Does bluetooth work in an aluminum camper? Victron vs. Renogy

[RV Squirrel]

Merlin,
I saw your response just as I was about to respond to David. In the interest of time, I'm going to post my response and then read yours.  I hope that this does not seem inappropriate, but it takes me awhile to digest the good info in these posts!

David,
Thanks for the advice on solid copper wire.  BatteryCablesUSA.com seems like a good resource if I  choose to by pre-made cables. 

Victron recommends the use of "multi-stranded" cable (see picture).  I know what stranded is... but do not know if "multi-stranded" is an industry term, or if there is a better term to search for.

I've posted questions about extra fuses/circuit breakers to Victron, but I'm not quite able to understand the answers.  I think that they may be in Dutch.  Here are the questions and the answers.  Maybe you can help me understand them...

Orion (DC2DC)

Question 1) I have a travel travel that I pull with a tow vehicle. I plan to put the Orion-Tr Smart in the trailer, and have it powered with the 12V from the 7-pin connector on the trailer hitch. Do I need a fuse on the input side of the Orion? Or would this be redundant with the fuse for the 7-pin connector in the tow vehicle (presumably 30A)?

Question 2) My batteries are already protected by a circuit breaker (placed near the batteries) that is appropriately sized for the gauge/length of the cable. Would it hurt to have an additional breaker on the output of the Orion? Should this second breaker be sized to the device (18A) or to the cable (which is already protected at 80A at the battery)?

Answer) I would fuse near the source as well. An short whether before or after the charger and batteries as well as vehicle electrical system needs to have some protection.

BlueSolar (MPPT)

Question 3) Do I need a fuse on the input side of the Bluesolar? Other vendors recommend this, but I don't see it in the Bluesolar user manual.
Answer) Solar panels need some sort of disconnect between panels and mppt as they should never be disconnected under load.

I admit that I'm confused by this last response. They have said that there should be a disconnect between the panels and the MPPT, but then they say that the panels should not be disconnected under load. Presumably, a fuse or circuit breaker would break the circuit when it is under load.

[DavidM]

I missed what looks like a 1, 2, all switch at the battery. Merlin is exactly right- do not switch batteries. Always keep both hooked up

I know I argued earlier that you may not need it due to voltage drop, but unless you test it with the TV engine running at various rpms, I would keep the DC2DC charger as otherwise the circuit could draw more than 30 amps and blow the TV fuse.

So, when do you start buying and installing components?

David

[RV Squirrel]

A new commandment:  "Thou shalt not connect in reverse polarity." 

I guess the idea of the 1-2 switch would be to have the ability to independently measure the voltages of both batteries.  This would be done to make sure that they were at the same voltage.  If they are connected together, then you can't measure the voltage independently of each other unless you manually disconnect them.  I was hoping to avoid that if I could.

Yes... my system has MC4 connectors, and I've been using connectors such as you have linked to gang the inputs together. I've recently learned that there is a limit to the current that can go through them, but I've even more recently forgotten what the limit actually is.  I should be okay with four panels though.

The TV will also serve as another source of power in the event that I'm away from shore power and don't want to (or can't) set up solar panels.  I think that I still need the DC2DC to compensate for voltage drop on the 10AWG cable from the TV, so that I know that I'm getting at least 14.4V to the lithium batteries.  I don't think that they would charge much with just 13V.  The DC2DC will also moderate the amount of current that is being sucked in from the alternator to the low resistance lithium batteries. 

I like data too, and may ultimately move to the Victron battery monitor.  Right now, I have an amp-hour/battery meter that seems to work, so I'll stick with it.  Do the small buttons on the BMV-702 ever wear out?

The sleep mode is not just with Battle Borns... I think that it may be with other lithium batteries as well.  I think that the idea is to prevent over-discharge.  Getting back out of it is a problem, because the BMS may keep any voltage from appearing at the battery terminals.  Any "auto-sensing" 12/24V charger won't see any charge and will think that it is not connected to anything.  Therefore, it's sometimes necessary to present another source of 12V to dupe the charger into thinking that it is actually connected to a 12V battery.

The AC2DC supplies 45A, but the DC2DC that I'm looking at only does 18A.  I think that I'll stick with a direct connection to that and get faster charging.  Also, that means that my DC2DC won't be on to broadcast BT... I wish there was a way to turn BT off when I wasn't using it on this device.  If it weren't for these things, I would consider routing all DC power through the DC2DC.

I wonder about the 14.6V output on the Progressive Dynamic devices.  I seem to recall that the max input for Battle Born lithium battery charging is 14.7V, which seems too close for comfort.  However Battle Born actually refers to Progress Dynamics products as being compatible for lithium charging.  Older lithium batteries operated around 12.8V... I think that this is what the Renogy Rover has as a "default" lithium absorption voltage.

[RV Squirrel]

I just ordered the Orion 18A and the BlueSolar 50A.  From what Merlin said, I know that the 30A would have been good enough for 4 solar panels, but decided that it would be good to have the option for more than 4 panels in the future.  I also got the dongle for the BlueSolar, so that I can "plug in" bluetooth when I wanted to use it.  The BMV702 (or the MPPT Control Unit) may be a good option in the future if I want to see data without using bluetooth.

The 2-stage AC2DC has been ordered, and I already have the batteries.  Now I need to figure out circuit breakers/fuses, cables, crimps, switch, and undoubtedly other things that I'm missing.

Merlin had recommended this https://www.amazon.com/Blue-Sea-Systems-Circuit-Breakers/dp/B000KOVBXQ/ref=sr_1_8?crid=QXQ1VWTL4TEY&keywords=30a+dc+circuit+breaker&qid=1648430723&sprefix=30A+dc+c%2Caps%2C95&sr=8-8
but I am wondering how it compares with this https://www.amazon.com/Blue-Sea-Systems-Circuit-Breakers/dp/B0055MV7AA/ref=sr_1_2?crid=2TF2GI8078DQP&keywords=Blue%2BSea%2BSystems%2B7035%2B187%2BSeries&qid=1648596090&sprefix=blue%2Bsea%2Bsystems%2B7035%2B187%2Bseries%2Caps%2C85&sr=8-2&th=1.  Both are described as being "Blue Sea Systems 7035 187 Series", but the picture and cost are different.

I heard back again from the Victron user group.  They didn't clarify on the solar panels, but did suggest that it was not necessary to have protection on the input to the DC2DC.  They also said that protection on the output would not be a bad idea, and recommended that it be sized to the DC2DC (with a little buffer).  They mentioned fuses though.  When I asked about this in the past, they recommended MEGA fuses instead of circuit breakers... ironically, the smallest MEGA fuse that I've seen online is 40A, which seems much higher than what I'd need for the output of an 18A DC2DC.

Thanks to Pinstriper, I have an idea for how to assemble an aluminum battery tray to fit about the wheel wells, using brazing rods that I had already purchased from HFT (I forgot that I had them).

Thanks for Merilin and David as well.  I'm sure that I'll still have questions though.  I'll be sure to post pictures when everything is installed.  This may be awhile though!

[Merlin]

Awesome stuff. I think you're headed toward a great system. Good work. For your latest questions:

Multi-stranded cable just means the strands are made up of strands. It's very easy to work with wire and the larger gauges are ofter referred to as welding cable.

I don't think you need a fuse on the input side of the Orion DC-DC.

The important thing is have a breaker that prevents overcurrent from starting a fire if there is a device failure. Having a small capacity breaker on big wire is ok. The other way around is not.

Disconnecting panels under load with a fuse can cause a spark large enough to melt things. A DC breaker is better if you want to disconnect from the MPPT under load. In fact, this summer I'm going to replace a fuse box with a breaker box at the solar array at my cabin. I don't want someone else to pull a fuse with lots of amps running around.

I see I was wrong (first time ever) about the Battle Born batteries not liking 14.6A charging. That is their upper limit for bulk charging so you should be ok with your new PD AC-DC converter.

If you fully charge the batteries independently to exactly the same voltage and then connect them in parallel, they will work together as one battery and you never need to independently check them.

I have used both of the breakers you have linked to. Your choice!

If you use MEGA fuses, you will also need switches. I used MEGA fuses in my very first wind power installation and found they took up a lot of space and added complexity by needing switches too. The main advantage is they are cheap compared to CBs.

The Victron charge controller I use says in the specs it will wake up even 0V batteries. That may not be the case with the one you have?

I'm looking forward to learning from you about how this all works and what installation/design issues come up. Go for it!

[RV Squirrel]

Sorry for not responding for awhile... I've been ordering and receiving stuff.  Had I known that this thread would contain this much insight on batteries and everything else, I would have chosen a different "subject" for the initial entry.  We're way beyond bluetooth now....

I still have some things to consider, and am hoping that folks can provide insight.  But first I'll address Merlin's question. 

The Victron charge controller I use says in the specs it will wake up even 0V batteries. That may not be the case with the one you have?

The SmartSolar datasheet mentions a "Fully discharged battery recovery function".  The BlueSolar datasheet does not.  I've tried to verify this through the Victron user's group, but was not able to get a conclusive answer.  I'd like to think that the BlueSolar supports "reactivating" a "sleeping" lithium battery, but I guess that I won't know until (heaven forbid) my batteries do actually get discharged to that point.

I'm been scratching my head with another question... if I have the a positive bus bar with different size cables connected to it, including big beefy cables to the battery, big beefy cables to the inverter, and not as beefy cables to everything else (chargers, controllers, DC loads), then how do I size the amperage of the circuit breaker that is connected to the battery?  If I pick a big one that will accommodate the current to the inverter, then it may be too big for the other cables connected to the bus bar. 

For example, let's say that the battery and inverter are connected to the bus bar via 4AWG cable, and the battery has a 80A circuit breaker.  Cables to the chargers, controllers, DC loads are 8AWG.  (See attached cables, breakers and bears... oh my!).   If the cable to the solar controller shorts out somewhere between the bus and any other breakers/fuses that I may have for the controller, then this cable may overheat if the current is above the rating for 8AWG cable, but lower than the 80A necessary to trip the breaker at the battery.

I'm wondering if I should not consider attaching the inverter to the bus bar at all, and use a smaller breaker (e.g. 50A) to protect the other cables/devices.  If I add an inverter in the future, then I'd have a direct connection to the batteries via 4AWG cable with its own 80A circuit breaker.

Here's another silly question...  will a breaker trip if the amount of current exceeds the rated amount in either direction?  For example, if I have a 30A breaker next to a battery because I think that the loads won't exceed 30A, will the breaker switch if I get 40A of current from a charger into the controller?

Any recommendations for bus bars?  I'm currently looking at https://www.amazon.com/AMRB-2126-Blue-Sea-MaxiBus-250/dp/B07BS1L8LG/ref=sr_1_18?crid=1Y1YO1M2OQB9&keywords=blue+sea+bus&qid=1648863102&sprefix=blue+sea+bus%2Caps%2C78&sr=8-18 and https://www.victronenergy.com/dc-distribution-systems/busbars.  Ideally, I'd need something that would have 6 posts, unless I could put more than one high-current connection per post.

Finally, any recommendations for test ammeters?  I am using the built-in capability of my multimeter that goes to 30A, but I'm looking for something that will do at least 100A.  I suspect that this will be a clamp meter.  Are any made in the US?

Although I've not purchased a Renogy controller or battery, they do have a chart that comes in quite handy when considering  wire gauge and fuse sizes.  I've attached it as well.

[DavidM]

Like I said in an earlier post, I would size all wires to and from the buss (except for the inverter) as 8 gauge and protect that with a single 75/80 amp breaker. That way you do not need the yellow breakers serving each individual service.

FWIW the maximum current table that you posted above is from the NEC and is for AC building wiring. Actual ampacity data is much higher and I suspect the NEC table downrates it for multiple wires packed in a conduit. If you want to follow the NEC requirements then increase the wire size to #6.

If you will PM me your email address I will send you a comprehensive wire sizing program that includes ampacity tables. It takes a bit of Windows skill to install it as it is very old and doesn't have a self installer. Download all of its files and put them in a Windows/Program/Wiresizer folder. Then set up a link to the .exe file in the Windows start page.

Wire the positive lead to the inverter directly from the + battery terminal through an appropriate sized fuse. For a 1,000 watt inverter located 10' from the batteries, #4 wire should work but go with #2 if farther, protected with a 100A fuse. You should wire the negative lead to the buss so the inverter's current will be picked up by the shunt.

Yes breakers and fuses will trip or blow no matter which direction the current is flowing.

The 6 position buss bar looks fine.

I think all DC clamp on ammeters are made in China except perhaps for the expensive Fluke's and I am not even sure about those. Chinese brands come and go on Amazon but the Klein Tools brand has been around a while. Longevity means at least people are buying them over time, right. I used a friend's Klein tools ammeter once, and I wasn't impressed by its ability to hold its zero. But you might have to pay $300 for a Fluke to do better. Make sure that the meter reads both AC and DC current. Many try to fake you out by saying AC/DC in the title but the fine print says AC current only.

David

[Merlin]

David did his usual great job on the questions. My only addition would be to ask about the need for a bus bar. I don't know where all the equipment will be located, but if it's all in the same space as the batteries, just connect everything to their posts?
Also, I don't own a separate meter for DC amps. I get amp in/out readings from monitors in the equipment. All my stand-along electrical testing stuff is Klein which my dad (professor of EE) recommended as ok mid-quality equipment that doesn't require a second mortgage to buy.

Edit: I forgot to add that I've used the West Marine wire sizing guide for 12VDC circuitry.

https://www.westmarine.com/WestAdvisor/Marine-Wire-Size-And-Ampacity

[DavidM]

If you connected everything to the battery posts, at least for the positives where would you put the breaker? You could use a battery post but that means removing all circuits if you want to use my screwdriver method switching them off. With the buss you can easily remove one without affecting the others.

You can't do it on the negative battery post either because you need to tie the shunt there. You could tie all of the negatives to the shunt terminal upstream of the battery though. That means you only need one buss which makes sense if room is tight.

I noticed that WM's ampacity table is the full wire ratings, not the reduced NEC ones. Their chart is great for normal use: most circuits are either voltage drop sensitive and you should use 3% for those. Others aren't so 10% is fine. My Wiresizer program calculates it exactly based on circuit length and current.

I tried attaching the Wiresizer program to this post. The .exe file is only 80 kB and the 7 data files are small-another 10 kB, but the system wouldn't accept them all.

David

[DavidM]

Well, I got the .exe file and one of the data files attached by individually attaching and modifying the previous post, but after two files it locked me out.

David

[RV Squirrel]

I put the .exe and .dat files into a folder named Wiresizer within c:/programs.  The exe seemed to execute, but gave me an error message "wiresz31 file not found".  I suspect that it is looking additional DAT files (which appear to be simple text files).

Thanks for the suggestions, but I like the idea of connecting to a bus.  Right now, everything is connected to one terminal, and it is difficult to work with.  I will probably mount the equipment on a vertical board, with the components (switch, circuit breaker, solar controller, DCDC) on one side of the board, and with wires and buses on the other side.  The components will be accessible from inside a kitchen cabinet (which has a door on it).  The wiring will be on the opposite side, which is where the AC2DC currently sits.  I suspect that I'll have problems accommodating everything on one side of the board, especially when considering the bend radius of the thicker cables.  The downside with this approach is that it won't be easy to get to the buses in order to disconnect things with David's screwdriver.  The upside is that it will minimize the number of exposed connections, and cable runs will be very short (less than 5' in one direction). 

I'll probably use 8AWG cable, as David recommends, with a separate 4AWG cable (with its own fuse) to my 750W inverter if/when I add it.  I'll be sure to connect the negative to the shunt.

For the 8AWG cable, I'm wondering if I really need 75A/80A of protection.  Without an inverter, I can't imagine current draws over 50A.  My AC2DC can only charge at 45A, the DC2DC can only charge at around 20A, and the solar controller (with 4 solar panels) can only charge at 30A.  If only one is charging at a time, then the max would be 45A.  However, the 75A would definitely be needed in the unlikely situation that I was connected to shore power and solar panels at the same time (I manually position my solar panels now, and really only do this when I'm at a primitive site that does not have shore power).

Thanks for the heads-up about AC/DC ammeters.  I see now that some of them have AC/DC in the title, but that is for measuring voltage... many of the cheaper ones only measure AC amperage.  I didn't notice that before.

[DavidM]

The OP Tom and I have struggled to upload the Wiresizer program to him by email. I just tried downloading the executable .exe file I uploaded a few days ago and holy s&%$ it works. So I have uploaded the other .dat files to this post that are required to make it work. Combine the .exe file and the .dat file in the above post with these additional six files in one folder and hold your breath and double click on the .exe file. It should open.

I just tried it and IT WORKS, HURRAY!

David

[RV Squirrel]

It is working for me too!  I copied all of the files into c:/Program Files/Wiresizer, and then put a link to the .exe file on me desktop.  Although it seems like the files can be located anywhere, just as long as all of the files are in the same folder.  Thanks Dave!

[DaveL]

You might also want to spend some time looking at info on line about good cable connectors as someone suggested.  A standard hand crimper for wiring sizes greater than 14 or 12 gauge may be problematic.  Last time I wired a vehicle for towing I used dual 10 gauge wiring in parallel (it ended up being cheaper this way) and used a Harbor Freight hydraulic connector crimper ($40 at the time) for secure connections.  I have used it since for other battery and ground connection (4 - 8 gauge wiring) and it did a good job for infrequent use.

[DavidM]

Cable crimping tools seem to come in two size ranges: 18-10 and 8-1/0. Since it looks like all of your work will be in the larger size, get one for about $35 on Amazon. If you ever need a 2/0 or 4/0 go to an auto parts store. They can usually make one up for you.

David