MPPT Solar and Lithium Question

[daleyocum]

Originally Posted by uncle_bob

So here's actually a real question that might be answered:

There are all these cute "assistants" you can load on the Multi. I did a quick read on each of them. None popped out as an obvious goodie. Did I miss something?

Bob

I didn’t use any of the assistants and don’t really understand why they are there. I think the Venus pretty much makes them obsolete in my (and your) application. At least that’s what I told myself.

[uncle_bob]

Hi

Ok, I just wanted to be sure I didn't miss something really obvious on the assistants. Maybe "you need to load the Yack Assistant to talk to the Venus.". As far as I can tell from the very limited descriptions they are basically "glue" to get the Multi to work with this or that other Victron / non-Victron gizmo.

If and when the Venus ever pops out of the wonderful world of shipping confusion, I'll get a chance to play with it. Assuming smoke is not the result, things likely will make more sense at that point. Seeing it in front of you actually working is always the best answer to all of these "what if's"..... ( ... are these *really* the right cables .... are they long enough .... )

Just got the standard robot email from PKYS on the Venus. It apparently is not hooked to anything involving tracking. "Did you receive your order?" it asks. If you click on "no" it just goes to the web site. If you click on "yes" it asks you to generate a review. Wonderfull coding .... yikes !!!! Not a knock on Peter, I'm pretty sure he didn't write the code.

========

I did an equalization run ( manual equalization ) on the batteries with the MPPT yesterday. Mostly I was just curious to see what it looked like. At the start the batteries were at zero current at 13.6V. They ran up to 14.4 in about 15 minutes. Current was in the 4 to 5A range as the sun dodged in and out of the clouds. Once it got to 14.4, the current dropped to < 1A in another 5 minutes or so. This is all with 400AH of battery. I would *assume* that each one pulled 1/4 of the total. I have on easy way to verify that. Bottom line, the "cycle" is around 1AH for the set of batteries. A charge cycle of 0.25% C is .... errr ... not much of a concern. My guess is that the results would not have been much different from 13.5 to 14.6. I just happened to have things set to 13.6 and 14.4.

======

I got around to the old converter cable yesterday. There is *plenty* ( and then some ) of cable to get to the location of the Multi. Hooking up the negative seems like a slam dunk. It just adds copper and lowers the drop involved. I'm still up in the air on paralleling the two current carrying conductors. A lot will depend on just how desperate I get after the new cable comes in for the next pass at the main wire.

Bob

[uncle_bob]

Hi

Well, the world's most expensive cable experiment is done. The biggest thing I could get through the existing concealed holes was a 1/0 for the + and a 2 for the ground. That plus paralleling the old converter cables will have to do the trick.

Certainly not ideal, but for a 1600W inverter ( so 123A (plus losses) at 13V) probably adequate. The old "1,000W" inverter ran on number 4 .... This will be set up better than the stock one was. ( 1000W at 12V => 83 A plus loss).

Stupid wire math follows .... Number 4 is 21 mm^2, Number 2 is 33 mm^2, 1/0 is 53 mm^2. The added #6 from the old converter is 13 mm^. Old net was 21. New net is 66 on the plus and 46 on the minus. The ground is actually a bit larger, but that's enough math.

Charging, I figure I'm fine for anything the Multi can put out. Since this is a do nothing mostly / charge sometimes / invert rarely setup, that all seems to work out.

Back to fun and games in the hot sun ....

Bob

[pdavitt]

Originally Posted by uncle_bob

Hi
If and when the Venus ever pops out of the wonderful world of shipping confusion, I'll get a chance to play with it. Assuming smoke is not the result, things likely will make more sense at that point. Seeing it in front of you actually working is always the best answer to all of these "what if's"..... ( ... are these *really* the right cables .... are they long enough .... )
Bob

Bob,


Don't have a Venus GX but I got my CCGX about two weeks ago. The first thing I did was to plug in an ethernet patch cord from my router and wire 12VDC with a 1A fuse to the CCGX. I did not connect it to anything else. The thing fired up, immediately connected to Victron, and started a firmware/OS update. Not sure if the Venus GX works the same way, but it should since both have the same operating system.

After it finished the firmware update I went to the Victron VRM Portal https://vrm.victronenergy.com/login created an account and registered the CCGX. You must leave the Venus GX on and connected to the internet to register it with the VRM Portal.

Since I haven't gotten my Inverter/Charger or Batteries yet, I can't speak to what happens when you plug everything together. Should be fun.


Pat

[uncle_bob]

Hi

At least the Venus has popped out of shipping limbo land and now shows due here on Monday. I likely will have everything else in and running before it gets here. *Then* I'll find out if I crushed the CAT-5 cable when I pulled the power wires .....

The good news is that out in the full sun on the street, the MPPT is keeping the batteries nice and happy. The bad news is that out on the street with no real power the trailer is "rather warm". Mid 90's again today ....

So much fun !!!!

Bob

[fran&frank]

I just posted an example of when you might want to program an assitant on your multiplus. See my most recent post:

http://www.airforums.com/forums/f37/...ml#post2122144

--Frank

[uncle_bob]

Hi

With the Battle Born's the BMS takes care of the whole "no charge below this temp" and "no discharge below that temp" sort of stuff. Since I have two inside the trailer and two out in the battery box, it could get interesting otherwise.

======

Well, it turns out that the Amazon modified Multi was *just* a bit shorter than the real one. How much shorter ... enough to matter. Off to find the saw and chop a bit off the housing of the Multi. Think that will impact my warranty? . I probably could move the drawer up a bit and get it to clear. Either way it's a bit of messing around. This way the Multi will slide around a bit better. That will be needed if I'm going to use the stock mounting plate.

Bob

Bob

[steverino]

Hey Bob
I see you were able to fish inverter cables through the pan, but what do you think about (or why did you decide against) running the inverter cables across the coach in the underfloor chase, and then forward along the street side wall under the ALDE radiator cover? It doesn’t seem to get too hot in there, provided the cables are dressed toward the floor. I haven’t pulled those covers off yet, so maybe I don’t know what I am talking about :-)


Sent from my iPad using Airstream Forums mobile app

[uncle_bob]

Originally Posted by steverino

Hey Bob
I see you were able to fish inverter cables through the pan, but what do you think about (or why did you decide against) running the inverter cables across the coach in the underfloor chase, and then forward along the street side wall under the ALDE radiator cover? It doesn’t seem to get too hot in there, provided the cables are dressed toward the floor. I haven’t pulled those covers off yet, so maybe I don’t know what I am talking about :-)


Sent from my iPad using Airstream Forums mobile app

Hi

I have other plans for the space under the radiator..... Also the fins are mighty sharp. ( I'm going through Bandaids at a pretty good rate). You would need some way to protect the cable from getting cut by them.

====

Still trying to work out how to tie the converter down. Even with cutting the case a bit there still isn't a lot of room ...

Bob

[uncle_bob]

Hi

Well, the Venus got here and I've got everything plugged in. It talks fine to the Multi and the BMV-712. They both popped up and did there thing. The Venus actually got here on Sunday, I simply didn't think to check for a Sunday postal delivery.

So, is there some magic to getting a MPPT 100/20 to talk to a Venus? I've swapped cables and connectors around. The Venus gets a bit confused about where the BMV is until you reboot it. It never seems to "see" the MPPT. There is a pull down for the TX port function, it's set to "normal communication". Oddly the RX port has no "normal communication" setting. It's set to "load configuration" which I believe is the default setting. AFIK all firmware on everything is on the latest versions. The MPPT is MIA with or without smart networking turned on. With it turned on it happily shares data with the BMV.

Grrrr .... I thought I was going to get this wrapped up before the 4th ....

We're having fun in the sun Sensor by my feet reads 100F ....

Bob

[pdavitt]

Just for grins, have you tried swapping the VE.Direct ports on the Venus GX that the BMV and MPPT are plugged into? You could have a bad port.


Just trying to help,
Pat

[fran&frank]

So you already updated all the firmware. Just to to confirm, you have your bmv connected to the venus with a ve.direct cable, your mppt connected to the the venus with a ve.diect cable, and multiplus connected to the venus with a ve.bus (RJ45) cable? Which mppt charger do you have? You said the mppt shares data with the bmv, can you see all the devices in the graphical display on the venus?--Frank

[uncle_bob]

Hi

Ok, here's the gear involved:

Smart Solar MPPT 100/20 ( = the one with built in Bluetooth)
BMV-712 (= also Bluetooth built in )
Multi 2000
Venus GX
Orion DC/DC
Battle Bourn batteries.

The MPPT simply does not show up in any way on the Venus. I can swap cables. I can swap ports. I reboot the Venus (again and again ...). The MPPT simply does not show up. It is happy to Bluetooth network with the BMV. It chats with the phone app just fine. All the various firmware updates appeared to go fine on everything ( The Bluetooth stuff gets two updates).

Since the four com pins on the MPPT are "multi function", I'm wondering if the MPPT needs to be power cycled to get into the "chat" mode. That was not the case with the Multi or with the BMV. I do find it weird that there is no "normal communication" setting for one side of the port. There is a "two way communication" setting on the Venus. I have not tried anything with is set differently.

The cables to the MPPT and BMV are genuine Victron VE.Direct ( 0.9 M if that matters). The Multi cable is just a normal CAT-5 that I had in stock. The Venus seems to do what it's supposed to other than the MPPT issue. It does get a bit hot, but it's hot out ...

Lots of fun !!!

Bob

[uncle_bob]

Hi

Well, a little digging suggests that "remote on/off" is the correct (non-default) setting for the RX pin. There is some yack that the smart Bluetooth networking is not good to use with the Venus. I'd tried it both with and without the smart network earlier. The RX pin change did noting, Power cycling the MPPT and Venus did nothing. Swapping cables and ports yet again did nothing.

It's looking to me like either this model of MPPT does not talk VE.Direct or that I have a defective unit ...... yet another setback ....

Bob

[daleyocum]

I have the new SmartSolar version with the built in bluetooth. I didn’t have to do anything special, I just plugged it in with ve directand it all just worked. I wonder if yours needs a software update? How that’s done I don’t know. Victron’s site mentions certain versions of firmware for the MPPT controller and for the ve direct bus itself (whatever that means.)

[SilverHouseDreams]

Slightly related to the discussion at hand, has anyone been able to get the VE.Sart Networking to work? I have tried it numerous times, the BMV-712 states it is transmitting data and the MPPT states that it is "waiting for data" perpetually. I have reset and deleted the network and recreated it, same problem every time. I have tried creating the network on the BMV and then joining that network from the MPPT, I have tried creating it on the MPPT and joining it from the BMV.

[uncle_bob]

Hi

It appears to matter which MPPT you have in terms of the defaults for communications. The "larger units" come default set for communication. The "smaller units" ( mine is a 100/20) are set to a different default.

I had no problem getting mine to do the Bluetooth networking. I set up the network master on the MPPT and then told the BMV-712 to join the network. It happily did so and both units showed they were exchanging data.

Firmware updates for the Smart Solar units and BMV-712 both work the same way. You connect to the device with the phone app. It checks this and that in the background. It then pops up and asks if you want to update the firmware or not. There is a separate firmware image ( and revision ) for the Bluetooth part of the gizmo and for the main operating part of it. Two updates are not uncommon.

You can check the revision of both parts with the app. A bit of digging on the Victron site will give you a listing of the current firmware revisions. You can use the app to see what the current firmware is. All my devices are up to date as of last week. Since the app does all the checking, that's not a big surprise.

The Venus is a bit different. It updates as soon as it connects to the internet. There is a pop up that shows what is happening. I seem to recall there is a way to force an update check as well.

The Multi is a bit of.a PIA to update. That involves a USB adapter, a Windows PC and a bit of patience. In that case you head off to their web site and download a firmware image with only minimal checks. I have no idea (and don't want to find out) what happens if you try to upload the wrong image. I would *hope* that there is a check and an error message .... there would be if I had coded it all ....

========

No change in status overnight. I did get the Multi to switch invert / charge only via the Venus rather than by the front panel switch. As with all things Multi, it took some poking to get it done. It either ignores the switch in this mode ( which I think it should ) or it needs the switch to be on. It may have taken a while to get going or the switch is what did it. I'm leaving it as is ( switch on ) for now.

Lots of fun !!!

Bob

[waninae39]

i broke down and ordered the mutiplus 3k. it was shorter than the 2k(wont fit in my 22FB)
i have two 100/30 Victron mppt ctrl and one BB 100AM lion battery now
i have two mppt ctr since i plan to get another set of SS for the roof, to complete the 160w panel on the rear . I am looking at the narrwo 90w am solar panels. 3 will fit on my 22fb roof, 2 on one side and 1 one the other

when down i will have 160+270W= 430W
plus 200AH with BB Lion

i am making room for the a 2nd BB 100AM lion battery along with the mutiplus 3k.

all will just fit under road side under the front bed.
i have to move one support board and will likely rewire the very messy As wiring and collocate the +ve and -ve bus bars

once the mutiplus 3k. comes in and i get it all setup, ill post pics of my setup.

i have two

[uncle_bob]

Hi

A single MPPT 100/30 will handle 30*14.4 = 432W of panels. That *assumes* they are all compatible voltage outputs. Indeed multiple controllers will help with shading issues.

Bob

[SilverHouseDreams]

I have roof top solar and am adding portable solar. My panels feed into a BlueSea 3 way switch so that I can combine or disconnect the panels, so when the roof is mostly shaded and the portable panels are in full sun I don’t lose out on the portable panel’s output.

Adding more charge controllers also adds more feedback/parasitic load...and more complexity in general.