Looking for Electrical System Feedback - Solar, Victron, LiPO4 battery, SmartPlug

[Kyacker]

Originally Posted by AirMiles

Airmiles experienced an issue in shaded areas where the voltage from the panels dropped to the point where the MPPT wasn't energizing the charging system output. So, when voltage dropped down below a point (I can't remember where that was, Airmiles, remind me?) charging wasn't happening at all.



In full parallel I could certainly get more amps and charge faster, but what's the bottom voltage rail?



The Victron 100/30 and 100/50 needs "battery voltage plus 5 Volts" to turn on and "battery voltage plus 1 volt" to stay on. Others have had problems with their Victron controllers not getting enough voltage to turn on and have fixed this issue by re-configuring to series to increase the voltage.



Running parallel your panels will give higher Amps at lower Voltage. Running series will give higher voltage at lower amps. But in both configurations, your wattage will be similar and will not change how fast your battery charges.



Watts = Amps x Volts

400W = 23.5 Amps x 17v in parallel = 32.75A of battery charging at 12.2V

400W = 11.75 Amps x 34V in series = 32.75A of battery charging at 12.2V



When in series-parallel and your battery is at 12.2V, the Victron 100/50 controller will convert the 34V and 11.75A input into 32.75A output at 12.2V. (This would exceed a 100/30's 30 Amp Maximum output so you would only get 30A with a 100/30.



When in parallel and your battery is at 12.2V, the Victron controller will convert the 17V and 34A input into 32.75A output at 12.2V.



Notice you get 32.75A output from the controller with both parallel and series-parallel.

- "How much would you pay for 2.75A?"

- "Well I can tell you exactly. $97.75." (The difference in price from the 100/30 to the 100/50)


Excellent point on the speed of charge.

I’m going to go with the series parallel configuration with the intention that if I ever wanted to go with more panels I’d add two more at the same time.

[SCOTTinNJ]

Originally Posted by Kyacker

Yea I've already boxed that up for return. I may use the savings there to up the MPPT to 50A.

I have the 100/50 with 400w in parallel. I've not noticed a situation where I thought "gee, i wish my controller would turn on." I find if there is light, I'm getting at least some charge. Often earlier in the morning than I would have imagined.

Also, I do not charge with my truck. Just found I didnt need it. Unless it's a miserable rainy day, you'll get a lot of solar on the open road.

Lastly, I've been pleased with my battle borne batteries. In parallel they will each push out 100 amps. So two will put out 200 amps. Not sure about the batteries the OP was considering, but when I was shopping some of the bigger lithiums were limited to 100 amps output. At 12v this is "only" 1200w. You wont be able to fully power a larger inverter. In fact with 2 battle borne batteries I dont believe you can fully power a 3000w inverter. You would need three batteries.

[SCOTTinNJ]

Originally Posted by SCOTTinNJ

I have the 100/50 with 400w in parallel. I've not noticed a situation where I thought "gee, i wish my controller would turn on." I find if there is light, I'm getting at least some charge. Often earlier in the morning than I would have imagined.

Also, I do not charge with my truck. Just found I didnt need it. Unless it's a miserable rainy day, you'll get a lot of solar on the open road.

Lastly, I've been pleased with my battle borne batteries. In parallel they will each push out 100 amps. So two will put out 200 amps. Not sure about the batteries the OP was considering, but when I was shopping some of the bigger lithiums were limited to 100 amps output. At 12v this is "only" 1200w. You wont be able to fully power a larger inverter. In fact with 2 battle borne batteries I dont believe you can fully power a 3000w inverter. You would need three batteries.

If this is the battery the OP is contemplating it looks like it can supply 400 amps. So that's good.

https://lithionicsbattery.com/produc...-neverdie-bms/

[daleyocum]

Originally Posted by SCOTTinNJ

I have the 100/50 with 400w in parallel. I've not noticed a situation where I thought "gee, i wish my controller would turn on." I find if there is light, I'm getting at least some charge. Often earlier in the morning than I would have imagined.

Also, I do not charge with my truck. Just found I didnt need it. Unless it's a miserable rainy day, you'll get a lot of solar on the open road.

Lastly, I've been pleased with my battle borne batteries. In parallel they will each push out 100 amps. So two will put out 200 amps. Not sure about the batteries the OP was considering, but when I was shopping some of the bigger lithiums were limited to 100 amps output. At 12v this is "only" 1200w. You wont be able to fully power a larger inverter. In fact with 2 battle borne batteries I dont believe you can fully power a 3000w inverter. You would need three batteries.

Same with me. I’ve never noticed my solar controller not coming on when there’s sun out.

[AirMiles]

Originally Posted by Kyacker

- "How much would you pay for 2.75A?"
- "Well I can tell you exactly. $97.75." (The difference in price from the 100/30 to the 100/50)

The one point about the "potential" 2.75A you may get with a 100/50 controller over a 100/30 controller is that in my 100 days of boondocking this summer, I never exceeded 30A of charging and therefore would not have gained any more battery charging from a 100/50 controller.

Here is how my 100/30 works with 400W of solar. At the crack of dawn, my solar panels output 1W. That is equal to 0.5A at 20V. (Remember Watts = Amps x Volts). This wattage increases sloooowly to maybe 200W by 9 am. Your battery voltage also increases slowly from 12.2V to maybe 12.9V by 9 am. Now we have 200W = 15.5A x 12.9V. By noon, your Wattage could increase to 400W, but now your battery Amps will probably be near its 14.4V Absorbtion level. Let's do the math 400W = 29A x 14.4V. So even IF you were to get 400W of solar production (extremely rare), you still would be below the 30A maximum output of a 100/30.

Again, you can look at my actual solar production from thirty days in June and 30 days in October. I never got close to the 30A limit of a Victron 100/30 with 400W of Solar panels. In this post, I did all the calculations for you: http://www.airforums.com/forums/f37/...ml#post2177229

From my experience, a 100/50 is not worth $97 more if you are never going to add more solar panels. If you are considering adding more solar panels in the future, the $97 would be well spent. 100% of the time my controller was below its 30A pontential and 99.9% of the time the system was below the 80% potential level recommended by Bob.

[SCOTTinNJ]

Originally Posted by SCOTTinNJ

If this is the battery the OP is contemplating it looks like it can supply 400 amps. So that's good.

https://lithionicsbattery.com/produc...-neverdie-bms/

Just as a point of reference. This 300 ah battery only outputs 120 amps continuous. That wont run a large inverter.

https://www.lithiumion-batteries.com...on-battery.php

[Kyacker]

Originally Posted by AirMiles

From my experience, a 100/50 is not worth $97 more if you are never going to add more solar panels. If you are considering adding more solar panels in the future, the $97 would be well spent. 100% of the time my controller was below its 30A pontential and 99.9% of the time the system was below the 80% potential level recommended by Bob.

Thanks again for all of the info AirMiles. I've really enjoyed reading your posts. To your point, I think it's worth the $97 to me to have the flexibility in the future if I want it. I'll wire it like it's going to happen and we'll go with the 100/50. I actually have to return the 100/30 that I bought anyway because of a misleading picture on Amazon suggesting it was the one with bluetooth, when in fact, it was not. The guy that I bought it from has been really good and responsive.

Originally Posted by SCOTTinNJ

Just as a point of reference. This 300 ah battery only outputs 120 amps continuous. That wont run a large inverter.

https://www.lithiumion-batteries.com...on-battery.php

I'm going to be using a new battery that they haven't released just yet. This is a 450Ah battery and has a maximum discharge current of 675A and a pulse current of 4500A. I think we'll be fine.

[SCOTTinNJ]

Originally Posted by Kyacker

I'm going to be using a new battery that they haven't released just yet. This is a 450Ah battery and has a maximum discharge current of 675A and a pulse current of 4500A. I think we'll be fine.

Nice!

[AirMiles]

Originally Posted by SCOTTinNJ

I have the 100/50 with 400w in parallel. I've not noticed a situation where I thought "gee, i wish my controller would turn on." I find if there is light, I'm getting at least some charge. Often earlier in the morning than I would have imagined.

I'm just pointing back to the Victron Manual that recommends series-connected panels for maximum efficiency and sharing actual experiences where there was a low voltage turn on issue per the Ops request.

[SCOTTinNJ]

Originally Posted by AirMiles

I'm just pointing back to the Victron Manual that recommends series-connected panels for maximum efficiency and sharing actual experiences where there was a low voltage turn on issue per the Ops request.

Yea. I dont know what's right.

But I do agree with this part you wrote. Which was a big reason I went to 100/50 and parallel.

"From my experience, a 100/50 is not worth $97 more if you are never going to add more solar panels. If you are considering adding more solar panels in the future, the $97 would be well spent."

[AirMiles]

Originally Posted by daleyocum

Be sure to also get the Multicontrol panel. You would think Victron would have made turning the inverter on and off easy from the LCD screen but, alas, they did not.

To Airmiles’ point on series-parallel. I think he’s right in the cases where all the panels are receiving about the same amount of light, even shaded light. The higher voltage of that arrangement would win. If it’s uneven how much each panel is getting it’s harder to predict which will win. All parallel does give you the ability to have an odd number of panels which, in my case, was important. I have 500w on the roof but sometimes add a ground panel if the sun exposure in the campsite warrants it. You can’t do that with series-parallel.

I’d say run 6ga down from the roof just in case you change your mind later on even if you chose series-parallel. If you decide to put 500w up on the roof (which you should if you have room) then the decision is made for you.

Thanks Dale & Scott, I couldn't agree more! I'm here to share information and not be a series-parallel troll. I just want to help people think through all the alternatives and choose which is best for them.

[Kyacker]

Alright! Got the schematic all updated with all the discussion we've had here. I've never made so much progress in so little time on anything. Sure is a lot of fun to have a bunch of experienced folks around here to bounce ideas off of!

https://www.wallytheairstream.com/bu...ctrical-system

[AirMiles]

Originally Posted by Kyacker

Alright! Got the schematic all updated with all the discussion we've had here. I've never made so much progress in so little time on anything. Sure is a lot of fun to have a bunch of experienced folks around here to bounce ideas off of!

https://www.wallytheairstream.com/bu...ctrical-system

I'm not an expert on this fancy of a system, but I'm glad that I could participate. One other comment I have is what fuse/breaker are you planning to use coming out of the Victron Controller? I would suggest a breaker, one size larger than the Amp output of the controller. I have a 40A coming out of my 30A controller. Picture: http://www.airforums.com/forums/f448...ml#post2167314

Also, are you going to add wire sizes to the schematic? Again, I don't know the sizes between all of your high-end equipment. Maybe someone can help there? I used 6g between my controller and bussbars for my simple little system. I assume you are going to place the batteries inside and all equipment in close proximity.

Thanks for thinking out loud with us on Airforums. Its fun to spend someone else's money.

[waninae39]

this is my Ac AND dc DEPLOYMENT

be sure to run extra CAT cables when do any update as you dont want to do that job again.
plus in the future you may have a need for them

plus remove fuses and replace with breakers
add more shut off switches

[Kyacker]

Originally Posted by AirMiles

I'm not an expert on this fancy of a system, but I'm glad that I could participate. One other comment I have is what fuse/breaker are you planning to use coming out of the Victron Controller? I would suggest a breaker, one size larger than the Amp output of the controller. I have a 40A coming out of my 30A controller. Picture: http://www.airforums.com/forums/f448...ml#post2167314

Also, are you going to add wire sizes to the schematic? Again, I don't know the sizes between all of your high-end equipment. Maybe someone can help there? I used 6g between my controller and bussbars for my simple little system. I assume you are going to place the batteries inside and all equipment in close proximity.

Thanks for thinking out loud with us on Airforums. Its fun to spend someone else's money.

Yes, I'll be sizing the wiring up next. I found a really nice calculator on www.BayMarineSupply.com 's website that will help with that. Correct on proximity. The battery will be within 12" of the controllers. The longest run will be from the MPPT to the solar panels. I plan to even keep the shore power within 12-24" of the inverter/charger.
We're going to go with a rear bedroom configuration with a dinette and L-shaped couch in the front of the airstream, so I plan to hide all of these electronics there so they're secure, accessible, and I can vent them as well.
Thanks for all your help!

Anyone have a great supplier for wire they prefer? I know that AM Solar is one everyone likes!

Originally Posted by waninae39

this is my Ac AND dc DEPLOYMENT

be sure to run extra CAT cables when do any update as you dont want to do that job again.
plus in the future you may have a need for them

plus remove fuses and replace with breakers
add more shut off switches

I plan to use breakers across the entire system, they just didn't have a good block for that in the drawing software. Great advice on the wiring. Always better to run more than you'll ever need.

[AirMiles]

I need to correct one of my previous comments on Watts = Amps x Volts. What I was describing was the lead-acid charging model with bulk, absorption and float modes. With the Lithium battery you are contemplating, I believe you will only use bulk mode and your battery will have a very flat voltage curve with low resistance. With these Lithium characteristics, you may frequently get greater than 30A from your controller and a Victron 100/50 is likely worth the additional $97.50 even with 400W of solar.

[uncle_bob]

Hi

The 3000 hybrid can pull > 400A for a modest amount of time off the batteries. Just how much it does pull will depend on how heavily you load it's output. How well your cabling and batteries hold up at this level is very much a "that depends" sort of thing. 4/0 AWG is not out of the question in this case.

Fuse wise, there are always a number of specs on a fuse. The one we mostly notice is how much it will pass continuously ( = for long time periods). There will always be shorter time numbers with higher current ratings. The fuse(s) are there to protect the wire as much as anything. Sizing them is not always a slam dunk.

Best guess with a 3000 is you want to handle 3000 W at 11V and 90% efficiency (yes even lithium's sag under heavy load). That would be .... yikes .... a 300A fuse. You could slightly smaller with some care. 3KW is not the full time output of the inverter.

If you *do* go with a 300A fuse, you will need something significantly heavier than 4/0 cable. The biggest legit fuse on 4/0 is 260A per NEC guidelines. People *have* been known to push things a bit. It's not a recommended thing to do.

If you *really* want to have fun, the 3000's peak output is 6KW. You now need a 600A fuse and a piece of wire with a one inch conductor (not the whole wire including insulation, just the copper part). Good luck routing a pair of those (one positive, one negative) anywhere.

Yes this can get pretty crazy ....

Bob

[pdavitt]

Originally Posted by uncle_bob

Hi
If you *really* want to have fun, the 3000's peak output is 6KW. You now need a 600A fuse and a piece of wire with a one inch conductor (not the whole wire including insulation, just the copper part). Good luck routing a pair of those (one positive, one negative) anywhere.

Yes this can get pretty crazy ....

Bob

Bob makes a very good point. As larger battery banks and Inverter/Chargers are being used in the RV world, at some point the 12V battery system becomes untenable. Try routing a 750MCM cable or the cost and size of a 600A DC circuit breaker.



The only viable alternative is to up the battery system voltage to 24 or 48 volts. I realize this presents an issue with powering 12V appliances and devices, but that is easily overcome. I just completed a 48V system for a expedition vehicle, with a 10KWh battery bank, so it is doable.


Pat

[Kyacker]

Originally Posted by pdavitt

Bob makes a very good point. As larger battery banks and Inverter/Chargers are being used in the RV world, at some point the 12V battery system becomes untenable. Try routing a 750MCM cable or the cost and size of a 600A DC circuit breaker.



The only viable alternative is to up the battery system voltage to 24 or 48 volts. I realize this presents an issue with powering 12V appliances and devices, but that is easily overcome. I just completed a 48V system for a expedition vehicle, with a 10KWh battery bank, so it is doable.


Pat

Certainly explains why home systems are 24/48V systems!

[pdavitt]

Originally Posted by Kyacker

Certainly explains why home systems are 24/48V systems!

Yep, I live in a full size off-grid house with a 48V 88Kwh battery system.
Pat