possible and source all your accessories in 12v. Doing so means you won't need an inverter (built into most power stations). You can get a lot more battery than comes in most "power stations" for less money than a power station, less weight than a power station.

Solar generators (which is a ridiculous description in itself) are useful and have their place, but not for me.

 

[zimm]

Good points all around. The newer ecoflow have the better LifePo battery chemistry too.

Another option I have since you mentioned avoiding AC.... I have a Honda EU2000 generator too. I could put that with the trailer in a tongue box and use it when A/C is needed (which I think would be rare). Then I just need to focus on having DC storage solution for the fridge in the Jeep and also a DC power solution in the trailer which the solar can handle and also the 7 pin connector while driving can charge too (a little bit).

 

[510Steve]

I actually rented a trailer from cruise America last fall and they have an onboard Li battery that was charged through the 7 pin. I was curious on how they regulated the current. I discovered they used a solar charge controller as essentially a dc-dc charger. The bonus was they also had 200watts of solar on the roof so it was able to charge both from the alternator as well as from solar.

 

[zimm]

More brain storming..... My main battery is due for a replacement (2018). This could be a good time to do a Genesis dual battery set up and that will give me plenty of juice to run my fridge and everything is under the hood without a bunch of wires and boxes taking up space in the back. Hmmm... The downside is that it's $700 plus I need another $600 for dual AGM batteries. But it also give me back up for starting the engine too.

For the trailer, I can rig up a deep cycle or lipo battery with a solar charger and panel. Not sure how the 7 pin connector will wire up to charge while on the go.

 

[bgenlvtex]

Good points all around. The newer ecoflow have the better LifePo battery chemistry too.

Another option I have since you mentioned avoiding AC.... I have a Honda EU2000 generator too. I could put that with the trailer in a tongue box and use it when A/C is needed (which I think would be rare). Then I just need to focus on having DC storage solution for the fridge in the Jeep and also a DC power solution in the trailer which the solar can handle and also the 7 pin connector while driving can charge too (a little bit).

I use a Champion 2000 to run my A/C (Elwell) , it's going to take a bunch of battery to run A/C for any appreciable amount of time. 1 gallon of gas runs my A/C all night long and any surplus goes to my house battery, so it too is hot in the morning.

 

[510Steve]

More brain storming..... My main battery is due for a replacement (2018). This could be a good time to do a Genesis dual battery set up and that will give me plenty of juice to run my fridge and everything is under the hood without a bunch of wires and boxes taking up space in the back. Hmmm... The downside is that it's $700 plus I need another $600 for dual AGM batteries. But it also give me back up for starting the engine too.

For the trailer, I can rig up a deep cycle or lipo battery with a solar charger and panel. Not sure how the 7 pin connector will wire up to charge while on the go.

This is sorta what my setup looks like. I have a larger AGM for starting and mild backup. Off the battery I am running 10ga to my Victron 18Amp DC-DC charger. That is feeding an off brand 50ah LifePo⁴ under the hood to run my 12v accessories as well as a small 400watt inverter that I use for charging ebikes and things like that. I also have a shunt inline to keep track of my battery capacity.

 

[Mike W]

off brand 50ah LifePo⁴ under the hood

just a general best practice FYI.... avoid running LiFePO4 in high heat areas like under the hood of a vehicle. It is better to keep them in cab. The life of the battery will be significantly impacted by this. (Lookup the spec sheet on your pack/cells). DCDC chargers also get pretty hot, so if you have to install them in the engine bay, put them up front in direct airflow in front of the radiators. They will down rate the amperage if they get heat soaked from the engine also. Even better though is to keep the DCDC charger close to the batteries its charging, otherwise you will have voltage drop and they won't perform as well. Try to minimize voltage drops in general, but especially on the output side of a DCDC charger. I run 6AWG for my 50 amp redarc DCDC and reliably get 48+ amps into my 340ah LiFePO4 bank.

 

[JackAttack]

Hey mate,

I don't rate the solid state "solar generators" or "Power packs" which seem really popular over in the US. They're expensive and virtually impossible to repair. I recommend having a system built with separate batteries and chargers which will be more reliable and better value for money.

For the Jeep

120AH Lithium Battery in a battery box (EXAMPLE: Home Page - Adventure Kings)
25A DCDC Charger & 50A Wiring Kit (EXAMPLE: Home Page - Adventure Kings)

This will reliably provide 2-3 days of power running your ARB fridge without any charging. To maintain indefinite power, you will only need to drive 2.5 hours a day to offset the daily power usage of your fridge. As mentioned already, don't place lithium batteries or DCDC chargers in the engine bay.

You could consider going a 40A DCDC charger (Home Page - Adventure Kings) which would only need 1.5 hours to maintain indefinite power. Either is fine but 25A is all you really need.

For the Trailer

From what you've mentioned you'll probably be looking at up to and around 100A of usage a day.

300AH Lithium Battery (Home Page - Adventure Kings)
40A DCDC charger (Home Page - Adventure Kings)
300w to 500w of solar

This battery will give you 2-3 days without any charge but will require only 2.5 hours of driving or 2.5 to 4 hours of solar to offset your daily power usage.

cheers,

 

[Mike W]

I recommend having a system built with separate batteries and chargers which will be more reliable and better value for money.

I am not sure I agree here. I think for most people, most common uses, a prebuilt box (which contains a lithium battery, dcdc charger, inverter, 12v converter, solar charge controller, etc) is simpler, easier to use, portable and enough for most normal car camping use cases. It's also tough to say that a prebuilt system is less reliable or less value... it is hard for most people to know how to built complex 12v systems and adding up all the components is expensive. Reliability is tricky.. In my system I have way more connection points and things to ensure are safe and properly designed and operational than a prebuilt box. Even the time it takes to properly design, build a custom system is a pretty significant thing and most folks don't have general electrical knowledge.

I totally get the more advanced reasons for building a system. I'm a big nerd, who spent lots of time and money on a custom system. I love it for many reasons, but I also recognize how nuts it is to have 4,200 watt hours of power in my Land Rover. If you just need to run a fridge and other lower power items for a few days and have somewhat normal access to alternator or solar charging, then a prebuilt box can handle things. My system opens up other possibilities such as pure electric heating (heated blanket and 200w space heater), running high amp water pumps for a shower, leaving lights/radios on 24/7. Running air compressors with the engine off and not worrying about it ever. Running 1kw inverter 24/7 and other silly behavior. But I don't recommend this to people. I mostly point people at the prebuilt boxes.

My setup is 340 amp hours, 4,200 watt hours and cost over $4,500 USD. Its nuts.. and while I love it, its overkill. I spent more than a month on this project, ripping out my old AGM dual battery setup which had voltage drop issues and nowhere near enough capacity. I had spreadsheets to figure out wire gauges and lug sizes with correct post hole sizes for each component and mapped out everything in the vehicle to optimize its capability. It is installed under my rear drawer system where the 3rd row seats used to be. The drawers and top is removed for this photo.

 

[510Steve]

I am going to have a slight disagreement with you guys on the LiFePo4 under the hood argument.
Almost every battery BMS is going to have a high temp cut-off that will shut the BMS off if the cells reach typically 140*.
This has literally never happened, even in Death Valley. The cells are insulated inside & by the battery "box" so the cells will never see the full temp of the engine bay. I would by far more concerned with accidently charging below freezing. However my charger is bluetooth enabled so I shut it off whenever I know I'm going to be in sub 32* weather.
Also, one other thing to note, LiFePo4 batteries are rated to 80% of capacity @ 3000+ cycles.. Which is damn near 10 years of daily 0-100% of SOC. These cells will calendar age long before this will ever happen, even if I were to cut their lives in half due to heat exposure.
At 200% of the available capacity and likely twice to 3X the calender life, and 10 X the cycle life of an AGM , for merely $100 dollars more than an Odyssey, I think I am money ahead.