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Old 01-03-2019, 06:34 PM   #11
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Gotta go with your battery manufacturer's recommendations. Battleborn recommends 14.6 volts. Who knows why the difference using the same battery type.
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Old 01-04-2019, 06:07 AM   #12
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Your 'numbers' are breath-taking. We have three charging sources: 1) a Magnum 2812; 2) 810 watts of solar through a MidNite Classic controller; and, 3) a second 280 amp Nations alternator with an external Balmar regulator. Our 500 ah lithium 'system' came from Starlight Solar (Elite).

All three charging sources have mostly suitable (another topic) programming allowing us to tailor our chargers to our lithium pack. The question, therefore, isn't whether these charges can charge at your elevated voltages, but whether they should.

We have run extensive full charge/discharge cycles on our system. Here is a Table of two of our discharge runs:

Calculated
State of Charge ---Resting Voltage (2 runs)
100%----------------13.71----13.91
90%-----------------13.36----13.36
80%-----------------13.35/6--13.36
70%-----------------13.28
60%-----------------13.21----13.21/22
50%-----------------13.19
40%-----------------13.18----13.19
30%-----------------13.12
20%-----------------13.02----13.04
10%-----------------12.89
0%(500ah)----------12.47----15.50
516ah----------------11.92/93

Based on this table we have selected 13.4 volts as our normal target/operating voltage. If we know we're going to be off-grid for an extended time, we'll reprogram chargers to take us to 100% SOC (generally 13.8 volts).

Although the manufacturer suggests "equalization" charging at 14.2 volts, most commentators caution that maintaining lithiums at 100% may not be healthy for the pack. We do run our charger(s) at 14.2 every few months to check and re-attain 'equalization'. This is equivalent to 3.55 volts/cell. We have deliberately taken the voltage higher to 'see' what happens and were surprised to see how quickly, from 3.55 volts, the cell voltage soars. It is easy to see how damaging charge levels could be attained by taking the charge voltage above 14.2v.

For us, the bottom line is: Why operate this pack above 13.4 volts? Not only do we avoid the possibility of damaging overcharge, but further, by operating between 80-90% SOC we get to use 'most' of our pack's capacity while backing down from that high (100% SOC) charge level that many believe to stress the pack. (Indeed, it is our understanding that for storage, an SOC between 50-60% is recommended).
Elitepowersolutions.com (is that your vendor) says 15.2 volts is the maximum for a 4 cell pack. Ours wouldn't even charge (at least very slowly) at the voltages you use. Does anyone else use such low voltages on a lithium bank?
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Old 01-04-2019, 11:22 AM   #13
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Elitepowersolutions.com (is that your vendor) says 15.2 volts is the maximum for a 4 cell pack. Ours wouldn't even charge (at least very slowly) at the voltages you use. Does anyone else use such low voltages on a lithium bank?
I have 2 100ah Stark Power Li batteries that I charge with the Promaster's stock 220 amp alternator, which depending on ambient temperature charges at 13.8 to 14.2 volts.

I use the shunt based Victron BMV 712 battery monitor internal relay to disconnect charging when the SOC reaches 95%. The resting battery voltage at that point is about 13.4 volts.

Once every month or so I charge the batteries with a 10 amp AC Li battery charger that charges at 14.6 volts until the charge current drops to 0 amps to reset the Victron's SOC to 100%.
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Old 01-04-2019, 02:32 PM   #14
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I have 2 100ah Stark Power Li batteries that I charge with the Promaster's stock 220 amp alternator, which depending on ambient temperature charges at 13.8 to 14.2 volts.

I use the shunt based Victron BMV 712 battery monitor internal relay to disconnect charging when the SOC reaches 95%. The resting battery voltage at that point is about 13.4 volts.

Once every month or so I charge the batteries with a 10 amp AC Li battery charger that charges at 14.6 volts until the charge current drops to 0 amps to reset the Victron's SOC to 100%.
Hi Tom,

Your charging method is what others I know have adopted and is working well for them. That is what I am going to be doing with the EliteSolutions system I am putting together now. Will follow your method of calibrating the Victron monitor as well. As far as charging voltage, taking your and Winstons' recommendation. These charging voltages concur with early Lithium adopters finding in the field.

Curious, I have the same 220amp alternator, what range of current do you see coming through ?

Santiago
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Old 01-04-2019, 11:17 PM   #15
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Hi Tom,



Curious, I have the same 220amp alternator, what range of current do you see coming through ?

Santiago
Depending on depth of discharge, I typically see 75 - 80 amps at idle. I've never looked at the amps while driving, but the batteries reach 95% within 45 minutes to 1 1/2 hours of driving. The wire from the engine battery to the house batteries is about 10-12 feet of 2awg wire.

If I'm going sit for a day without driving, I idle the engine about 15 minutes to heat shower water in a 4 gallon marine hot water heater connected to the engine cooling system and that puts back about 20ah.

I'm thinking about running the hot water beater off my 1000 watt inverter (it has a 750 watt heating element as well) because once the water is hot from driving it might not take much at all to keep the water warm. I'm going to test that this spring.
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Old 01-05-2019, 01:48 AM   #16
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Depending on depth of discharge, I typically see 75 - 80 amps at idle. I've never looked at the amps while driving, but the batteries reach 95% within 45 minutes to 1 1/2 hours of driving.
Hi Tom, thanks for the information that gives me a preview of what to expect. I will likely experiment with more than one charge wire gauge to see how it affects charge current.

Sounds like you have an Isotherm water heater. I am getting one too but will start using the 750 watt 120vAC element. Later on when I connect to engine coolant I will consider terminating engine coolant somewhere near engine using a plate heat exchanger. The outgput side of the exchanger will have a different coolant chemistry routed back to the water heater and maybe a space heater as well. Nothing like free energy.

Thanks again for inspiring many of us looking at lithium charging safely using the Victron 700 series monitor with relay output. Brilliant concept.

Santiago
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Old 01-06-2019, 05:22 PM   #17
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BattleBorn batteries are 100AH, not 50 I have two in parallel in my 2001 Roadtrek. I put them in a year ago with a 2000w inverter and a stand alone Lithium charges that charges to 14.2. Once per month I excersise my generator and bring the batts up from 13.4v to 14.2v to equalize them. This is what Battle Born recommends. I have one Vicrton solar controller and Grape 180 w solar panel. This set up works great so far. No over charging from alternator or solar. Itís a sweet set up. I would be hesitant to listen to armchair experts. Go with advice from people who have real, first hand experience with the systems. IMHO.......
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Old 01-06-2019, 06:04 PM   #18
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BattleBorn batteries are 100AH, not 50 I have two in parallel in my 2001 Roadtrek. I put them in a year ago with a 2000w inverter and a stand alone Lithium charges that charges to 14.2. Once per month I excersise my generator and bring the batts up from 13.4v to 14.2v to equalize them. This is what Battle Born recommends. I have one Vicrton solar controller and Grape 180 w solar panel. This set up works great so far. No over charging from alternator or solar. Itís a sweet set up. I would be hesitant to listen to armchair experts. Go with advice from people who have real, first hand experience with the systems. IMHO.......
Battleborn is hardly ďexpertsĒ. They purchase cells from China and assemble them here.

Here is my favorite source for accurate information on LiFePO4 batteries. Read and learn: https://marinehowto.com/lifepo4-batteries-on-boats/
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Old 01-06-2019, 06:24 PM   #19
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BattleBorn batteries are 100AH, not 50 I have two in parallel in my 2001 Roadtrek. I put them in a year ago with a 2000w inverter and a stand alone Lithium charges that charges to 14.2. Once per month I excersise my generator and bring the batts up from 13.4v to 14.2v to equalize them. This is what Battle Born recommends. I have one Vicrton solar controller and Grape 180 w solar panel. This set up works great so far. No over charging from alternator or solar. Itís a sweet set up. I would be hesitant to listen to armchair experts. Go with advice from people who have real, first hand experience with the systems. IMHO.......

How are you preventing overcharging from the solar or the alternator? From all the information we have been seeing lately, lithium batteries should not be held at a fixed voltage or floated, although this is contrary to what nearly all the drop in battery folks say, possibly because they want to be able to use existing charging systems, and very few of them will have full shut off charging sources.


I would agree with Jostalli that Battleborn doesn't seem to be very much at the top of tech, which is a bit of a surprise. Even a lot of the data and calculations on their website are wrong. They are an offshoot of Dragonfly which has been around quite a while and was started by a quite knowledgeable guy, from what I have seen. Dragonfly always assembled hear and claimed to have their own BMS in the batteries, but never really caught on. I am not certain if they are still doing all of the assembly here or buying the now readily available drop in batteries complete form China. I have read information each way on that.
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Old 01-06-2019, 06:40 PM   #20
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And if they are drop-in replacements for Lead-Acid does that mean they are able to be used in freezing conditions? Do they have temp sensors and keep energy from flowing in when the cells are below freezing?

I know my Telsa works hard to prevent issues with charging when it's cold. They run coolant between the cells when you plug-in to charge and they are below freezing the coolant is heated as part of the cabin heat system and run thru until the batteries have warmed up. Then and only then does the power go to the batteries.

Same thing if you start to drive. You will find that the normal engine braking (called regen on an electric car) is disabled until the batteries have warmed up.

I can just see the sun beating down on my freezing RV and sending the solar power racing to the batteries stored under the vehicle. If the built-in BMS doesn't cut them off what's going to stop the batts from charging when frozen? That's a situation that will KILL a lithium battery.

-Randy
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