Simple electrics set up (Renogy based)

[lucysd]

Hello everyone,
i'm a total beginner in the electrics topic. Was reading this forum for a week, find it very informative but i still have some (many!) questions. Would really appreciate if someone could give me a hand. (And please excuse my English, i'm not a native speaker)

So, we are going to buy 200W solar panels and 100Ah LiFePo4 for our van. Main consumers would be 60W compressor fridge and 2kW chinese webasto in colder months + few phones, laptop, led. We travel for a long time and sometimes camp at one place for 2-3-4 days.

Does this set makes sense to you? Do we definitely need something else?

Renogy 12V 100Ah Smart LiFePo4

12V 100Ah Smart Lithium Iron Phosphate Battery

The Renogy Smart Lithium Iron Phosphate Battery enables auto-balance among parallel-connections and provides more flexibility for battery connection thanks to its RJ45 communication ports. If you are searching for a deep cycle battery for caravan, cabin, or marine use, then this lightweight...

eu.renogy.com

DCC50S 12V 50A Dual Input DC-DC Battery Charger with MPPT

DCC50S 12V 50A Dual Input DC-DC Battery Charger with MPPT

The Renogy 50A Dual-Input DC-to-DC MPPT Battery Charger can utilize connected solar panels or an alternator linked to a starting battery. It's a smart way to keep fully charged and off-grid longer whether you're using Flooded, Gel, AGM, or Lithium batteries.

eu.renogy.com

BT-2 module

BT-2 Bluetooth Module for RS485 Port

The BT-2 can connect to Renogy charge controllers with a RS232 port and is used to pair charge controllers with the Renogy APP.

eu.renogy.com

We have 2000W modified sine wave inverters. Someone said it should work fine for the fridge if we charge it with 12V.
And guess we'll check aliexpress later for the charger as it is way to expensive on Renogy website.

And my questions are:

1. Is DC-DC with MPPT better than separate devices? Renogy one is cheaper (i guess) and just looks easier to set up for a total newbie like me. Are there any reasons why people still prefer separate Victron devices for example?
2. Do we need two BT-2 modules for battery and for DC-DC or one module connected to DC-DC would also show me info on the battery? Should we also (or instead) get Renogy monitor screen? I read some bad reviews about Renogy app.
3. I saw some new 100Ah battery with self-heating & Bluetooth on Renogy website. Guess it won't fit under the seat but still wonder - is it better than the one i mentioned above?

12V 100Ah Pro Deep Cycle Lithium Iron Phosphate Battery w/Bluetooth

High quality solar system meets your energy need. Go and start green life with our excellent solar products.

eu.renogy.com

4. Still considering other brand 100Ah battery. Have you heard of Enjoybot? How bad/good it is comparing to Renogy? All i can see is that it is 100EUR cheaper.

ENJOYBOT 12V 100AH LiFePO4 Lithium Battery High & Low Temp Protection Deep Cycle Rechargeable 1280 Wh - Built With 100A BMS

Enjoybot 12V 100Ah lithium battery is a deep cycle battery made of lithium iron phosphate, only 23.6lbs, offers a lightweight, efficient, and long-lasting green power solution. With impressive 1280Wh capacity and up to 5000 cycles, this deep cycle battery provides unparalleled sustained power...

enjoybot.com

Thanks and greetings from Poland

 

[roadtripper]

And guess we'll check aliexpress later for the charger as it is way to expensive on Renogy website.

Personally with anything managing lithium I'd stick to reputable brands from known sources. There is a huge amount of energy in them and you are fitting them under your seats. There are many areas to save some cash in, this is not.

1. You want MPPT in solar not PWM. All in one devices save space so great if that's important to you. It does mean if one function fails you might need to spend more on replacements. Also you may have to compromise on one of the functions.

3. Self heating is ideal if you are regularly charging where temperatures inside the van drop below zero. I'd say it's a nice to have in the UK but I suspect more important in Poland. If there prices are close enough get self heating, the battery bank is (hopefully) a long term investment. Note that you either need batteries that self heat or a charger that cuts charge at zero.

With your inverter I'd suggest going full sine wave. They really are not that different in price these days and tend to reflect the quality of the inverter. If you are running the fridge on 240v then it's pretty vital it works and doesn't let you down. The Renogy ones do a neat trick of being able to route your EHU through them so they change over from external mains supply to running the inverter. One important point to consider is most battery manufacturers recommend 100ah battery per 1kw of inverter to keep current levels under control.

Your English is fine Welcome to the forum.

 

[Higgidav]

I have the self heating battery under my drivers seat. I have fitted it stood up but I think they can also be fitted laid on the side. Last winter the temperature in the van went below zero a lot so I was please I went for the self heating battery as the cost difference was marginal.

 

[drinfinity]

I have 100Ah Renogy, the same DCDC as you plan, 100W solar, and one BT2 module on the charger. This will show you on the app the voltage on van and leisure batteries, and how much charge is going to each. I have the inbuilt Bluetooth on the battery, but its stage of charge estimate is generally wrong, so not really worth it.

The app also shows some history (maximum and minimum volts, current and power) on each day.

 

[drinfinity]

In a cold place the self heating could be useful, and I would get it instead of battery Bluetooth if I was buying again. The system automatically limits charge current when it is cold, although if I need to use the van in the cold I’ll have the heaters on and the battery will be warm soon enough.

I buy lots of stuff from AliExpress, and I have a cheap Veevor heater, but not a big Li charger that is going to be putting out 50 amps.

 

[lucysd]

3. Self heating is ideal if you are regularly charging where temperatures inside the van drop below zero. I'd say it's a nice to have in the UK but I suspect more important in Poland. If there prices are close enough get self heating, the battery bank is (hopefully) a long term investment. Note that you either need batteries that self heat or a charger that cuts charge at zero.

Hi, thank you so much for the answer. Guess we should consider self-heating battery and now looking at this Renogy item. Although it has only one review on EU site and not the best one. Too bad we can't fit self-heating + BT version under the seat as the price is much better.
About inverter and AC-DC charger - can you recommend any brands or particular models maybe? Or it's better to stick to the Renogy ones?

I have the self heating battery under my drivers seat. I have fitted it stood up but I think they can also be fitted laid on the side. Last winter the temperature in the van went below zero a lot so I was please I went for the self heating battery as the cost difference was marginal.

Thank you Higgidav. Are you talking about Renogy self-heating 100Ah battery or about bigger self-heating+BT version? If it's the latter one (19cm) did you have to adjust you seat in some way?

 

[Higgidav]

Hi,

I fitted the self heating 100Ah battery together with the Bluetooth plug in dongle. The Pro version has only just launched. If its bigger then it will not fit standing up.

 

[lucysd]

I have 100Ah Renogy, the same DCDC as you plan, 100W solar, and one BT2 module on the charger. This will show you on the app the voltage on van and leisure batteries, and how much charge is going to each. I have the inbuilt Bluetooth on the battery, but its stage of charge estimate is generally wrong, so not really worth it.

In a cold place the self heating could be useful, and I would get it instead of battery Bluetooth if I was buying again. The system automatically limits charge current when it is cold, although if I need to use the van in the cold I’ll have the heaters on and the battery will be warm soon enough.

Thanks! I was actually wondering how important it is to have BT module on the battery itself. I don't have any experience yet so don't know how i can use the info it provides. Some youtubers suggested it's better to get BT module on DCDC and screen monitor for the battery. Did you mean DCDC+BT-2 would give me enough information about my leisure battery too? Or for that i'd need to have battery with inbuilt BT like you have?

 

[drinfinity]

Did you mean DCDC+BT-2 would give me enough information about my leisure battery too? Or for that i'd need to have battery with inbuilt BT like you have?

Yes, DCDC + BT2 gives you enough. It shows voltage on the battery, and the charging current. If you have Bluetooth on battery, this will also show the load current. However, the current measurement in the battery reported through the inbuilt Renogy battery Bluetooth is not accurate, so it always underestimates the state of charge. For an accurate measurement you could add a smart shunt on the load side. Not really essential to start with, it just gives you some more numbers to worry about.

 

[lucysd]

Sorry, two more questions.

1. If i buy Renogy Monitoring Screen for Smart Lithium Battery will i get accurate information on the state of charge?

Monitoring Screen for Smart Lithium Battery Series

High quality solar system meets your energy need. Go and start green life with our excellent solar products.

eu.renogy.com

Or i'd need more expensive monitor with shunt for this?

Considering ordering Renogy 100Ah Smart lithium battery with monitor and DC-DC + MPPT 50A with BT-2 module.

2. Is it true that Renogy 2-in-1 dc-dc with mppt device would charge battery slower (if i have 200-300W solar panels) as it has limit max 25V (guess i explain it completely wrong, sorry about that) and also that its charging current dividing MPPT and alternator in half?

 

[roadtripper]

About inverter and AC-DC charger - can you recommend any brands or particular models maybe? Or it's better to stick to the Renogy ones?

Those are two different things. You can get combined units (I have one on my boat) but they tend to be larger than the space available in small vans.

If you want to charge the battery from EHU then CTEK, NoCo and Victron are all good brands. For install a popular choice is the Victron IP22 series.

 

[drinfinity]

Sorry, two more questions.

1. If i buy Renogy Monitoring Screen for Smart Lithium Battery will i get accurate information on the state of charge?

Monitoring Screen for Smart Lithium Battery Series

High quality solar system meets your energy need. Go and start green life with our excellent solar products.

eu.renogy.com

Or i'd need more expensive monitor with shunt for this?

Considering ordering Renogy 100Ah Smart lithium battery with monitor and DC-DC + MPPT 50A with BT-2 module.

2. Is it true that Renogy 2-in-1 dc-dc with mppt device would charge battery slower (if i have 200-300W solar panels) as it has limit max 25V (guess i explain it completely wrong, sorry about that) and also that its charging current dividing MPPT and alternator in half?

1. The monitoring screen alone will use the current reading from the battery system. My experience (n=1) is the Renogy battery under-reads the charging current. Therefore if you want an accurate state of charge, you need the shunt. However, I just look at the voltage as an estimate.

2. Your solar panels will need to have a maximum voltage within the rating of the charger. If it is one 300W panel and it has the correct voltage you are good. If it is 3x100W panels, connect in parallel and you are good.

The MPPT will use as much solar power as it can before feeding in from the alternator. So if you are driving down the motorway on a sunny day, it will push 50A from the solar.

 

[drinfinity]

(Before anyone else points out the deliberate error, 50A at 12V is 600W and we are talking about a 300W panel, but the point is it prioritises the solar feed…)

 

[lucysd]

Hello again! Finally we bought our batteries, Renogy DC-DC with MPPT and some other stuff. But we got kinda stuck when it came to the fuses and circuit breakers. Would appreciate if someone could clear things up for me again

1. Did we choose fuses of the correct type and with correct amperage? Not sure about the main fuse (the one after the batteries) - should we use 200A instead of 250A?
2. Isn't 70mm2 wire too big? We first thought about 50mm2.
3. What are your thoughts on 100A circuit breakers? Are they reliable enough? Saw some videos on youtube where they got activated at 50-70A.
4. Where to put 20A fuse: closer to the solar panels (on the roof) or closer to MPPT?

Would be happy to hear your opinion and advices! Thanks.

 

[drinfinity]

Solar panels - mine came with an inline fuse in the cables already, close to the panel.

For the line between vehicle battery and Renogy DCDC, at the battery end you can connect onto an existing empty fused terminal on top of the battery. I put another fuse close to the DCDC end, as your solar will also charge the vehicle battery.