Southwest My Solar Boondocking Upgrade Journey - Part 1

[Llittle54]

Can you explain your last point more? “The charge controller will only charge Lithium once a day”?

[daleyocum]

[QUOTE=Llittle54;2195047]Can you explain your last point more? “The charge controller will only charge Lithium once a day”?[/QUOTE

With lead acid batteries the solar controlller will use the battery voltage to determine how discharged the battery is and charge it accordingly. Lithum has a pretty flat discharge curve, the output voltage stays constant (more or less) as the battery discharges. That means to do a good job at battery charging the charge controller needs to talk to the battery monitor. That would be the Victron BMV712 typically.

The Victron solar controllers aren’t smart enough to do this by themselves. Without a central controller they just wake up in the morning and charge the batteries once each day. With the Venus or Color display the system monitors the state of charge constantly and keeps topping off the battery over the course of the day.

[Llittle54]

[QUOTE=daleyocum;2195271]

Originally Posted by Llittle54

Can you explain your last point more? “The charge controller will only charge Lithium once a day”?[/QUOTE



With lead acid batteries the solar controlller will use the battery voltage to determine how discharged the battery is and charge it accordingly. Lithum has a pretty flat discharge curve, the output voltage stays constant (more or less) as the battery discharges. That means to do a good job at battery charging the charge controller needs to talk to the battery monitor. That would be the Victron BMV712 typically.



The Victron solar controllers aren’t smart enough to do this by themselves. Without a central controller they just wake up in the morning and charge the batteries once each day. With the Venus or Color display the system monitors the state of charge constantly and keeps topping off the battery over the course of the day.

Good info! I had not been aware of this fact even with a lot of research into replacing with lithium. (Could be my synapses just hadn’t made the connection)
So to be clear even with a BMV 712 my Victron MPPT will not communicate adequately with the lithiums?
Could you detail (here or in PM) how you installed your Orion. I also have a F150, where and how you tapped into the 7 way and carried on into the trailers system. Thanks

[Troutboy]

I installed the Orion in this thread and have a F150. It’s also in the wiring diagram in this thread. Let me know if you have any questions.

The most important thing that the Orion does is isolate the lithium’s from the tow vehicle. If you do not isolate them, it is possible to drain your lithium’s as they try to charge the tow vehicle battery. I have read where some people just disconnect the charging from the tow vehicle all together.

[daleyocum]

[QUOTE=Llittle54;2195408]

Originally Posted by daleyocum

Good info! I had not been aware of this fact even with a lot of research into replacing with lithium. (Could be my synapses just hadn’t made the connection)
So to be clear even with a BMV 712 my Victron MPPT will not communicate adequately with the lithiums?
Could you detail (here or in PM) how you installed your Orion. I also have a F150, where and how you tapped into the 7 way and carried on into the trailers system. Thanks

That is correct, the BMV712 and the MPPT controller by themselves don’t talk to one another. That means the MPPT controller just does the best it can. The Venus or Color display contan the smarts to really do the right thing with the state of charge info. This thread is the nerdy story where all this came to light. Battleborn also weighed in.

[Gulliver72]

I am ready to pull the trigger today to order the major components for my 25’ Airstream FC FB.
I also have a Ford F-150 TV. I have not been able to find the Orion 12/12/9 isolator anywhere! Where did you get yours, and is it absolutely critical to system operation?
Thanks. Kent

[pdavitt]

Kent,


You can find it here:


https://shop.pkys.com/Same-Voltage-a...ers_c_795.html


I highly recommend PKYs for all your Victron needs. Call Peter Kennedy, the Owner, and he will price out a package deal.


Pat

[Llittle54]

Originally Posted by Gulliver72

I am ready to pull the trigger today to order the major components for my 25’ Airstream FC FB.
I also have a Ford F-150 TV. I have not been able to find the Orion 12/12/9 isolator anywhere! Where did you get yours, and is it absolutely critical to system operation?
Thanks. Kent

Here is a quote from BattleBorn as a reply to a question I sent. I have an F150, Victron 100/30 and 712BVM. I asked if I needed isolation if I installed their batteries.

“For your setup with a towable, you most likely will not need the LI-BIM. The reason is the 7 pin trailer connector is usually a very thin wire and you will not get much amperage back to the lithium bank, therefore the isolator isn’t really necessary. If you have a thicker gauge of wire specifically for charging running back to your bank then I would check that the amperage doesn’t exceed 100 amps. If it does then let me know and we can suggest a B2B charger that you can use.”

Any comments?

[pdavitt]

Originally Posted by Llittle54

Here is a quote from BattleBorn as a reply to a question I sent. I have an F150, Victron 100/30 and 712BVM. I asked if I needed isolation if I installed their batteries.

“For your setup with a towable, you most likely will not need the LI-BIM. The reason is the 7 pin trailer connector is usually a very thin wire and you will not get much amperage back to the lithium bank, therefore the isolator isn’t really necessary. If you have a thicker gauge of wire specifically for charging running back to your bank then I would check that the amperage doesn’t exceed 100 amps. If it does then let me know and we can suggest a B2B charger that you can use.”

Any comments?

It's not so much the amperage as it is the voltage. Below is a quote from the Battleborn Install Manual.


"For your Bulk/Absorption stage, the ideal voltage is between 14.2v-14.6v. For full charge and balance, the absorption mode should be set to last for at least 20 minutes per battery (for multiple batteries in parallel)."


The Orion DC/DC Converters accept an input voltage of 8-17 volts and output a constant voltage that is settable between 10 and 15 volts. Most alternators will not consistently generate the 14.2-14.6 bulk charging voltage recommended by Battleborn.


Battleborn's comments about the amperage are correct.


Pat

[Gulliver72]

Thanks everyone.. Great info.

[Gulliver72]

Originally Posted by daleyocum

For what it’s worth, here is how I did the install in the same trailer. I’m not sure I’d split the battery bank just because of the huge cable you’d need but that’s just me.

Since these were taken I expanded to five batteries and so had to take over the next under-bed cabinet.

Daleyocum-I’ve been studying your photos in-depth, as we both have the same FC, and I will be doing much the same in my install.
I noticed what I consider to be a mistake in your set up. I believe it’s important to pull from opposite corners of the parallel battery bank. Otherwise most of the draw will come from the first battery in the run. This will cause that battery to fail prematurely.

[daleyocum]

Originally Posted by Gulliver72

Daleyocum-I’ve been studying your photos in-depth, as we both have the same FC, and I will be doing much the same in my install.
I noticed what I consider to be a mistake in your set up. I believe it’s important to pull from opposite corners of the parallel battery bank. Otherwise most of the draw will come from the first battery in the run. This will cause that battery to fail prematurely.

That’s a good point. I think anyone doing an equivalent install should consider that if their layout makes it easy. I’m not sure in my installation at least, I’d add another 4’ of 00 wire just to equalize the minimal difference in draw across the batteries. (I now have five batteries, an update from the photo, so they continue into the next small cabinet.)

4’ of 00 wire has a resistance of .0003 ohms. At 100 amps and 14v, that’s a drop of .06v. In my installation the inverter is at one end of the line of batteries so there would be more wire involved doing it as you describe. I was trying to keep the wire run as short as possible between the batteries and inverter.

It is true, however, that the first battery is working harder. How much shorter its life will be given the low resistances involved I don’t not have a good feel. Thanks for bring this up, though. I hadn’t considered that.

[uncle_bob]

Originally Posted by pdavitt

It's not so much the amperage as it is the voltage. Below is a quote from the Battleborn Install Manual.


"For your Bulk/Absorption stage, the ideal voltage is between 14.2v-14.6v. For full charge and balance, the absorption mode should be set to last for at least 20 minutes per battery (for multiple batteries in parallel)."


The Orion DC/DC Converters accept an input voltage of 8-17 volts and output a constant voltage that is settable between 10 and 15 volts. Most alternators will not consistently generate the 14.2-14.6 bulk charging voltage recommended by Battleborn.


Battleborn's comments about the amperage are correct.


Pat

Hi

An enormous lot depends on just what is going on in the truck. In slow traffic / at idle, the voltage on your alternator can / will / does drop. Your lead acid battery will not put much out at a voltage above 12.6V. That's way past the 13.3 that the lithium batteries start pushing current.

The wire involved is somewhere in the 0.03 to 0.06 ohm range and at 0.6V that will give you 10A to 20A of current. That may not seem like much. If you are stuck in traffic for a couple hours ( been there / done that) it's a pretty good load on the trailer batteries.

Bob

[uncle_bob]

Originally Posted by pdavitt

Kent,


You can find it here:


https://shop.pkys.com/Same-Voltage-a...ers_c_795.html


I highly recommend PKYs for all your Victron needs. Call Peter Kennedy, the Owner, and he will price out a package deal.


Pat

Hi

You can also drop in on Peter. He has a retail store and has a lot of stuff in inventory there. It's a bit "interesting" to find. Getting there with a trailer in tow is technically possible. I would not recommend trying it. The streets are a bit narrow / crowded.

His background is in boats rather than RV's. He both sells and has done installation of this stuff (in boats). Anything he recommends doing will be plenty good enough for use on land. His prices are as good as any out there.

Indeed highly recommended, but by no means the only person I would ever buy from. Miles and miles ahead of doing this on Amazon or a "no phone number" web site. You very much want to buy from somebody who can talk you through the issues that *will* come up.

Bob

[Gulliver72]

Thanks Pat. Found my Victron Orion from PKYS at your suggestion. Great price/shipped out 1 hr after order placed. Wonderful!

[pdavitt]

Any time.
Pat

[afk314]

All of us who have done lithium upgrades have faced the question of "how much should I over-design the system in case..." - sometimes the level of over-engineering is pretty intense, sometimes not so much. This, however, makes it hard to know what one minimally needs to do.


The Orion comes in 9A, 18A, and 30A in 12V (at least, probably even more). I've seen most people here install the 30A version, but now we're starting to see some 9A units.



I will check my truck's fusing for the 7 way, but I seem to remember the aux power is fused by a 30A fuse. But, thats probably a little high considering 30A through 10AWG is near ampacity max especially considering the long run. But, really, I'm just guessing.


What size is the right size for this use case?


Thanks!
Adam

[daleyocum]

Originally Posted by afk314

All of us who have done lithium upgrades have faced the question of "how much should I over-design the system in case..." - sometimes the level of over-engineering is pretty intense, sometimes not so much. This, however, makes it hard to know what one minimally needs to do.


The Orion comes in 9A, 18A, and 30A in 12V (at least, probably even more). I've seen most people here install the 30A version, but now we're starting to see some 9A units.



I will check my truck's fusing for the 7 way, but I seem to remem7ber the aux power is fused by a 30A fuse. But, thats probably a little high considering 30A through 10AWG is near ampacity max especially considering the long run. But, really, I'm just guessing.


What size is the right size for this use case?


Thanks!
Adam

I’d go the the largest Orion your truck can drive on that pin. My F150 is pretty whipy in that regard so I picked a small 9amp Orion but that may have been too conservative. As it stands, with 500w of solar on the roof and that 9amps, the batteries are always fully charged on driving days. Some extra current would be handy, though, in deep shade where getting out the generator wouldn’t be appreciated by our neighbors.

[uncle_bob]

Originally Posted by afk314

All of us who have done lithium upgrades have faced the question of "how much should I over-design the system in case..." - sometimes the level of over-engineering is pretty intense, sometimes not so much. This, however, makes it hard to know what one minimally needs to do.


The Orion comes in 9A, 18A, and 30A in 12V (at least, probably even more). I've seen most people here install the 30A version, but now we're starting to see some 9A units.



I will check my truck's fusing for the 7 way, but I seem to remember the aux power is fused by a 30A fuse. But, thats probably a little high considering 30A through 10AWG is near ampacity max especially considering the long run. But, really, I'm just guessing.


What size is the right size for this use case?


Thanks!
Adam

Hi

Having a 30A fuse on the aux power is pretty normal. The wiring is normally number 10 AWG and it is only rated to 30A as well. I've never seen a rating on the 7pin, but I would not be surprised if it is rated at 30A as well.

Is the spec on the Orion for current in, current out, or really for total power? My understanding (possibly wrong .... ) is that the rating applies to output current. If you are putting out 30A at 14.4V and taking current in at 12V ... you are well over 30A on the input side.

Best practice is to design for 80% on a circuit. That would be 24A in this case. Indeed since there's nothing else on the circuit that *is* getting into overkill in this case.

I would not go with anything over the 18A unit ....

Bob

[Omnial]

That's awesome.... Can you please tell me the model number of the PV Selector Switch?

Thanks.