Lithiums in a motorhome?

[goboatingnow]

Just be aware if you are sourcing a bench power supply , that it has over voltage protection so that the outputs can be used to charge batteries.


dave

[folivier]

Getting closer to my charging profile. After resetting the Link 2000 to factory defaults and raising the charged voltage to 14.2 here are the results:
Started at 13.32 volts and 115 amps
30 minutes: 13.73 108amps
1 hour: 13.79 103amps
1:30 13.82 104amps
2:00 13.98 97amps
2:30 14.19 71amps
2:35 14.23 52amps BMS alarm started beeping
2:45 14.24 48amps I shut off charging
So the BMS alarmed at 14.2 volts where it is supposed to.
I think for the next charge cycle I'll move the ambient temp setting from 70 to 80. That should drop the max voltage from 14.4 to 14.2 (I'm using a set value instead of temp monitoring).
At least I'm going in the right direction now.
The SOC at start was 95.9 but I don't think it was fully charged since I've been trying different charge settings.
I did try moving the inverter shunt but it didn't work. Need to study that some more.
For this test the Link 2000 voltages were still 0.4 V higher than the battery.
At the end of the test the individual cells were #1 @ 3.534, #2 @ 3.555, #3 @ 3.544, #4 @ 3.571

[deckofficer]

Now for the fun part. Running a heater on that bank to cycle it a few times. A bank that size ought to run a 1500 watt heater for 8 hours before reaching 80% DOD.

[folivier]

LOL, no thanks deckofficer. Not looking to do research just trying to get this working properly. One more charge cycle to make sure it's dialed in right then I'll start looking at the engine alternator. Probably just change out the regulator to the MC-614 Balmar to be safe.
I did shut off shore power for 4 hours today and used 9.7% of capacity. So I can definitely make it overnight plus some. That's really what I'm shooting for.

[Stu Jackson]

Originally Posted by folivier

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!

If your Link 2000 is still working, I suggest reading the manual (RTFM!) which shows you that you can get a %SOC on the display. Also make sure that you have the F11 function set properly to have only the house bank control the combined I/C.

Good luck.

[deckofficer]

Forest,

As you are an early adopter of LiFePO4 on your Newell forum, you might not be totally aware of these cell's capabilities. Many years ago I was in the Sea of Cortez in my Cal 40 that I just upped the ante by having one the first Trace 2012 inverters (around 1990) and to be able to power galley appliances I installed (8) 6 volt golf cart batteries, modest by today's standards. On a hot Baja day I wanted to show off my system and invited some other Bridge players for some games in A/C comfort. They assumed the gen-set would be running for this comfort, but I wanted the quiet of the inverter for cards. We played Bridge for about 3 hours and pretty much ran those batteries down to empty. That was 544 lbs of lead for 3 hour of continuous A/C run (it was over 100*). Damn Peukert effect. Your LiFePO4 bank weighs 308 lbs and would run the A/C for 7 hours and your bank would still be at 13 volts (80% DOD). Until you have pulled big loads from that bank, you won't know how different LiFePO4 vs lead is.

Lead is Dead.

[T1 Terry]

I would recommend you buy a Junsi cell logger from somewhere like HobbyKing. Spend the big$$ ($28) and get the unit that has logging capability, sample at 30 sec intervals and monitor your cell voltages, you can down load it to you computer and see just how the individual cells are reacting to what you are doing to the battery. You can also wire a smoke alarm (or something quieter if you prefer) across the alarm port, set the cell HV to 3.6v and LV to 2.8v, stay between these 2 voltages, even when charging or heavy discharging, and the cells will look after themselves. If a cell hits 3.6v while charging, stop charging for a while and let the normal loads pull a bit out of the battery, then resume charging.
We have a private group (around 100 members) that have been using Li batteries in caravans and motorhomes for some time now, 3 of us are getting close to the 3 yr mark now. Only 1 in that group is 100% reliant on the batteries for everything, cooking, water heating, air con (it gets hot and humid in an Aust summer) fridge and freezer and start battery. He lives full time on the road, boon docking I think is the US term, we call it free camping, he free camps 100% of the time and relies on solar with a bit of alternator charging when travelling. We still have a few issues to sort with the alternator charging relating to cell over voltage, he used power dumping via his inverter into the hot water service to pull down the battery a bit but you can only heat water so much :lol:
When you get more comfortable with your new battery you will be able to discover the whole new world available to you, if the inverter can handle it, anything you used at home you can use without worry from these batteries. Air con over night while free camping, wake up to freshly cooked bread and hot coffee from the espresso machine, cook breakfast on the induction cook top, all before the sun has come up to get the solar happening, that level of comfort and flexibility.
Just a bit of info that may help, none of the group use cell balancing boards on their battery pack, a few tried and had less than satisfactory results, so they put the boards where they belonged….. the Junsi does all the monitoring required as far as cell voltage, either a Victron, linklite or Plasmatronics controller does the SOC and other battery monitoring.

As has already been said, watch the wiring, belts and alt temp, these batteries are very hard on under sized wiring and over rated equipment on the charging side, it won't just restrict the charging capabilities like it did with lead acid, it will melt the insulation off the cables and let the smoke out of charging gear where the manufacturer over stated it's output capabilities

T1 Terry

[folivier]

Thanks for all of the advice it's really appreciated. So far the batteries are exceeding my expectations. I'm just having fits getting my old inverter to charge them like I want. I'm thinking of ordering a separate charger from TORNADO SCIENCE GROUPS LIMITED - LiFePO4 battery,Lithium Battery,LFP Battery in China. They can set up a charger at 14.0 volts and 140 amps with 120vac input. This will be a CC/CV charger and sounds like it will meet my needs. A simple on/off charger that I can use the Victron monitor to shut off if necessary. Should do just bulk then absorb mode with no float. And I should be able to mount a remote on/off switch.
The cost will be about $420 delivered.
What do you think? Should it work?
Another question, my 20KW generator alternator is a Hitachi LR140 40 amp. Wondering if I should just disconnect it? Won't need it to charge the batteries since if I'm running the gen set I can run the charger.

[deckofficer]

Forest,

Until one of the well versed users replies, I'll toss out something for you. IMHO, prior to lithium batteries, design engineers for charging sources knew that whatever the peak output of the charger (inverter's charger, engine alternator), it would quickly taper due to lead acid's early surface charge. With lithium the output will stay at max for 95% of the charge, hence heat build up. For you to go to a dedicated lithium battery charger means that charger was designed from the ground up to deliver its output for long periods of time and just might be the easiest cure for efficient and fast charging.

I use a dedicated lithium designed charger and so far it is working great. 14.6 volt and 50 amps. It holds 50 amps for close to 2 hours on my 100 a-hr bank and tapers for about 10 minutes and turns off. Here is a link to it http://www.evassemble.com/index.php?...&products_id=9

The above is a 50 amp charger for $209, below is a 100 amp charger for $320 http://www.evassemble.com/index.php?...products_id=11


On my 50 amp charger it employs enough heat sink to run at about 20 amps continuous, above that the fan will cycle on. This charger has charged my (2) packs over 200 times without any issues.

[deckofficer]

Here is a picture of the 50 amp lithium battery charger. Weighs about 9 lbs.

[folivier]

Thanks deckofficer, I've contacted them to see if they can set up the charger with a max voltage of 14.0 or 14.1 since my BMS alarms at 14.2
The Housepower BMS alarming at 14.2 has been one of my problems in getting my charging profile set up. Kinda a pain to have the alarm start beeping at the end of the charging cycle. I did set the Victron monitor to alarm at 14.1 since that's inside and easier to turn off the charger before the BMS starts beeping. The BMS is in a basement compartment.
But by limiting the voltage to 14.0 max am I getting the full capacity out of my batteries?

[Maine Sail]

Originally Posted by folivier

But by limiting the voltage to 14.0 max am I getting the full capacity out of my batteries?

I have a 400Ah Winston pack and charge to 13.8V and allow the current to fall to 1.25% of "C" before charge termination. This amounts to 5A of net accepted current at 13.8V..

A few weeks ago I capacity tested my bank at a .25 "C" load, 100A on a 400Ah bank, and pulled 425Ah's out of it before the lowest cell hit 2.800V.

Keep in mind that a 400Ah lead acid battery would need a miniscule load load of 20A in order to deliver 400Ah. I was using 4X that current and still got 425Ah's. At -425Ah's I then dropped it a load similar to what an LA battery could handle and got another 15Ah's of capacity!

When the lowest cell hit 2.800V I shut down the .25C/100A load. The cell voltages re-bounded so I then turned on a 15A load and got another 15Ah's out of the bank for 440Ah's before it hit 2.800V at a 15A load...... This was with a charge to only 13.8V & 5A accepted current.

[folivier]

""If your Link 2000 is still working, I suggest reading the manual ""

Unfortunately my Link2000 is one of the earlier ones and only allows a few adjustments. SOC is most definitely not one of them nor is F11. Actually the only things I can change are the battery type either LA or gel, ambient temp, charged voltage, and battery capacity.
That's why I'm looking for a stand-alone charger.

[folivier]

Thanks Maine Sail that's reassuring. Balqon wants me to get the charging voltage between 14.0-14.2 for full capacity but it looks like you're getting that plus some lagniappe with your charging to 13.8V. I'm just not satisfied with my older inverter and don't want to change it out since it still works well and haven't found one that works with LiFePO4. That's why I'm looking for a charger that will give me the results I want without hitting 14.2 where my BMS alarms. Plus with a separate charger I can turn it on/off when I want or have the BMS or Victron monitor shut it off.

[folivier]

Just had another thought. I could just disconnect the BMS buzzer so it doesn't beep at 14.2
This would allow either the Link2000 to charge or if I add a separate charger that has max 14.6 vdc then let it charge. I could set the Victron battery monitor to alarm at whatever voltage I want then turn off the charger.
The BMS should continue to give me the high voltage disconnect.