Design Assistance

Greetings All,

Needing some simple help with Victron Equipment… If someone could take some time and advised best practices and equipment selection that would be great as solar is out of our realm.

Overall we are looking at no inverters needed in the system, all will be handled with a GerboGX, Solar Controller, Battery Protect, and Shunt (assuming this is mostly what we need).

We are looking at needing around 55-60watts of 12vdc power at all times. We are looking at a 200ah LiPo4 battery which is about 2400watts to my understanding. We would like to link the panels together in series although we do not plan on shading, this would ensure the panels produce the best scenario from my understanding.

Panels would be something 200w a piece x2 to make 400w array… something like BougeRV specs listed below.

We would like an option to add shore power (120v) to an enclosure so we can operate with or without solar panels as site needs change, this can be something as simple as a Victron charger that will charge the batteries since we run off the batteries. What is a safe charging amperage? Should it roughly match the panel output?

Is there a way to determine reserve power time where sunlight is not present at all? I am looking for something around 1.5 days on average backup with a high-output amperage charging circuit.

We would like to run the CerboGX to control some relays and have remote access, it looks like it keeps recommending the SmartSolar MPPT 150/70 Tr VE.Can series MPPT in this instance. Is this correct? Other MPPT would only be bluetooth capable?

BougeRV Specs:

Maximum Power (W) - 200±3% W
Open Circuit Voltage Voc (V) - 36.4V±5%
Max Power Voltage Vmp (V) - 31.7V±5%
Max Power Current Imp (A) - 6.3A±5%
Short Circuit Current Isc (A) - 6.6A±5%
Solar Cells Efficiency - 25%
Series Fuse Rating - 15A

Solar Zone 3, Arkansas specifically but normally Texas area.

In sum this sound quite good.
But I would recommend you more battery capacity. The 200Ah is about 2,4kWh, and this might be not enough as you plan a continous draw of 55-60W. This alone is about 1,4kWh. In addition you have some short time consumption, I guess. So you might have a total consumption of 2kWh per day. To get this energy from a 400Wp solar system every day will be difficult.
This might work in a region where you have 12h of sunshine every day, but as we don’t know where you are located this is hard to say.
So in best case you increase the solar power and the battery capacity. If you can guess the forecast, it might be enough to encrease the battery only.

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You can use a 100/50 and connect to the Cerbo with a ve direct cable. You don’t need 150/70; that’s quite a step up to the enthusiast range.

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Thank You

Apologies, Solar Zone 3, Arkansas but normally Texas. I would also like to add a shore power 110/120 charger something maybe putting out like 20A, is there a Victron product you recommend?

Also What is my purchase list from Victron?

100/50 MPPT
Shunt? If so, which is recommended?
CerboGX
Battery Protect? If so, which is recommended?
Anything else recommeded by Victron?

If you want to keep it simple, you can get a battery like this with Victron Communication. You won’t need a shunt or battery protect. You will need at least a 20-30A AC charger. There are plenty from Victron. 12V 300Ah Pro Series - LiFePO4 Cranking & Deep Cycle Lithium Battery (Dual Purpose)

I totally agree with your recommendation if it were local but this will be remotely managed from 10 hours away with critical systems on it so Bluetooth is a no-go.

Everyone else in my industry is doing a setup like I am mentioning, just not sure if they are running battery protects or not. Almost everyone has a shunt it seems in the mix. All are using a CerboGX, just hard to get a full list from anyone who is running systems like these because most paid to have them built.

So I guess with mentioning the above, would you recommend a battery protect? A buss bar? Etc. a lot of these devices are IP POE but we will be pushing them with 12vdc to keep the watt draw a lot lower as was suggested to me.

I’ve maintained a lot of solar platforms around this wattage just never built one from ground up that wasn’t already engineered if that makes sense.

No, you connect the battery to the cerbo along with MPPT and can monitor it on VRM. * Victron Comms - CANBUS entire string of batteries to Victron Ecosystem

This looks long but he sets up 2 of them. https://www.youtube.com/watch?v=pIXSKpi-TRo

Owen,

If I decided to go with the Epoch batteries, I would only need what then in addition? CerboGX and a 100/50 MPPT controller? No battery protect? As far as charging or providing a shore power I see they have a 12vdc 50a charger (Epoch) would that be recommended over lets say Victron’s 12/30 or 12/50 charger?

Just trying to guage an idea that will enable me to make this both solar and shore power when required. In that case would you recommend the 2x panels in series or parallel for a string?

Would you recommend if I am going to 300ah battery to move to more than 400watts of solar across the 2 panels? My total estimated wattage is no more than 60 watts.

Lastly if I decided to go with another lithium manufacturer to save money on batteries, I would just need a smart shunt and what a Victron VE.Bus BMS to make everything work? I am just concerned about battery replacements as I am a dealer for a certain brand of batteries that are easily accessible vs a custom battery from Epoch. I can walk in a get batteries same day vs waiting on a shipment from Epoch.

I just want to be able to weigh out the different possibilities.

Thanks!

I don’t think there’s anything out there quite like the Epoch battery. You could go with a cheap lithium option, but then you’ll need a T-class fuse or something suitable, plus a shunt and a battery protect for remote switching or low voltage disconnect. When you add up the cost of all those components along with the time to wire everything and run cables, the Epoch starts looking pretty attractive.

The great thing is you can use any DC charger you want. Once you know how much capacity you plan to use from the battery and how quickly you want to recharge it, you can size everything perfectly. If you’re only planning to take a 300Ah battery down to 30% before charging, then a 10A charger might be all you need. But if you want to draw it down to 0% and recharge it in a day, you’ll need something closer to 30A.

When you’re adding two panels, either series or parallel will work fine. Parallel is better for dealing with shading issues, but the current will be higher in the cables so you’ll need slightly larger wire.

I’m currently running 400W of solar on a 24V system configured as 2P2S. During winter, I typically get between 1kWh and 1.5kWh per day. In summer, that jumps up to around 2.5kWh. If you can achieve similar results, you’ll be getting anywhere from one-third to three-quarters of your battery charge from solar alone.

If you do decide to add another battery, you won’t need a VE.Bus BMS since those are specifically designed for Victron lithium batteries. You’ll just need a fuse, isolator, shunt, and battery protect if you want the ability to disconnect remotely or based on state of charge percentage.

I agree the Epoch seems to be a good choice, I am just concerned about battery replacement although most of my experience I’ve worked on most of these systems as SLA and not LiPo4 batteries I see most of these systems having bad batteries after 1-2 seasons needing replacement and we just swap out whatever batteries are bad.

In my experience let’s say the panels are 2x 185-200watt producing panels and a Tycon charge controller that’s 30a. The batteries I’ve maintained are 75ah SLA x4 which puts them in the 300ah range we are discussing. Their replacement although again not LiPo4 is only $215 each. Lithium looks like I can get reliable 200ah ones for about $600. If a shunt runs $100 or less and another $100 on a battery protect, I was simply looking at IF I had a bad battery replacing let’s say a 200ah for $600 or so is cheaper than $1500 for a single 300ah from Epoch.

It’s the BMS I am not sure about IF you needed a BMS for a 3rd party battery something that can be $300 to $1k alone. Searching YouTube it seems to be a split arena where ALOT of people are programming the smart shunts and going that route to installing multiple smaller batteries vs the one large one. I am not sure how Epoch warranties their battery and how hard of a time it would be to prove or disprove the battery was working correctly season after season especially due to the abuse on construction sites.

Is Epoch a great solution sure but for a construction site that’s remote seems like replacement might be harder and more costly. Maybe I am just being over sensitive because I see SLA fail and I am worried that LiPo4 will also fail. Regardless I don’t think I will discharge below 50% ever unless we get no favorable sun for days. That being said IF I went with Epoch do you feel their charge controller for shore power is a better solution than Victron or same/same.

Regardless your opinions are highly valuable to be and I am extremely thankful for your experiences. I would not question Epoch for my home or personal project like RV whatsoever but for this deployment I am nervous due to the cost of replacement.

Thoughts on the above in general?

You can stack multiple 100Ah batteries together to create a larger capacity system if needed. However, if you want large capacity, you’re typically better off getting one big battery instead. This approach offers several advantages, including simplified wiring with fewer connections and potential failure points, enhanced BMS capabilities since large batteries usually have more robust Battery Management Systems with higher charge and discharge amperage capacity, and better system integration as single large units often work more seamlessly.

Regarding charging and discharging, you can charge and discharge as much as your system requires, and you don’t need to worry about maintaining specific charge percentages for optimal performance. However, you should avoid keeping batteries at 100% charge continuously or leaving them at 0% for extended periods, as this can impact longevity.

The key is finding the right balance between capacity, cost, and reliability for your specific deployment needs.

12V 50A Battery Charger from Epoch looks ok, but is also expensive. It looks like it will only do lithium, so you won’t be able to use it for other chemistry. It is IP 67, which is good. The Victron IP67 is only 25A. The Victron is universal, and you can adjust the charge current and select the chemistry.

Even though that 300ah battery is more expensive I think it’s the best route in just concerned about if it goes bad let’s say 2 seasons in but hopefully won’t with all the handshakes it does with victron.

Can you assist with calculations at let’s say 60 watts max what time of run time no sun this could produce and also what the recharge rate would be if I tied the panels together realistically with 400 watts worth of panels (2x200) with the following specs on a 12vdc…

|Max Power at STC|200W|
|Open Circuit Voltage|36.5V|
|Short Circuit Current|6.86A|
|Optimum Operating Voltage|31.3V|
|Optimum Operating Current|6.38A|
|Maximum System Voltage|1000VDC|
|Maximum Series Fuse Rating|15A|
|Module Efficiency|20.7%|

I was seeing something like maybe 2.3 days but not sure if my calculations are right off that 300ah battery and a recharge of about 9 hours off solar when taking into account my load.

Again I’m not use to solar so this isn’t an easy task.

TIA!

At 60W, you will get 2.3 days, maybe a little more from a 300AH battery. I have a 200W panel, it’s mounted flat and winter ATM. I am getting 0.4-0.5kwh a day from that, so your worst production with 2x200W will be slightly less than 1kwh a day.

Good info. Any idea on recharge rates? Even if it wasn’t producing more than 50% curious what the amp output would be to battery after my 5a load.

This is a 200W panel on a 12V system I have. I get just over 6amps max from the controller between 10am and 1pm. You will have double with 2x 200w. You will get more during summer but you need to design your system for winter.

Sounds good thanks for all the info. What panel are you running?

It’s just a dirt-cheap panel from the 4x4 centre. I have it across the bow of my tinny to cover the carpeted cast deck. It just keeps the sun and water off. I have 10m lead with an Anderson plug into the shed and charge my 12V batteries.

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