Separate DC-DC and Solar MPPT chargers

[Alanmh]

Ok, so, I am thinking of adding a new solar panel (once I have got a new AGM leisure battery) and chances are it will have a Voc too high for the CTEK DC-DC charger and will need a separate Solar MPPT charger.

I know lots of others have done this, and despite searching, I cannot find if how it is preferred to wire the (say Victon MPPT) to the CTEK. Do i connect to the solar input (effectively two MPPT controllers in series? or something else?

Thanks in advance

Alan

 

[Pete C]

Don't connect it to the Ctek, connect it to the battery directly.
Pete

 

[Salty Spuds]

Ok, so, I am thinking of adding a new solar panel (once I have got a new AGM leisure battery) and chances are it will have a Voc too high for the CTEK DC-DC charger and will need a separate Solar MPPT charger.

I know lots of others have done this, and despite searching, I cannot find if how it is preferred to wire the (say Victon MPPT) to the CTEK. Do i connect to the solar input (effectively two MPPT controllers in series? or something else?

Thanks in advance

Alan

I have separate mains/solar/DC-DC chargers. Everything goes straight to the battery.

 

[Alanmh]

Thanks for your replies. I guess I am worried about 2 intelligent charger inputs when the engine is running and the sun is shining. Doesn't seem quite right somehow.

 

[AsInNoVolts]

I have separate mains/solar/DC-DC chargers. Everything goes straight to the battery.

How do you prioritise one type of charging over another in this case? I'm trying to set up a system using solar and DC-DC charging, and can't get my head round how it works (both in terms of prioritising and in regulating/protecting the leisure batteries).

 

[Loz]

I have 2 connected to the same battery each will decide if it needs to charge.

 

[Salty Spuds]

How do you prioritise one type of charging over another in this case? I'm trying to set up a system using solar and DC-DC charging, and can't get my head round how it works (both in terms of prioritising and in regulating/protecting the leisure batteries).

There's no need to, it largely sorts itself out. All my kit is Victron using the same Lithium profile. When the battery is charged all the chargers go into "Float". If we're on EHU & the battery drops, either the mains or solar (if there's light) will kick in. If the engine is running, the DC-DC will kick in. At the end of the day, its irrelevant where the charge is coming from, as long as it's there when needed & off when the battery is charged.

 

[Dellmassive]

@AsInNoVolts

As above the dc_dc and solar will work individually.

Each will sample the leisure battery voltage and decide to charge or not.... Independently.

Unless you have Victron kit.... Which has a VE direct feature than enables the units to talk to each other and sync the charging.


What normally happens is when the leisure battery is low both chargers will detect the low voltage and apply full power in an attempt to charge the battery.. as the LB voltage rises the chargers will independently adjust the charge profile to suit...

Untill the LB is full, and both are in float mode.

As above ... It's important to set the charge profile to the correct battery setting that you have.

 

[AsInNoVolts]

@AsInNoVolts

As above the dc_dc and solar will work individually.

Each will sample the leisure battery voltage and decide to charge or not.... Independently.

Unless you have Victron kit.... Which has a VE direct feather than enables the units to talk to each other and sync the charging.


What normally happens is when the leisure battery is low both chargers will detect the low voltage and apply full power in an attempt to charge the battery.. as the LB voltage rises the chargers will independently adjust the charge profile to suit...

Untill the LB is full, and both are in float mode.

As above ... It's important to set the charge profile to the correct battery setting that you have.

Amazing, thank you so much. In that case, I'm looking at the following set up. Any chance of your thoughts on it?

- 330W SP
- Smartsolar 100/20 MPPT
- DC-DC Charger (cant work out what amp rating I need and was thining about getting victron orion in the hope it ties in a little better with mppt)
- 2x 180Ah AGM batteries
- DC-AC Inverter (can't work out how much wattage I need - its only to charge laptops and run a blender)
- Some sort of battery monitor? (is this required if i have the the victron app?)

 

[Salty Spuds]

Amazing, thank you so much. In that case, I'm looking at the following set up. Any chance of your thoughts on it?

- 330W SP
- Smartsolar 100/20 MPPT
- DC-DC Charger (cant work out what amp rating I need and was thining about getting victron orion in the hope it ties in a little better with mppt)
- 2x 180Ah AGM batteries
- DC-AC Inverter (can't work out how much wattage I need - its only to charge laptops and run a blender)
- Some sort of battery monitor? (is this required if i have the the victron app?)

Assuming this is a camper/day van & not some kind of commercial food (smoothie) outfit, or you have a specific requirement for all that power, I think you're OTT & don't have a balanced system. IMHO, a single 180Ah battery will be plenty, a 100Ah Lithium would be even better. 150-180 Watts of solar will do the job, a 800W inverter will probably run your blender unless it's a commercial jobby.

 

[Dellmassive]

@AsInNoVolts

see here for more info:

[Guide] Mobile Solar Panels ? . . . - How I Did It -

Mobile Solar Panels ? . . . - How I Did It - There is loads of background to this . . . . . but for now here is a vid for you all. =] Just remember W = V*A and as a general rule a good 100W panel will give you up to 6A charge with good sun. 25w = 1.5A 50W = 3A 100w = 6A 200w = 12A 300w = 18A...

www.t6forum.com

[Guide] DC-DC Charger (for leisure battery) -- How I Done It --

DC-DC Charger (for Leisure battery) -- How I Done It -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

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Battery Chargers - How I Did It -

Battery Chargers - How I Did It - So its that time of year again, cold, rainy. . . . . . . flat battery =[ This time we look at Battery Chargers. Our vans will most likely come with a AGM style starter battery, for this type of battery we need a "Smart Charger" . . . . but what does this...

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Battery Monitoring -- How I Done It --

Battery Monitoring -- How I Done It -- Part #1 Battery monitoring is a very important part of your 12v system . . . . whether its just the vans starter battery or your leisure setup keeping an eye on the power in your battery bank will keep you from breaking down and make sure your weekends...

www.t6forum.com

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[AsInNoVolts]

Assuming this is a camper/day van & not some kind of commercial food (smoothie) outfit, or you have a specific requirement for all that power, I think you're OTT & don't have a balanced system. IMHO, a single 180Ah battery will be plenty, a 100Ah Lithium would be even better. 150-180 Watts of solar will do the job, a 800W inverter will probably run your blender unless it's a commercial jobby.

Ok, I appreciate the honest advice! You are correct in assuming that this is not a commercial smoothie outfit, but it will be the permanent home for my girlfriend and I - hence why I have been planning a somewhat larger system. Though I am of course now asking myself if I should have invested in a juicer and pomegranate de-seeded...

Already got the solar panel, so sticking with the 330W, and it came with a smartsolar 100/20 MPPT, so that's also a done deal, but maybe need to reconsider the rest of the system now. If I was to stick with 2x180AH in parallel, would I have to size the DC-DC charger for 360Ah? So, (360*0.2) + the load draw amperage from the appliances ?

 

[Salty Spuds]

Ok, I appreciate the honest advice! You are correct in assuming that this is not a commercial smoothie outfit, but it will be the permanent home for my girlfriend and I - hence why I have been planning a somewhat larger system. Though I am of course now asking myself if I should have invested in a juicer and pomegranate de-seeded...

Already got the solar panel, so sticking with the 330W, and it came with a smartsolar 100/20 MPPT, so that's also a done deal, but maybe need to reconsider the rest of the system now. If I was to stick with 2x180AH in parallel, would I have to size the DC-DC charger for 360Ah? So, (360*0.2) + the load draw amperage from the appliances ?

The lead acid batteries will only take what the DC-DC will deliver, plus you don’t want to be charging lead acids too quickly, so 15A /battery sounds fine to me. Also don’t forget that the solar will still be charging at the same time.

 

[AsInNoVolts]

The lead acid batteries will only take what the DC-DC will deliver, plus you don’t want to be charging lead acids too quickly, so 15A /battery sounds fine to me. Also don’t forget that the solar will still be charging at the same time.

Sorry, my bad, they are AGM batteries...

 

[Dellmassive]

AGM is a style of SLA or sealed lead acid.

The best version of SLA in my opinion.

The upgrade from those is lithium.

 

[Salty Spuds]

Sorry, my bad, they are AGM batteries...

Same thing goes, they are just a variant of a Lead Acid battery.