basic battery upgrade questions

Maxcamp

We bought two 100ah Battleborn Li-Po batteries before our inaugural 9-week trip, run off the 2021 Wefco 8200 charger/inverter system which does not fully charge them.  Installed in passenger side bed storage, ran #8 THHN wires in liquitight conduit, from the factory terminal box on trailer frame and back again via battery shut off switch.  Probably need to do some further rewiring- other folks seem to use much heavier conductor sizes.

Nucamp has given us the data to upgrade the Wefco to properly charge Li-Po batteries, but the plethora of info on other gear is overwhelming.
What do we need for basic battery monitoring and charge control?
Here is our preliminary list, guidance welcome.

1. WFCO WF-8950L2-MBA Replacement RV Power Converter Lithium-Ion Main Board

https://www.amazon.com/gp/product/B07TZNCFG4

To have a reasonably accurate meter of charge state I’d appreciate some guidance.   Are these appropriate?

2. Victron Energy BMV-712 Smart Battery Monitor (Grey)

www.amazon.com/dp/B075RTSTKS

This seems to be the higher end version with display, the Smart Shunt appears to be the lower end version without display.

3. Victron Energy Temperature Sensor for BMV-702/712Victron Energy Temperature Sensor for BMV-702/712

I am not clear if this is needed or works with a pair of batteries in series.  I bought the battleborn heated batteries so they’ll charge in colder weather.

www.amazon.com/gp/product/B01M06654A

4. Are folks de-wiring the LED battery indicator on the Nucamp factory panel by  the door?

Appreciate all the insights already posted and any guidance you can provide.
We have not done any solar upgrades and will hold off on that for now, can use generator when needed.

Denny16

We got the Victron 712 battery monitor and temp sensor, works great with the Victron solar controller to monitor and charge our battery.  The lights by the door are just an indication thst the battery has a charge or not, mid level lights are not very accurate.
 Cheers 

pthomas745

The Smart Shunt does everything the "712" shunt does.  Once bluetooth became normal on phones, and the Victron Apps became popular, the 712 display,  and the issue of how to run wires to the display, cut holes for the display, and....have to get up to look at the display....made the display a bit redundant.  So, the Smart Shunt will save you money and the work of the display install.

If you have factory installed solar: you have access to the Victron App that will provide monitoring of the solar input, and the battery voltage.  The Smart Shunt is a nice step up, giving you access to the actual amp hours consumed.  The two apps will work in tandem to help you monitor your system.

Temp sensors for the lithiums:  a sensor might be interesting, but what you really need to know is: does your lithium batteries have a temperature sensor that stops charging when the temperature is below freezing?  The temp sensor would either be part of the battery management system.  If they do, then the Victron temp monitor may also be redundant.  If your batteries are already inside, the temp monitor won't really tell you a whole lot. 

We have several threads on the lithium batteries and the "need" to pay several hundred dollars, plus the install cost, for a converter that provides a "full" charge on a lithium battery.  If you boondock often, and have the factory installed solar with the Victron controller, that setup will completely charge your lithium batteries.  There is no real reason to swap out the converter in that case.  Your solar will do a complete charge.  If you are not on the road, a regular battery charger will put a complete charge on your batteries.

The best thing on your list to have would be the either one of the shunts. 

Dutch061

I would suggest larger than 8-gauge wiring between your batteries and the switch since you will be using the WFCO Converter (upgraded). It is possible that it will work with 8-gauge, the test would be to see if it indeed can deliver 50 Amps to the batteries which you can monitor via the shunt. Main reason I am suggesting larger wire is in reference to the Airstream bulletin and their steps for upgrading grounds to prevent corrosion. I have made posts regarding the corrosion, which also has a copy of the Airstream bulletin. 

I went with a Progressive Dynamics model 9160ALV in our 400 and installed it inches away from the battery junction block under the bed. I done this to make sure that the 8-gauge wiring wasn't a restriction of any kind in my effort to charge the batteries. I can get the full 60 Amps through the shunt, so I am very happy with that. 

Battleborn Batteries have both a low temperature charge protection AND a low temperature discharge prevention built into the BMS. They (BB) cost more upfront but in my opinion, they are worth it, I have 4 of them. There are lots of other choices and I encourage everyone to investigate and make decisions based on their style of camping and budget. I would NEVER suggest someone adding things that are put on a credit card and not paid off at the end of the month! 

With that said, having the temperature senser for additional protection is not a bad idea, they are a minimum investment compared to the rest of what you are doing or have done already. I have one and if nothing else it has given me great peace of mind knowing that I can see what the temperature is in my battery compartment under the bed. 

As far as the OEM installed LEDs for battery SOC, they are set for the voltages of AGM or SLA batteries and are of ZERO value with Lithium. 

Brad

Marceline

Maxcamp8 said:

To have a reasonably accurate meter of charge state I’d appreciate some guidance.   Are these appropriate?

2. Victron Energy BMV-712 Smart Battery Monitor (Grey)

www.amazon.com/dp/B075RTSTKS

This seems to be the higher end version with display, the Smart Shunt appears to be the lower end version without display.

The BMV-712 and the SmartShunt are functionally identical. The only difference is the display. I got the SmartShunt because I didn't want to have to run the wiring for the display. 

Maxcamp

Great info thanks all.  Battleborn will be responding to me as well separately.

WildBill442

Great Thread, thank you all.  We have a new TAB400 due to arrive in late April and we are trying to lay out our first upgrade plan.  I have reviewed many posts here and on the NuCamp related Facebook pages.  It is a little tricky to ferret out the specifics of the 2022 units vs prior, but I think I have a grasp of the basics.  Here is what I think I need to do.  I added this here as it parallels the original post so closely.  Your comments are greatly appreciated.

1. Swap in 2 100Ah Battleborn batteries to get to lithium/ better capacity utilization.  I believe the GC2 form factor is the appropriate drop in for the AGM's as delivered with the 400.
2. It is my understanding that the 2022 converter is lithium compatible as delivered, and only requires flipping the "little white switch".
3. It is my understanding the the Victron Solar Charge Controller as delivered is nearly maxed out (amperage) by the factory installed roof-mounted solar panel.  To make use of any meaningful solar capacity add-on, an additional Victron solar charge controller should be installed and connected to the solar accessory port. 
4.  To have a reliable measurement of battery status, a Battery Monitor should be installed.  The Victron Smart Shunt  seems to be the unit of choice as the display unit is redundant given the features of the app that can interface to either, and to the solar charge controller.

Denny16

Sounds like you got it in one.  Happy trails and stay safe.
 Cheers 

Horigan

@WildBill442, Regarding the solar controller capacity.  Most supplemental solar panels include the solar controller, so what is plugged into the solar port is already adjusted to directly charge the battery.  I would confirm your solar port wiring is connected straight to the battery, verses to the solar input of the Victron controller.  I would be surprised if it's not connected directly to the battery.

tphaggerty

Actually, you can go with standard, not GC, battery form. The only real reason to go with the GC format is if you are going to use solid bus bars instead of battery cables to connect the batteries. The 6V AGM “GC” batteries that nuCamp installs, at least in my 2018 400, look just like regular 12V batteries. That will save you about $100 per battery. 

I used standard format Renogy lithium batteries and they fit fine - the new Renogys were a bit wider (longest measure) and a bit shallower than the nuCamp AGMs. Battleborns are almost the exact same size as the AGMs.

I would open up the battery compartment and measure the batteries before ordering. To be honest, I wouldn’t spend the money until you have done a few outings first. I think lithium is great, but, IMO, you only need them if you consistently hit 50% or more usage on the AGMs, which we do camping in the NE for 4 or more days at a time. Awesome for boondocking, overkill for weekend trips (again, in my opinion/experience).

Maxcamp

Battleborn called us back with recommendations as follows for our pair of 100ah Battleborn batteries having battery heaters for low temp charging.

1a. Contrary to Nucamp advice, do not upgrade the Wefco converter element of the power station to the newer Wefco lithium-switched model.  It would undercharge at 13.6v, without battery balancing, versus higher charge needed for Battleborn to trigger battery balancing.

1b.  Buy the Progressive Dynamics PD4135K 35 amp Power Control Center (from etrailer, others).  It looks like this is a swap out of the entire unit, not just the converter.  So possibly a lot more wiring.  Don't know until we see it.  Don't know if the circuit breakers and automotive fuses are a one for one swap or if need variants as well.

2. for charge monitoring, the Victron BMV-712 has the digital readout we desire and also bluetooth monitoring.  Yes the bluetooth Smartshunt would also work and be cheaper.

3. temperature monitoring option not needed, the battery heaters obviate.

4. no specific recommendations on wire (awg/kcmil) size.  Right now everything is no.10. The NEC tables for 120/240v amp/wire size don't necessarily apply at 14.xx volts.

5. Inquired about on-board 120v to 12v inverter, our 2021 320S does not appear to have one despite a Nucamp telecom indicating we did!  ("some do, some don;t" ... they don't have a record of what they built?.  No 120v power at any outlet when not on landside or generator power.)  For the modest medical heating pad we need they suggested just using an inverter that plugs into the cigarette lighter rather than hard-wiring something.

6. Battleborn indicated the factory Victron solar charge controller is maxed out with the factory 105 watt panel, if we add suitcase solar we would need to upgrade it.  Did not write down model as not much solar availability in new england camping and will hold off on this.  HOWEVER the settings need to be CHANGED to accommodate the higher Battleborn charge.  They emailed instructions that vary depending on whether the version onboard has bluetooth access or has dip-switches.  Again, NuCamp could not tell us what they installed.

Components arriving this weekend but waiting for the latest 12" of snow and ice to melt off (and less mud...) before taking our near-new trailer out of covered storage even temporarily.   

I must say, I find NuCamp lack of documentation truly dismaying.  Forensic investigations to determine what we bought and how it is to be used, adjusted, or drained should not be required!  That said, they have been readily available and attempted to be helpful during calls on our inaugural trip.  

pthomas745

If you add an extra solar "suit case", panel, you would just add a panel that has a lithium capable solar controller.  No need to change your Victron controller out.

The 400's have installed inverters.  The 320's do not.  Many owners have installed their own inverters in the 320.  There may be just a bit of errors in translation here. I use "portable" inverters plugged into the 12V ports for many small jobs.

And: I have a small heating pad, and a "warming blanket".  I have never been able to make these work on any inverter I have tried.  ( I have three different sizes).  I haven't tried them on a big inverter wired directly to the battery.  There is something about the electronic controllers in the blankets that do not mix well with the inverters.  (I'm a bit vague on the real reason, though.)

VictoriaP

pthomas745 said:

And: I have a small heating pad, and a "warming blanket".  I have never been able to make these work on any inverter I have tried.  ( I have three different sizes).  I haven't tried them on a big inverter wired directly to the battery.  There is something about the electronic controllers in the blankets that do not mix well with the inverters.  (I'm a bit vague on the real reason, though.)

I wonder why? I’ve had no trouble running a 140 watt heating pad on a Jackery or Goal Zero, in both cases using their onboard inverters. Haven’t tried a portable inverter on the Tab yet though.

pthomas745

I honestly don't know. When I plug the pads/blanket into a Kill A Watt power meter on a 110V outlet at home, the power draw is not too high (70 watts?) but, the draw is not steady.  For example, it constantly cycles from 70w to 10w to 5W back to 70W.  Continuously .  I expected a gradual power draw until they reached a certain temperature, and then move to a more "steady" draw.  The smaller inverters (one a pure sine wave) just were unable to keep up, and shut down after just a couple of minutes.  I think an inverter drawing directly from the battery (like your Jackery/Goal Zero) is much better at keeping up with the wattage changes. 

I will also be replacing my 12V sockets here in a day or so.  Maybe that was the weak link?

Denny16

Thomas, the Victron solar controller has a blue tooth app available, which allows setting changes to the controller for lithium batteries.  The app runs on most smart phones.
 Cheers 

Dutch061

Maxcamp8 said:

Battleborn called us back with recommendations as follows for our pair of 100ah Battleborn batteries having battery heaters for low temp charging.

1a. Contrary to Nucamp advice, do not upgrade the Wefco converter element of the power station to the newer Wefco lithium-switched model.  It would undercharge at 13.6v, without battery balancing, versus higher charge needed for Battleborn to trigger battery balancing.

1b.  Buy the Progressive Dynamics PD4135K 35 amp Power Control Center (from etrailer, others).  It looks like this is a swap out of the entire unit, not just the converter.  So possibly a lot more wiring.  Don't know until we see it.  Don't know if the circuit breakers and automotive fuses are a one for one swap or if need variants as well.

2. for charge monitoring, the Victron BMV-712 has the digital readout we desire and also bluetooth monitoring.  Yes the bluetooth Smartshunt would also work and be cheaper.

3. temperature monitoring option not needed, the battery heaters obviate.

4. no specific recommendations on wire (awg/kcmil) size.  Right now everything is no.10. The NEC tables for 120/240v amp/wire size don't necessarily apply at 14.xx volts.

5. Inquired about on-board 120v to 12v inverter, our 2021 320S does not appear to have one despite a Nucamp telecom indicating we did!  ("some do, some don;t" ... they don't have a record of what they built?.  No 120v power at any outlet when not on landside or generator power.)  For the modest medical heating pad we need they suggested just using an inverter that plugs into the cigarette lighter rather than hard-wiring something.

6. Battleborn indicated the factory Victron solar charge controller is maxed out with the factory 105 watt panel, if we add suitcase solar we would need to upgrade it.  Did not write down model as not much solar availability in new england camping and will hold off on this.  HOWEVER the settings need to be CHANGED to accommodate the higher Battleborn charge.  They emailed instructions that vary depending on whether the version onboard has bluetooth access or has dip-switches.  Again, NuCamp could not tell us what they installed.

Components arriving this weekend but waiting for the latest 12" of snow and ice to melt off (and less mud...) before taking our near-new trailer out of covered storage even temporarily.   

I must say, I find NuCamp lack of documentation truly dismaying.  Forensic investigations to determine what we bought and how it is to be used, adjusted, or drained should not be required!  That said, they have been readily available and attempted to be helpful during calls on our inaugural trip.  

1A. The issue that you would continue to have if you were to upgrade the converter alone in the WFCO PDC (Power Distribution Center) is the gauge of wiring between it and the batteries. The Converter would not work properly based on my testing. 

1B. This is a self-contained unit in an enclosure and will accept up to 4-gauge (on the PD9160ALV anyway) cables. It is a converter only, so you remove the OEM WFCO Converter, it is 2 screws and 5 wires. This makes for a much cleaner install and most importantly it will allow max charging. BTW, you could use a 60 Amp also with 2 batteries if you were so inclined. It all depends on how long you want to take to recharge and what you will use.

2. I used a BMV-712 and finally installed the gauge this past winter so I could see it. Either one will work for you, but I like the idea of a backup plan with the gauge.

3. This is a loaded comment, only because it depends on where the batteries are installed. If you are installing them inside, I would add the temperature probe for $30 and use standard non-heated batteries from BB.

4. I am attaching a chart for reference. 

5. As @pthomas745 already said, no inverter on 320's

6. Not sure which controller they use on a 320, our 400 BDL has a 75/15, which means a maximum of 75 volts and up to 15 Amps. NuCamp installs a "Smart Controller", which means it is Bluetooth equipped and you can use the Victron App to connect to it. Setup is very simple.

I have been down this road all the way, having installed 4 x BB's, Converter, etc. Please send me a message if you have questions, I am glad to help.

Brad 

Denny16

The 320s normally have a Victron 75/10 Controller installed by the factory, as the solar panel is smaller.  Controller’s are size by the watt output of the solar panels being used.  According to Victron, the 75/10 is good for up to a 100-watt solar panel.  The 75-15 is rated for 200 watts.
 Cheers 

Maxcamp

Very grateful for all your experiences and comments.  The learning curve on MEP upgrades the first time is steep, the second time around often goes better. 
Will have to test the Sunbeam heating pad on my truck 12v outlet before starting; maybe we do want a hardwired inverter.  Glad Dutch061 flagged this potential issue!

Ordering some terminal blocks for a cleaner setup more conducive to re-wire for the inevitable future changeup /upgrade.  Trying not to overbuy on components, and test and harden systems in the yard before hitting the trail.  [Of course, we could not have anticipated the factory e-brake wires would be improperly designed/installed and rub on the tyre on bumps only and fail at 12000 feet at 4F temp.  But that is a separate post.]

Bayliss

@Dutch061 and @Maxcamp8, I want to upgrade my (WFCO 8735P) 35-amp power center/converter so that it is compatible with charging a lithium battery (specifically, a 100 Ah Battleborn.)  Since the Progressive Dynamics PD4135K contains the converter only, am I correct in assuming that you simply transfer the AC breakers and wiring from the WFCO case to the Progressive Dynamics case?  (That appears to be all that is necessary based on what I have read.)  Thanks!

Dutch061

From what I have been able to decipher, it appears that this is an entire Power Distribution Center (PDC), which includes all of the AC and DC components. You would still have to remove all of the wiring and reconnect etc. 

I would reach out to WFCO and Progressive Dynamics both to see if they offer just a replacement converter that you could swap out instead of changing the entire PDC. If so, that would be the simplest, removing 5 wires (2 DC and 3 AC) and 2 screws. 

If that is not an option, alternately you could install a PD9130LV separately from the PDC and remove the WFCO Converter. If you were to do this, you could actually use a PD9145ALV and reduce the charge time further. You could install a 120 VAC outlet in place of where the OEM converter was wired in and use a couple of short lengths of wire (8-gauge minimum but suggest 6-gauge) to connect the DC output back to the PDC.

Brad

Bayliss

Thanks, @Dutch061.  Looking at the PD4135K on etrailer.com, it appears that it only has the DC connections and that you have to supply the AC side of it.  I don't have a problem with doing that, but I will also explore the other options you suggested.

Maxcamp

So I'm at phase two of this upgrade now.  Two 100ah battleborns on passenger side wheelwell working well for us, 4-5 days boondocking in the shade without plug-in power leaves us at 30-40% power.  Biggest draw down is a few hours per night use of a 120v 500w plug-in inverter* Sunbeam heating pad.  Can watch the %SOC go down 1% every 7-10 minutes of use.  (*Best Tek 500w pure sine wave inverter, MRZ50-11BU.)  Heating pad does not heat up as well on inverter, compared to normal socket.

Appalachians/Canadian maritimes camping is iffy for solar- heavily treed and limited sun.  That said, ready to add a solar suitcase and 20-ft or longer 10awg umbilical to the mix. 

A 200w Rhenology suitcase comes with a decent 20a controller.  Following @SLJ example I would relocate the controller close to the batteries under the passenger side.  An intriguing 300w off-brand suitcase comes with a deficient controller that reviewers recommend replacing.  Hence the idea of going with a 30a or 50a Victron MPPT that I can monitor with the Victron smart phone App.

Can I replace the existing MPPT controller with a larger one and wire BOTH the suitcase and TAB rooftop solar to it or does each solar panel need it's own controller?

RTWCTS

Maxcamp8 said:

Can I replace the existing MPPT controller with a larger one and wire BOTH the suitcase and TAB rooftop solar to it or does each solar panel need it's own controller?

I think the problem you'd run in to is matching specs on the rooftop solar and the briefcase. Putting mismatched panels on the same controller would result in less performance (as I understand it all). I added a second Victron controller for our 'ground array' solar, accessable through the passenger side door.

Edit to add: We went with a 30A controller because we own a bunch (400W worth) of briefcase panels...ready for zombie apocalypse

Also, if you go with all Victron components you can sync them all in the App. The MPPTs will get data from the Smartshunt. This is good because the shunt is closer to the battery and gets more accurate measurements (it still all works if not synced though).

elbolillo

We also went with the 100/30 Solar charger. However, I ran it out into the Nautilus space. This way I can run the wire out through the bottom hole in the cabinet and the door can remain closed.

Hammick

There is actually a benefit to having a converter that won't fully charge your Lithium batteries.  They will last longer if not charging to 100%.  You can charge them to 100% with solar or a separate charger as others have mentioned.  I like to be able to change the charging voltages so when we get a TAB 400 we will be installing the Victron Multiplus.

Marceline

Maxcamp8 said:

So I'm at phase two of this upgrade now.  Two 100ah battleborns on passenger side wheelwell working well for us, 4-5 days boondocking in the shade without plug-in power leaves us at 30-40% power.  Biggest draw down is a few hours per night use of a 120v 500w plug-in inverter* Sunbeam heating pad.  Can watch the %SOC go down 1% every 7-10 minutes of use.  (*Best Tek 500w pure sine wave inverter, MRZ50-11BU.)  Heating pad does not heat up as well on inverter, compared to normal socket.

If you're using the heating pad to warm up your bed, have you considered using an old-school hot water bottle instead? 

elbolillo

Hammick said:

There is actually a benefit to having a converter that won't fully charge your Lithium batteries.  They will last longer if not charging to 100%.  You can charge them to 100% with solar or a separate charger as others have mentioned.  I like to be able to change the charging voltages so when we get a TAB 400 we will be installing the Victron Multiplus.

Actually that is not correct. LiFePO4 batteries need to be charged to 100% and maintain an absorption charge to allow the batteries to balance correctly.

Hammick

elbolillo said:

Hammick said:

There is actually a benefit to having a converter that won't fully charge your Lithium batteries.  They will last longer if not charging to 100%.  You can charge them to 100% with solar or a separate charger as others have mentioned.  I like to be able to change the charging voltages so when we get a TAB 400 we will be installing the Victron Multiplus.

Actually that is not correct. LiFePO4 batteries need to be charged to 100% and maintain an absorption charge to allow the batteries to balance correctly.

elbolillo said:

Hammick said:

There is actually a benefit to having a converter that won't fully charge your Lithium batteries.  They will last longer if not charging to 100%.  You can charge them to 100% with solar or a separate charger as others have mentioned.  I like to be able to change the charging voltages so when we get a TAB 400 we will be installing the Victron Multiplus.

Actually that is not correct. LiFePO4 batteries need to be charged to 100% and maintain an absorption charge to allow the batteries to balance correctly.

If you charge your LifeP04 batteries to 100% on a regular basis they won't last as long.  If you don't need all the capacity best to lower the charge voltage.  If you need the capacity then by all means charge to 100%.

You are correct the BMS won't balance the cells until they are close to fully charged.  Most BMS's will turn on balancing at 3.4 vpc which is 13.6 volts for a 12v LifeP04.

An absorption charge for  LifeP04 is not needed.  Just bulk.  You will also want a float voltage if you have loads on the batteries.  When we are at our offgrid place (48v 280ah LifeP04 battery bank) I set the bulk to 54.4v, absorb to 54.4v (one minute absorb time) and float to 54v.  When the place is vacant with light loads I lower both the bulk and float to a setting below 54v.  This changes based upon the weather and proximity to winter solstice.  I don't like them sitting above 80% when we aren't there unless I know cloudy weather or snow is setting in for a few days.  They get balanced out when we are using the place.

It is not harmful if they get out of balance.  Grade A cells that have been matched should go a long time at lower voltages without getting out of balance.  You would probably be fine charging to 100% just a few times a year.  Charging to 100% will synchronize your shunt based battery monitor if you have one.

This is the exact same reason why cell phones that constantly charge to 100% have their battery degrade faster.

Maxcamp

@Marceline, the hot water bottles sound like a great idea the next time I camp without the wife!
Heating pad is for my back as spinal debility takes over from a career in Construction.

All, thank you for the inputs and ideas.  Will go with separate Victron MPPT and a through-wall female 
Anderson RV outlet with cover.  Leaning towards the name-brand 200w suitcase solar.

Phase Three is upgrading the vehicular charge system with a DC to DC charger from the new truck.
Rare to see any electrical hookups at our preferred campsites, and those sites that have them are usually taken already.
1. Add two multi-terminal blocks, substitute switchable 30A circuit breakers for the inline Maxi fuses I used.
2. Renology (or Victron) 30A DC to DC converter, close to batteries, 8awg output 6awg input from truck per their tables (30-40 ft routing)
3. Battery Isolator Relay (Blue Sea SI-ACR) close to batteries, 6awg positive
4. Anderson fem. outlets at TV bumper and T@B front box, 6awg male umbilical between when towing
5. 6awg homerun from TV battery, 1" heater hose protected, and pair 60A inline switchable breakers. 
Oh boy, more crawling under the truck and trailer!

Looking into various battery terminal mount options to reduce battery-top clutter and give me room for battery kill switches to use when parked at trailheads.  These newfangled vehicle key codes can be duplicated when live?  Truck tailgates are being stolen?  Good grief.  Something to be said for a rustbucket as deterrant.

Still contemplating a Phase Four upgrade to 3000w inverter and 400ah of Battleborns to run microwave and A/C, but the kitty is bare after buying my duodecennial (12-year) vehicle upgrade.  We have a Ryobi 1800w generator that can do both and never use it, too noisy.

Last fall we think we finally achieved more hours actually camping than hours working on camper and truck systems starting in fall 2021.   From NuCamp outright defects to Marmots eating wires to optional upgrades, been quite a ride.

elbolillo

Hammick said:

elbolillo said:

Hammick said:

There is actually a benefit to having a converter that won't fully charge your Lithium batteries.  They will last longer if not charging to 100%.  You can charge them to 100% with solar or a separate charger as others have mentioned.  I like to be able to change the charging voltages so when we get a TAB 400 we will be installing the Victron Multiplus.

Actually that is not correct. LiFePO4 batteries need to be charged to 100% and maintain an absorption charge to allow the batteries to balance correctly.

elbolillo said:

Hammick said:

There is actually a benefit to having a converter that won't fully charge your Lithium batteries.  They will last longer if not charging to 100%.  You can charge them to 100% with solar or a separate charger as others have mentioned.  I like to be able to change the charging voltages so when we get a TAB 400 we will be installing the Victron Multiplus.

Actually that is not correct. LiFePO4 batteries need to be charged to 100% and maintain an absorption charge to allow the batteries to balance correctly.

If you charge your LifeP04 batteries to 100% on a regular basis they won't last as long.  If you don't need all the capacity best to lower the charge voltage.  If you need the capacity then by all means charge to 100%.

You are correct the BMS won't balance the cells until they are close to fully charged.  Most BMS's will turn on balancing at 3.4 vpc which is 13.6 volts for a 12v LifeP04.

An absorption charge for  LifeP04 is not needed.  Just bulk.  You will also want a float voltage if you have loads on the batteries.  When we are at our offgrid place (48v 280ah LifeP04 battery bank) I set the bulk to 54.4v, absorb to 54.4v (one minute absorb time) and float to 54v.  When the place is vacant with light loads I lower both the bulk and float to a setting below 54v.  This changes based upon the weather and proximity to winter solstice.  I don't like them sitting above 80% when we aren't there unless I know cloudy weather or snow is setting in for a few days.  They get balanced out when we are using the place.

It is not harmful if they get out of balance.  Grade A cells that have been matched should go a long time at lower voltages without getting out of balance.  You would probably be fine charging to 100% just a few times a year.  Charging to 100% will synchronize your shunt based battery monitor if you have one.

This is the exact same reason why cell phones that constantly charge to 100% have their battery degrade faster.

The 12V Battle Born Batteries sit comfortably right in the middle of these ranges. We recommend a bulk and absorption voltage of 14.4 V. A float is unnecessary since lithium-ion batteries do not leak charge, but a floating voltage under 13.6 V is fine. 

elbolillo

If you were to fully charge and discharge your Battle Born Batteries every day, they would last you between 10 and 15 years. With a 10-year warranty, our lithium batteries will keep you powered for years to come.