Frank’s lithium battery and inverter upgrade

[lewster]

Best to check with Lithoinics to get their take on how differing ground potentials will or will not effect their BMS control system.

Since Victron is the only lithium system that I install, the Orion DC to DC converter is an integral part of this equation.

For alternator charging, I use 2 Orions in parallel for a 60 amp charging capacity on an Interstate and one for trailers (30 amp max.) with a manual disconnect that is normally left open when solar charging is involved. The Orions physically isolate the grounds from each other by using a transformer in the circuit, similar to the way a marine isolation transformer works so that there is no physical tie between the boat and it's shore power line.

If there is a problem with the voltage differentials, I would not think it would effect the charging (lower voltage than 14.2 VDC will still charge the battery IF it is above the resting voltage of same) but will take significantly longer. My concern would be damage to the BMS.......but then again......I am not familiar with the Lithionics' elecytonics and really can't comment on the net results.

[fran&frank]

Thanks Lew--I just sent them an email about this concern.--Frank

[wulfraat]

I think you can disconnect the black.. but the brakes would still work as variable voltage is sent through the blue. I *think* easy to test

[fran&frank]

The engineer at Lithionics replied to me about the concerns raised above with tow vehicle voltage and ground potentials, and I am paraphrasing him in the following statements. The Lithionics BMS is opto-isolated so it is not impacted by ground loops or multiple ground potentials. Also it uses positive side switching and a military-grade solid-silver-alloy gas-sealed contactor that is able to take the hit of transient voltage and current spikes....easily up to 1000 amps or surges. And, their BMS has integrated transient voltage suppression diodes in the system or "TVS." Their BMS runs on their proprietary Opto-Loop or opto-relay network that is impervious to EMI-RFI radiation and earth-ground issues.

Other BMS like Victron BMS units are a MOSFET diode-type negative-side switching connect-disconnect device which can be susceptible to inductive kickback during many BMS or charging device events, called "transient voltages." It also uses various forms of digital signal processing at the millivolt level, such as CANbus. This makes them prone to this issue if not addressed in some other way (such as with the Victron Orion).

So I can't say I understand all of the above but I'm accepting their explanation that its not a problem in my setup with their battery. --Frank

[wulfraat]

Cool!

[SteveTag]

As Engineering Manager at Lithionics Battery, we are receiving questions about what makes our NeverDie Battery Management System different from the other lithium ion batteries available. For an Airstream installation, the most significant difference is that batteries with negative-side switching (NSS) use a MOSFET diode disconnect type BMS. Our USA-made batteries use positive-side switching (PSS) using military-spec gas-sealed contactors with solid-silver-alloy contact points. The downside to NSS BMS batteries is that of inductive kick-back and ground-loops on the negative chassis side. These are called Transient Voltage events and they cause great harm to the BMS in the battery, and therefore, it becomes necessary to install a DC-DC converter in-line. With a Lithionics Battery, that is not necessary. Our BMS is opto-isolated and impervious to ground loops, and, we have built in Transient Voltage Suppression diodes to further protect against inductive kick-back coming from the multiple chassis ground point. We have 7 years of installation experience in the RV world and to understand how to integrate an intelligent battery into complex RV's and yachts.

[wmcneil]

Frank, you mention in an earlier post that you will be using the temperature sensor in the battery monitor to turn off the charger when temp is below 32. Does the battery also have internal circuitry to protect it from charging when temp is below 32? (This would provide a second margin of safety.)

[BoldAdventure]

Originally Posted by SteveTag

AIt often takes many years and much experience to understand how to integrate an intelligent battery into complex RV's and yachts.

No it doesn't. Marketing speak is marketing speak.

[fran&frank]

wmcneil the battery's internal BMS does not have a feature to shut off charging sources at below freezing to my knowledge, hence the need to use this feature with the victron multiplus and bmv-702. But I believe thats true of most lithium batteries and BMS. My back up is the manual disconnect switch!

[SCOTTinNJ]

I was told by Battle Born that their batteries have a built in low temp cutoff.

[wmcneil]

Originally Posted by fran&frank

wmcneil the battery's internal BMS does not have a feature to shut off charging sources at below freezing to my knowledge, hence the need to use this feature with the victron multiplus and bmv-702. But I believe thats true of most lithium batteries and BMS. My back up is the manual disconnect switch!

Frank,
If the battery internal BMS does not have any low temperature protection against freezing, then you will definitely need to ensure that any additional charging source (Ex: TV charging pin connected to TV alternator, solar charger) is not connected when the battery temperature is below freezing. You could achieve this in an automated fashion by inserting a relay between each additional charging source and the battery + terminal. The relays would need to be high-current relays (200 amps), and would be controlled by the bmv-702 relay. If you didn't want to add such relay circuits, then you need to manually make sure no charging sources are connected when the battery temperature is below freezing.

Bill

[SteveTag]

Multiple grounding potentials will not harm a Lithionics Battery. Multiple charging voltages are acceptable as well. You can easily short-charge our batteries because we manage the bottom end of the cells at deep discharge for balance as well as top-end balance the cells at high charge. A charging voltage of 14.0 will fill the battery to about 92%, and, you can use charging voltages all the way up to 14.6 volts, which fills the battery to 100%. We have designed the system specifically for RV and Yacht users...the toughest installations in the world by far.

[fran&frank]

Bill,
For the time being I am going to use the bmv-702 and the charge assistant in the Multiplus inverter/charger to shut off the charger in cold weather and throw the manual disconnect which will disconnect the solar and inverter/charger as well. Will add a switch in the charge line from the tow vehicle which I will keep off most of the time anyway, but especially in cold weather. After I use the system for a while I'll cinsider if I want to add a relay to automate the disconnect in cold weather. Thanks for the suggestions Bill.-- Frank

[SteveTag]

We are now shipping our 7th Generation BMS with the option of deploying an internal temperature sensor that prevents sub-freezing temperature "net" charging of the battery. There are pro's and con's to having this kind of lock-out intervention on a battery. We are in discussions with Airstream directly along with other OEM RV makers about whether they want to deploy the temperature protection or "intervention" circuit by default. Our circuit will be intelligent: at sub-freezing temperature, it will detect the net power consumption to know if the current flow is net in or net out, and if it is "net out" it will permit discharging below freezing, thus it won't deny the customer the use of the power. Be careful to avoid temperature sensing that shuts down discharging below freezing! That's not necessary!
Stephen Tartaglia
Engineering Manager
Lithionics Battery

[wmcneil]

Originally Posted by SteveTag

We are now shipping our 7th Generation BMS with the option of deploying an internal temperature sensor that prevents sub-freezing temperature "net" charging of the battery. There are pro's and con's to having this kind of lock-out intervention on a battery. We are in discussions with Airstream directly along with other OEM RV makers about whether they want to deploy the temperature protection or "intervention" circuit by default. Our circuit will be intelligent: at sub-freezing temperature, it will detect the net power consumption to know if the current flow is net in or net out, and if it is "net out" it will permit discharging below freezing, thus it won't deny the customer the use of the power. Be careful to avoid temperature sensing that shuts down discharging below freezing! That's not necessary!
Stephen Tartaglia
Engineering Manager
Lithionics Battery

Stephen,

Of course we do not want a circuit that prevents discharge below freezing, that is why an external relay disconnect has to disconnect only the charging source from the battery, and not the battery from the loads it is servicing.

* You mention "cons", please be more specific about exactly what the cons of the Lithionics net detection implementation are?

* Is your net detection capability available for shipment in Lithionics batteries now?

Bill

[fran&frank]

So I just want to make sure I understand the last two posts. If I am using the BMV-702 with a temperature probe and connect the BMV-702 to my multiplus inverter/charger via one of the auxiliary inputs, I can program a charge assistant in the multiplus to not let the charger turn on below a set temperature. But the multiplus inverter function continues to work and battery will supply 12 V power--irregardless of what battery I am using, correct? I realize there are other approaches that use relays to disconnect other charge sources, but I'm not familiar with those or planning to use them. I'll be trying out the charge assistant this weekend.--Frank

[wmcneil]

Originally Posted by fran&frank

So I just want to make sure I understand the last two posts. If I am using the BMV-702 with a temperature probe and connect the BMV-702 to my multiplus inverter/charger via one of the auxiliary inputs, I can program a charge assistant in the multiplus to not let the charger turn on below a set temperature. But the multiplus inverter function continues to work and battery will supply 12 V power--irregardless of what battery I am using, correct? I realize there are other approaches that use relays to disconnect other charge sources, but I'm not familiar with those or planning to use them. I'll be trying out the charge assistant this weekend.--Frank

Frank,
Yes, using the Charge Assistant with the aux input as you describe will allow only the Mplus charger function to be turned off, and the inverter will continue to operate. Also, use of a relay circuit as I described, and as AM Solar uses in their cold weather disconnect package, only disconnects the charging source, and does not prevent the battery from servicing its loads.

Bill

[wmcneil]

Originally Posted by SteveTag

We are now shipping our 7th Generation BMS with the option of deploying an internal temperature sensor that prevents sub-freezing temperature "net" charging of the battery. There are pro's and con's to having this kind of lock-out intervention on a battery. We are in discussions with Airstream directly along with other OEM RV makers about whether they want to deploy the temperature protection or "intervention" circuit by default. Our circuit will be intelligent: at sub-freezing temperature, it will detect the net power consumption to know if the current flow is net in or net out, and if it is "net out" it will permit discharging below freezing, thus it won't deny the customer the use of the power. Be careful to avoid temperature sensing that shuts down discharging below freezing! That's not necessary!
Stephen Tartaglia
Engineering Manager
Lithionics Battery

Stephen, my understanding of a limitation of the above is that if the battery temp is below freezing, then if the net current flow becomes into the battery, the battery will disconnect and remain disconnected until the temperature rises above freezing. Is my understanding correct?

Bill

[BoldAdventure]

Originally Posted by wmcneil

Stephen, my understanding of a limitation of the above is that if the battery temp is below freezing, then if the net current flow becomes into the battery, the battery will disconnect and remain disconnected until the temperature rises above freezing. Is my understanding correct?

Bill

If the battery is below freezing you shouldn't charge it. That is correct.

Your batteries can discharge however below freezing. But the colder they get, the faster their performance declines.

I will say this though, I ran some tests this winter, and while it was 20 outside, my battery system while still on was reporting internal temps of about 40 degrees. The electronics depending on where you stick them will stay warmer a bit longer.

Each of my cells has an individual temp gauge on my system. So it's easy to view each cell's state of charge and temperature.

[SteveTag]

Hi Bill,
Yes, you are correct. The temperature must rise to a value above 32F in order for the Battery Management System to re-connect and allow charging. If you need any detailed information, simply send an email to info@lithionicsbattery.com.
Stephen