SOLAR advice-Yes I have searched the forums.

[sparkplug]

Sorry - I just realised Briance is near Limoges.

Didn't make the connection until now!

I used to live in a village just outside Orange which is neither close to Briance, nor all that far away!

Of course Minitel was all the rage back then and France led the world before the Internet came of age!

Happy memories.

 

[Midwestdrifter]

You probably have a loose connection somewhere. Get out your volt meter and start probing.

 

[RVCuisineScene]

You also may at some point want to clean up the system by securing the wiring to prevent chafing and possible shorting; installing sheathing, cable ties etc. And insulated covers over the "+" posts on the batteries, if you drop a wrench on them you could be in for quite a surprise.

 

[autostaretx]

The CTEK is not an inverter .... it's acting as an isolation relay.

So it only needs the *positive* big wires (to connect the batteries)

To power its "smarts" it only needs a feeble negative connection (they're powering its internals)

BUT: Somewhere, you *do* have to have the two battery systems have a Fat Wire(tm) "common negative connection"
(you wouldn't be the first member to miss that, or to wonder where it is/was)'

So if the two batteries are already both connected to the frame (the house may do it through a monitor's shunt), all conditions for currents to flow in a "circuit" are satisfied. It's not the CTEK's job to do that.

--dick

 

[autostaretx]

Regarding "solar isn't working any more" ... you DID disconnect the solar panels from their controller *before* disconnecting the battery, and you DID connect that battery before reconnecting the panels to their controller, correct?
Controllers can get confused (or damaged) by leaving the panels connected but their "battery" connection floating free.

--dick

 

[Briance]

This was the issue... nothing was done on purpose.

Patched up and charging on its own... although the charge controller shows ——— which I read goes away once a full charge is put on it.

Thanks everyone, trip is back on!

 

[sparkplug]

Thanks everyone, trip is back on!

?

 

[HarryN]

That's a good explanation - thanks Dick

However, the CTEK itself doesn't have any 'fat' wires going to ground. The only part of the circuit that does is the OEM vehicle battery earth and that's a very long way away from my leisure batteries (on rear wheel arch).

Here's what my setup looks like:

I still don't really understand why there isn't a very fat negative wire to complete the 'fat wire' portion of the circuit.

What I do know is that CTEK have confirmed it's correct, it works, and none of the wires get warm.

The rest I'm putting down to the "magic stuff" in the box

Hi, where are you tapping into the sprinter to get the 120 amps?

The usual body builder guide locations are 40 ish amps IIRC.

Thanks

 

[sparkplug]

I would love to answer your question HarryN - but I'm not sure I understand it.

My circuit really is just as per the diagram I posted and I can't see where I mentioned 120 amps?

Possible confusion with the "Smartpass 120" which is a power management system which does some magical things to optimise the power from the alternator while it charges your leisure batteries. It also does the power distribution so when your leisure batteries are full it will pass any surplus charging current back to your vehicle battery.

If that wasn't your question, then ignore me

 

[HarryN]

I would love to answer your question HarryN - but I'm not sure I understand it.

My circuit really is just as per the diagram I posted and I can't see where I mentioned 120 amps?

Possible confusion with the "Smartpass 120" which is a power management system which does some magical things to optimise the power from the alternator while it charges your leisure batteries. It also does the power distribution so when your leisure batteries are full it will pass any surplus charging current back to your vehicle battery.

If that wasn't your question, then ignore me

Thanks

It appears that the smart pass system (the two boxes) are a combination of a solar charge controller and a battery to battery charger.

The typical MB has a connector under the seat area for providing 40 amps for user draw to other connection use.

I interpreted that this unit will try to run at substantially more than 40 amps draw.

Did you connect to the 40 amp connection point? This might still be ok if the battery pack is a relatively modest size flooded type battery, but if it is a larger AGM or LiFe pack, it could pass quite a lot of amps.

Did you connect directly to the engine start battery and bypass the MB related items?

Maybe that ctek unit is really just a smart relay and not a battery to battery charger?

 

[sparkplug]

Following the CTEK instructions I've made the connections directly at the battery with a 300A fuse - so I'm guessing it's passing some high amps through it.

The system I've installed comprised two components; the D250SE and the Smartpass 120.

The D250SE is described on their website as:

The D250SE is a fully automatic, 5 step charger that supplies up to 20A of power to any 12V lead-acid or lithium* service battery from 40–300Ah. It has selectable charge algorithms for AGM and lithium* batteries and can use power through its dual input from alternator, solar panel and wind power. When the service battery is fully charged, the D250SE will automatically redirect maintenance charge power to the starter battery. The D250SE can maintain a stable output up to 20A to vehicles fitted with smart ECU controlled alternators and also has a temperature sensor for optimised charging, regardless of weather conditions. *) 12V lithium batteries (LiFePO4, Li-Fe, Li-iron, LFP)

The Smartpass is described as:

Smartpass 120S is a 120A Power Management Solution which distributes, controls and maximises the available energy from your alternator to power service batteries and consumers. SMARTPASS 120S handles all 12V batteries between 28-800Ah. The Smartpass 120Ss Battery Guard function ensures that critical equipment such as radio, emergency lights and navigation systems always have power and take priority when the voltage on the service battery is low disconnecting non-critical consumers. The unit’s Battery Guard will protect your service battery from total discharge and built in over temperature protection reduces charge current before the battery temperature gets too high. SMARTPASS 120S is compatible with the D250SA and D250SE 20A on board chargers.

I believe that the two units combined allow for 140A charging

I'm not sure what the distinction is between a Smart Relay and a B2B charger - all I know is that the CTEK works incredibly well!

I don't use the built in MPPT controller on it as my 2 x 140w panels have too high an open circuit voltage even when wired in parallel so I've connected a Victron 100/20 directly to the batteries.

I've heard people 'hack' the system by putting an old laptop charger into the solar inputs so you can fool it into thinking it's getting PV in when you hook the charger up to shore power. I've never needed to do that though as I have generous capacity in my battery bank now, good solar and it's rare for me to stay in one place without driving for more than a couple of days.

 

[autostaretx]

I'm not sure what the distinction is between a Smart Relay and a B2B charger - all I know is that the CTEK works incredibly well!

All a smart relay does is join the two batteries when the voltage on one (or either) side rises above something like 13.2 volts (i.e. there's a charging source of some sort operating).
When neither side has that high a voltage (charger now off), it disconnects ("un-joins"?) the two batteries.

No other brains (unless there's an extra little wire or two telling it to join (no matter what) or not to join.

B-to-B chargers are fully automatic systems that provided controlled voltages and/or currents to optimize the current going into the battery-under-charge. They're also one-direction-only, so they may give alternator power to the house, but they won't give house power to the starter.

--dick

 

[sparkplug]

Ah - OK. Thanks for the clarification Dick.

So the CTEK system sounds like a combination of the two then.

The D250SE being the B2B charger and the Smartpass acting as a sort of smart relay but with some extra layers of sophistication.