Right Questions to Ask when buying 'All-in-one' Battery

[geekgonewild]

First of all, THANK YOU – I’m thrilled to find this forum with the scope & depth of knowledge I found here!


My project is to install Solar Power System on my trailer, which could handle 3,000-3,500 Watt continuously, with 3,500-4,000 peak wattage – essentially mirroring 30 AMP shore connection.

Core items in my future setup, specs of which match:
- Six 300 Watt solar panels Nom Voltage: 30V, VOC: 40V, 9.8A. (Already purchased)
- All-in-one 48V battery system with about 10kwh capacity & 80amps of continuous current. (Will be purchasing)
- Off-grid All-in-one Charger+Inverter (48V to 110AC + 12V DC) and (150VOC, 80A & MPPT). (Will be purchasing)

Weather conditions: -5F to +110F, 20%-80% humidity, up to 80mph winds (including while driving).

What I need is help on all-in-one battery system I’m buying from China. Specifically, what are the right (or all) questions I need to ask?

So far, questions from my lists are (I enumerated them for easier reference):

1. Low & High Voltage Protection?

2. Low & High Current Protection?

3. Low & High Temperature Protection?

4. Does it have passive and active cell balancing?

5. Customization: Option to install heating pad (film or plate)? And, how easy to install without voiding warranty.

6. Installation: min space needed on Sides, Top & Bottom.

7. Connections, Monitoring or Communications? (including for applying changes): Bluetooth, Wifi, Wired? What software available?

8. Does it talk other components, like Off-grid All-in-one Charger+Inverter - I'm looking for.

9. Shipping, handling within/outside of the US.

10. Inspection (at the port of entry and elsewhere)

I would love to hear from everyone to expand on these questions and topics and share their list(s).

Again, thank you for sharing your thoughts from your past experiences to help others, like me.

 

[Samsonite801]

Those are all great questions... The only one I could think I'd want to add:

11. Would you be able to sell me a custom model where the lid isn't glued on and sealed, so I don't have to cut it open with a die grinder later after the warranty expires?

 

[MichaelK]

Could you please go into a bit more detail about your loads, and at what time of the day you expect to be running them. I know you stated 3000W continuous, but what kinds of loads are those and how long will they be running.

What I've found to be very true is that for whatever load you are trying to run, you need at least 2X the number of panels as the load. That is is the load really is 3000W+, then you are going to need 6000W+ of panels to fuel it.

I'd say as configured, your setup is going to disappoint you.

 

[geekgonewild]

Could you please go into a bit more detail about your loads, and at what time of the day you expect to be running them. I know you stated 3000W continuous, but what kinds of loads are those and how long will they be running.

What I've found to be very true is that for whatever load you are trying to run, you need at least 2X the number of panels as the load. That is is the load really is 3000W+, then you are going to need 6000W+ of panels to fuel it.

I'd say as configured, your setup is going to disappoint you.

I certainly failed to indicate that the heaviest load in the travel trailer is its air conditioning (one 15kBTU unit) with 2k-2.5k running and about 2.5-3k peak watts in extreme cases (~120 F outside temps) when sun is nearly vertical, when panels also near their peak wattage generation. Coupled this with 10kW battery bank, math checks out even with adding for a few hours of evening cooling when sun is low.

With 10kwh pack of usable energy, I run 3kw loads for over 3 hrs with all solar panels disconnected while upgrading from 12v to residential 48v solar panels. Received it 10 days ago; its been solid so far.

I am planning to delete this post because I mistakenly posted it in DYI forum, But, I would appreciate any thoughts on how this system can disappoint me to avoid any problems by learning from you.

 

[geekgonewild]

Those are all great questions... The only one I could think I'd want to add:

11. Would you be able to sell me a custom model where the lid isn't glued on and sealed, so I don't have to cut it open with a die grinder later after the warranty expires?

I will add this great point on serviceability. I’m planning a bit larger stational – this time - DYI setup for our family cabin. I will certainly want to be able to easily service the unit, say replace or upgrade cells or other components.

I recommend all-in-one battery only if someone who cannot do DYI.
I much prefer to a custom DYI built because of many things, like 1) when someone else builds, they will take shortcuts, because they have to be profitable; 2) with dyi one has solid control over quality of parts, assembly & labor (thx to learning opportunities from forums like these); 3) build to your initial needs but also with options to cost-effectively scale up to meet your future needs; 4) you build it, you’d know how to fix it; 5) ….

I am planning to delete this post because it is posted in this forum by mistake. You can PM me if you have questions.