Critique my solar setup!

[dwh]

I emailed Bluesea CS to see if solar power will charge the starting battery similar to CTEK. No response yet.

The CTEK doesn't charge the starting battery from the solar unless you have the SmartPass (if I recall correctly).


The ACR will do it.

The Blue Sea ACRs will tie the batteries when it senses voltage rising on either side (charging going on).

So if the engine battery is getting charged and the voltage rises on that side, the ACR will tie the batteries and both will charge.

If you have the solar on the aux battery, as that battery charges and the voltage rises, the ACR will tie the batteries, and both will charge.

 

[V85562A]

Thanks dwh just edited my original post

 

[dwh]

Yea. The problem that you might run into though, is that when voltage drops on either side, the ACR will disconnect the batteries. So if you put a heavy load on the aux battery - say a coffee pot or microwave, it might draw down the voltage enough to force a disconnect.

And (I think) the 120a Blue Sea unit doesn't have a switch to force an override and keep them tied. The 500a unit does.

You might consider the Samlex ACR instead. It's rated for 160a and can be rigged with a switch and forced on or off. Dunno what the price is...

http://www.samlexsolar.com/rv-power-products/ProductDetail.aspx?pid=478

 

[dwh]

Don Rowe has it for $110:

http://www.donrowe.com/Samlex-ACR-160-Automatic-Charge-Isolator-p/acr-160.htm

 

[huang]

I beg to differ on the CTEK comment. It will charge both batteries under some conditions. From the manual:
D250S DUAL
The D250S Dual has 2 inputs. The Service battery will be charged from the alternator, solar panel, or both in combina- tion. The solar panel adjusts itself to the Starter battery voltage. The Starter battery will be charged and maintained directly by the solar panel if the Service battery is fully charged.

Ric

 

[dwh]

I beg to differ on the CTEK comment. It will charge both batteries under some conditions. From the manual:
D250S DUAL
The D250S Dual has 2 inputs. The Service battery will be charged from the alternator, solar panel, or both in combina- tion. The solar panel adjusts itself to the Starter battery voltage. The Starter battery will be charged and maintained directly by the solar panel if the Service battery is fully charged.

Ric

Ahh. Good catch, I wasn't sure if I was remembering that correctly, and it's been a few years since I looked at that manual.

 

[DiploStrat]

...Not sure any of us run a coffee maker with it though.

CTEK makes nice products. Lifeline and Audi, among others, recommend their shore chargers. Many folks can accomplish the same or better function for less money and space, but the D250S/SmartPass combo is nice, especially if it allows you to eliminate an MPPT solar charger. (Sterling Power makes larger, battery to battery chargers, if you really need one.) And remember, you can run B2B's in parallel. (Friend of mine does this on a Unimog with a really low voltage alternator.)

That said, your coffee maker is attached to your batteries, not your charger. If your battery bank and inverter are of the right size, you can fire up your coffee maker, microwave, air conditioner, or whatever. I do it all the time. The only thing that the CTEK might limit is your recharge time.

(Dirty secret: For various reasons associated with the perverse nature of lead acid batteries, a big battery bank, even coupled to a monster alternator, is going to spend most of its recharge time at around 50A, so the D250S isn't really that bad, especially if coupled with a SmartBank.)

 

[ETAV8R]

CTEK makes different products. My friends and I don't have the smart pass and have had no issues.

 

[DiploStrat]

My friends and I don't have the smart pass and have had no issues.

It is not that you will have issues; it is that you will have a much lower maximum charge rate, that is, 20A vs. 100A.

The whole purpose of B2B products like the CTEK D250S or the various Sterling A2B or B2B is to raise your alternator's output to 14.4v or higher at 20C. If your alternator is already running at 14 to 15v, then these products provide little or no advantage over a simple relay.

 

[ETAV8R]

It is not that you will have issues; it is that you will have a much lower maximum charge rate, that is, 20A vs. 100A.

The whole purpose of B2B products like the CTEK D250S or the various Sterling A2B or B2B is to raise your alternator's output to 14.4v or higher at 20C. If your alternator is already running at 14 to 15v, then these products provide little or no advantage over a simple relay.

In camp under solar power? The alternator isn't on during this situation.

Not sure we're on the same page. My CTEK has a temp probe that is placed near the 2nd battery for optimum charging from either solar or via alternator when engine is running.
I'm not concerned with my set up. It is tried and tested.

 

[V85562A]

Yea. The problem that you might run into though, is that when voltage drops on either side, the ACR will disconnect the batteries. So if you put a heavy load on the aux battery - say a coffee pot or microwave, it might draw down the voltage enough to force a disconnect.

And (I think) the 120a Blue Sea unit doesn't have a switch to force an override and keep them tied. The 500a unit does.

You might consider the Samlex ACR instead. It's rated for 160a and can be rigged with a switch and forced on or off. Dunno what the price is...

http://www.samlexsolar.com/rv-power-products/ProductDetail.aspx?pid=478

That's a good point. I'm assuming the alternator will keep the voltage high enough to stay connected? I'm partial to Bluesea products. Price is definitely attractive on the samlex unit tho.

99.9% of the time this setup will be running a fridge only so I don't mind starting the truck up for occasional cup of joe or 15mins to run a steamer. It's 1500 watts for 90 seconds per cup. So if my calculations are correct that will be roughly 4ah per cup which the panels will make up in 30mins or so.

Even a simple switch like the Bluesea 6006 will work (money saved can go to nice copper cables). I imagine it functioning similar to an on board switched jumper cable for heavy loads. Just got one in for $22 shipped.


Will be posting a revised diagram for second revisions soon. Going with a single AGM and housing it in a mobile tool chest (or some scrap pelican cases I have) to build a thermostat controlled pc fan ventilated solar generator. Solar panel wires to MPPT CC will be MC4 and alternator to house battery wires will be quick detach Anderson connectors.

Appreciate all the help, definitely learning a lot.

 

[V85562A]

Got me thinking, why not just connect the Anderson plugs when I need additional amperage from the alternator and do manual isolation? K.I.S.S. for lower cost and nothing to break.

Pros
More reliable
Much Cheaper

Cons
When connected repeated discharge of starting battery will shorten lifespan. Will not discharge house battery first.
When not connected, no float charge from solar. Still needs battery tender if parked for long periods (Already doing this now).
Have to manually connect plugs vs automatic (but used very occasionally so I don't mind)
Any other cons?


CC, Battery, Inverter will be housed inside rolling case. I'll be cutting holes directly into the plastic case for 12v sockets, panels, vents, etc. Unplug when I need extra cargo or hook it up to my off grid panel.

 

[dwh]

Cons
Forgetting to disconnect.

 

[DiploStrat]

Two Mints in ONE!

One more time with feeling!

CTEK makes some very nice products. The D250S is a dual purpose device, a B2B and a solar controller. (Actually, I suspect that it is an MPPT charger with two front ends.)

-- As a B2B, it draws down the voltage of the donor battery (if required) to force the alternator to produce amps. It then boosts that voltage (as required) to compensate for wire loss, temperature, etc. and provide a multi-step charge to the destination battery.

-- As a solar controller, it does the same thing from a solar panel.

In either case, the maximum output is limited to 20A. Depending on the size of your battery bank and the state of charge, this may be perfect or a bit low. Read more here: http://smartercharger.com/wp-content/uploads/2010/11/D250S-DUAL_EN.pdf

The SmartPass integrates an intelligent relay to allow an additional 80A of charge, from your alternator, during the boost/bulk stage. Once your charge rate drops to the 20A that the D250S can provide, then the relay opens and the D250S completes the absorb/accept stage and drops to float.

A very nice system and it all integrates automagically. My only point is that much of this is no longer required with a modern truck and a good relay, intelligent or key controlled, can do most of the same thing for alternator charging, at less cost.

The CTEK is really attractive if it saves you the cost of a separate solar controller or if you know that that your alternator does not put out more than 14v.

I spent a lot of time looking at these products and like them a lot. In the end, I went with a relay and separate solar controller as I needed more amps and I had too large a solar panel for the CTEK.

 

[pexic]

Try this : http://evcomponents.com/lifepo4-cell/winston-lifepo4-12v-60ah-cell.html instead of that 105Ah
-It will last much longer
-It will store more usable energy
-You will save a lot of weight (at least 20Kg)
-It will use less space
-Can be charged very quick

one drawback - I think is more expensive but you are the only one who can put these in balance and then decide.

good luck!