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r3meyer

Converting my Monaco to Lifepo4 batteries and 735watts of solar

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Posted (edited)

So my 1998 Monaco came with the standard chassis battery and 2 12v deep cycle marine batteries for the house.  I knew when I bought it they would not last long and my first trip in it was very cold.  Just running the heater at night proved enough to drain the 2018 dated batteries that PO had put in there.  So I sat down and ordered all my needed parts to do the conversion.

In my last 5th wheel setup I did 3-4 years ago I built a 100amp hour pack.  (4) 3.2v Calb LifePo4 cells with a BMS.  It was more than enough power to keep up with my demand and heavy inverter use for the microwave, air compressor, coffee pot and whatever else my wife wanted to run.  The cost to build that pack with a battery management system was about $800.  Today you can jump online and buy one of the battle born or Renogy 100ah batteries for about $800-$900 ready to go.  For most campers that is plenty.  

Since building my last pack the technology has come along way.  One of the biggest  advances is the solar controllers.  They come with lithium charge settings built in and instead of needing to put in a monitor screen you can view and make changes with your phone via bluetooth.

This time around I ordered my cells directly from China off of alibaba.  I have never ordered anything from them but it was pretty much like ordering off of amazon.  I ordered (4) 200ah 3.2v cells and 15 days later they showed up at my door.  Cost was $634.00.  Once they got here, I ran down and picked up my solar panels from a local shop.  (3) 245w 36v panels.  735 watts for $135.

 I paired the 2 with a battery protect and 100v/50amp solar charger from victron which was about $450.

I spent a little time cleaning up the battery bay as all the years with Flooded Lead acid had taken its toll on it.

 

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Edited by r3meyer

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Nicely done. My single 330w panel works great to keep my four 6v Costco batteries charged. Of course I'd like to add more solar and possibly two, or even four, more 6v batts. I have plenty of room in the battery compartment, just have to  build a rack to stack them.

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added a lithium battery last trip to see what I thought, will be adding another and adding new solar and controller to my monaco, moving my old panel to the new enclosed

 

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my trailer came with a GoPower solar one panel system, intellipower fuse braker box charger converter 75 amp

can I just add lipo batteries, or do I need a Lipo charger

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14 hours ago, J Alper said:

my trailer came with a GoPower solar one panel system, intellipower fuse braker box charger converter 75 amp

can I just add lipo batteries, or do I need a Lipo charger

You'll need to get rid of that controller. It's PWM (inefficient) and doesn't allow for absorption voltage adjustment. Any good MPPT controller should allow for absorption voltage adjustment for a wide variety of batteries, including LiFePo4.

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On 6/2/2019 at 1:25 AM, J Alper said:

my trailer came with a GoPower solar one panel system, intellipower fuse braker box charger converter 75 amp

can I just add lipo batteries, or do I need a Lipo charger

Your converter will work fine.  Solar is all in what you want from it.  As socaldmax mentioned its a PWM charger.  Thats old tech.  If you want to squeeze every bit of power from the sun that you can while its out you want a MPPT charger.

Would you want to build a Lipo battery, or buy an off the shelf (battle born, renogy, Etc)?

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On 5/31/2019 at 8:40 AM, 2011BFD said:

added a lithium battery last trip to see what I thought, will be adding another and adding new solar and controller to my monaco, moving my old panel to the new enclosed

 

What did you go with?

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Got it for 650$

Screenshot_20190603-085709_Chrome.jpg

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18 minutes ago, 2011BFD said:

Got it for 650$

Screenshot_20190603-085709_Chrome.jpg

Damn!  Thats a great price.  Those batteries are amazing.  They have all the battery management built in so its the easy button for sure.  What solar charger are you going with?

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I am reading that right?

what is the advantage going to Lipo if the battery is a 100 ah?

I think my flooded 6 volts are 240 ah 

 

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1 hour ago, indianjoe said:

I am reading that right?

what is the advantage going to Lipo if the battery is a 100 ah?

I think my flooded 6 volts are 240 ah 

 

Weight and reliability. 

Also, it's not exactly apples to apples, as a 13.2v nominal LiFePO4 can generally be discharged to about 10.0v isolated, where a typical Lead Acid can only be discharged to 11.6v isolated.  

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One thing to keep in mind is you MUST run some sort of battery management with LiFePO4.  Fires are likely otherwise.

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So you would you do lipo without a solar set up?  Can you charge those thru the genset?

You need

The batteries

a controller for the battery charge?

Solar panels

Solar controller MPPT

Then you are good?

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1 hour ago, realbadlarry said:

So you would you do lipo without a solar set up?  Can you charge those thru the genset?

You need

The batteries

a controller for the battery charge?

Solar panels

Solar controller MPPT

Then you are good?

In addition to that, I'd recommend a Battery Management System, which allows you to track how many amps you have put into the batteries and how many amps you've taken out. Using battery voltage as a measure of SOC isn't really precise enough to get the best out of Lipo batteries. It should also have a high voltage cutoff (from the charger) and a low voltage cutoff (from the load) to protect the batteries from being overcharged or discharged. 

A lot of times, the battery cells are balanced for you before they ship them. If not, you need to connect up a cell balancer like pictured above and get all of the cells to the same voltage. Then you need to provide a charge voltage that is no higher than the mfr's recommended voltage, like 14.4v, or whatever it is. Once the battery pack is fully charged, you'll see a jump in voltage and a drop in current, called the "knee." This indicates that the batteries are full and have changed internal resistance.  

Once the bank is full and the BMS is calibrated to the size and fully charged bank, it can start counting how many amps discharged and how many amps are left and it will give you a precise % of charge from that and recharge accordingly.

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LifePo4 batteries are really alot like buying anything else.  The brand will have a spec sheet.  You just have to stay within those specs.  The reason most people dont understand them is since the beginning of time people have been using a standard flooded lead acid.  Lifepo4 seems to be black magic to them.  Most standard equipment will work just fine with lipo.  You just need to make sure you have a BMS that will keep anything from happening to them.  Get drunk and forget to turn off that stereo blasting tunes @ 4am, it will make sure that when you run out of power it will keep the batteries from doing any harm.

Here is the spec sheet for my (4) cells.

915695569_ScreenShot2019-06-04at4_01_07PM.thumb.png.dd1b3035e53af696adb784f89fdd3e18.png

 

Everything about them is designed  for how I use my coach.  My inverter charger is a 2000W.  That means the max it will use is 166 amps.  Well below the 600amp @ 10sec, 400amp @ 3min, and 200amp constant rating.

If I only ever bring them down to 80% (4) cells = 11.68v I can do that 2000 times.  I have them set to disconnect @ 12v.  The bms starts beeping at you and if you have an LED hooked up to it or a gen start, it will do that also.  When I am going to use the coach I have them charge up to 14.2v.  When I put it in storage I have it only set to 13.3V.  Lipo does not care where it sits.

You can see what they did on my 3 day little trip.  I left the fridge running on electric both days to test the setup and make sure it was working.  I had to find things to turn on to purposely kill the battery and activate the battery protect.

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Posted (edited)

Hey "r3meyer"

I picked up a new Tiffen Red last month and it came "Solar Ready" whatever that means as I haven't delved into it yet and Im not ready to swap out my Batteries,  but could you please provide some info on the Solar Panels you picked up (3) 245w 36v panels.  735 watts for $135.

 

Thanks

Edited by GROPER

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13 minutes ago, GROPER said:

Hey "r3meyer"

I picked up a new Tiffen Red last month and it came "Solar Ready" whatever that means as I haven't delved into it yet and Im not ready to swap out my Batteries,  but could you please provide some info on the Solar Panels you picked up (3) 245w 36v panels.  735 watts for $135.

 

Thanks

Crap.  I thought I put the link in there.  Here you go.

https://santansolar.com/products

Near as I can tell they gut solar projects and sell off the panels.  Mine were "blems".  As in they had those snail trails that panels create sometimes.  As you can see from my readings they work just fine for being flat mounted to the top of an rv in the pines for a weekend adventure.

Word of advice.  Check to see what gauge cable they gave you coming off the roof.  That will determine what amount of solar voltage / amperage you have to setup.  Or once you figure out what you have post it up and I can point you in the right direction.  Lots of cheaper options than Victron systems... but damn its nice to just use bluetooth and know its going to work as advertised.

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On 6/3/2019 at 11:54 AM, Rockwood said:

Weight and reliability. 

Also, it's not exactly apples to apples, as a 13.2v nominal LiFePO4 can generally be discharged to about 10.0v isolated, where a typical Lead Acid can only be discharged to 11.6v isolated.  

I'm trying to learn as much as I can before I make the solar leap.

My moho has 4 6v batteries, each rated at around 240 amp hours. If I am calculating it right at 12v if have 480 amp hours.  I should still have way more amp hours then one LiFeP04 and at almost half the price. With just 2 6v you still would have more amp hours maybe not a 140 more but still more then a 100 and at a 4th the price? 

I'm just trying to wrap my head around this. I'm not sure in what way they are more reliable. If you mistreat either type they wont last. Maybe a longer life span? As for the  weight difference, in a 26K lbs motorhome it's not even a consideration, other vehicles maybe.

The batteries do have a cool factor and no water is very appealing but for me I'm just not sure if the cost is worth it. Now the Bluetooth charger controller seems like a no brainer. 

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27 minutes ago, SANDPSYCHO said:

I'm trying to learn as much as I can before I make the solar leap.

My moho has 4 6v batteries, each rated at around 240 amp hours. If I am calculating it right at 12v if have 480 amp hours.  I should still have way more amp hours then one LiFeP04 and at almost half the price. With just 2 6v you still would have more amp hours maybe not a 140 more but still more then a 100 and at a 4th the price? 

I'm just trying to wrap my head around this. I'm not sure in what way they are more reliable. If you mistreat either type they wont last. Maybe a longer life span? As for the  weight difference, in a 26K lbs motorhome it's not even a consideration, other vehicles maybe.

The batteries do have a cool factor and no water is very appealing but for me I'm just not sure if the cost is worth it. Now the Bluetooth charger controller seems like a no brainer. 

They will definitely take more discharges, to lower voltages, than a lead acid.

FAQ_LiFePO4_cycle-life_based_on_DOD1.gif

Trojan_Gel_DOD_vs_Life.jpg

The other advantages I forgot to mention are how fast they can charge compared to a lead acid and the power density (physically smaller). They also have a non-linear discharge curve, meaning those 100ah you get will be more efficient than a similar LA battery:

lifepo4.jpg

Of course, this still doesn't mean you get double the power.

That being said, I'm a huge nerd about this kind of thing, but still have regular lead acid batteries in my motorhome and just run an inverter generator a large portion of the day so we can do whatever we want.  LiFePO4 cells are cool, but for the same price you have more options unless you really hate the sound of a generator running.  The only time we're dry camping without hookups is in Glamis, where generator noise isn't really a problem since there are mufflerless 450s and RZRs running around everywhere anyway...:nag:

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14 minutes ago, SANDPSYCHO said:

I'm trying to learn as much as I can before I make the solar leap.

My moho has 4 6v batteries, each rated at around 240 amp hours. If I am calculating it right at 12v if have 480 amp hours.  I should still have way more amp hours then one LiFeP04 and at almost half the price. With just 2 6v you still would have more amp hours maybe not a 140 more but still more then a 100 and at a 4th the price? 

I'm just trying to wrap my head around this. I'm not sure in what way they are more reliable. If you mistreat either type they wont last. Maybe a longer life span? As for the  weight difference, in a 26K lbs motorhome it's not even a consideration, other vehicles maybe.

The batteries do have a cool factor and no water is very appealing but for me I'm just not sure if the cost is worth it. Now the Bluetooth charger controller seems like a no brainer. 

The long and short of it is YES you do have 480 amp hours.  But flooded lead acid you CANNOT DISCHARGE 100%.  You can only discharge down to 50% without doing damage to the batts.  So you really only have 240 usable amp hours.

My 200amp lipo pack was $630.  When I built this same thing 4 years ago for my old 5th wheel they were double the cost.  I did a 100ah pack.  Even then it out performed my old setup of (4) 6v golfcart batteries and it was one of the best selling features when I listed it for sale.  Most dont want to learn how to use LIFEPO4 and a battle born is plug and play.

A 4 battery 6v system was around $400 @ costco.  You have to deal with keeping them clean and full.  They tend to eat everything around them from the off gassing.

Lead Acid = LS2 and 2D combo.  You have to rebuild that 2D often.  Although cheaper it costs much more in the long run.

LifePO4 = LS2 and Albins combo.  Cry once and enjoy the shit out of it.

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39 minutes ago, r3meyer said:

A 4 battery 6v system was around $400 @ costco.  You have to deal with keeping them clean and full.  They tend to eat everything around them from the off gassing.

Adding water isn't to bad but the cleaning and corrosion is. Over the life of 4 6v the extra 200 bucks doesn't seem as bad if you don't have to deal with that BS. 

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11 minutes ago, SANDPSYCHO said:

Adding water isn't to bad but the cleaning and corrosion is. Over the life of 4 6v the extra 200 bucks doesn't seem as bad if you don't have to deal with that BS. 

You'll get at least 2x the life out of them (very likely they'll outlast your tolerance for the coach around them) without having to worry.  Run them until the battery management kicks in and shuts it down just like you do with your battery powered tools.  They'll be aight. :bigrin 

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As the price of these go down the temptation grows larger for me... There is a seller on ebay that uses new chevy volt cells and configures 12volt packs from 50 to 400 ah or more with bms for a pretty good price however when it came down to it the odd shape of them would not fit in step of my moho where my two gc batts currently live.  However I do goof around with solar, batteries and inverters at the house to power some things to minimize getting into the higher tiered rates so they still intrigue me somewhat. 

I found a guy that had purchased and was selling a 400ah pack with bms for basically half price at 1k and seemed like a great deal but what bothered me was that he said that even with light loads his inverter would start having low voltage alarms because of the lower voltage that lithium supplies.  I do not know if he just had a junky inverter or what but he was selling more because he got in over his head and did not want to upgrade his charger and what not so he just spent another 2k for a pair of those battle born drop ins for 200ah and he was more than happy with them.

I mention this as the cost per amp hour might be worth it to some people out there looking into this subject that do not have space limitations.

 

 

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On 6/5/2019 at 1:23 PM, rayspeed said:

As the price of these go down the temptation grows larger for me... There is a seller on ebay that uses new chevy volt cells and configures 12volt packs from 50 to 400 ah or more with bms for a pretty good price however when it came down to it the odd shape of them would not fit in step of my moho where my two gc batts currently live.  However I do goof around with solar, batteries and inverters at the house to power some things to minimize getting into the higher tiered rates so they still intrigue me somewhat. 

I found a guy that had purchased and was selling a 400ah pack with bms for basically half price at 1k and seemed like a great deal but what bothered me was that he said that even with light loads his inverter would start having low voltage alarms because of the lower voltage that lithium supplies.  I do not know if he just had a junky inverter or what but he was selling more because he got in over his head and did not want to upgrade his charger and what not so he just spent another 2k for a pair of those battle born drop ins for 200ah and he was more than happy with them.

I mention this as the cost per amp hour might be worth it to some people out there looking into this subject that do not have space limitations.

 

 

I would be nervous buying a used lipo pack from a “random”. Or at least have a full amp hour test done and verified before purchase.  A 400ah pack that was damaged do to mis management might actually only be a 40ah pack.

there a ton of sellers that list used lifepo4 batteries and give the actual amp hour rating when they sell them.  I remember a while back there was a guy selling 100 cells ranging from 150-190ah for 45 each used.

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On 6/5/2019 at 6:38 AM, SANDPSYCHO said:

I'm trying to learn as much as I can before I make the solar leap.

My moho has 4 6v batteries, each rated at around 240 amp hours. If I am calculating it right at 12v if have 480 amp hours.  I should still have way more amp hours then one LiFeP04 and at almost half the price. With just 2 6v you still would have more amp hours maybe not a 140 more but still more then a 100 and at a 4th the price? 

I'm just trying to wrap my head around this. I'm not sure in what way they are more reliable. If you mistreat either type they wont last. Maybe a longer life span? As for the  weight difference, in a 26K lbs motorhome it's not even a consideration, other vehicles maybe.

The batteries do have a cool factor and no water is very appealing but for me I'm just not sure if the cost is worth it. Now the Bluetooth charger controller seems like a no brainer. 

I just wanted to give some clarification on the differences between LiPo and GC batteries, which are currently the best value for RV batteries. 

1. Yes, Lipos are still more expensive, but at this current price point, not by much. Inspired by this thread, I'm looking at replacing batteries in both trailers with LiPo batteries. One set is 200 AH per cell, the other is 271 AH per cell. If I buy 16 of the 200 AH, I would install 4 cells in the small trailer for a total of 200 AH and 12 cells in the big trailer for a total of 600 AH. Total cost with shipping via ship is $2157. At this price, I'm replacing 4 GC batteries in the small trailer that cost $400 with 4 cells that cost $539.25. That's only $139 more than GC batteries. The big trailer would get 12 cells totaling 600 AH at a cost of $1,617.75. To get that much equivalent power from GC batteries would cost $1200 for 12 of them, so the price difference in this case is only $417.

The price for 12 of the 271 AH cells is $2265. I'm negotiating to get them down to $2200 for the set. At that price, I'd have a 271 AH bank in the small trailer for $733 and a 542 AH bank in the large trailer for $1,467. I would rather have 271 AH in the small trailer and the added cost would only be $333 (vs 4 GC at $400) for the small trailer and $467 extra over the cost of 10 GC batteries at $1,000. In the small trailer, it's not a straight comparison because the LiPos would provide an extra 51 AH.

2. The other advantage is weight. GC batteries weigh 63 lbs ea. A set of 4x 200AH Lipo cells weighs about 50 lbs. So 4 GC batteries weighs 252 lbs, while the Lipo batteries weigh 1/5 of that at only 50 lbs. In the big trailer the weight savings would be even greater, 150 lbs for LiPos vs 756 lbs for GC, a total savings of 606 lbs.

3. Size. Lipos take up about 1/4 of the space of GC batteries. If you buy the LiPos as individual cells, you have a lot more flexibility in how you package them.

3. Power output. Lead acid batteries lose about 20% power due to the Peukert Effect. Basically for every 100 AH of power you put into them, you're only going to 80 AH out at best, it gets worse with higher current draw. GC batteries are rated at 20 A discharge rate. If you pull more power than that, the total capacity drops rapidly. If you're drawing 10 A off of a fully charged 440AH GC battery bank, you could expect to get 20 hrs of use before you hit 50%. If you're drawing 100 A, you won't get 2.2 hrs out of it, more like 1.5 hrs or less. Plus the batteries will get really hot by the end of that, possibly boiling off a little water, then if you try to rapidly charge the batteries, they'll get even hotter, which makes them a pretty inefficient power source. Lipo batteries are the opposite. If you have a 200 AH bank, you could draw 200 A from it until you hit 20% and it won't be affected at all. It might get a little warm, but not hot and it's not boiling it's chemistry away. They also take high current rate charges easily. You could charge a LiPo bank at 1C (it's rated capacity) meaning a 200 AH bank could be charged at 200 AH without any harm and would be fully charged in less than an hour. Some mfrs even list much higher charge rates as being acceptable. Lead acid batteries taper off their current draw as they get closer to fully charged, so it might take you 5 hrs to get back up to 80% and another 3 hrs to get back up to 100%. So a lot of those hrs that genny is running, it's not doing that much good. 

4. Efficiency and lifespan. With Lipo batteries, you put in 100 AH, you can use all of it, as long as you don't go below 20% for max. life. You can go down to 10%, but you'll be shortening the life slightly and going down to 0% will shorten it a little more, but nothing like how that kills lead acid batteries.

Here's a chart from Trojan showing depth of discharge vs battery life. If you never go below 50%, you can expect about 1,000 charge cycles. Lipos are conservatively rated at 2,000 charge cycles, some mfrs list theirs as 6,000 cycles. Either way, they should last at least twice as long while being discharged down to 20% instead of 50%.

cycle_graph.jpg

5. Ease of use and maintenance. Lipo batteries don't require water and don't corrode battery terminals. That's a really nice benefit. They're much easier to monitor via a BMS. You set a high voltage cutoff that is slightly lower than the mfr specifies (like 14.4v instead of 14.6v) then you set a low voltage cutoff (like 10.6v instead of 10.4v) and it will open the breaker and protect the battery. If you have a 600 AH bank, you could charge it at up to 600 A rate (if you had that much battery charger power or solar power) and be fully charged in less than an hour. Once the bank is balanced and fully charged, the BMS will monitor every watt that goes out and every watt that goes in and will tell you your current state of charge in 1% increments. They self discharge very slowly (5% in 24 hrs after charge, then 1%/mo.), GC batteries self  discharge at about 16%/mo. at 80*, even faster if the temp is higher. 

Those are the reasons why I'm switching over. In the past, I've let the solar charge the batteries in storage to prevent them from self discharging but since I never went to check the batteries over the summer, the batteries dried up and were pretty much destroyed in 1 or 2 yrs. With Lipos I can completely disconnect them and just let them sit for up to a yr and they'll still be almost at the same level as when they were last used. They're much easier to maintain for a lazy guy like me.

Hope this helps!

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