FWC Electrical basics and upgrading to lithium!

[Karlton]

What a great topic and discussion! I think my AGM batteries are finally on the way out. And I say finally because I am running the original batteries in my 2017 Hawk making them about 6 years old. I'm going to consult this thread as I switch over to lithium this fall. I'll probably have questions about what to do with the Victron BVM, but I'll search around prior to posting.

 

[Vic Harder]

What a great topic and discussion! I think my AGM batteries are finally on the way out. And I say finally because I am running the original batteries in my 2017 Hawk making them about 6 years old. I'm going to consult this thread as I switch over to lithium this fall. I'll probably have questions about what to do with the Victron BVM, but I'll search around prior to posting.

Do post questions! The big thing about the BVM (or any shunt) is to ensure that ALL grounds go to the shunt (or a buss bar first) and ONLY the -ve battery post is connected to the other end of the shunt.

 

[Karlton]

Thanks, Vic. You were very helpful when I set up my solar and BVM a few years ago and it was great to see your comments in this thread.

Cheers

 

[Vic Harder]

;-)

 

[Shelbdad]

I'm preparing to make my journey down at least some part of this rabbit hole, and have really appreciated all the great questions and feedback on this forum. I'm second owner of 2013 Hawk and surprisingly just now seeing very poor battery performance from my two AGM's (assume they are original, sticker says delivered March 2013!). Until diving into the several related threads on this forum, I had no clue that I should have been actively managing the batteries. Obviously things must have gone mostly ok, given that we've been fairly active in use of our FWC and just now are having degraded conditions reaching a point of needing to do something about it. My guess is the solar system must have been the primary reason the original batteries have held on for so long (especially here in sunny SW Colorado). So what I have is what appear to be two 75 AH AGM batteries, a Blue Sky Solar Boost 2000E 25 amp MPPT Controller fed from what I'm pretty sure is 120W solar panel. An Iota Power Converter DLS 30 with IQ4 (very seldom use shore power). When I started having indications of low battery performance, I was a bit puzzled why this would be the situation given that I thought it was getting power from my truck while on the road (some initial issues cropped up during an extended road trip to Baja). I initially thought I might have a bad SurePower 1314 isolator and was ready to replace that when I realized that the ground connection was attached to the wrong connector, and when I properly connected it, heard then solenoid engage, and confirmed with voltmeter that the isolator was seeing truck batter voltage.

So thinking that might have solved some part of the problem, the good folks on this forum have me understanding that the factory wiring is likely under-sized, so charging from the truck (06 Tundra, not smart alternator) is probably not really a winning proposition. Now I'm realizing that my first stop is to get a proper battery monitor so I can understand what is truly going on with the various components, etc. Seems there is very strong support here for the Victron BMV 712 Smart (with Bluetooth). Since my Blue Sky gives me visual voltage display, I'm looking hard at the Victron SmartShunt (https://www.victronenergy.com/battery-monitors/smart-battery-shunt). It seems to do everything the BMV 712 does, except without a display/ability to program from the display. Given it has bluetooth capabilities, I don't see this as a drawback and there seems to be a pretty reduced cost. Curious to know if anybody has check into this or use the SmartShunt? It's pretty clear to me that the battery monitor is something that I really should be using to get a better picture of what's going on with the battery/power system. Where I go next, I'm not exactly sure. I like the idea of going down the Lithium route given the reduced weight and what appears to be superior performance. However, I'm not sure if it is worth replacing the components I already have that seem to be serving me well so far, but I plan to ring up Blue Sky and talk with them about my solar controller and it's ability to properly charge Lithium batteries. As well as Iota to understand the same thing (though it appears this might be less of a concern based on some of the feedback that I've read here on WTW). Power from my truck may be something worth upgrading (for sure getting properly sized wiring seems to be a no brainer). DC-DC charger seems like a logical piece of equipment, but again, maybe not necessary. Anyway, I'm just now on a path to better understanding this system. I'm intrigued by Lithium, but it seems to me if things are set up well with AGM and I can do better job monitoring/controlling battery charging/status, it probably doesn't make a lot of sense for me to go down the Lithium path. Anyway, I'd appreciate any feedback folks have. Again, I really appreciate this forum and there is a ton of great information. I'm a little slow on the uptake for some of this. Cheers,
Russ

 

[Dipodomys]

... Now I'm realizing that my first stop is to get a proper battery monitor so I can understand what is truly going on with the various components, etc. Seems there is very strong support here for the Victron BMV 712 Smart (with Bluetooth). Since my Blue Sky gives me visual voltage display, I'm looking hard at the Victron SmartShunt (https://www.victronenergy.com/battery-monitors/smart-battery-shunt). It seems to do everything the BMV 712 does, except without a display/ability to program from the display. Given it has bluetooth capabilities, I don't see this as a drawback and there seems to be a pretty reduced cost. Curious to know if anybody has check into this or use the SmartShunt? It's pretty clear to me that the battery monitor is something that I really should be using to get a better picture of what's going on with the battery/power system. Where I go next, I'm not exactly sure. I like the idea of going down the Lithium route given the reduced weight and what appears to be superior performance. However, I'm not sure if it is worth replacing the components I already have that seem to be serving me well so far, but I plan to ring up Blue Sky and talk with them about my solar controller and it's ability to properly charge Lithium batteries....

I'm in pretty much the same position. Original 2x 12v batteries are giving out, so I ordered a new 200 AH lithium battery and I'm figuring out what cascade of other changes that'll require. Here are a couple things I just recently learned, which I don't think have been addressed in this thread yet.

Regarding charge controllers/chargers, they tend to have presets that may or may not be appropriate for whatever battery you get. While a LiFEPO4 cell is chemically the same regardless which brand you choose, there may be significant differences in terms of how the cells are managed by the battery's BMS (battery management system). As a result, I think it's worth diving into the specs for whatever battery you order to see what it wants in terms of 1) bulk/absorption voltage, 2) absorption time, and 3) float voltage. The bulk/absorption voltage is the voltage at which the charger will determine that the battery is "full". Absorption time is how long the charger will hold the batter at that voltage before it stops delivering current to let the battery "relax". Float voltage is the threshold below which the charger will resume charging. You'll also want to look at the specs for your charge controller/charger to see whether it can meet the specifications for the battery.

For example, I ordered a Kilovault 2400 (200 AH) LiFePO4 battery. It wants a bulk/absorption voltage of 14.1 V with an absorption time of < 2 minutes, and a float voltage of 13.4 V (or better yet, 2-stage-no-float). The manual for the Zamp ZS-30A solar charge controller in my 2017 Fleet says that its LiFePO4 setting delivers bulk/absorption 14.4 V and that it switches to float charging after charging current drops to 1 A or the absorption timer times out at 4 hours. Kilovault's technical support confirmed that this could be problematic, and I might be better off with one of the controller's other settings (e.g. gel or AGM). But those settings are also not ideal. So... I ordered a Victron solar charge controller that I know can be programmed to exactly what the battery wants. These batteries are expensive enough that it seems worthwhile to treat them right. On this note, I'll also be disconnecting the existing alternator charging circuit until I can add a programmable DC-DC charger.

As for battery monitors, I'm likely to get a Victron BMV-712, though I'm not sure I need an external shunt monitor. The Kilovault batteries have an internal monitor, which displays on a mobile device via bluetooth.

The last thing I'll add is that when you're looking at batteries, you should consider Kilovault. They didn't popped up in my online research when I started shopping, so I wouldn't have known about them except for a friend's recommendation. This friend is an electrical engineer who spent much of his career working in solar energy and he set up his off-grid home with Kilovault batteries. They're less expensive than brands like Battleborn and Dakota Lithium and they have some great features, like a built-in battery heater, bluetooth monitoring, and the ability to handle more current than competitors. They also have a pretty good warranty.

 

[pvstoy]

I'm preparing to make my journey down at least some part of this rabbit hole, and have really appreciated all the great questions and feedback on this forum. I'm second owner of 2013 Hawk and surprisingly just now seeing very poor battery performance from my two AGM's (assume they are original, sticker says delivered March 2013!). Until diving into the several related threads on this forum, I had no clue that I should have been actively managing the batteries. Obviously things must have gone mostly ok, given that we've been fairly active in use of our FWC and just now are having degraded conditions reaching a point of needing to do something about it. My guess is the solar system must have been the primary reason the original batteries have held on for so long (especially here in sunny SW Colorado). So what I have is what appear to be two 75 AH AGM batteries, a Blue Sky Solar Boost 2000E 25 amp MPPT Controller fed from what I'm pretty sure is 120W solar panel. An Iota Power Converter DLS 30 with IQ4 (very seldom use shore power). When I started having indications of low battery performance, I was a bit puzzled why this would be the situation given that I thought it was getting power from my truck while on the road (some initial issues cropped up during an extended road trip to Baja). I initially thought I might have a bad SurePower 1314 isolator and was ready to replace that when I realized that the ground connection was attached to the wrong connector, and when I properly connected it, heard then solenoid engage, and confirmed with voltmeter that the isolator was seeing truck batter voltage.

So thinking that might have solved some part of the problem, the good folks on this forum have me understanding that the factory wiring is likely under-sized, so charging from the truck (06 Tundra, not smart alternator) is probably not really a winning proposition. Now I'm realizing that my first stop is to get a proper battery monitor so I can understand what is truly going on with the various components, etc. Seems there is very strong support here for the Victron BMV 712 Smart (with Bluetooth). Since my Blue Sky gives me visual voltage display, I'm looking hard at the Victron SmartShunt (https://www.victronenergy.com/battery-monitors/smart-battery-shunt). It seems to do everything the BMV 712 does, except without a display/ability to program from the display. Given it has bluetooth capabilities, I don't see this as a drawback and there seems to be a pretty reduced cost. Curious to know if anybody has check into this or use the SmartShunt? It's pretty clear to me that the battery monitor is something that I really should be using to get a better picture of what's going on with the battery/power system. Where I go next, I'm not exactly sure. I like the idea of going down the Lithium route given the reduced weight and what appears to be superior performance. However, I'm not sure if it is worth replacing the components I already have that seem to be serving me well so far, but I plan to ring up Blue Sky and talk with them about my solar controller and it's ability to properly charge Lithium batteries. As well as Iota to understand the same thing (though it appears this might be less of a concern based on some of the feedback that I've read here on WTW). Power from my truck may be something worth upgrading (for sure getting properly sized wiring seems to be a no brainer). DC-DC charger seems like a logical piece of equipment, but again, maybe not necessary. Anyway, I'm just now on a path to better understanding this system. I'm intrigued by Lithium, but it seems to me if things are set up well with AGM and I can do better job monitoring/controlling battery charging/status, it probably doesn't make a lot of sense for me to go down the Lithium path. Anyway, I'd appreciate any feedback folks have. Again, I really appreciate this forum and there is a ton of great information. I'm a little slow on the uptake for some of this. Cheers,
Russ

Years ago sitting on Wandering Sage back porch we discussed the possibility of changing over to Lithium system. Seems like if your system is working but just the disposable component... the battery... is reached it's end of life, then why change the whole system, just replace the battery and go on with your system. How many years has this been working fine for you?

If the system is not meeting your demands then it is a great time for a upgrade. Upgrade can be replacing parts in the existing system like DCDC truck charging with wire upgrade. Adding a battery monitor or adding solar, or more. So just tweaking the current system.

If you have the time and money and look forward to converting to a lithium system as you look at your future power needs, or just want the latest best products, It would be the time to dive in before paying for a battery replacement twice.

Asking questions and searching out what it would take in time, equipment and money to accomplish the end objective is relatively cost free to plan it out.

My 2015 Hawk Flatbed has the existing 2 AGM batteries (reported that they were not treated well early in life) but they are still doing ok. I plan to just replace the batteries when that time comes with same AGM. Maybe see if next size up would fit in the available space.

In the long run I might benefit from Lithium, but in the short term time and money to go that route is not what I want to spend time and money on when the current system is meeting our needs. For me the freedom to not be concerned with having a lithium battery in extended sub freezing temperatures charging limitations, I'm not ready for that. Sure it is getting better and is easily manageable (Mental road block).
Cheers, Patrick

 

[Vic Harder]

Sounds like two new AGM's and a Victron Shunt are all you need right now, and if your usage patterns don't change, you will get another 5+ years of easy camping. You were doing fine without the alternator (your 1314 wasnt even connected!) so a 6AWG upgrade can likely be put off as well until after you get a baseline with your new batteries and monitor.

"As for battery monitors, I'm likely to get a Victron BMV-712, though I'm not sure I need an external shunt monitor. The Kilovault batteries have an internal monitor, which displays on a mobile device via bluetooth."

The Victron 712 IS a SHUNT based monitor. As is the remote shunt (obviously).

 

[Dipodomys]

"As for battery monitors, I'm likely to get a Victron BMV-712, though I'm not sure I need an external shunt monitor. The Kilovault batteries have an internal monitor, which displays on a mobile device via bluetooth."

The Victron 712 IS a SHUNT based monitor. As is the remote shunt (obviously).

Sorry if I wasn’t clear. I understand that the Victron 712 is a shunt based monitor, as is the monitor that’s built into the Kilovault battery. So I’m just questioning whether those two different shunt based monitors, one internal and one external would be be uselessly redundant or whether I’d get some value out of the Victron that I can’t get out of the battery’s internal monitor. I think the Victron might provide more detailed historical usage stats, and I like having a mounted display rather than relying on my phone or other device.

 

[CreekRob]

I'm not sure the battery monitors are worth it, especially with SLA batteries. I've owned about three brands of coulomb-counting (shunt) monitors, from Victron, Xantrex and can't remember. They're OK, but as the SLAs age and capacity changes you have to recalibrate using the capacity you determine. So it's a guesstimate anyway. I found using voltage and occasionally amps I could monitor it just as well.

Lithium is trickier, since it discharges differently and it's hard to get SOC via voltage. But they don't need minding as closely, since as with your phone the penalty for running them flat isn't the same as with SLA. But YMMV.

The longevity, weight, and faster charging of lithium make them a no brainer IMHO if you have the initial outlay. Better warranties often too. Charging a lead acid is never that efficient using spotty solar and occasional driving; the only way (over 20 years of trying) I could consistently get a real 100% with SLA was 24 hours on shore power.

But now with LiFePO4 I can put back almost 100Ah of power in a few hours of driving in the sun using FWC's Redarc setup. I had previously useed a Kisae DMT1250, which is also a combo controller/B2B unit, and that put even more power in via driving. That means you can get by with less battery capacity in many cases.

I have been very pleased with the Dakota Lithiums FWC uses. Good support. 11 year warranty, and they have internal heating in case one gets below freezing in the camper. I'd recommend them, but not the cheapest.

Good luck with the upgrades.

 

[Dipodomys]

I finally had a chance to see and compare what's available from the shunt-based monitor built in to Kilovault batteries and the Victron BMV-712. The Kilovault monitor does not provide the historical usage stats that the Victron does, but it does provide state of charge (SOC) and information about battery health including estimated capacity and number of cycles.

I prefer the information and the interface of the Victron, and I'll probably install it for that reason, eventually. But I don't think it's really necessary.

 

[cs0430]

I have read about the Victron 712 needing to meet certain criteria before it will reset to 100% SOC. Does that mean it will count "down" as it recognizes output, but despite it registering input coming through the negative terminal it will only show an increased SOC when it reaches 100%?

 

[Vic Harder]

I have read about the Victron 712 needing to meet certain criteria before it will reset to 100% SOC. Does that mean it will count "down" as it recognizes output, but despite it registering input coming through the negative terminal it will only show an increased SOC when it reaches 100%?

Interesting question. Yes, there are criteria. You can even switch off the "reset to 100%" function (I have). And yes, it will count down, and it will register in and out going through the negative terminal and shunt. The SOC reading changes as electrons flow in and/or out.

For example, let's say you have a 100AH battery, and it is presently at 75% SOC, so 75AH remaining. You pull out 25AH to run your fridge for the day, and put in 30AH via solar. At the end of that day, you will be reading 80% SOC. Make sense?

Vic

Vic

 

[cs0430]

Interesting question. Yes, there are criteria. You can even switch off the "reset to 100%" function (I have). And yes, it will count down, and it will register in and out going through the negative terminal and shunt. The SOC reading changes as electrons flow in and/or out.

For example, let's say you have a 100AH battery, and it is presently at 75% SOC, so 75AH remaining. You pull out 25AH to run your fridge for the day, and put in 30AH via solar. At the end of that day, you will be reading 80% SOC. Make sense?

Vic

Vic

Hey Vic! Thanks for responding and providing as much info as you obviously have to this forum. Obviously a newbie here. Long time lurker and we are getting a Hawk shell in Q1-Q2 2024 so lots of questions are starting to come up.

I think I was misunderstanding the "reset" functionality. I read it as if I had a 100ah battery at 75% remaining, used 25% over a day but charged 30% the 712 would show 50% remaining despite actually being 80% full and that it would only increase in % back to full when the battery was charged to 100%.

 

[highseasvelo]

Hi All - Great thread! Recently purchased a 2001 Grandby and have been updating the electric system to lithium. Still have some tidying up on the wires, but we've installed:

• Two LiTime "mini" 100 amp lithium batteries (19 pounds each)
• Renogy 2000 watt inverter/charger (2/0 gage wire to the house bank)
• 100 amp Blue Sea fuse panel (8 position to replace the former 6 position)
• Blue Sea battery switch
• Bus Bars with 2 gage wire to the house bank
• 40 to 200 watt circuit breakers, as identified by the installation manuals
• Victron SmartShunt

Next on the to-do list:

• Connect the inverter to the 110v circuit breaker and add two additional 110v outlets.
• Wire three 100 watt Sun Powered Yachts flexible solar panels and connect to the existing GoPower PWM Solar Charger.

Future list:

• Install a Renogy 60 amp DC to DC charger
• Install a 100/30 Victron MPPT solar charger

Couple of questions for the community at-large:

• Inverter/Charger: I've mounted this 50 pounder to the wall inside of the couch horizontally. I've placed it here to muffle the fan noise and avoid getting damaged by gear if it were mounted to an interior wall. I'm likely going to install vents in the couch if heat becomes an issue. Am I making a mistake for this location or orientation (manual said don't install vertically)?
• Solar: The camper came with a glass 100w panel on the roof with a 30 amp PWM charger. For now I plan on wiring the three flexible panels in parallel and joint them at the 40 amp circuit breaker that connects to the solar charger. With them all in parallel, I'll be around 28 amps peak power. Granted I'm mixing panel types to an old generation controller. Am I making a mistake with this (temporary) approach?
• Any other observations of the install?

Thanks

 

[craig333]

I'm not sure the battery monitors are worth it, especially with SLA batteries. I've owned about three brands of coulomb-counting (shunt) monitors, from Victron, Xantrex and can't remember. They're OK, but as the SLAs age and capacity changes you have to recalibrate using the capacity you determine. So it's a guesstimate anyway. I found using voltage and occasionally amps I could monitor it just as well.

Lithium is trickier, since it discharges differently and it's hard to get SOC via voltage. But they don't need minding as closely, since as with your phone the penalty for running them flat isn't the same as with SLA. But YMMV.

The longevity, weight, and faster charging of lithium make them a no brainer IMHO if you have the initial outlay. Better warranties often too. Charging a lead acid is never that efficient using spotty solar and occasional driving; the only way (over 20 years of trying) I could consistently get a real 100% with SLA was 24 hours on shore power.

But now with LiFePO4 I can put back almost 100Ah of power in a few hours of driving in the sun using FWC's Redarc setup. I had previously useed a Kisae DMT1250, which is also a combo controller/B2B unit, and that put even more power in via driving. That means you can get by with less battery capacity in many cases.

I have been very pleased with the Dakota Lithiums FWC uses. Good support. 11 year warranty, and they have internal heating in case one gets below freezing in the camper. I'd recommend them, but not the cheapest.

Good luck with the upgrades.

I never had an issue with solar charging my batteries to 100% with only a few hours. Even using shore power only required a couple of hours. What kind of batteries were using?

 

[ridinlarge10]

Hi everybody! New user here but long time lurker for good information. I used this and many other discussions on this site to educate myself on the electrical system in my 2021 Grandby as well as on lithium battery installs and component upgrades.

I recently installed two dakota lithium 135 AH batteries into the factory location of my camper, battery compartment on the left just inside the rear door. They are slightly smaller than the factory batteries and fit in there very well. Using information I got from here I purchased a victron bluetooth dongle and installed it into my overland solar 100/15 mppt in place of the cable running to the circular screen mounted in the cabinet face. I was able to hook up using the Victron app on my phone, update the firmware of the mppt, and update the settings for lithium batteries. Dakota Lithium tech support was very helpful with me in ensuring all the settings were correct for their batteries.

I also removed the factory circular mppt screen/controller in the side of my cabinet and replaced it with a victron bmv 712 battery monitoring system. The two screens are exactly the same size. I installed the shunt that came with the bmv 712 in my existing battery compartment. By taking the doors off of the cabinets and drilling one small hole from the battery compartment up through the bottom of the compartment above it I was able to snake the data cable up through it and under the stove top, on top/behind the heater, and down to the monitor screen by following the path of factory wires, lines, etc. I have large hands so it was tight but very do able for the diy'er.

With the Victron App this worked amazingly, and was the simplest set up I could come up with for my existing setup and was done in half a day. Just got back from a 10 day baja trip and this worked great for us the whole time. I have the largest 130L fridge that is two way and our older AGM batteries were toast before, dieing with just minimal light useage. I have the 160 panel on the roof. I also have the overland solar bugout flexible panel for more options with forest/camp charging when parking is not ideal for maximizing solar charge.

I was crunched for time before the trip so I did not tackle the wiring upgrade or a DC/DC converter to maximize alternator charging but will likely do that at some point in the future. I found that i did not need it with my battery capacity and drive time for this trip. I do not have a smart alternator but dakota lithiums tech support told me that even if i did their batteries with the bms were fine this way.

The dakota lithium batteries were not cheap but they have an 11 year warranty, have an internal battery management system with temperature regulation, and the 135Ah batteries have the capabilities of automotive use so no issues with direct alternator charging.

All said the battery upgrades and system components cost around $3000 and more than exceeded my expectations and our electrical use.

I am no expert on any of this, in fact, I am extremely thankful for the experts in here that helped me understand the systems and components involved with our campers! Thank you all for your time and information! I felt compelled to write this in hopes that it will help someone in the future who was struggling with the process as I was. I am sure there are better/more efficient ways, but this works, so I wanted to pass it on, because it was relatively simple and easy.

Thanks again! Hope this helps someone, somewhere in the future!

Happy Camping,
D

 

[J D]

For the Victron Orion 12/12-30A charger, I do want the "isolated" version don't I?

 

[Vic Harder]

For the Victron Orion 12/12-30A charger, I do want the "isolated" version don't I?

Not necessary. You will wind up bypassing the "isolation" anyway. Isolated is intended for marine applications.

 

[J D]

Thanks Vic, much appreciated.