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Old 11-13-2023, 09:44 AM   #1
Boba911
 
2018 19' Tommy Bahama
Warwick , Rhode Island
Join Date: Oct 2020
Posts: 98
Solar Sizing question

I have a a 2018 Tommy Bahama 19 ft AS with the factory solar package (1@ 95-watt panel). My batteries are now 6 years old (2@ 80 amps Lifeline). Although they seem to be working fine, I am the type that believes in preventive maintenance. My need that I have calculated is 66amphr/day at 900-watt hours. Also, I only plan to camp without power no more than for 2-3 days at a time. I do have a small generator that i will also carry with me. So, I want to upgrade to 2 100-amp hour AMG Renogy batteries plus add a 180 Zamp suitcase. I considered upgrading to Lithium but AM Solar's quote for all that is needs to make this change was about $5k with me doing the install.

So, my questions are; 1. will the AMG upgrade provide me the capacity i need for 2-3 days of power at my stated usage? 2. Do I need to change my current charge controller? 3. Should I also change the inverter from 1000w to 2000w and why? 4. Any other thoughts or needs would be helpful for this conversion.
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Old 11-13-2023, 11:08 AM   #2
Rivet Master
 
2019 22' Sport
High River , Alberta
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Quote:
Originally Posted by Boba911 View Post
I have a a 2018 Tommy Bahama 19 ft AS with the factory solar package (1@ 95-watt panel). My batteries are now 6 years old (2@ 80 amps Lifeline). Although they seem to be working fine, I am the type that believes in preventive maintenance. My need that I have calculated is 66amphr/day at 900-watt hours. Also, I only plan to camp without power no more than for 2-3 days at a time. I do have a small generator that i will also carry with me. So, I want to upgrade to 2 100-amp hour AMG Renogy batteries plus add a 180 Zamp suitcase. I considered upgrading to Lithium but AM Solar's quote for all that is needs to make this change was about $5k with me doing the install.

So, my questions are; 1. will the AMG upgrade provide me the capacity i need for 2-3 days of power at my stated usage? 2. Do I need to change my current charge controller? 3. Should I also change the inverter from 1000w to 2000w and why? 4. Any other thoughts or needs would be helpful for this conversion.
It seems like lots of capacity for three day stays. But it depends what you want to run.

I've calculated our usage at about 30 Ah per day, and we use two GC2 (6 volt golf cart) batteries with a useful capacity of around 100-120 amp hours, and only a 40 watt portable solar panel. In sunny weather, 4 days is easy and the batteries are still at 12.4 or 12.5 volts when we leave. (We run out of grey water capacity first.)

But we're only running the refrigerator on gas, the water pump, water heater circuit board for maybe an hour a day, lights, and recharging a phone or two. Furnace usage might be a half hour first thing in the morning if it's cold out.

So you seem to be running 120 volt electric appliances. A small coffee maker might use 700 watts. A hair dryer will be over 1000. The former would be fine with a 1000 watt inverter, but the latter needs more.

You would need to check the capacity of your charge controller. It's probably sufficient, but it may not be efficient. It's probably a PWM controller, and only about 70% efficient. A more expensive MPPT controller would be more than 90% efficient, so you would get more out of the solar panels.
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Old 11-13-2023, 11:56 AM   #3
Rivet Master
 
2007 16' International CCD
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Somewhere , Colorado
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Unless you have an electric only fridge, your estimated daily power usage seems high to me too. Your actual usage is critical to your question.

200Ah of lead acid batteries - including AGM - will only give you about 100Ah of usable power before the drawdown risks damaging the batteries. (Lithium would give you close to the full 200 Ah.) So, at 66Ah per day on AGM’s your goal of 2-3 days unplugged is totally dependent upon solar. Remember, in poor solar conditions, which are not uncommon, you will get trivial recharging no matter how many panels you have.

Power conservation is always your best friend.
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Old 11-13-2023, 02:21 PM   #4
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Somewhere , Colorado
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P.S. Upon reflection I realized I didn’t directly address your questions:

1) Yes, if you have good solar conditions, and if you deploy the portable, and if you keep reorienting the panel to the sun. Otherwise, no.

2) The existing “charge controller” (aka converter) should be fine until/unless you upgrade to lithium.

3) whether or not you need a 2,000w inverter depends on if you want to run 120v devices that draw more than 1,000w. If you do this upgrade, I suggest you get a lithium compatible one so that you don’t need to replace it again in the event of a possible future lithium upgrade.
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Old 11-23-2023, 09:03 AM   #5
Boba911
 
2018 19' Tommy Bahama
Warwick , Rhode Island
Join Date: Oct 2020
Posts: 98
Lithium upgrade

I am also thinking of upgrading to Lithium batteries but not happy about price. AM Solar has recommended Life Blue @ $1050 each (100ah 12V). I want to locate these batteries in the front battery box, and I am told these batteries are fully waterproof. I have also looked at Battleborn, Renogy, Li Time, Weize and Power Urus. Many of these either say waterproof or water resistant. So, 3 questions; 1 Does anyone have experience with these batteries; 2. Are any waterproof: 3. best lower price Lithium option of the above-mentioned batteries? Thanks for your input.
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Old 11-23-2023, 12:33 PM   #6
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2019 Interstate Lounge Ext
Noblesville , Indiana
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Quote:
Originally Posted by Boba911 View Post
I am also thinking of upgrading to Lithium batteries but not happy about price. AM Solar has recommended Life Blue @ $1050 each (100ah 12V). I want to locate these batteries in the front battery box, and I am told these batteries are fully waterproof. I have also looked at Battleborn, Renogy, Li Time, Weize and Power Urus. Many of these either say waterproof or water resistant. So, 3 questions; 1 Does anyone have experience with these batteries; 2. Are any waterproof: 3. best lower price Lithium option of the above-mentioned batteries? Thanks for your input.
Electrical Engineer here (Purdue) so I'll be gentle. I have the Life Blue battery. At the time, they were a good value since they were heated and had an internal shunt which allowed monitoring their state of charge via a Bluetooth app. However, if I were looking for a simple solution today, I'd run with the Renogy 'Smart' 100AH battery with their Renogy ONE Core monitor. A few tips:

First, voltage means almost nothing on Lithium Batteries. You have to monitor their state of charge using a shunt, either external or internal.

Second, If you don't have a victron solar charger, which I don't believe airstream used in 2018, you'll need to replace yours since the old school chargers didn't have the correct charging profile for Lithium.

Hold on...

Your converter (charger) Isn't lithium compatible. You either have to change out the charging section of your existing one, replace it completely or use an outboard Lithium compatible charger.

The 7 pin from your tow vehicle can no longer charge your rig. you'll need a DC to DC converter to elevate your charge line and apply the correct charging profile to your Lithiums.

A 2k inverter will not have sufficient current from a pair of 100AH lithiums (at 1C discharge) and really have no effect on the conversion from wet batteries to Lithium.

Solar AM is a good firm and mostly likely, I'm repeating their $5k advice.

If I were you, I'd put a new pair of AGMs in and add another couple hundred watts of solar.

'Boiler Up, Hammer Down'
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Old 11-23-2023, 12:59 PM   #7
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2021 27' Globetrotter
Cave Creek , Arizona
Join Date: Jul 2022
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Just a quick reply on solar in actual use...we have a 27' GT with two factory panels, so 190w, plus two 100w Renogy panels I use as portables plugged into a Renogy MPPT controller. In actual use, I see 180w regularly on the portables with great sun, good orientation and ~70F, when clouds pass over, out falls to as low as 20w. Fortunately, in the Arizona mountains in the summer, it's cool and almost always sunny, so we keep our two Battleborn 100ah batteries topped off (plus we run a little Honda to make coffee, etc.)



We do have the 12v compressor fridge (works wonderful compared to a absorption, but has the power draw downfall) and we are 'Zonies, so cold is not our friend, and run the furnace pretty warm compared to most, and of course, that sucks power for the furnace fan.
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Old 11-23-2023, 01:18 PM   #8
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2021 16' Bambi
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With our dearly departed 2021 16' Bambi I converted to lithium so I guess that qualifies me to respond.

It depends how handy you are but it's not too big of a deal to do it yourself and does not have to be all that expensive. Lithiums are a huge improvement as pointed out. First for your batteries, if you're just weekend camping some of the inexpensive brands I think are just fine. I don't think you need top of the line batteries with thousands of cycles. Just make sure they fit in your box. Aside: with our Bambi it came with a cheap plastic Camco box and I had to replace it with tongue box for security and to fit our larger batteries. Hopefully you have the standard issue metal box.

You'll either need a new converter board or replace the charger with a lithium profile enabled one (as pointed out above). WFCO can tell you what you need. At the time with the Bambi they sold a board with a switch on it. It took me about an hour to put it in (with a modest amount of cursing). They no longer sell this board and there is a new AD (auto-detect) charger. However, if you look around the forums it's not terribly reliable detecting lithiums like it should. The PD lithium charger has a great reputation but will be more expensive.

Other than that, I'd add a Victron shunt to monitor battery state of charge. This can be done regardless of the battery conversion. If you have one negative lead going to the negative bus bar then it can fit in the rats nest. Ours was under the dining seat. It's not a big deal either and I think mandatory if you want to know how the batteries are doing.

Off the top of my head that's $600 batteries + $120 converter (maybe more) + $130 shunt = $850.

Last, if you really think you need a 2000W inverter (running the microwave?) then I'd check the wiring gauge from the battery to be sure it's sufficient, it might not be a simple swap.
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Old 11-24-2023, 07:17 AM   #9
Boba911
 
2018 19' Tommy Bahama
Warwick , Rhode Island
Join Date: Oct 2020
Posts: 98
Thank you all for your advice on this conversion. I am a Mechanical engineer but worked in Semiconductor production most of my career so I know enough about power electronics to know I must ask advice. Don't want to burn the place down. The Tommy Bahama 19 ft AS has a rat's nest of wires under the street side dinette area. Also located in this area is the water pump under the rat's nest! I am very concerned about putting the solar controller in this area and don't see any other place to put it. I think the charger goes under the fuse panel so that shouldn't be a problem. Has anyone had to make this conversion within this area and where did you locate the new components? the components are 1. Victron Smart Solar Charger MPPT, 2. Victron Blue Smart charger, 3. DC/DC Charger. Thanks for all the feedback.
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Old 11-24-2023, 10:51 AM   #10
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2023 25' Globetrotter
2021 16' Bambi
Forest Lake , Minnesota
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Quote:
Originally Posted by Boba911 View Post
Thank you all for your advice on this conversion. I am a Mechanical engineer but worked in Semiconductor production most of my career so I know enough about power electronics to know I must ask advice. Don't want to burn the place down. The Tommy Bahama 19 ft AS has a rat's nest of wires under the street side dinette area. Also located in this area is the water pump under the rat's nest! I am very concerned about putting the solar controller in this area and don't see any other place to put it. I think the charger goes under the fuse panel so that shouldn't be a problem. Has anyone had to make this conversion within this area and where did you locate the new components? the components are 1. Victron Smart Solar Charger MPPT, 2. Victron Blue Smart charger, 3. DC/DC Charger. Thanks for all the feedback.
Sounds very similar to our dearly departed Bambi. In the rat's nest I added a second solar charger for the external panels and an inverter (Bambi's don't have inverters) and I was able to squeeze them in. The panel on the table side had some room. I couldn't reach the screw holes so I screwed the devices to a piece of 3/4" plywood then put Velcro on the back and slapped them on the wall which I find works pretty well when I can't get to the screw holes.

AS "mounted" our 150|35 controller by laying it on top of the mass of wires. Replacing it with the smaller 75|15 helped some.
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Old 11-26-2023, 12:23 PM   #11
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2021 30RB Classic
West Sacramento , California
Join Date: Jul 2023
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Quote:
Originally Posted by vanderwielen View Post
Electrical Engineer here (Purdue) so I'll be gentle. I have the Life Blue battery. At the time, they were a good value since they were heated and had an internal shunt which allowed monitoring their state of charge via a Bluetooth app. However, if I were looking for a simple solution today, I'd run with the Renogy 'Smart' 100AH battery with their Renogy ONE Core monitor. A few tips:

First, voltage means almost nothing on Lithium Batteries. You have to monitor their state of charge using a shunt, either external or internal.

Second, If you don't have a victron solar charger, which I don't believe airstream used in 2018, you'll need to replace yours since the old school chargers didn't have the correct charging profile for Lithium.

Hold on...

Your converter (charger) Isn't lithium compatible. You either have to change out the charging section of your existing one, replace it completely or use an outboard Lithium compatible charger.

The 7 pin from your tow vehicle can no longer charge your rig. you'll need a DC to DC converter to elevate your charge line and apply the correct charging profile to your Lithiums.

A 2k inverter will not have sufficient current from a pair of 100AH lithiums (at 1C discharge) and really have no effect on the conversion from wet batteries to Lithium.

Solar AM is a good firm and mostly likely, I'm repeating their $5k advice.

If I were you, I'd put a new pair of AGMs in and add another couple hundred watts of solar.

'Boiler Up, Hammer Down'
Chiming in on this one as it addresses the issues.

Adding a 2kw inverter involves serious wiring changes and requires lots of lithium to work. Maybe take that out of the AM deal and have them requote?

I have two 100ah Battleborn batteries and a Redarc dc to dc converter in the battery box of my AS Classic. 10k miles and all is good.
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Old 11-26-2023, 08:54 PM   #12
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2018 26' Flying Cloud
WARNER ROBINS , GA
Join Date: May 2016
Posts: 133
Popping in to tell our story...2018 FC 26 RBT...converter (wfco)went out (twice) replaced it with progressive dynamics, courtesy of Airstream replacing it when we were in San Diego at the Navy Base. Deep Cycle battery guy suggested we replace batteries that were damaged from bad converters with 2 220 amp hour 6 volt Lifelines. Talked to Atkinson electronics and they upgraded our charge controller to handle the new batteries and the extra 90 watt solar panel on the roof. There are three panels now. System operates flawlessly, and the 6 volts last forever, even when the furnace runs. This was way less expensive than an entire lithium overhaul. Especially since Airstream helped out with the converter and half of the battery replacement. (they can be very accommodating)
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