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Complete solar novice, out to sea.

Tamara Mcneely

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Joined
Aug 23, 2021
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Hey guys and gals, I’m Tamara

So I need a few pointers with a yet to be installed system left in my hands after a recent breakup. I have a basic understanding of what needs to be done after studying with my ex a couple of years back, but with all life’s challenges we never got round to it, and I’m afraid I got rusty, as I do no electrical work on a regular basis. It’s a 24volt system he bought based on a youtube video that I think is linked to this forum. Our plan was to power a stationary camper. The hurdles he met (and eventually gave up on) were mostly attaching it to the existing camper electrical system. After a bit of personal research, I believe my inverter may be wrong as it doesn’t have a transfer switch, any further explanation on that would be much appreciated, as well as any opinions on what to do with the converter, the shore power fuse box etc…. Bypass them, or remove completely along with anything else? Again, I am a noob, so apologies if I sound foolish ?

Thanks!
 
Cool so this is not a marine application ;).
Welcome to the forum.

Please list the components your have so we no what your are working with and can give better advice.
First to know is if you have an inverter/charger or just plain inverter.
Product links help us get the details.
 
Haha, no, she’s solely land based ?
Thanks!
Here’s a list of the parts, more or less, he did get some different models but i‘m pretty sure they’re to the same specs. I also know that he got the batteries from big battery, not battleborn. I believe he consulted with them to check they were right for the system. There is no writing on them whatsoever though, so can’t confirm ?


Thank you!
 
Haha, no, she’s solely land based ?
Thanks!
Here’s a list of the parts, more or less, he did get some different models but i‘m pretty sure they’re to the same specs. I also know that he got the batteries from big battery, not battleborn. I believe he consulted with them to check they were right for the system. There is no writing on them whatsoever though, so can’t confirm ?


Thank you!
Please post a picture of your inverter and of your battery.
Maybe that will be enough info to get the ball rolling.
 
Here they are, sorry I can’t be more specific with the batteries, he apparently did confirm with the supplier they were suitable.
 

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Here they are, sorry I can’t be more specific with the batteries, he apparently did confirm with the supplier they were suitable.
Ok that appears to be a plain old inverter.

Is there an automatic transfer switch among your components?
 
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Can you please provide a picture of the converter?
The converter is usually inside the ac/dc distribution panel.
 
I’m certain there’s no transfer switch based on the list, I’ll check once I’m back though, does that mean I can use the inverter I have? Will check the converter too.
 
I’m certain there’s no transfer switch based on the list, I’ll check once I’m back though, does that mean I can use the inverter I have? Will check the converter too.
You can probably use the inverter you have with a discrete automatic transfer switch.
Your converter is probably not an effective charging solution for your battery.
If you go the discrete component route you will likely want to get a proper ac charger.

Alternatively you could sell your inverter and get an inverter/charger with built in automatic transfer switch.
This makes integration much easier and has a lot of advantages.
I urge you to consider an inverter/charger.

If you want more explanation of why its a good idea I will write it up on request.
 
I will take your advice, thanks! Where would be the best avenue to sell? I definitely wouldn’t turn down your reasoning as to why it’s a good idea ?. Lastly, hard as might, I can’t see anything online ref the issue he was having (Maybe because the solution is so obvious??!!) If you don’t mind, going on the assumption that the converter is not suitable, how would you best connect this system to the camper?
 
I will take your advice, thanks! Where would be the best avenue to sell?
You could try this https://diysolarforum.com/forums/inverters-and-all-in-one-units-for-sale.41/

I definitely wouldn’t turn down your reasoning as to why it’s a good idea ?.
Discrete inverters have have received very little research and development in probably a decade or more.
These were developed when lead acid was the only battery chemistry that made sense to target.
Inverter/chargers are eating the discrete inverter's lunch.

An inverter/charger is...
A built in automatic transfer switch.
An ac2dc charger.
An inverter.
If you need 2 or more of the 3 functions an inverter/charger is the way to go.

Low frequency vs high frequency
Low frequency inverters have substantial surge handling capability, think minutes at 125-150% capacity.
High frequency inverters usually have 2x surge but only for ~20ms.
High frequency surge capability is only significant to the marketing department of the inverter company.
Its very hard to find a discrete low frequency inverter.
Its a fairly common feature on inverter/chargers.

Automatic Transfer Switch(ATS)
A discrete ATS usually has a switchover time of ~100ms.
That means the clock on your microwave is likely going to need resetting.
Also a personal computer is very likely to reboot or possibly hang.
Also the alternating current is un-synchronized between the inverter and shore power.
That means when ATS switches it can be kind of rough on certain appliances.
With an inverter/charger its very common for the transfer to take less than 20ms and to be synchronized.
Your appliances won't notice the change.

Microprocessors
Because inverter/chargers are currently under active development they are gaining new features all the time.
The killer feature is an integrated microprocessor that makes a lot of other features possible.
As mentioned earlier the syncronized transfer is enabled by the microprocessor
With microprocessors comes the ability to have granular configuration of many functions.
The major ones are the charge and discharge profiles.
LFP batteries really benefit from the ability to fine tune the charger parameters.
The most important parameter in the discharge profile is the low voltage disconnect.
This allows your inverter to quit inverting before the BMS disconnects.
Legacy inverters usually have a low voltage disconnect which is too low for practical use with LFP batteries.
The commodity BMSs which are popular here are not designed to disconnect a significant load more than a handful of times.
You BMS protects your battery and your inverter's low voltage disconnect protects the BMS.

Lastly, hard as might, I can’t see anything online ref the issue he was having (Maybe because the solution is so obvious??!!)
What problem are you referring to?
If you don’t mind, going on the assumption that the converter is not suitable, how would you best connect this system to the camper?

Depends on whether you go with a inverter/charger or discrete automatic transfer switch.
Both will work but the topology will be slightly different.
 
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I don't want to write your converter off.
It may still be of some use, even if its just administratively disabled and left in place as a backup.
Like the first runner-up in a beauty pageant.
 
I don't want to write your converter off.
It may still be of some use, even if its just administratively disabled and left in place as a backup.
Like the first runner-up in a beauty pageant.
Thanks so much for that info! Well I’m happy to have a backup and use an inverter/charger as a primary. There is no shore power at all, nor will there be. So the problem was that we were unsure about how to most easily integrate the inverter, busbar etc into the existing camper electrical system/appliances. Again, it’s probably fairly obvious to those in the know, but he didn’t get very far, and I’m in the same boat. If I were to set up the system as the video had it, it would be fairly straightforward (I think), it’s just the camper part. Thanks again for your help!
 
Thanks so much for that info! Well I’m happy to have a backup and use an inverter/charger as a primary. There is no shore power at all, nor will there be. So the problem was that we were unsure about how to most easily integrate the inverter, busbar etc into the existing camper electrical system/appliances. Again, it’s probably fairly obvious to those in the know, but he didn’t get very far, and I’m in the same boat. If I were to set up the system as the video had it, it would be fairly straightforward (I think), it’s just the camper part. Thanks again for your help!
No generator either, confirm?

If there is no generator or shore power this gets easier.
No need for a transfer switch if there is no shore power or generator
Also no need for an ac charger is there is no shore power or generator
 
No generator either, at least not at the moment, this isn’t my main location, so it’s no biggie. Exactly, there will be nothing but solar ?
 
No generator either, at least not at the moment, this isn’t my main location, so it’s no biggie. Exactly, there will be nothing but solar ?
Allrighty then.

Do this at your own risk.
I take no responsibility for anything you may do.


All your electricity is going to come from the sun.
If you ever add shore power and/or a generator you will have to make some changes to your setup.

Test and check your inverter.
1. Test to see if there is continuity between ground and neutral.
2. power the unit up and there should be...
120 volts difference between hot and neutral​
120 volts difference between hot and ground​
0 volts difference between neutral and ground​
3. inverter should have a equipment grounding lug.
If you get anything different please report back.

The drawing represents the ac side of your ac/dc distribution panel.
Normally the master breaker is connected to the shore power inlet by some 10/2 NMD90 wire.
You will change that to connect it to your inverter.

tamara_no_ats(2)-ac.jpg

Since this is a stationary setup of a typically mobile system you will want to read these 2 links.

See the bit about pounding a copper rod into the ground.
Also see the bit about using GFCI outlets for kitchen, bath and outside.
Also see the bit about there being exactly one and only one bonding point.
That single point will be bonded to the frame and to the planet.

Connecting the system to the dc side of the distribution should be pretty straight forward but I need to see pictures of the ac/dc distribution panel.
Pictures should include the one with the door open to show the ac and dc maps plus 2 more pictures with the cover off to show the ac and dc sides of the panel.

@FilterGuy please check my work.
Doubly important because I'm fasting today which means no coffee.
 
If you have kids or similar you may want to do more to disable the converter than just turning the breaker off.
 
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