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Old 09-06-2023, 08:02 AM   #1
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Name: JD
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Adding more LiFePO4 batteries?

I recently bought a Chin's 100 Ah LiFePO4 battery for the FrankenScamp electrical system.
I have 300 watts of solar on the roof and a Tracer 40 amp MPPT charger that I set up for the lithium battery.
I recently found a used 2000 watt inverter that is also a 30 amp switch for the incoming power to the trailer.
The plan is to add a second Chin's battery to have 200 amps of current draw capacity (200 amps each with some surge allowed) to allow for full power output.
The main use would be for short period AC to operate the all electric camper microwave and other appliances like the critical caffeine production. The main power load would be the microwave that has a peak power draw of 1500 watts.
Who else has experience with this type of setup and has suggestions?
Also I recently replaced the old Norcold 490DE with a DE105 Danfoss compressor fridge and it is much quieter and may be more efficient as to power usage than the old swing compressor.
The idea is that when we make short stops the inverter will provide AC power for the microwave and perhaps electric cooking appliances as SWMBO does not want LP gas in the cabin. The inverter air conditioner draws less than 900 watts and could be used briefly, but is not really an option for long time usage as the total 2500 Watt hours and you would not want to use all of that anyway.
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Old 11-19-2023, 09:59 AM   #2
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I see that nobody has answered you. I have done approximately what you propose. I had one 100Ah LiFePO4 battery and a year or so later added another one of the same make and size. So a total of two Battle Borns of different age. Mixing the two did not cause any problems. I would not have done it if they were different of different types or significantly different ages.
I later added a 3000W inverter.
On inverter power from the batteries, it is no problem to run the AC, microwave, hot water kettle, or any other typical plug-in appliance. The biggest draw is the 1500W kettle.
Things to pay attention to:
Make sure to follow the inverter manufacturers guidelines for cable size. In my case that meant 4aught for the inverter and 2aught for the batteries. and keep the runs to the battery very short. Make sure the cables connecting the batteries are equal length and very short. Don't attach the cable terminals to cables yourself (and by no means solder them in as some YouTubers do). Use a vendor that attaches them with a hydraulic crimper. You won't be able to twist the cables, so be sure you tell the vendor how to orient the terminals. In my case one was turned 90 degrees, and another faced the opposite direction. Mock up your cable runs using a heavy rope to get the length just right. I used Battery Cables USA and they have excellent directions on how to specify the orientation of the terminals.
In practice, the setup works fine for using these big 120V loads for reasonable periods of time. The 1500W kettle draws 130A DC measured by the Victron shunt. That is a lot of DC amps. Your cables need to be up to that load! See above.
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Old 11-19-2023, 10:57 AM   #3
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Originally Posted by Air Doug View Post
Make sure to follow the inverter manufacturers guidelines for cable size. In my case that meant 4aught for the inverter and 2aught for the batteries. and keep the runs to the battery very short
Is that 4 awg for the inverter or 4/0? Same for the batteries; 2 awg or 2/0 awg?

Both 4 awg and 2 awg would be too small for efficiencies. We use 2/0 awg for our two 100 ah SOK LiFePO4 batteries and also 2/0 awg for our 2,000 watt Progressive Dynamics inverter/transfer switch.

Food for thought,

Perry
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Old 11-19-2023, 11:10 AM   #4
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Originally Posted by Air Doug View Post
I see that nobody has answered you. I have done approximately what you propose. I had one 100Ah LiFePO4 battery and a year or so later added another one of the same make and size. So a total of two Battle Borns of different age. Mixing the two did not cause any problems. I would not have done it if they were different of different types or significantly different ages.
I later added a 3000W inverter.
On inverter power from the batteries, it is no problem to run the AC, microwave, hot water kettle, or any other typical plug-in appliance. The biggest draw is the 1500W kettle.
Things to pay attention to:
Make sure to follow the inverter manufacturers guidelines for cable size. In my case that meant 4aught for the inverter and 2aught for the batteries. and keep the runs to the battery very short. Make sure the cables connecting the batteries are equal length and very short. Don't attach the cable terminals to cables yourself (and by no means solder them in as some YouTubers do). Use a vendor that attaches them with a hydraulic crimper. You won't be able to twist the cables, so be sure you tell the vendor how to orient the terminals. In my case one was turned 90 degrees, and another faced the opposite direction. Mock up your cable runs using a heavy rope to get the length just right. I used Battery Cables USA and they have excellent directions on how to specify the orientation of the terminals.
In practice, the setup works fine for using these big 120V loads for reasonable periods of time. The 1500W kettle draws 130A DC measured by the Victron shunt. That is a lot of DC amps. Your cables need to be up to that load! See above.
Also, the best way to assure even discharging and charging of the batteries in a parallel configuration, is to connect the plus to one battery and the neg to the other battery. In that case, even length battery cables are not so important and the batteries will charge and discharge the same. With Battle Born, the maximum continuous discharge rate for 100 AH batteries is 100 amps. A 3000 watt inverter can load two batteries to a higher level than that, or about 250 Amps total. Other brand batteries may recommend less than the 100 amp rate as their max. I don't understand the desire to run the AC off of only two 100 AH batteries. It will only run for a short time, the batteries are heavily loaded and the power must re replaced by charging them back up. Combine that with a 1500 watt kettle (obviously not run at the same time) and other loads, and it will be easy to run the bats clear down. Then, what do you do tomorrow?

As far as making up the cables is concerned, anyone can do that at home quite well. Harbor Freight has a hydraulic crimper that is cheap and works very well. Greenley makes a very good professional bolt cutter style mechanical crimper as well. No need to order specially built cables if you don't want to, just make them yourself.

The reason to not solder the connections is that if the connection overheats, it might melt the solder and fail completely. If done well, with the right size wire, and considering the limited power available with only two batteries, soldering is probably fine. But I agree that crimping is better, and shrink wrapped, if one has the correct tools.
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Old 11-19-2023, 11:10 AM   #5
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When I wanted to add a 3rd Battleborn battery I checked with them and they suggested that if paralleling them, adding a battery should be within 2 years of the originals.
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Old 11-20-2023, 11:55 AM   #6
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Originally Posted by Perryb67 View Post
Is that 4 awg for the inverter or 4/0? Same for the batteries; 2 awg or 2/0 awg?

Both 4 awg and 2 awg would be too small for efficiencies. We use 2/0 awg for our two 100 ah SOK LiFePO4 batteries and also 2/0 awg for our 2,000 watt Progressive Dynamics inverter/transfer switch.

Food for thought,

Perry
2 aught means 2/0 AWG, 4 aught means 4/0 AWG.
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Old 11-20-2023, 03:00 PM   #7
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2 aught means 2/0 AWG, 4 aught means 4/0 AWG.
I don’t ass u me. I prefer to clarify.

Enjoy,

Perry
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Old 11-20-2023, 06:10 PM   #8
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Hey Raspy, good to chat again. I agree with you that it is good to keep the discharge below 100A per battery. The peak discharge we have is about 130A for 3 or 4 minutes only. We laugh about our $1000 cups of coffee brewed from the inverter-powered inverter. Because of supply chain issues during covid when I did the installation, I couldn't get a quality 2000 watt inverter, hence the 3000.
As for running the AC, consider this actual example. We pull into a rest area in the plains of SD in the summer. It is hotter on the asphalt than the 105F air temp. We want to make lunch and walk the dog. We run the AC, only 650 watts, for 15 minutes while making sandwiches. Batteries recharged in 2 hours of driving.

Perry, 2/0 is pronounced and spelled two aught. Just sayin.
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Old 11-20-2023, 08:45 PM   #9
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Originally Posted by Air Doug View Post
Hey Raspy, good to chat again. I agree with you that it is good to keep the discharge below 100A per battery. The peak discharge we have is about 130A for 3 or 4 minutes only. We laugh about our $1000 cups of coffee brewed from the inverter-powered inverter. Because of supply chain issues during covid when I did the installation, I couldn't get a quality 2000 watt inverter, hence the 3000.
As for running the AC, consider this actual example. We pull into a rest area in the plains of SD in the summer. It is hotter on the asphalt than the 105F air temp. We want to make lunch and walk the dog. We run the AC, only 650 watts, for 15 minutes while making sandwiches. Batteries recharged in 2 hours of driving.

Perry, 2/0 is pronounced and spelled two aught. Just sayin.
Your reasoning makes sense with the 3000 watt inverter. I used the AC in my X22 just as you do and it worked fine. A quick cool down when stopped for a break, or after arriving at camp from a long day of towing. You must have a non-typical AC since it only draws 650 watts. That is what my window unit drew too, and it was 8000 BTU. Recharging from the tow is an excellent option. I did it with an Anderson plug and large dedicated conductors to a dc-dc 30 amp charger, when I was using lithium batteries. Before that I ran the conductors straight to the AGMs with no separate controller. The only problem I had was with the dc-dc charger getting confused with the solar output. One would see the output from the other and think the batteries were charged, then shut off. I was running a Gopower solar controller and a Victron dc-dc charger. Then should have both been Victron and able to talk to each other.
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Old 11-20-2023, 10:03 PM   #10
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Long Discussion

If I were you, I would also add a battery-to-battery charger. I did a similar installation and there is quite a bit of discussion about the performance.

https://www.fiberglassrv.com/forums/...ead-92081.html
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Old 03-02-2024, 05:39 PM   #11
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Hey Raspy, good to chat again. I agree with you that it is good to keep the discharge below 100A per battery. The peak discharge we have is about 130A for 3 or 4 minutes only. We laugh about our $1000 cups of coffee brewed from the inverter-powered inverter. Because of supply chain issues during covid when I did the installation, I couldn't get a quality 2000 watt inverter, hence the 3000.
As for running the AC, consider this actual example. We pull into a rest area in the plains of SD in the summer. It is hotter on the asphalt than the 105F air temp. We want to make lunch and walk the dog. We run the AC, only 650 watts, for 15 minutes while making sandwiches. Batteries recharged in 2 hours of driving.

Perry, 2/0 is pronounced and spelled two aught. Just sayin.
This is a really interesting and helpful thread. Thanks everybody.

Also, where does one get air conditioners that draw less than 1000 watts? What make are they? I am interested.
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Old 03-02-2024, 06:49 PM   #12
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Quote:
Originally Posted by Air Doug View Post
Hey Raspy, good to chat again. I agree with you that it is good to keep the discharge below 100A per battery. The peak discharge we have is about 130A for 3 or 4 minutes only. We laugh about our $1000 cups of coffee brewed from the inverter-powered inverter. Because of supply chain issues during covid when I did the installation, I couldn't get a quality 2000 watt inverter, hence the 3000.
As for running the AC, consider this actual example. We pull into a rest area in the plains of SD in the summer. It is hotter on the asphalt than the 105F air temp. We want to make lunch and walk the dog. We run the AC, only 650 watts, for 15 minutes while making sandwiches. Batteries recharged in 2 hours of driving.

Perry, 2/0 is pronounced and spelled two aught. Just sayin.
In my world it can be pronounced two slash zero, not two aught, that's why I didn't ass u me but simply clarified. Not all parts of the country or installers are the same. I always double/triple check before making any decision, and only after clarifying first. I've run into many who don't realize there is a difference between 2/0 and 2 awg, and let's face it, there's many here who don't know that difference.

Perry
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Old 03-02-2024, 06:57 PM   #13
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Zack, glad you found it useful.
The Snoozy Camper and predecessors use regular window air conditioners. I think mine is a 5000 BTU Kenmore, but it doesn't really matter. You can shop for one that has the lowest wattage.

Perry, you caught me assuming! I didn't know about the different ways of referring to 2/0. I guess its true of how lots of things are called, most of which I know little to nothing about.
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Old 03-02-2024, 07:05 PM   #14
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My mini- split is an inverter unit and it draws very low power and is 9000 BTU and 120 volt.
In my case I used two batteries because they are rated 100 amps discharge each and this is determined by the BMS for each battery.
It is possible that with the starting surge and the slightly higher than 100 amp discharge could trip the Battery Management System and cause some consternation.
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Old 03-19-2024, 07:54 PM   #15
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I am looking to purchase a medium size Lithium battery. Trying to decide between the LiTime mini or the SOK 100 Ah LiFePO4 deep cycle. Does anyone have experience with or opinions about these batteries? Suggestions and advice are most welcome.
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Old 03-20-2024, 07:51 AM   #16
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I am looking to purchase a medium size Lithium battery. Trying to decide between the LiTime mini or the SOK 100 Ah LiFePO4 deep cycle. Does anyone have experience with or opinions about these batteries? Suggestions and advice are most welcome.
You might want to start a new thread so you can get wider readership.

But, to answer, I have an SOK. I like it because I can easily replace bad cells in the future. Price and performance are good.
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