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Old 07-12-2013, 09:16   #1
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Lithiums in a motorhome?

New member here. Please be kind since I don't have a boat but a motorhome. Travesty I know, but I'm in the process of pulling out 6 8D LA batteries for the house systems and install a Balqon 1000 amp hour lithium system of 4 cells. Which are stuck in Dallas waiting for the weather to clear to get here. This will have a BMS with HV & LV cutoffs.
Unfortunately the motorhome crowd is too scary so there is very little information. My motorhome has a Detroit series 60 with a Penntex 270 amp alternator with a P-4000 remote regulator. This feeds through a Surepower 31922 isolator to charge 2 8D LA start batteries and the 6 8D LAs which I am replacing with the lithiums. I have a Xantrex Freedom 2500 inverter with Link 2000 remote which should handle the charging when plugged in. Also have a 20KW generator. I should be plugged in most of the time and when boon docking use the generator for charging.
The only thing I'm concerned with is the alternator. Been doing some reading here and there is great info. So my 1st question is which is the best way to protect the alternator and belts? I could change the regulator to a Balmar MC-614 assuming it's compatible with the Penntex alternator. Or use something like a Sterling Prolatch relay, but not sure if this will protect the alternator from overheating or when the lithiums are full. I don't drive more than about 5 or 6 hours a day when traveling so the main charging will come from the inverter.
I'd appreciate any help on this.
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Old 07-12-2013, 10:25   #2
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Re: Lithiums in a motorhome?

There is a very long and detailed thread here which has lots of good information:

LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

and another:

Lithium Batteries (for the rest of us)

Basically, 13.8 to 14 volts max is plenty.
Float, you really don't need to.
Make sure your belts are up to the job.

I've got Lithiums in my boat as well as home's backup power system.
I'd never go back to lead even if it was free.
Steve
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Old 07-12-2013, 10:50   #3
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Re: Lithiums in a motorhome?

Hello and Welcome,

Just some ideas for you and sources for info re RV's . I found this thread when doing an internet search on my Victron charger...it led me here to Cruisers Forum.Remember we are talking LiFePO4 batteries....it will keep the naysayers at bay, not just refering to them as Lithium as we often do.

Lithium Ion Batteries for RV Motorhome House System - LFP / LiFePO4 | Technomadia

Hope this helps,
Pete
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Old 08-12-2013, 14:53   #4
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Re: Lithiums in a motorhome?

folivier, I think charge acceptance will be the only issue. Your MH is more high end than my last MH, and here is my story with just LA on it some 30 years ago. Upgrade from (2) 12 volt 85 a-hr LA to (8) 225 a-hr 6 volt LA. On my very first boondock camping that I ran the new larger bank down, and driving to my next destination, the wiring coming from the alternator to the larger housebank caught fire due to the higher and longer amp pull. The LiFePO4 cells have a much higher charge acceptance than LA, so make sure everything downstream can handle high amps for a long period. If your regulator is programmable, that would be the easy way, just roll output back to what the rest of the system can handle.
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Old 08-12-2013, 19:48   #5
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Re: Lithiums in a motorhome?

I've spent a few weeks reading through those 2 threads and it's helped a lot. At least I know the difference between cobalt & iron.
I've met Chris & Cherie, in fact they're a big reason why I'm going with LiFePO4 batteries.
I will probably change my alternator regulator to the Balmar MC-614. That should protect the alternator & belts from overheating. One question: if the LiFePO4's would reach full charge will the MC-614 protect the alternator? I will still have 2 8D LA's for starting.
Thanks for all the advice.
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Old 10-12-2013, 11:41   #6
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Re: Lithiums in a motorhome?

Use the 614's Belt Management function to find the sweet spot where you get the max amps (the LFPs will take everything the alternator can provide!) without overheating the alternator (>210F or whatever the techman says). Install the alternator temperature sensor as part of the 614 upgrade. If I was doing the conversion I would start the alternator output (using Belt Management) at 80% and adjust, probably up, until the sweet spot is found.

DO NOT
install the battery temperature monitor.

You might want to PM T1 Terry in Australia. He has been "cruising" the outback for three or four years in his land yacht using a LFP bank for his house loads.
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Old 11-12-2013, 14:32   #7
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Re: Lithiums in a motorhome?

Another question I have: has anyone seen one of these leak? If so how do you deal with the leak?
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Old 12-12-2013, 02:48   #8
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Re: Lithiums in a motorhome?

Which SOC meter would you suggest?
I just want a reading inside the motorhome to keep track of usage and when to recharge.
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Old 12-12-2013, 05:54   #9
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Re: Lithiums in a motorhome?

Quote:
Originally Posted by folivier View Post
Which SOC meter would you suggest?
I just want a reading inside the motorhome to keep track of usage and when to recharge.

The only decent way I have found to track these is with an Ah counter or what is commonly called a Battery Monitor.

I manually re-set at 13.8V and ≤5A (less than or equal to 5A) of current being accepted by the bank.

Our Peukert is set to 1.01 but I feel it is leaving us with more capacity, at our loads (avg 5-8A on a 400Ah pack), than the P 1.01 represents.. I plan to recreated that with a discharge test this winter to see if my assumption is correct.

13.8V with ≤5A going into the bank, is our "full".... We use a Xantrex Link-Pro but the Victron BMV-600 is a better value. Be cautions of battery monitors with a "built in" pre-chosen Peukert value (usually 1.25). They WILL NOT be accurate on a Li bank... Victron & Xantrex make battery monitors that allow for programing a Peukert as does Philippi...

If you charge to 14.0V (slightly shorter current taper at the very end) then I would also use ≤5A at 14.0V..

Counting on "automatic re-sets" with Li I have found rather unreliable because the voltage moves so little....

The absolute best approach is to MANUALLY reset them when "known full" and with Li, unlike LA, this can happen very quickly which makes for much easier "known-full" resets...

This winter I will be experimenting with a Smart Gauge. I could NOT garner a single response from Smart Gauge to multiple emails. I have had the US distributor also trying to get me an answer but to no avail.

I have strong doubts about the Smart Gauges ability to work on LI but I still want to try it. If it does not work I will experiment with it on LA...
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Old 12-12-2013, 06:49   #10
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Re: Lithiums in a motorhome?

So my Freedom 2500 with Link 2000 remote might do this since it allows a peukerts setting as low as 1.00 and displays amps available.
I guess I could do this and always add a SOC meter later if needed.
I was thinking of maybe this: EV Display - CleanPowerAuto LLC but it may not give me anymore information than what my Link 2000 does?
Or a VictronBMV-600.
Thanks!
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Old 12-12-2013, 08:27   #11
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Re: Lithiums in a motorhome?

Quote:
Originally Posted by Maine Sail View Post
The only decent way I have found to track these is with an Ah counter or what is commonly called a Battery Monitor.

I manually re-set at 13.8V and ≤5A (less than or equal to 5A) of current being accepted by the bank.

Our Peukert is set to 1.01 but I feel it is leaving us with more capacity, at our loads (avg 5-8A on a 400Ah pack), than the P 1.01 represents.. I plan to recreated that with a discharge test this winter to see if my assumption is correct.

13.8V with ≤5A going into the bank, is our "full".... We use a Xantrex Link-Pro but the Victron BMV-600 is a better value. Be cautions of battery monitors with a "built in" pre-chosen Peukert value (usually 1.25). They WILL NOT be accurate on a Li bank... Victron & Xantrex make battery monitors that allow for programing a Peukert as does Philippi...

If you charge to 14.0V (slightly shorter current taper at the very end) then I would also use ≤5A at 14.0V..

Counting on "automatic re-sets" with Li I have found rather unreliable because the voltage moves so little....

The absolute best approach is to MANUALLY reset them when "known full" and with Li, unlike LA, this can happen very quickly which makes for much easier "known-full" resets...

This winter I will be experimenting with a Smart Gauge. I could NOT garner a single response from Smart Gauge to multiple emails. I have had the US distributor also trying to get me an answer but to no avail.

I have strong doubts about the Smart Gauges ability to work on LI but I still want to try it. If it does not work I will experiment with it on LA...
Hello folivier,

The above is where I want to go and as of yet do not "RE-SET " manually....I feel this will be a must as the two monotoring systems I have disagree with one another .I have only a few months practical use , and am nowhere near as intelligent in this field as Maine Sail and others posting here for you.

I have the Victron Battery Monitor Mail Sail is refering to that gives you a SOC as well as other info in my pilothouse

and

the simple BMS identical to Chris @ Technomadia, located close to my Battery bank installed in the floor of my bedroom.

I use the BMS as a high level and low level automatic cut off in case of a problem ( yet to have one) and for monitoring only. It is connected on only one battery in each parelle set ...middle of the group....and its readings are taken from there.

I use the "capacity" display on the simple BMS and it seems to give me a more accurate reading than the Victron that drifts the longer I am away from shore power and not toping off my batteries at 3.55 volts under charge.

If you read my various posts you will see I have a used set of batteries and Elite power recomended thier individual +/- 10.00 $ each bleed off boards to ensure my batteries can get topped off equally.

It works for me as I see the little red lights comming on as the charge voltage comming in to each individual 60 amp cell ( I have 84 of them ) is reaching the desired 3.55 volts. ( in charging condition ) They bleed off charging power so as not to overcharge the quicker cells as the slower ones catch up. This must be done with much less amps going in than when on full charge as the boards do not handle lots of incomming amps...its simple and I hope I am not confusing things.

These individual tiny boards are my ultimate reference and In the previous posts you will see where those much smarter than me explain why the Victron begins to drift away from the truth in it's display SOC the longer you go between top off charges and then re-sets it "SOC" to come in line with the BMS " CAPACITY "when fully charged.

I hope this helps...it is the same BMS as Chris at Technomedia with only 4 points of monitor centrally located in the parelle string AND the Victron Battery Monitor ....which I need to learn how to reset MANUALLY as better understood and explained by others.

Best Regards,
Pete
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Old 08-01-2014, 15:49   #12
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Re: Lithiums in a motorhome?

I just finished the install of 4 1000amp cells from Balqon in my motorhome. Also have the Housepower BMS installed and a Victron BMV-600 for monitoring. I have an older Freedom 2500 inverter/charger with the older version of Link 2000.
I'm getting 100-115 amps charging rate but only able to get the charge volts up to 13.6
I'm seeing about 0.4 volts higher on the Link display (14.0 v) than the Victron and at the battery using my Fluke (13.6).
I'm pleased with the capacity so far but wondering if charging at 13.6 volts will give me any problems other than a slightly reduced capacity. I discontinue charging when the amps drop to 5. Mr. Samra recommended getting the charge voltage up to 14.2 but haven't been able to get the LinkPro to go that high. Any suggestions?
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Old 08-01-2014, 16:11   #13
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Re: Lithiums in a motorhome?

interesting thread..
any chance you had photos or a blog of the install?

thx
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Old 08-01-2014, 17:05   #14
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Re: Lithiums in a motorhome?

Here is a picture of the installed cells in the compartment where there was a rack with 4 8D size lead acid batteries.
Im detailing the install on this forum: Lithium battery install
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Old 09-01-2014, 06:29   #15
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Re: Lithiums in a motorhome?

Quote:
Originally Posted by folivier View Post
Here is a picture of the installed cells in the compartment where there was a rack with 4 8D size lead acid batteries.
Im detailing the install on this forum: Lithium battery install
Forest,

For balancing the best tool I have found is a bench top power supply. The Mastech EX series is about the best value. I have a Mastech 3030EX and a 3050EX..

For balancing in a motor home I would think you would be similar to a boat and would want to top balance.

A trick I use is to wire the pack in series then charge until the highest cell hits 3.8V then STOP.

Now break them out of series and wire them in parallel. Let them sit for a day or two and then charge the entire pack to 3.8V as measured at the battery terminals. When in parallel they will self balance but this takes TIME. As the cells balance become closer and closer less and less current flows between cells and it can take time for them to become balanced.. Allow the current to stop dropping, or moving downward, at 3.8V but do not go above 3.8V as a parallel pack..

I honestly don't know how anyone could own Li cells and not own a bench top power supply but folks do. They just make life so much easier. Once you own one you will like never use a standard charger again for tinkering, set up and testing.......

The reason to charge in series first, until the highest cell hits 3.8V, is because you will only be charging a 1000Ah pack. It will still take a LONG while. While below 14.4V or so you can parallel all the chargers you want to get more current and speed the process. But do watch the individual cell voltages because when they hit the upper knee they can hockey stick, and it happens rather suddenly..

When you break them down and wire them in parallel you are now charging a 3.2V 4000Ah pack and even "finish balancing" the pack can take days, even with a 50A power supply....

TIP: Set the max current of your power supply to about 10% less than its rating. For a 50A supply they run well at 45A etc.. It will run cool and can do this for days on end.




Quote:
Originally Posted by Foliver
On gel setting now. That is what Balqon recommended.
Good point! I'll set it for lead acid (only have LA or gel settings) then I can use the ambient temp setting to bring it down a bit if it's too high.
I think part of my problem is the inverter is reading 0.4 volts higher than the Victron monitor and battery.
Where is the link sensing voltage? This is CRITICAL! If it voltage senses anywhere other than the positive battery & negative terminals, and the shunt should be VERY close to the neg terminal, than you will get inaccurate readings especially when pushing the inverter hard.

The Link 2K's are also now VERY, VERY old and have a tendency to drift...

One thing I have learned is that voltage sensing is critical in Li batteries. Voltage must be sensed at the battery terminals or a risk of over charge or poor charge performance is possible.

You are going to want a LARGE alternator and MC-614 regulator. This regulator has a dedicated voltage sense wire that carries nothing but voltage and it also allows current limiting of the alternator to protect it.. The v-sense wire on the 614 does not power the reg or do anything but sense voltage, thus accurate readings. The ARS 5 uses the power wire to power the reg and sense....

For most chargers they have no means of sensing voltage other than through the cables you are pushing 100A through, and this results in INACCURATE readings to the charger. If you go all the way to full the batt term voltage and charger voltage will eventually match up, you need current for voltage drop, but when in bulk, which you are most of the time, the voltage will usually be off.

As an example if your inverter is pushing 100A and you have it set for 14V but the actual battery terminal voltage is 13.7V the charger will begin limiting current because it is technically limiting the voltage to 14.0V and that is what the charger is seeing. The batteries can take the full amount but the charger thinks they are at absorption voltage thus starts cutting back current to maintain the voltage. You will still get decent output but usually not full output....

For the fastest charging of Li it is critical that you are properly sensing voltage. I am going to guess your alt is suffering from the same problem?
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