Solar Panels B2b And Smart Alternators ...

[Alby42]

Thanks in advance for any advice ( good or bad )
My current camper ( T 5.1 ) 12v leisure battery system works well for me and I was aiming to replicate in the T6 due soon. ( 100w solar panel CTEK d250 and 120 Smartpass 100 amp battery and ctek mains charger )

Now with the smart alternator, regen braking etc to think about and more powerful solar panels available, I've been reading up ( thanks to the forum posters ) and wondering if I should

1. Go for the new D250SA and limit solar panel voltage to match with 2 110amp batteries and mains charger.
I am trying to reduce 240v install in the van so the charger would not be built in, I just need a 300W inverter ( no not for the charger ) to meet any 240v loads.
2. Give the cat another goldfish, blow the budget, hide the bills from the wife and go for something more expensive and hopefully more effective.

Follow on question
My current set up allows the solar to charge the start battery when leisure is topped up, the D250SA trickle charges the start battery as well. The trickle charge should take the start battery above the nominal 80% does this matter ? To my mind as soon as the engine starts it will drop the capacity but the smart alt will not kick in until below 80%.

Apologies if this has been covered before... I’ve trawled through as much as possible... I know what to avoid now

 

[travelvolts]

Hi Alby,to be honest the CTEK would struggle to charge 2 x batteries with only a 20 amp output. You would be much better off with the Redarc BCDC1240D which has 40 amps output and will accept solar panels up to 32 VOC. Please note that this will not trickle charge the van battery from the solar input. I would still fit a mains charger as well. You can't always rely on solar and if you aren't planning on covering a bunch of milers one day it would be good to have the mains option. In terms of overall system cost it isn't a big chunk of money.

 

[Alby42]

Thanks, I will be keeping mains charger in van but for use as needed.. I’m aiming to camp in places without mains as much as possible... current set up is good for at least 5 / 6 days and I aim to increase that with 2 nd batt ans better solar panel.. I’d like to keep trickle charge to start batt from solar mainly for when van parked up outside house.

 

[t0mb0]

I agree trickle charge is useful. You can always buy a separate trickle charge gizmo though, something like a votronic battery master or similar. Last time I looked they were around £40 or thereabouts.

 

[travelvolts]

Understood. I can make up a little add on to enable you to achieve trickle charging the van battery from solar if you decided to go with the Redarc.

 

[Alby42]

Thanks. Pm’d

 

[andys]

I agree trickle charge is useful. You can always buy a separate trickle charge gizmo though, something like a votronic battery master or similar. Last time I looked they were around £40 or thereabouts.

So could I wire one of these Votronic trickle chargers from the Load output of my victron solar charger so that it only charged when there was solar output from the fixed panel on my roof?

 

[t0mb0]

So could I wire one of these Votronic trickle chargers from the Load output of my victron solar charger so that it only charged when there was solar output from the fixed panel on my roof?

By "Load output", do you effectively mean the leisure battery? If so, yes it certainly should work when the solar is active. However, it might also come on at other times, I believe they allow current to trickle from the leisure to the starter whenever the leisure is 0.5v or so above the starter.

 

[superchargedpolo]

So could I wire one of these Votronic trickle chargers from the Load output of my victron solar charger so that it only charged when there was solar output from the fixed panel on my roof?

The LOAD on the victron MPPT is designed so that any appliance attached to it will be disconnected below a certain voltage, OR connected above a certain voltage. You can manage these cut offs in the app.
So, in theory, you could set it up to connect a trickle charger above a certain voltage, once the main leisure batteries are charged.

 

[andys]

By "Load output", do you effectively mean the leisure battery? If so, yes it certainly should work when the solar is active. However, it might also come on at other times, I believe they allow current to trickle from the leisure to the starter whenever the leisure is 0.5v or so above the starter.

Like @superchargedpolo says, the Victron solar controllers have a charge output for the leisure battery and a separate load output to drive something else directly. I’ll give this a go then, it seems an easy and cheap solution and all the wiring could be done under the driver’s seat. I’ll put a switch inline so I can disconnect the facility if needed.

 

[superchargedpolo]

@andys I don't think you even need a switch. You can leave the load "always on" or "always off" in the victron connect app, if your MPPT is the bluetooth version. They really do think of everything

 

[andys]

@andys I don't think you even need a switch. You can leave the load "always on" or "always off" in the victron connect app, if your MPPT is the bluetooth version. They really do think of everything

Good thinking

 

[superchargedpolo]

Let me know how you get on with it. I am planning on using the same logic for an install in a few weeks.

 

[andys]

Let me know how you get on with it. I am planning on using the same logic for an install in a few weeks.

Will do, just ordered one from eBay now.

 

[andys]

Ok this came today so I went out and wired it in the van. I used 2.5mm stranded cable, fused at each end with crimped terminals as it won't be very accessible once I put the seat back. I've wired it from the load output of the solar to the starter battery side of the C250DSA, then set the load output to turn on above 13v and off at 14.7v, does this sound about right?

An interesting and unexpected side of this setup is that if you switch the load output to "Always on" then the output becomes live whether there is any solar output or not, and begins to trickle charge the starter battery from the leisure battery.


This could be useful if you were on a mains hookup with no decent solar, or in an emergency anytime. For £30 this was a decent add-on and plugs the gap in my electrical setup nicely

 

[Alby42]

Thanks for replys. Travelvolts has set me up, just need a van to fit it all in.

 

[travelvolts]

Ok this came today so I went out and wired it in the van. I used 2.5mm stranded cable, fused at each end with crimped terminals as it won't be very accessible once I put the seat back. I've wired it from the load output of the solar to the starter battery side of the C250DSA, then set the load output to turn on above 13v and off at 14.7v, does this sound about right?

An interesting and unexpected side of this setup is that if you switch the load output to "Always on" then the output becomes live whether there is any solar output or not, and begins to trickle charge the starter battery from the leisure battery.
View attachment 32394

This could be useful if you were on a mains hookup with no decent solar, or in an emergency anytime. For £30 this was a decent add-on and plugs the gap in my electrical setup nicely

I would keep an eye on things during mains charging as this could confuse the D250, especially as the D250 already trickle charges the vehicle battery from solar.

 

[andys]

I would keep an eye on things during mains charging as this could confuse the D250, especially as the D250 already trickle charges the vehicle battery from solar.

Thanks will do, although I wouldn't do it very often, I intend to plug it in on Sunday when I'll be working in the garage all day to monitor it and see what it does when the starter battery reaches full charge.

I don't use the solar input on the Ctek though, I have a separate Victron for that, so I believed that the starter battery side is completely isolated from the other side when the ignition is not on. Is that right?

 

[travelvolts]

Yes, that's right but it pays to be vigilant until you know that all is well.

 

[andys]

Switched the trickle charger on (leisure battery already on mains hookup) about 9:00 this morn, with the starter battery reading 12.4v and the Victron app showing that 1A was being drawn to charge it. At 12pm the starter battery was at 12.7v and the current pulled had dropped to 0.3A so it looks like the Votronic trickle charger is monitoring the SOC of the starter battery when deciding how much current to feed in. I'm going to look again at 3pm.