Adding a lithium Ion battery to FWC

That is consistent with my understanding of how these things work and thanks again for posting the details of your set up.

I have a very simple BMS, that so far in bench testing has worked well:
http://www.batteryspace.com/PCM-with-Equilibrium-function-for-12.8V-LFP-Battery-Pack-30A-limit.aspx

My plan is to primarily charge this with a programable MPPT solar charge controller (from Victron) so I can set the charging parameters to match the battery pack. I will connect it to the truck as well through a blues sea ACR, but generally leave it isolated unless it is desperately needs a charge.

cdbrow1 said:
I am in California Central Valley so extreme cold is not a problem when stored. I do head into the Seirras and Great Basin at any time of year and I used the system into the single digits last year without trouble. My batteries are inside in the stock location (below the furnace) so I assume they are warmer than the exterior (there are no battery vents). My supplier does not recomend charging when the battery (not ambient) is below freezing, but discharge is allowed down to -30C. There is no issue of fire, but there is an issue of "dendrite growth" and failure of the cell.

The Battery Management System (BMS) is the most important component - make sure you know how yours works.

https://starkpower.com/safety-of-lithium-ion-batteries/
Click to expand...
 
Some photos of the rig and the aforementioned Ice Cream int he middle of the Playa... Enjoy.

full

full

full
 
Everything is continuing to work well this summer with multiple trips to Point Reyes, Black Rock and thereabouts.

Over the long holiday weekend (when I generally DON'T travel) I did make two changes which have been on my to-do list for a while.

I replaced the IOTA power converter with a new LIFePo specific charger and I added a relay switch to my inverter so it powers the internal 110 outlet directly.

This work required removing the internal cabinets covers and was a major PITA. As far as pain to gain ratios go it was probably not worth doing.

The power converter...

The IOTA IQ4 has been working fine, but it is not designed to work with LIFePo batteries. Both IOTA and Starkpower said it should be fine - but there were a lot of caveats from both. I went with a Progressive Dynamics 110 Volt 45 AMP charger set at 14.6 Volts. The unit is slightly larger than the factory unit and was a problem to make fit in the space - I ended up moving the factory wiring harness a bit. and installing the unit on the floor of the space - not the ceiling as FWC had done.

Specs - Home 3 - Progressive Dynamics

There were no issues with installing the charger and it puts out a rock steady 14.6 volts. Fan speeds are noticeably faster when on shore power and the batteries are charging at a higher rate than the factory IOTA (30amps).

The Outlet relay -

I also installed the Xantrex inline power relay for my ProWatt inverter. These means that I can run the inside oulet off shore power OR the inverter without manually switching anything. Easy install by running wire from the outlet to the inverter and back.

PROwatt SW Inline Transfer Relay

Seems to work flawlessly - like everything I have used from Xantrex. My inverter (2000Watts) is about 3 years old and sees alot of use. I have run my home fridge off it when then power was out and run powertools and small portable A/C units as well. Takes them all without complaint. It is used at least 3 times a week to run the 700watt microwave in the FWC.
 
Maybe I am mistaken - but 14.6V seems a little high for charging a 4 cell LiFePO4 battery pack. While I wait for my FWC, I have been testing out an LiFePO4 pack consisting of 4 CALB 100Ah packs on the bench with a Victron MPPT solar charger with adjustable set points over the past couple of months, and doing a lot of reading. I initially set my charger to 14.6V (3.65V/ cell which is the manufacturers max charge voltage per cell), but quickly found out that while this may 100% charge the battery, it is risky as it tends to unbalance an older battery pack. This probably is not an issue with your newer pack, but it may become an issue over time. The BMS will address this imbalance issue - but it takes time and wastes power to do this, and while it is balancing, some of the cells can be overcharged. While I have only done a few cycles, 14V, or even 13.8V will get the battery to 95% SOC just as quickly, and doesn't seem to unbalance the pack, meaning the BMS never has to bleed off the high cells, and hopefully the battery will last longer. I also set a very low 'float charge' voltage at 13.2V (which is at the operating voltage of the pack) just to make sure not to overcharge the pack.

There is some great information (all thought hard to sort through) over at cruiser forums - these guys use their batteries much like camper batteries, and seem to have been using LiFePO4 much longer than the camper crowd:
http://www.cruisersforum.com/forums/f14/lifepo4-best-practices-157703.html

The consensus seems to be to stay away from the 'knees' in the charge and discharge curves for the longest battery life. It is a total paradigm shift for those of us used to lead acid batteries.
 
rando said:
Maybe I am mistaken - but 14.6V seems a little high for charging a 4 cell LiFePO4 battery pack. While I wait for my FWC, I have been testing out an LiFePO4 pack consisting of 4 CALB 100Ah packs on the bench with a Victron MPPT solar charger with adjustable set points over the past couple of months, and doing a lot of reading. I initially set my charger to 14.6V (3.65V/ cell which is the manufacturers max charge voltage per cell), but quickly found out that while this may 100% charge the battery, it is risky as it tends to unbalance an older battery pack. This probably is not an issue with your newer pack, but it may become an issue over time. The BMS will address this imbalance issue - but it takes time and wastes power to do this, and while it is balancing, some of the cells can be overcharged. While I have only done a few cycles, 14V, or even 13.8V will get the battery to 95% SOC just as quickly, and doesn't seem to unbalance the pack, meaning the BMS never has to bleed off the high cells, and hopefully the battery will last longer. I also set a very low 'float charge' voltage at 13.2V (which is at the operating voltage of the pack) just to make sure not to overcharge the pack.

There is some great information (all thought hard to sort through) over at cruiser forums - these guys use their batteries much like camper batteries, and seem to have been using LiFePO4 much longer than the camper crowd:
http://www.cruisersforum.com/forums/f14/lifepo4-best-practices-157703.html

The consensus seems to be to stay away from the 'knees' in the charge and discharge curves for the longest battery life. It is a total paradigm shift for those of us used to lead acid batteries.
Click to expand...

I agree with everything you said here. I have my Alternator set at 14.1 and my solar at 14.0 for this exact issue. If I was ordering that charger/converter today I would have gone with a lower voltage - but I ordered it last spring and was just waiting for the right time to install. I probably won't use it too much, but if I find that I am I will eventually get one with a lower voltage - probably 14.1. There are very few amps between 14 and 14.6 to be had - and the risk is not worth it.
 
Did you have a converter installed by FWC from the factory that you replaced?

I am wondering what to do about the IOTA IQ4 system that will come with my FWC. Reading the spec it seems that it is not really compatible with a lithium pack: http://www.iotaengineering.com/iq.htm

I wonder if you can adjust the voltages somehow? I have no problem voiding the warranty to open up the IOTA and see it is can be changed.
 
rando said:
Did you have a converter installed by FWC from the factory that you replaced?

I am wondering what to do about the IOTA IQ4 system that will come with my FWC. Reading the spec it seems that it is not really compatible with a lithium pack: http://www.iotaengineering.com/iq.htm

I wonder if you can adjust the voltages somehow? I have no problem voiding the warranty to open up the IOTA and see it is can be changed.
Click to expand...
I have the old IOTA, but I think somebody wants to buy it. IOTA and Starkpower both said it it should "be fine" but I that is not the gold standard I needed. I did use it and kept an eye on the voltages and it never seemed to trigger the BMS.
 
The system has finally started giving me grief. Honestly I am surprised it has been trouble free for so long. I did some long drives over xmas - Sac to Redwood NP the back to Sac then up to Honey Lake area via Chester. VERY wet and cold on the coast (snow down to 1,500 feet) and very cold (saw 16F at one point in the mountains). On the drive back from the mountains I saw my camper batter gauge was spiking to 15+ volts. Rather than fuss with it in below freezing temps I just disconnected it and kept going. Today I spent some time looking at it and it appears to be an regulator problem. The regulator (Balmar 614) is programmed NEVER to exceed 14.4 volts, but it is dosing so. It is also not triggering the overvolt idiot light. I have checked voltage with three different gauges and all Show similar voltages - but the Balmar shows a much lower voltage.

This does not seem to be a LiFePo battery problem - even when hooked up to lead acid batteries the regulator is over-charging. The fact that I first noticed it in very cold conditions made me concerned that it was a LiFePo problem - thankfully they seem to be working fine.

I will try to dig into this a bit more before I hit the road on Saturday. If I can't fix it I might have to carry my generator again to charge up the batteries. Yikes.
 
My understanding is that LiFePo4 batteries are not to be charged under 0ºC.

http://gwl-power.tumblr.com/post/77599670684/faq-low-temperature-operation-what-is-the




Lithium Iron Phosphate Parameters







Nominal voltage

3.2 Volts





Peak voltage

3.65 Volts

Note our new data on capacity versus charge voltage



Absolute Minimum discharge voltage

2.0 Volts





CV charge voltage

3.65 Volts

100% charge



CV charge voltage

3.5 Volts

95% charge



Charge Temperature

0°-40°C





Discharge Temperature

-10°-60°C







See also: http://gwl-power.tumblr.com/post/77599670684/faq-low-temperature-operation-what-is-the

http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures

One reason I have not considered LiPoFe is I do camp in below freezing temps.

jim
 
Below freezing temperatures shouldn't be a problem if the battery compartment gets a little heat from the cabin.
 
I have tracked down the problem - the regulator's CPU is locked up. Had no idea it had a CPU - much less that it could lock up - but there you are.

No matter what the battery voltage is the regulator thinks it's 9.6 volts. Therefore it is going into "full charge" all the time - during one VERY SHORT test it was putting 170 AMPS into the batteries (probably for 15 secs or so - before I shut it off). It is a credit to the battery maker that they took this abuse without complaint. Once the voltage started to rise above the trigger point the BMS would kick in to protect them.

The long term solution is to buy a new regulator since I am out of warranty by 6 months. Short term solution is to bypass the second alternator entirely and just tie all the batteries together. Redundancy is nice sometimes.

From talking with the vendors the problem is not a result of the battery chemistry - but the mounting location I choose for the regulator. They think the spot is too hot - they want me to move it to cooler location. They don't recomend anywhere over 150F - although this is not in the manual anywhere.
 
I have finally solved the issues I was having. Replacing the regulator did not get the system back to 100% and our extremely wet weather in Nor Cal prevented me from digging in too much until last night.

The problem was again overcharging - although not has bad as before. The Regulator was trying to get the voltage to 14.0, but the voltage kept creeping up (at very low amps) - to the point that the battery BMS would cut in (14.8 volts).

Digging into it today I found the problem I had connected my battery combiner incorrectly which was causing the problem.

I must have done this when I pulled the regulator a few weeks ago. As soon as I corrected the wiring (and labelled everything properly). It all worked as designed again. Voltage holds at 14.0 as programed and the amps never rise above 0.

Again the issue was not battery related but in this case human error. Even with the problems I was able to spend 2 nights camping in really cold (and windy) weather at new years - just charging the batteries using the factory alternator.
 
I really need to start labeling my work. Nothing like troubleshooting a few years later and going "now what the heck is this wire?". When I originally installed the camper battery I must have been been low on wire and used all white 10ga wire. Now it just drives me crazy when I try and trace it. Part of my problem is when I start a project I want to finish it, now. Not wait a day or two ( or even an hour to drive down the wire store) to make sure I have the stuff to do it properly. Also stems from having a decent collection of stuff at home. Hmmm, needs a 2 /12 inch bolt and all I have is 2" and 3". I guess the 3" will do. That sort of stuff happens and even if intend to put the right part in later I rarely do.
 
craig333 said:
I really need to start labeling my work. Nothing like troubleshooting a few years later and going "now what the heck is this wire?". When I originally installed the camper battery I must have been been low on wire and used all white 10ga wire. Now it just drives me crazy when I try and trace it. Part of my problem is when I start a project I want to finish it, now. Not wait a day or two ( or even an hour to drive down the wire store) to make sure I have the stuff to do it properly. Also stems from having a decent collection of stuff at home. Hmmm, needs a 2 /12 inch bolt and all I have is 2" and 3". I guess the 3" will do. That sort of stuff happens and even if intend to put the right part in later I rarely do.
Click to expand...
Craig your thoughts hit home for me also.
Frank
 
craig333 said:
--snip--
Hmmm, needs a 2 /12 inch bolt and all I have is 2" and 3". I guess the 3" will do. That sort of stuff happens and even if intend to put the right part in later I rarely do.
Click to expand...
Doesn't that "failure" fall into the "If it ain't broke, don't fix it" bucket? ;)

Paul
 
craig333 said:
. Hmmm, needs a 2 /12 inch bolt and all I have is 2" and 3". I guess the 3" will do. That sort of stuff happens and even if intend to put the right part in later I rarely do.
Click to expand...
cut off wheel quickly makes a 3" bolt = 2 1/2" ;-)
 
As does a hacksaw. I just wish I documented my projects (other than on WTW) so at least I knew my thought process at the time.
 
craig333 said:
As does a hacksaw. I just wish I documented my projects (other than on WTW) so at least I knew my thought process at the time.
Click to expand...
So true... I have a black wire in the middle of my battery wiring. I put red tape on the ends so I will HOPEFULLY remember it is not a ground wire.
 
Wanted to provide another update on this thread.

The batteries are still working fine. I had continued problems with my voltage regulator (BalMar 612). I had replaced it once and then the second unit started acting up. The BalMar equipment is very high quality and I don't blame them at all. I switched from a multistage regulation to a fix regulator running 14.1 volts (also a BalMar unit). This has been rock solid for many months. I spent a week dry camping on the California Coast and had zero issues with the setup. I used the microwave and CPAP every night and never saw the battery drop below 80%.
 
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