BAC Forum
General Boards => Technical Support => Topic started by: Anand Shah on January 05, 2022, 12:54:46 AM
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Dear All
I have been searching for info on Lithium conversion and can’t seem to answer a few questions, so posting them here. Sorry if they have been answered before.
I have a 2007 Marquis Lapis C15, with 3 flooded chassis batteries and 8 8D but dying Lifeline AGMS. I have what looks like an original 2-bank PWM solar controller and approx 600w of solar on the roof (original panel + 5 more). Magnum inverter (don’t know the model and it is parked far from me) with the non Lithium-setting remote. The coach is all electric.
1: Where does Aladdin get its solar voltage input? From the charge controller?
2: Is it recommended to change from PWM to MPPT, anyone know of a two-bank controller, or a DC-DC charger to keep the chassis batteries charged from the house ones?
3: Is the Magnum ARC remote a drop in replacement that adds lithium settings? I know I need to figure out if it is compatible with the model - will go check this weekend?
4: Other than balancing the lithium batteries and the battery appropriate voltage and charge settings, both on the solar controller and the inverter, is there anything else I need to do in changing the house batteries? Are there any Aladdin things I need to know, or process steps I should adhere to?
I’m likely to go with 8 200AH LiPo4 which should give me significant energy storage as we plan to boondock quite a bit on future travel.
Thanks in advance and for all the incredible help on this forum.
Anand
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Your limiting factor for that big of battery bank is your solar; 600w of solar will only give you about 30 amps of charge for about 5 hrs/ day or 150 amp hrs. Sooner or later (sooner in this case) you will have to run your generator to charge your battery bank. Lots of good info out there on solar, try AM Solar in Eugene Or and Battle Born batteries in Reno Nv. Good luck with your project!
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There's a lot in your questions. I'm in the process of installing LiFePo4 batteries on my coach. I'm currently in the planning stage so maybe my "plan" will help with some of your questions.
1) I'm installing 3-206AH 12V SOK batteries (to replace 6-6V 100AH). Make sure to check your battery supplier if you want to put large number in parallel...i was considering 6-100AH Battleborn and was highly discouraged (from battleborn resaler) from putting that many in parallel due to issues with voltage drops and balancing.
2) You don't necessarily need to replace your Inverter with one with "Lithium settings". Here's the setting SOK recommended and my inverter (Xantrex SW2512) can do this with existing lead acid settings:
Absorption volt: 14.6
Float voltage: 13.8V
Equalization: DISABLED (recommend setting Equalization volt=14.6V and time=0 in case of accidental engagement)
Low voltage disconnect: 11V (I will probably set at 11.6V)
3) On my coach there is a Big Boy relay in my coach connecting chassis and coach batteries under various conditions.
I am re-wiring the Big Boy relay controller(BIRD) to add the function to OPEN (disable) this relay anytime my ignition is ON (simple diode "OR" with existing generator signal). I'm doing this since I don't want my engine alternator charging my big capacity coach batteries. Reason is, it could place large load on alternator (600AH of lithium) and also the voltage will be too high for my lithium batteries (LiFePO4 maxV=14.6). With 600AH of usable coach batteries my travel days aren't long enough to discharge my coach batteries (only fridge runs off AC underway). And if necessary I can run my generator to charge my Lithium house batteries while underway.
NOTE: It's ok for my Big Boy relay to close and charge chassis batteries at lithium settings from inverter/charger when running on shore power. You might not get full charge on lead acid at 14.6V but close enough for me. Some folks replace the Big Boy relay (and bird controller) with aftermarket designed for Lithium voltage settings - but I just don't find this necessary if I'm ok with compromises described above.
4) I've calculated my typical average load for 24hrs and with no solar figure I have to run generator about 4-5hrs per day to keep batteries up and providing 24hrs of expected loads. Likely I will run 2hrs AM and 2Hrs PM (during high power usage times of the day). For me boondocking is not the rule - I just want to be able to stay at some favorite state and local parks (week or so at a time) that don't have power without running my generator so frequently. And I want to be able to leave for long day and keep residential fridge and other minor loads ON running off battery. So that's how I arrived at 600AH.
I would recommend you do the charge/discharge exercise with your expected loads and charging rates. You mention wanting to get 8-200AH lithium to replace 8-200AH AGM - but most lithium are 12V so that would be 1600AH at 12V? If your current AGM batteries are 6V, you have 200*4=800AH of lead acid (400AH usable). For a day hard to believe you would need 1600AH @12V? You should probably try to measure your avg load when boondocking for a day to see what capacity you need to run your avg loads for the time desired. My avg load is about 350W during non geni run time. But I'm not running any electric heat or large loads when on battery only.
5) For the solar, I only have 2-100W panels and an older RV45D PWM controller. I need to upgrade this system but for now it looks like I can modify the settings to keep Lithium batteries in safe voltage area, with equalization disabled. Non optimal but ok for now. I'm probably going to upgrade to 600W solar with MPPT controller.
Anyhow, this is all in "theory" so far. I currently have my tray out being refurbished - its' off now getting some welding done to reconfigure the rails for it to accommodate my SOK cells (on order). Once I get this all hooked up and verified I'll update this group in separate thread. It seems it should work based on my research- if someone has red flags I'm all ears.
This turned out long winded. Hope it helped.
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This is SUPER helpful and thank you for taking the time to write it out; I may very well resize the bank based on the above and might need to learn something about the BIRD configuration. Would love to chat when you have competed your project and benefit from your wisdom. Will DM. I’m aiming to do this by March or April.
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Keep in mind if your 8AGM are 6V each and connected as 4 parallel banks of 2series connected batteries (12V) that you only have 800AHR of total capacity (400AH usable). The same current flows through a series connected battery so you can't add AHR capacity - so 2-200AH 6V batteries connected in series gives you 200AH at 12V (not 400).
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The 8 AGMs are 8x12V Lifeline 8DL
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Wow. Those things are around 150# ea so you have 1200lb of house batteries and about 13sqft of battery real estate. Just wow.
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Hi Gene,
Thank you for your "detailed" post #2. It sounds like you have done your homework concerning your project. I too am in the planning stage of taking my Marquis "off grid" due to Covid making all the nice campgrounds rich and inconsiderate of us with limited resources. I am still considering which lithium batteries give me the most bang for the buck. I added 3- 230 watt panels @ 29.6 volts and a Blue Solar MPPT 100/50 controller with bluetooth. So far, it stays ahead of my coaches requirements the way we use it. My inverter is the original Prosine 3.0 which handles all my 120volt demands. It also has the correct charge profile available for LiPo's. My back-up resource is to connect my 2 existing Siemans 75watt panels in series to get the 29volts and tie them into the array input. (They are presently disconnected because I cannot find the Heliotrope controller). Keep us in the loop as your plan unfolds. Fred
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Wow. Those things are around 150# ea so you have 1200lb of house batteries and about 13sqft of battery real estate. Just wow.
That costs me .5 mpg and they don’t even work! Badly needed project to replace them….
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Anand
1: Where does Aladdin get its solar voltage input? From the charge controller?
The Aladdin DC Interface (DCI) is responsible for reporting the solar volts and amps. The solar controller has a fused output for voltage reporting and a current sensor on the ground wire, both are connected to the DCI. There is a section in the Aladdin troubleshooting guide that discusses calibrating the DCI.
3: Is the Magnum ARC remote a drop in replacement that adds lithium settings? I know I need to figure out if it is compatible with the model - will go check this weekend?
I have not converted to Lithium batteries, but I came across the following information after our Magnum MS2812 failed and I was researching my options. I ended up having our invertor repaired which brought it up to the latest version, 6.0.
The inverter in your coach is probably an MS2812. Some of the All-Electric Patriots and Marquis came from the factory with two inverters and 8D AGMs.
Originally, only the ME-MR and ME-RC remotes were to include the new Lithium profile, that may have changed. It’s my understanding that to take full advantage of the Lithium settings you may need to upgrade your inverter. You can upgrade your existing inverter to the latest version (6.0) by installing a new control board. It can be DIY upgrade.
The control boards are kind of scarce right now, but I found some at Zonna Energy, ~ $330.00 with shipping, delivery time was about a week. The part number for the MS2812 controller is TCB-MS2812. If your invertor is not an MS2812, Zonna does list control boards for other models.
A call to Magnum would be beneficial, they are very helpful once you get through. Zonna Energy was also helpful.
Here are couple links for the Magnum Lithium setup.
Lithium Quick be Reference Guide
https://www.solar-electric.com/lib/wind-sun/Magnum-me-mr-Lithium-Battery-Settings-quick-start.pdf
Magnum Lithium Charging
https://www.solar-electric.com/lib/wind-sun/Magnum-Lithium-Program-Review.pdf
Here’s a YouTube video from Magnum that shows the MC-RC remote setup for Lithium (there are several others out there).
https://youtu.be/ZjPHMWEB5ww
-Scott
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Thank you Scott. Very helpful. I think you are correct on the inverter. Will look into the upgrade.
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I got my 3 SOK 206AH Lithiums finally installed today and things are looking really good. Bird controller was reconfigured as described above and my Trace (Xantrex) 2512SW settings were able to match manufactures recommendations. I also installed Thornwave Labs shunt and power monitor so will be running it through it paces over the next week (charge/discharge cycles). I'll probably just start a new thread and post pics and more details for those interested. The Thornwave power monitor has amazing (internal storage) logging and control capabilities and can monitor both coach and chassis battery voltages separately.
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Thank you for all the information. I am about to replace all my batteries and wanted to replace them with lithium. I just want to confirm a couple of things.
1. Are you chassis batteries still led acid? and charge with the alternator?
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Yes, chassis batteries are AGM. With my Bird modification, when the engine is running the BigBoy isolation relay opens and alternator charges only chassis AGM batteries. Alternator doesn't charge my house batteries when I'm driving -but this is the way I wanted it. House batteries will always charge on generator or shore power. Generator and shore power can charge chassis batteries only if engine is OFF (also my preference). Even though my inverter wasn't designed for Lithium I've ran numerous charge cycles with recommended manuf settings with no issue of any voltage or current excursions violating SOK specs. My ThornWave monitor can monitor every second for very long time so I am pretty confident of that. I did need to change the inverter/charger setting from LeadAcid to NiCad as for some reason it would terminate the bulk charge early on LeadAcid setting (after talking we Xantrex I think it tries to measure battery resistance to determine if it needs to bulk charge longer and since Lithium is much lower it tricks the charger). Anyhow, with that change the charge times, voltage and currents are all as expected. So I'm more than happy with my setup. The batteries have amazing capacity and current capability for the money.
BTW, my Thornwave monitors both battery voltages real time and with my Bird modification the BigBoy isolation relay opens and closes as specified as long as engine is off. In other words, deep discharge on lithiums opens the isolation to prevent discharge of the chassis battery yet closes as expected to charge both banks during a charge cycle.
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Thank you for the information. We have the same exact coach, and I will plan on doing the same conversion with mine.
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Since we have same coach you prompted me to add some pics. One shows the tap I made into one of the 2 wires going to "Ignition" connect back to "Genset" on Bird.
I previously had 6 lead acid. I was thinking of buying a new tray that I could configure better for the SOK I purchased since they needed to be turned sideways relative to original, but ended up having a local handyman here help with the job. He cut out the existing metal supports in the bottom of the tray and turned them sideways and then welded in pieces of old bed frame to "center" the SOK in the tray. They are offset a bit from each other since we were afraid the screws bumps on the top of SOK might interfere (we did this before I had batteries in hand). It would have been tight if we hadn't done that but it probably would have fit. The tray was cleaned up, rust removed, bearings serviced and all painted. He only charge $80 for all his work so well worth it rather than replace the tray.. which would have required welding some mounts back on the new tray too so not just a simple drop in.
I had new short cables built at a shop just up the road to interconnect the SOKs but I'm still using original longer +/- cabling back to inverter. I put plywood under each battery with some rubber anti-vibration padding... the plan is to maybe build a "portable" insulation box around them if I get into some colder weather so that's part of the reason for the plywood. New SOK's have heaters I guess. I just use staps to hold each from bouncing out. One last thing I want to do is mold some plastic covers for the terminals with a bag of that InstaMorph moldable plastic I have sitting here, and to find a way to build a plastic cover over the shunt. Probably don't absolutely need it but feels better to help prevent a short.
I've also attached couple screenshots of the Thornwave Labs monitor phone app. The graphing could be better as I can't separately scale the plots (to view zoomed in current and voltage together for example)... but if you're good at excel you can export the log and play all you want. The cursors in the app are accurate though. This monitor has worked flawlessly for me.
No more banging my head and dealing with filling wet cells and acid!
Oh, and the extra blue wire you see goes back to chasis battery as Thornwave has a 2nd battery monitor input. And don't forget to pull the temperature sensor at the inverter to disable temp compensation.
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Shouldn’t the shunt be on the negative , not the positive line? It is on my system.
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Thornwave monitor is designed to go on either. It's easier for me to have it up front to make connections and get access to it. Maybe not quite as safe with more exposed + terminals but I will cover it, and it's pretty well protected.
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I was reading your plan over and had another question. Can you outline the modification you did to the BIRD unit to isolate the charging from the alternator.
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Robert, I've added to pic with descriptions. My Bird had the GENSET input disconnected. The GENSET input was designed to OPEN the Big Boy relay for systems with generators that couldn't charge both chassis and coach batteries at the same time. It's a 12V input same at BIRD IGNITION input. I'm assuming this GENSET input is also not used on your coach. Just splice one of the 2 IGNITION wires (doesn't matter which one) with another wire+terminal and attach to GENSET input. That is the only BIRD change.
Intellitec support confirmed the above mod seemed like simple solution to what I wanted to accomplish. He warned one issue may be that due to higher resting voltage of Lithium compared to my AGM that my lithium would charge AGM continuously when running on battery only. I tested this and did not find it to be the case. After a full charge, the resting Lithium voltage is a little higher than AGM and I found my Lithium charging my AGM at 1-2A... but after an hour or so both batteries banks were discharging. The lithiums discharge at a higher rate - but no cross charging after an hour. That 1-2A for an hour or 2 is really nothing and doesn't seem like it should be a problem. Seems any system with mixed batteries like this will have the same issue unless you completely isolate the 2.
Another item to be aware of. When you turn ON the ignition switch on there is a 1-2second delay before Bird detects the condition and opens the Big Boy relay. I discovered this when reviewing my logs and noticed that one time when I quickly started the engine to move the coach a foot there was a large draw (360A) on the Lithium .. this was due to engine starter pulling current from the Lithium. This really shouldn't be a problem as long as BMS in Lithium doesn't trip. To avoid this I just turn ON ignition and pause 2 seconds before cranking.
As I've said before the logging capability of the Thornwave monitor allows me to literally pull logs from weeks back and review voltage, currents, power draw, temp, SOC, etc. I highly recommend it or something similar to be able to make sure everything is good with your setup.
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Nice work, Gene! I'm gonna have to measure my battery tray to see how much space is available. My FLA batteries won't last forever (I think I bought them in 2016). I saw the Thornwave unit a while back; how far can you roam from your batteries and still read the Thornwave data?
Again, nice work!
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Bill, I have no problems connecting to the Thornwave anywhere inside my coach. It's bluetooth so probably depends to some degree on how good the bluetooth is in your phone or tablet.