Power station build - choosing battery

[Rednecktek]

Nope, that's an 8s for 24v batteries. You need a 4s.

A 1500w cooker would make things easier for sure.

 

[Rednecktek]

I'm not good with understanding the ah and converting.
Combining 4 would then give me a 12.8V system, and 3865Wh, that was my thought process, but that reflects to 300ah right?
Thats okay.

You're fine, you've got the basic idea down and your numbers are close enough. Don't panic.

304ah × 12.8v = 3891wh

A 1500w cooker would run for 2 hours and still leave room for lights and small fridge.

 

[Jahlovje]

Giving it a second thought, perhaps it would just be better to go with the following setup:

An induction cooker when at campsites that have electricity an plug it into directly without the powerstation.
A gas cooker when being offgrid (which is not as common as being at a campsite)

And the following configuration for eveything else:

100ah battery like https://www.amazon.de/-/en/Temperat...fos.d85e497d-ab66-4790-acf8-e520aaf28cd3&th=1

2000w inverter from renogy
Redodo 20ah charger
Renogy Rover 40ah mppt

And if needed, I can always add a second batter in parallel right?

 

[AshleyL]

Docan? Docan recent reputation kinda horrible if you do a search about it for past year results.

Stick with Shenzhen Luyuan Technology Co., Ltd.

 

[Rednecktek]

A 100ah battery isn't going to feed a 2000w inverter, you'll need at least 2 batteries for that. Or the big battery build which gives you 300ah in the same-ish physical space as a 100ah.

40a will get you about 400w of solar panel. You can always add more chargers later but the cost difference between a 40a and a 60a is less thsn another 40a and less space.

Cooker can go either way.

As for Docan, personally I've always been happy with my orders and they're always better than AliSeller5551212.

Plus, thet have EU stock if that makes things easier.

 

[HarryN]

Your life will be a lot easier if you purchase pre-made Li batteries.

The savings of home built vs buying a commercial battery are not as significant as they once were.

The biggest mistake most people make in building a power station, including the commercial offerings, is far to low of battery capacity. As an example, your original post would need something more like 4 x 100 amp-hr @12 volt equivalent to work reliably. That is approaching 75 - 100 kg by the time it is all in the box.

 

[Rednecktek]

Your life will be a lot easier if you purchase pre-made Li batteries.

Easier? Yes, maybe. As fun? Not even close!

 

[Jahlovje]

Your life will be a lot easier if you purchase pre-made Li batteries.

The savings of home built vs buying a commercial battery are not as significant as they once were.

The biggest mistake most people make in building a power station, including the commercial offerings, is far to low of battery capacity. As an example, your original post would need something more like 4 x 100 amp-hr @12 volt equivalent to work reliably. That is approaching 75 - 100 kg by the time it is all in the box.

I guess I have to agree with you. A 300ah done DIY would cost me roughly 700 usd, an equivalent 300ah (the cheapest I can find) is 640 usd.

So much for my research

And I do agree with you Rednecktek, it must be fun, and I'm looking forward to making holes in a tool box, but when it comes to electricity, it's fun if you know what you're doing, for me it's just insecurity and stress

 

[HarryN]

Yes, but look at how much you are learning just by doing the research - it is a lot.

The renogy rovers are an exceptionally poor mppt charge controller. The reason is that they have very high standby power draw - even at night, and the real world operation does not match the manual very well. Also if your battery ever goes low and trips the BMS, the rover cannot recover it, as it pulls it's operating power from the battery - not from the sun.

I built my portable power station using a bogart engineering PWM solar controller and the monitoring, but victron also makes nice controllers.

I am a fan of 24 volt systems if you can swing it.

A lot of DC refrigerators come in 24 volt or dual 12 / 24 volt.

USB ports are similar - many will run on 12 or 24 volt.

 

[HarryN]

It is worth considering the idea of building your power system in two different boxes.

Box 1 for the DC portion, batteries, USB, DC connections, chargers, perhaps some SB 50 or larger connections to power the inverter.

Box 2 for the AC related items, or even just have the inverter mounted in the vehicle and plug it into box #1 as needed.

This is a good way to simplify it all in terms of budget, space constraints, and weight distribution.

 

[Jahlovje]

Yes, but look at how much you are learning just by doing the research - it is a lot.

The renogy rovers are an exceptionally poor mppt charge controller. The reason is that they have very high standby power draw - even at night, and the real world operation does not match the manual very well. Also if your battery ever goes low and trips the BMS, the rover cannot recover it, as it pulls it's operating power from the battery - not from the sun.

I built my portable power station using a bogart engineering PWM solar controller and the monitoring, but victron also makes nice controllers.

I am a fan of 24 volt systems if you can swing it.

A lot of DC refrigerators come in 24 volt or dual 12 / 24 volt.

USB ports are similar - many will run on 12 or 24 volt.

Would you mind helping me understand, why a 24V system is better, or even why it is intended to use?
I have no idea what even differentiates them

 

[Bluedog225]

Volts times amps equals watts.

Per math, higher voltage means fewer amps.

Fewer amps can be carried by smaller wire.

Smaller wire, fuses, etc can be meaningfully cheaper.

Many go to 48 volt for this reason.

 

[Jahlovje]

So If i'm lets say building a 24v system:
a 100ah 12 volt, is equivalent to 50ah.

Any "changes" looking for 2000w inverters? a 2000w 12v system is 2000w 24v system, all the same?
(sorry, this is childs play for you guys, I apologize!)

 

[Andrewr05]

So If i'm lets say building a 24v system:
a 100ah 12 volt, is equivalent to 50ah.

Any "changes" looking for 2000w inverters? a 2000w 12v system is 2000w 24v system, all the same?
(sorry, this is childs play for you guys, I apologize!)

Nope, a 2000w 24v inverter will output the same 2000w of 120/240v power.

 

[SupraSPL]

Amazon has an Ecoworthy 60A MPPT for $129. The best value MPPT as far as I can tell. It takes the BT-02 Bluetooth module which is $20 from ecoworthy. Also sold as "Bateria" if you prefer white color. They are both rebranded iPanda esmart4, 150V solar input and work on 12V 24V 36V or 48V batteries.

I measured 93% conversion efficiency with 40V solar panels on 12V batteries but it is hard to measure be cause the solar voltage varies constantly. I measured 95%+ efficiency using them as 36V to 24V buck battery chargers which is easy to measure because of steady current. Standby power is 1.5W.

 

[SupraSPL]

I just saw they have a 100A 250V version now for $236 branded isunenergy and Im pretty sure also uses the BT-02 Bluetooth module

 

[Jahlovje]

This is a lot of information for me
Spent like 6h of researching and looking prices and making a list, but then I was just like - again, what are my needs

I'm definitely going with this option:
- When at campsites, just plug the damn induction cooker into the grid
- When off grid, just buy the damn 80$ gas cooker and suck it up

That left me with the following:
- Two phones
- One laptop/tablet (probably tablet, you're on vacation)
- A fridge that runs constantly
- A couple of battery powered flood lights (for fine dining at nights)
- an electric scooter that needs recharging once a week if even

I basically need the inverter just for that scooter. And a 1000W inverter will be enough, and if later in life, I need more, I can always upgrade.

To me, it makes a lot more sense, to get as bigger the size battery as possible, just to be able to run these things for as long as possible (a week max, but less), without the use of solar (at the moment), because the biggest usage is the fridge.

I'm leaning towards this 12V:
300ah battery
Victron MPPT 100V 50 Amp (in the future it only has to get me through, filing solar)
1000W renogy inverter
Redodo 40 ACDC charger

as my main setup.
Solar panels (in the future).

I can top up my powerstation before going on a trip, and worst case scenario (when I run out of power), I can always put the powerstation on my electric scooter, sit on it, a scoot to the nearest grid (joke) (meant to say, buy the damn panels, and hook it up)

Makes sense?

And by the way, I appreciate every single comment, you guys are legends!

What would be a cheaper alternative to the above in 24V?
2x 100ah in series is already cheaper.. and more Wh..

​

 

[Andrewr05]

I've been running into that issue for years now.
But I enjoy researching things as much as I do bargain hunting, as much as I do putting it all together when I get it.

But that's also how you end up saying "Well... for only $20 more you can get X product rather than Y but than for only $50 more than that that you ca........"

It's a slippery slope.

Spent like 6h of researching and looking prices and making a list, but then I was just like - again, what are my needs

 

[Bluedog225]

Works good. And fast.

 

[Andrewr05]

Works good. And fast.

Those do indeed work wonderfully, I've cooked a crap ton with mine.

And the canisters are relatively cheap too.