(Yet another) Lithium Upgrade!!

[lonnie]

Good evening all,

Thanks to the wonderful information I've gathered from other threads (particulary [Broken Link Removed]) and help from DJL220 and Two on Tour I think I've finally got a plan for my upgrade.

The kit is ordered (thanks mainly to RogerIvy) and with the help of the diagrams in the post above, I've tried to map out the installation. I dont have a great amount of space in the 'garage' under bed and the diagram below is to scale.

I'm limited with Visio skills and the cabling in real life will be more ordered - but I guess it shows the general positioning.

Does it look ok to you experienced funsters? Or is it a dog's dinner?

My main concern is whether I'm trying to get two much kit in a confined area. My plan is to sort of 'box' the install in with ply but with large mesh 'windows'. Something like this on the front and end panels...

I'd welcome any feedback.

TIA, Martin

 

[DJL220]

Hi Martin
I would take the feed from you Alternator for the XS not the starter motor. I would also make sure there is ample room around the install for airflow if you are looking at boxing.
I added 2 mmpt on my install as below.
1) 100w panel (75/15)
2) 2 x 175 w panels (100/30)
Sure as they are not the same size you should do the same.
Regards
Darren

 

[Two on Tour]

Hi Martin
I would take the feed from you Alternator for the XS not the starter motor. I would also make sure there is ample room around the install for airflow if you are looking at boxing.
I added 2 mmpt on my install as below.
1) 100w panel (75/15)
2) 2 x 175 w panels (100/30)
Sure as they are not the same size you should do the same.
Regards
Darren

I think that Martin is referring to the starter (cab) battery on the feed for the XS.

 

[lonnie]

Hi Martin
I would take the feed from you Alternator for the XS not the starter motor. I would also make sure there is ample room around the install for airflow if you are looking at boxing.
I added 2 mmpt on my install as below.
1) 100w panel (75/15)
2) 2 x 175 w panels (100/30)
Sure as they are not the same size you should do the same.
Regards
Darren

Thanks Darren, apologies, I should have put starter battery - or just cab battery

 

[ianp]

Might you benefit from an RCD on the inverter output too, or possibly put it downstream (if suitable) from the change over switch (relay) which should be 'break before make' also I think....that way the one RCD serves both EHU and Inverter inputs to sockets etc.....again....I think !
In terms of 'panelling' I'm intending to use clear polycarbonate sheet ( 10mm but think 5 or 6 would suffice) as it has a good fire resistance and is easy to work and very 'visual'...... and in order to maximise surface area I'm intending to use both sides and use copper studs to pass through the sheet etc where suitable.....!

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[StillGoing]

Personally, with LifePO4, I’d fit an Ablemail AMT12-2 battery maintainer instead of the Battery Master.

 

[lonnie]

Might you benefit from an RCD on the inverter output too, or possibly put it downstream (if suitable) from the change over switch (relay) which should be 'break before make' also I think....that way the one RCD serves both EHU and Inverter inputs to sockets etc.....again....I think !
In terms of 'panelling' I'm intending to use clear polycarbonate sheet ( 10mm but think 5 or 6 would suffice) as it has a good fire resistance and is easy to work and very 'visual'...... and in order to maximise surface area I'm intending to use both sides and use copper studs to pass through the sheet etc where suitable.....!

Thanks Ian, two great points. I like the idea of the polycarb sheet!

 

[lonnie]

Personally, with LifePO4, I’d fit an Ablemail AMT12-2 battery maintainer instead of the Battery Master.

Cheers. More money

 

[bigtwin]

I suspect that your current solar configuration will be current limited by the 90W panel. Probably better to use a separate controller for that panel.

Ian

 

[ChrisL]

Personally, with LifePO4, I’d fit an Ablemail AMT12-2 battery maintainer instead of the Battery Master.

Can I ask why? I have cbe battery maintainer which starts charging the engine battery once the leisure battery gets over 13.6 volts, my Fogstar Drift battery is set to float at 13.61 volts and the battery maintainer keeps the engine battery at a steady 13.1 volts providing up to 4 amps if it is required. The CBE unit is £40 the AMT12-2 is £90.

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[lonnie]

Hi Martin
I would take the feed from you Alternator for the XS not the starter motor. I would also make sure there is ample room around the install for airflow if you are looking at boxing.
I added 2 mmpt on my install as below.
1) 100w panel (75/15)
2) 2 x 175 w panels (100/30)
Sure as they are not the same size you should do the same.
Regards
Darren

Interesting thanks Darren. My current setup is the 90 and a 175w into a 75/15. It seems to work but I'll double check and might need to keep the 90w on the old controller.

 

[ChrisL]

You have your solar panels wired in series which will make them less efficient if partially shaded and also they will deliver less amperage then wiring them in parallel.

 

[Lenny HB]

That confused me, you have labeled your mains sockets as 12v.
I fitted a RCBO on the output of my inverter, neutral has to be grounded for a RCD/RCBO to work, not all inverters allow this.

As bigtwin says the solar output will be limited by the 90w panel. I would never connect panels in series on a Motorhome far better in parallel.

Biggest problem I had in a small space was getting tight bends on large cables.

Here is mine in an unfinished state.

 

[lonnie]

I suspect that your current solar configuration will be current limited by the 90W panel. Probably better to use a separate controller for that panel.

Ian

Thanks Ian. I must admit, I never seem to get high wattages, even on bright and cool days. The max I've had in the last month was 152w...

I actually added the 90w to give the existing 175w a little 'boost' but it seems I may have achieved the opposite!

"A fool and his money...etc"

 

[Lenny HB]

The CBE unit is £40 the AMT12-2 is £90.

Went off the CBE unit after having one fail costing me a starter battery.

The Ablemail is only £60.

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[lonnie]

That confused me, you have labeled your mains sockets as 12v.
I fitted a RCBO on the output of my inverter, neutral has to be grounded for a RCD/RCBO to work, not all inverters allow this.

As bigtwin says the solar output will be limited by the 90w panel. I would never connect panels in series on a Motorhome far better in parallel.

Biggest problem I had in a small space was getting tight bends on large cables.

Here is mine in an unfinished state.
View attachment 952558

It's a thing of beauty already Lenny, you must have dainty fingers

I'll do more research on the cabling of the panels and it looks like getting them parallel is a no brainer!

And good spot, I'll correct the voltage on the sockets, thanks

 

[ChrisL]

Went off the CBE unit after having one fail costing me a starter battery.

The Ablemail is only £60.

Sorry to hear that Lenny, I hope i'd spot that if mine were to fail as the battery voltage is displayed on the b2b section of the Victron app and the Vanbitz Growler/immobiliser sends out a low voltage text as I discovered when the IP22 went to storage mode which wasn't high enough to trigger the CBE, easily fixed by raising the storage voltage to over 13.6 volts.
Re. The cost of the Ablemail, they've gone up in price unless you know where to get a discount.

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[DDJC]

Had a Fogstar Drift 280ah put in a few months back. Monster battery. The phone app tells me that it is 310ah. Recommend it.

 

[lonnie]

I suspect that your current solar configuration will be current limited by the 90W panel. Probably better to use a separate controller for that panel.

Ian

You have your solar panels wired in series which will make them less efficient if partially shaded and also they will deliver less amperage then wiring them in parallel.

So I've been giving this some thought after Ian and Chris's (and Lenny's) feedback and I have another question to ask if that's ok?

I now plan to leave the existing controller in place soley for the 90w panel and then parallel the two 175w into the new controller....

But, I'd rather not have to drill another hole in the roof so wondered if it would be possible to add the 90w as another 'string'.....

or will I have the same detriment of the 90w panel being in the same 'system'?

p.s. I'm still researching whether I can ground the neutral of the Giandel inverter!

 

[ChrisL]

So I've been giving this some thought after Ian and Chris's (and Lenny's) feedback and I have another question to ask if that's ok?

I now plan to leave the existing controller in place soley for the 90w panel and then parallel the two 175w into the new controller....

View attachment 952662

But, I'd rather not have to drill another hole in the roof so wondered if it would be possible to add the 90w as another 'string'.....

View attachment 952668

or will I have the same detriment of the 90w panel being in the same 'system'?

p.s. I'm still researching whether I can ground the neutral of the Giandel inverter!

This may help you decide how to wire your panels, you should be able to calculate the effects on your set up using the examples shown as a guide.

Using Mismatched Solar Panel Sizes in the Same Array

This blog post will teach you how using mixed and mismatched sizes of solar panels in the same array will affect the output of the entire array.

explorist.life

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[bigtwin]

But, I'd rather not have to drill another hole in the roof so wondered if it would be possible to add the 90w as another 'string'.....

or will I have the same detriment of the 90w panel being in the same 'system'?

You’re effectively paralleling all the panels. That’s ok if they have the same voltages, otherwise the voltage generated will be limited to that of the lowest rated panel (I suspect that would be less of a compromise than when you had them in series).

However, the best solution is to use two controllers. Could you not get both sets of cables through the existing hole, perhaps with a multi-cable gland on top?

Ian

 

[lonnie]

Thanks again both. The Explorist blog post was REALLY helpful thanks.

It helps me to see actual numbers so using the basic maths in the post, it looks like I'd see a vast improvement just switching to parallel (as the max voltages are virtually the same on the Victron panels)

It also reminds me that I added the 90w panel and saw a nominal increase of 4w

Hopefully my foolishness will help guide other funsters in the future!!

 

[bigtwin]

Thanks again both. The Explorist blog post was REALLY helpful thanks.

It helps me to see actual numbers so using the basic maths in the post, it looks like I'd see a vast improvement just switching to parallel (as the max voltages are virtually the same on the Victron panels)

View attachment 952717

It also reminds me that I added the 90w panel and saw a nominal increase of 4w

View attachment 952718

Hopefully my foolishness will help guide other funsters in the future!!

It’s good to see learning and acquired knowledge in action.

Ian

 

[Carpmart]

It's a thing of beauty already Lenny, you must have dainty fingers

I'll do more research on the cabling of the panels and it looks like getting them parallel is a no brainer!

And good spot, I'll correct the voltage on the sockets, thanks

Your colour coding and wiring plan on the panels is wrong too!

If you are doing series, you wire positive to negative of the next panel until you have completed the string, so you are effectively upping the voltage and reducing the amps. Useful as you need only smaller cables from the panels to the MPPT. I’ve started running my floor solar panels in series and I’m that impressed with the higher yield, I’m swapping the roof to series too! They kick in earlier and stay producing until later in the day due to higher voltage.

I’d run the pair of matched panels in series to the 100/30 and the smaller panel separately to your existing MPPT..

 

[ChrisL]

Your colour coding and wiring plan on the panels is wrong too!

If you are doing series, you wire positive to negative of the next panel until you have completed the string, so you are effectively upping the voltage and reducing the amps. Useful as you need only smaller cables from the panels to the MPPT. I’ve started running my floor solar panels in series and I’m that impressed with the higher yield, I’m swapping the roof to series too! They kick in earlier and stay producing until later in the day due to higher voltage.

I’d run the pair of matched panels in series to the 100/30 and the smaller panel separately to your existing MPPT..

Can you please let us see your comparison results as the above maths would tend to disagree with your post, also if you're going to rewire your roof panels to series, do a little test on your floor panels by putting them in partial shade and see what output you get, you can always move the floor panels but you can't easily move your roof panels out of shade.

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[Carpmart]

Can you please let us see your comparison results as the above maths would tend to disagree with your post, also if you're going to rewire your roof panels to series, do a little test on your floor panels by putting them in partial shade and see what output you get, you can always move the floor panels but you can't easily move your roof panels out of shade.

The above results are completely skewed by the 90w panel… I suggested keeping the 90w panel separate from his matched pair.

We specifically don't park in shaded areas so it’s of no bearing to me..

I’m aware of the pros and cons, but I’ve got three 200w matched panels on the roof and the (admittedly non scientific) test of the four 80w monocrystalyne folding floor panels run in 2s 2p so I can move the connected pairs easily, has provided me with all the ‘data’ I need to see to convince me that the pros for me of series, outweigh the cons!

We all have different use cases, I accept that, but for me it’s the right approach, I think!

Edit: Have a look at Roger’s views too!

Off Grid partial shading test

 

[cyberyacht]

Run my 3 panels in series but then they are matched units.

 

[StillGoing]

Run my 3 panels in series but then they are matched units.

Although mine are matched units, I wired them in parallel. I often find one panel can be in the shade while the remaining 2 are in the sun. If they were in series, one shaded panel would adversely affect the performance of the whole string of 3.

 

[lonnie]

I fitted a RCBO on the output of my inverter, neutral has to be grounded for a RCD/RCBO to work, not all inverters allow this.

Hi Lenny, I'd welcome your advice please (and any other knowledgeable folk!)

I contacted Giendel about their 2kw inverter...(I sent the image below to them too)

"I’ve been advised that I should install an RCD or RCBO between the invertor and the relay in the PDU but this would need the neutral to be grounded in the PDU. Is this possible/ advisable with your inverter?"

and their response...

"Yes, because the neutral and ground of our inverter's outlet is not bonded, they need to be connected through RCD."

This is my rail with the relay (Dold IK8701.12) on the left, next to the sockets MCB.

I was thinking of replacing the C16 sockets MSB with an RCBO like this one form CEF. However, whilst on EHU, there would effectively then be two RCDs in the circuit. Is this advisable?

The other question I have is how and where do I 'ground the neutral'?? I'm assuming it's quite easy but I'd hate to make a mistake and set the moho on fire

Thanks again for you help.

 

[Lenny HB]

and their response...

"Yes, because the neutral and ground of our inverter's outlet is not bonded, they need to be connected through RCD."

They have got that wrong as an RCD won't work on an inverter output unless the neutral & earth are bonded.

Have a look at Victron inverters much better quality.