Connect solar to Blue Sea system combiner

[1st Sail]

Starscream,

Thanks for the schematic. That is exactly the configuration I have been considering. Essentially three charge sources, solar, engine alternator, Shore AC/ Genset AC/DC. Is the switch between the and Bat 2 for isolating while charging with solar via the MPPT controller? If not are there any charge control issues with Solar charging while under power for a length of time?

[yukonbob]

See the article I submitted earlier for Starscream, I don’t think he read the whole thing, it is long.
https://marinehowto.com/automatic-charging-relays/
Read ALL the way down through multiple titles. Here is the schematic you want if installing and ARC/VSR (you can change out the 3 selector switches for a single 3 way switch); Or you can take it another route by installing a isolating battery switch which keeps the ignition and house loads separate (no voltage drop on sensitive electronics when starting the engine, but still allows emergency combining; although this also has its own set of issues)

[BOAT]

In the van I put the stuff behind tinted polycarbonate that mimics the tinted window that is on the other side of the wooden bulkhead:

the "fake window" opens up to reveal the combiner and stuff:

[yukonbob]

Nice job boat. Marine install on a camper van should last 100 years. I know you have all your stuff but if you're looking for tinned wire in teh future check these guys out:
https://tinnedmarinewire.com/wire/

No affiliation just have had multiple great customer services experiences with them and good prices.

[BOAT]

Nice job boat. Marine install on a camper van should last 100 years. I know you have all your stuff but if you're looking for tinned wire in teh future check these guys out:
https://tinnedmarinewire.com/wire/

No affiliation just have had multiple great customer services experiences with them and good prices.

That's a find! I just bookmarked your link - thanks greatly

By the way - I hid the Lithium batteries inside this central column cabinet that contains the new electric reefer:

The BlueSea Systems AC panels is behind the little door - also in that cabinet is the inverters, chargers, Residential AC gas and LP sensors and a central fan and duct for a central air setup that pumps the cold air into the bathroom in the back. If anyone is interested I can send pictures of the cabinet open - (the front of the cabinet is latched near those little wicker baskets and the whole front panel comes off).

[ncartercalfrac]

I would like to see how you organized the inside of that cabinet. That is a lot of services in one spot.

[Starscream]

Starscream,

Thanks for the schematic. That is exactly the configuration I have been considering. Essentially three charge sources, solar, engine alternator, Shore AC/ Genset AC/DC. Is the switch between the and Bat 2 for isolating while charging with solar via the MPPT controller? If not are there any charge control issues with Solar charging while under power for a length of time?

I think you are asking about the switch between the ACR and battery 2, with the 1 amp fuse? That switch is just for long term storage. It stops the ACR from draining the battery over the winter.

I haven't noticed any issues with running under power while the solar is connected. But, I also didn't look for anything under those conditions. I (did) read the article Bob posted but couldn't tell if my setup is really problematic or not. Will do more research over the next few weeks.

[Starscream]

Well I think I found an answer to the concern about solar charging the house batteries while the engine alternator is charging the start battery.

https://www.bluesea.com/support/article ... _Explained

The Blue Seas ACR is 'dual sensing', meaning that it senses charging voltage on one Or both terminals. To me, that means the ACR is fine with my setup, and the two batteries will be combined when both solar and alternator charging voltage is present.

Now, my question is whether the charge controller or the engine alternator have a problem with being combined like that. Back to google.

[Starscream]

According to this source, multiple regulated charging sources are fine. I read it on the Internet so it must be true.

https://shop.pkys.com/multiple-charge-sources


With that info, I can't see any issue with my setup. Would be happy to be schooled, though.

[yukonbob]

Regarding the long term storage switch:” 9- “An ACR will allow the start battery to drain into the house battery and leave it depleted.” = FALSE
This statement takes us directly to Myth & Lore #9 “An ACR will allow the start battery to drain into the house battery and leave it depleted.”

The fully charged resting voltage of a typical lead acid battery is about 12.72V. At any voltage above this point there is really no usable energy stored when discharging (see image below).

By now I know you are understanding it, but if not, this one is really quite simple. The ACR normally opens/un-parallels at just above or just at the 100% SOC point of a lead acid battery. If either battery bank dips below 12.8V the relay opens within 30 seconds. If it dips to 12.35V, the relay opens in just 10 seconds. The answer to this myth is that it is indeed false that an ACR will allow the start battery to discharge into the house bank. Your start battery cannot discharge into your house bank in 10 or 30 seconds.

The discharge graph below (voltage is the red line) was a typical marine battery undergoing a 20 hour capacity test. The battery was fully charged, equalized and had an open circuit voltage before the discharge test of 12.95V or what we refer to as a “surface charge“, despite having rested for a full 24 hours prior to the test. Because this was a 130Ah rated battery the discharge rate was 6.50A (130Ah / 20 hours = 6.5A discharge rate). At data point #1 the battery was at 12.95V and by data point 2 the battery was already below the open/isolated/un-parallel voltage of the ACR at 12.76V. You are seeing that correctly, by the time this battery hit 12.76V a paltry 0.002Ah worth of energy had been removed. If the ACR opens at 12.8V how much can we discharge either bank by? This answer is nothing worth even really discussing…“

Other stuff:
“One of the most common blunders we see on cruising boats is leaving the alternator wired to charge the starting battery first. This is most often the result of the Blue Sea Systems instructions not being very clear. “

“Why is it best to charge the house first? There are a number of reasons to do this but the best reason is to ensure the bank that needs the most charging is actually getting it and getting it as efficiently as possible.

#1 With large house banks wiring charging sources to the HOUSE bank means more efficient charging and more optimal voltage sensing for the alternator.

#2 With large house banks, wiring charging sources to the HOUSE bank means less chance of what is called relay-cycling. Please take the time to read the link below. Blue Sea Systems covers relay cycling very well so there is no sense in us repeating it.
https://www.bluesea.com/support/articl ... ing_Relays
#3 By wiring charge sources to the larger HOUSE bank the relay contacts need to pass just a few amps at best in order to charge the start battery. By feeding all charging to START means the relay must be able to handle the full rated current of the alternator and we are utilizing it at max duty cycle. We are also passing the charging current through multiple more terminations and fuses and there will be additional voltage drop.“

Not saying that your setup is wrong, wont work or will burn your boat down, but batteries are expensive and I like to get the most of of them, there’s also the environmental factor.

[Tomfoolery]

In the van I put the stuff behind tinted polycarbonate that mimics the tinted window that is on the other side of the wooden bulkhead:

the "fake window" opens up to reveal the combiner and stuff:

You do nice work, BOAT. Check out the OEM (upfitter) mess on the wheel well of my LiFePO4-powered system in my van. Not shown are the 3000W inverter/charger, the 600Ah battery, and the 300W solar panel charge controller.




For those looking to do a solar system in their boat or tow vehicle, this is not what it should look like. Connections seem to be professionally done, bu the layout is based on the order things got wired in.

[BOAT]

The issue of the 12 volt engine battery and the 14 volt house batteries running off the same alternator under power is a complicated problem that I have addressed in the picture below.

Hey Tom!
On the wire mess comments I understand. I had to plan the design. All the big stuff (batteries, inverters, chargers, and high current appliances) is close together in a central utility cabinet to reduce wire lengths. Maybe today I will pop the cover off the cabinet and take a picture

Then the protective gear is on the wall next to that cabinet (pretty much standard Navy electrical practice) - if mastreb were here he would approve.

The thing you guys have been posting about is the batteries being all connected during alternator charging. That is an issue.

If you look at this picture you can see that I have a battery to battery charger connected to the system that changes the voltage of the current from the alternator to accommodate any kind of system it encounters:



There are two very large lithium batteries right below this picture and that B2B unit makes sure the correct voltage to used to charge them when the alternator is providing power. The B2B units change the voltage to the correct output no matter what input voltage they get. They also properly charge the lithium in bulk, boost, or absorbtion state or you can even program it yourself to do custom charging protocols.

There are status lights on the unit to tell you what's going on and that's why I put all this stuff behind tinted glass so I could see the lights through the glass. Green and yellow on the charger =good, blue on the solar controller = good no lights on the fuses or breakers = good (fuses have red lights and breakers have red indicators)
Any red lights = BAD
That way I notice quickly every time I walk by on my way to the bathroom or refrigerator (time for beer!)

I recommend the B3B for charging off the alternator.

[Tomfoolery]

The thing you guys have been posting about is the batteries being all connected during alternator charging. That is an issue.
<snip>
I recommend the B3B for charging off the alternator.

Mine has a separate high-output alternator, which I think is 280A, just for charging the house battery. The charge controller, which is the big box in the middle of the photo above, balances the inputs from solar, charger, and alternator, and it's configured for the LiFePO4 battery that's part of the system. The upfitter sourced it all as a system from a single manufacturer (Lithionics or Xantrex or Schneider - hard to tell which is the actual manufacturer, as they're all tied somehow).

Just for your edification, here's a photo of the alternator on the engine that I found somewhere. It hangs low, but as long as I don't smash the plastic bumper bottom on a curb, the alternator will be fine. The standard chassis alternator is above it at about 1:00.

You can get a second alternator for your van, with mounts, if you wanted, but it sounds like you have it covered. Just have to watch the output of the standard alternator, as M-B has been putting limits on what upfitters can draw from it. Probably because they'd pull max amps for house batts if they could, and (I'm guessing) M-B isn't happy about dealing with warranty claims due to loads they didn't install, like house batteries and/or electric air conditioners (I can run the roof air for hours on the house batt).

[BOAT]

The dual alternators was an option that Sportsmobile offered when we bought the Sprinter back in 2004 but Paul at Sportsmobile said that if we were not installing a roof air unit it was not really necessary because their standard on the single alternator was heavy duty. He said if you do get the dual units to go all the way and get the optional idle control and all the other stuff Mercedes offers on thier big rig deisal trucks. It's all available on the Sprinter too, (well, it was in 2004).

Here's the deal on Sprinters in regards to batteries and A/C units -

You need to treat your Sprinter just like a big rig diesel. You can park all night long with the dash AC running and use way less fuel than running an AC residential or roof unit off a generator. When I got the van they told me if you are sleeping overnight in the Texas truck stop in summer just leave the engine on all night with the ac running and you will be fine. And that's just what we do. That way I don't cycle my batteries running the residential AC because they cost over 2000 dollars and a new alternator is only 500 bucks. If you do want to run the roof ac he recommended the dual alternator with idle control - way better way to run a roof air or a really big residential floor air unit. I would go dual alternator if I felt I needed the extra cooling but the dash seems to do fine in my van which is probably a little smaller than yours.

That's also why we use a residential air conditioner on the floor instead of a roof mounted RV type unit - the only time we run the residential air conditioner is when we are connected to AC power - the rest of the time the dash unit works much better and uses less fuel. The dash AC in our Sprinter makes the entire van an ice box even in the Arizona summer heat. it was designed that way.

So, you only need one really large inexpensive battery for you van to start. Starting with high cranking power is the key so a good old lead battery is best.

Spend your money on the house batteries and keep them seperate from the automotive system. If you want to run the roof air you do need the second alternator but it is best to keep the systems separate. I like the idea of a dedicated alternator for the coach if you are going to run roof AC.

I even have a big switch on the board there that will connect the house batteries directly to the van battery for an emergency start in case the lead battery fails, but in all other cases the two systems are completely separated from each other - the only connection between the two systems is that B2B unit and my big emergency bypass switch (for emergencies only).

[yukonbob]

The thing you guys have been posting about is the batteries being all connected during alternator charging. That is an issue.

That is an issue but not the one I have been discussing. B2B or DC/DC is what should be installed when mixing battery chemistry, voltage etc. With same battery type and a VSR/ARC you still get the most efficiency and longer battery life by putting all charge sources into the largest most used (usually the house bank).