A couple questions about my new Solar project

[xymotic]

Hi All,

Until my boat is finished with a complete refit, I'm living in a small 16' travel trailer. I decided to use some of the Solar that came with the boat to temporarily supplement the RV's power, and I've stumbled onto some questions that I'm hoping the experts here might know a thing or two about.

So the layout is 2 - 110 watt Kyocera Panels on the top of my van.
These are wired in series (with diodes between) to a flexcharge 25A controller with about 3' of 8 AWG.

Then I have a small 30A automotive breaker then to a small Blue seas distribution block.

Then 6' of 8 AWG cable to a Brand new Optima Yellow top battery, in an OEM second battery spot on the van. That Battery is OEM wired by chevy to the front which is an Optima Red Top starting battery that is maybe 1.5 Yrs old (and has been deep discharged once that I know of)

So my questions:

so far in the install not everything is hooked up, I have the two batteries connected, and then 8' of awg coming off the yellow top. Testing at the end of the wire after running the alternator for a while, I'm getting 12.6 which seems low, would that be a 'normal' loss through that length of wire?

I'd like to put a 2.5A Engel in the van powered off the van's two "start" batteries.

Do I need a fuse/breaker or switch between the Solar and the controller?

Next, I'd like to add another maybe 10' of 8AWG to the trailer connector, and make it so the solar/alternator can charge the trailers two wet house batteries (one grp 24 and one grp 27)

In reading online, it seems most people put in a 30-40A breaker and then 10AWG, and then line loss limits that connection to 10-15 amps. I had considered buying a echo charge to limit the connection, worried that I had potential to run a LOT of amps through that connection. But then I thought maybe I'm over-thinking this and that one night with 4 batteries should be OK.

I'm debating putting a Blue Seas battery relay in-between the trailer and the van to isolate the two systems so I can't run down the van via the TV set etc.

Any advice or opinions are welcome I'm looking to spend as little as possible on this, but will be living with it at least a year or two. Items like the relay could come out and be used in the boat when I get it closer to done. (but it will likely have WAY more solar and a larger controller.)

[Nemo55]

Pretty sure the second battery in the Van will be isolated by a solenoid and only becomes active to the vans alternator when the charge has fallen past a certain point. At least that is the common arrangement with Dual Battery set-ups on all the vehicles i have had.

Also the Automotive alternator will not (typically)push the charge more than 13volts to either battery, so you could be just reading the typical voltage for an automotive setup, if i read such voltage on my vehicle i would not be concerned at all.

Originally Posted by xymotic

Hi All,

Until my boat is finished with a complete refit, I'm living in a small 16' travel trailer. I decided to use some of the Solar that came with the boat to temporarily supplement the RV's power, and I've stumbled onto some questions that I'm hoping the experts here might know a thing or two about.

So the layout is 2 - 110 watt Kyocera Panels on the top of my van.
These are wired in series (with diodes between) to a flexcharge 25A controller with about 3' of 8 AWG.

Then I have a small 30A automotive breaker then to a small Blue seas distribution block.

Then 6' of 8 AWG cable to a Brand new Optima Yellow top battery, in an OEM second battery spot on the van. That Battery is OEM wired by chevy to the front which is an Optima Red Top starting battery that is maybe 1.5 Yrs old (and has been deep discharged once that I know of)

So my questions:

so far in the install not everything is hooked up, I have the two batteries connected, and then 8' of awg coming off the yellow top. Testing at the end of the wire after running the alternator for a while, I'm getting 12.6 which seems low, would that be a 'normal' loss through that length of wire?

I'd like to put a 2.5A Engel in the van powered off the van's two "start" batteries.

Do I need a fuse/breaker or switch between the Solar and the controller?

Next, I'd like to add another maybe 10' of 8AWG to the trailer connector, and make it so the solar/alternator can charge the trailers two wet house batteries (one grp 24 and one grp 27)

In reading online, it seems most people put in a 30-40A breaker and then 10AWG, and then line loss limits that connection to 10-15 amps. I had considered buying a echo charge to limit the connection, worried that I had potential to run a LOT of amps through that connection. But then I thought maybe I'm over-thinking this and that one night with 4 batteries should be OK.

I'm debating putting a Blue Seas battery relay in-between the trailer and the van to isolate the two systems so I can't run down the van via the TV set etc.

Any advice or opinions are welcome I'm looking to spend as little as possible on this, but will be living with it at least a year or two. Items like the relay could come out and be used in the boat when I get it closer to done. (but it will likely have WAY more solar and a larger controller.)

[xymotic]

Thanks Nemo, I'm pretty sure the two van batteries are wired directly. When I bought the van (from the military) the start battery kept getting discharged. I didn't know about the second battery, and it turned out to be sucking the life out of the start batt.

I haven't tried testing with the alternator on, just at idle. I was just expecting a 'charged' battery to be more like 13.3 instead of 12.6.

[Nemo55]

Yes your right, a new battery should read a charge of 13.5 , but most automotive systems degrade over time and end up being lower than that.
The alternator at idle wont do much unless it is full fielded by the regulator,,most setups will be charging at 13 or more as long as the draw is not too high or resistance is not too high,,but the batteries will commonly read lower.
In your case i would definatley get a charge control solenoid between those batteries,,unless of course your starter is a 24volt system.

Originally Posted by xymotic

Thanks Nemo, I'm pretty sure the two van batteries are wired directly. When I bought the van (from the military) the start battery kept getting discharged. I didn't know about the second battery, and it turned out to be sucking the life out of the start batt.

I haven't tried testing with the alternator on, just at idle. I was just expecting a 'charged' battery to be more like 13.3 instead of 12.6.

[noelex 77]

The first thing that strikes me is the flexcharge 25 is not MPPT, but you are connecting the panels in series making them nominally 24v when I think your system ( unless I have misunderstood) is 12v.
If the above is correct you need to connect the panels in parallel

[Cheechako]

I dont think a battery will read over 13 volts if it's sat a while after charging will it?

[Nemo55]

Yeah,,that was my thought as well,,usually the battery will keep a nominal charge of 12.5 surface voltage when sitting for a while.

Originally Posted by Cheechako

I dont think a battery will read over 13 volts if it's sat a while after charging will it?

[xymotic]

Originally Posted by noelex 77

The first thing that strikes me is the flexcharge 25 is not MPPT, but you are connecting the panels in series making them nominally 24v when I think your system ( unless I have misunderstood) is 12v.
If the above is correct you need to connect the panels in parallel

Thank you, I mis-spoke, they are in Parallel. good catch!

[noelex 77]

Originally Posted by xymotic

Testing at the end of the wire after running the alternator for a while, I'm getting 12.6 which seems low, would that be a 'normal' loss through that length of wire?

The voltage loss in wire is proportional to the current flowing. If the wire is not powering anything there is no voltage loss. Multimeters can measure voltage while only drawing a tiny current. So if the no appliances were connected and drawing power the reading ( if the multimeter is accurate) will show the true battery voltage almost irrespective of the wire size and length.
With the alternator running above idle speed and a battery that is not very flat the charging voltage should rise to about 13.8v in an automotive system. When the alternator is not running the battery voltage ( with no load on it ) will drop very gradually to around 12.7v if the battery is fully charged, depending on temperature and battery type.

[noelex 77]

Originally Posted by xymotic

Do I need a fuse/breaker or switch between the Solar and the controller?

The most important fusing is between the battery and the controler. Many people omit fusing between the controler and solar panel arguing if the wire can take the maximimum current of the panels there is no need for a fuse. The manufacturers recommend a fuse, but it ofen omitted.

[Nemo55]

I cant find anything wrong with your planned setup,,looks good enough to me,,probably overkill compared to many RV setups.

Originally Posted by xymotic

Hi All,

Until my boat is finished with a complete refit, I'm living in a small 16' travel trailer. I decided to use some of the Solar that came with the boat to temporarily supplement the RV's power, and I've stumbled onto some questions that I'm hoping the experts here might know a thing or two about.

So the layout is 2 - 110 watt Kyocera Panels on the top of my van.
These are wired in series (with diodes between) to a flexcharge 25A controller with about 3' of 8 AWG.

Then I have a small 30A automotive breaker then to a small Blue seas distribution block.

Then 6' of 8 AWG cable to a Brand new Optima Yellow top battery, in an OEM second battery spot on the van. That Battery is OEM wired by chevy to the front which is an Optima Red Top starting battery that is maybe 1.5 Yrs old (and has been deep discharged once that I know of)

So my questions:

so far in the install not everything is hooked up, I have the two batteries connected, and then 8' of awg coming off the yellow top. Testing at the end of the wire after running the alternator for a while, I'm getting 12.6 which seems low, would that be a 'normal' loss through that length of wire?

I'd like to put a 2.5A Engel in the van powered off the van's two "start" batteries.

Do I need a fuse/breaker or switch between the Solar and the controller?

Next, I'd like to add another maybe 10' of 8AWG to the trailer connector, and make it so the solar/alternator can charge the trailers two wet house batteries (one grp 24 and one grp 27)

In reading online, it seems most people put in a 30-40A breaker and then 10AWG, and then line loss limits that connection to 10-15 amps. I had considered buying a echo charge to limit the connection, worried that I had potential to run a LOT of amps through that connection. But then I thought maybe I'm over-thinking this and that one night with 4 batteries should be OK.

I'm debating putting a Blue Seas battery relay in-between the trailer and the van to isolate the two systems so I can't run down the van via the TV set etc.

Any advice or opinions are welcome I'm looking to spend as little as possible on this, but will be living with it at least a year or two. Items like the relay could come out and be used in the boat when I get it closer to done. (but it will likely have WAY more solar and a larger controller.)

[noelex 77]

Originally Posted by xymotic

In reading online, it seems most people put in a 30-40A breaker and then 10AWG, and then line loss limits that connection to 10-15 amps. I had considered buying a echo charge to limit the connection, worried that I had potential to run a LOT of amps through that connection. But then I thought maybe I'm over-thinking this and that one night with 4 batteries should be OK.
)

Boats do this without any problems. If the start battery is flat in many systems it is paralleled with the house battery to start the engine, but your correct the interconnecting cables will carry a lot of current when the batteries are very different states of charge. I think you may find it difficult to keep a 30A breaker closed if the batteries are at very different voltages. I would upsize the wire and breaker size, but you could try the smaller wire and the only harm will be blowing the fuse or tripping the breaker very quickly.
I would not do it like this on a perminant basis.

[noelex 77]

Originally Posted by xymotic

I'm debating putting a Blue Seas battery relay in-between the trailer and the van to isolate the two systems so I can't run down the van via the TV set etc.
.)

You should not be running any of the batteries much below 50 % for reasonable life anyway. At this level they will still start the van.
If its critical the van always starts a VSR would gard against mistakes.

[xymotic]

Ok, so new question:

The Flex-Charge says to run the voltage sense wires directly to the battery. I figured there was little difference running a 14ga wire 8' vs just attaching the wire to the distribution block that is directly attached to the battery with 8ga wire.

So when I get it wired up, a relay clicks on and off endlessly for the divert function, but it never goes into charge mode.

Here's the install:



On the controller, from left to right:
1) INPUT + (goes to solar panel +)
2) BATTERY + (wired to circuit breaker and then distribution + and then battery +
3) Divert Output (empty)
4) Charge indicator (empty)
5) BATT + sense (fused and then going to distro block/battery
6) BATT - Sense (going to distro block/battery)

Am I wrong in thinking sense wires to distribution block is the same difference as directly to the battery?

[Nemo55]

go to Flexcharge.com and put this extension on the end of the address string,,,,or just search for your application manual there /flexcharge_usa/manuals/nchc_manual.pdf