NDS MPPT, Redarc B2B/MPPT and lithium

[GMLS]

Good afternoon all,
We had a quick look over our new Rapido today which we will be collecting on 1st September. I arranged to have a couple of solar panels fitted which are made by NDS and I think we have about 360w, which was the most that could be accommodated. The dealer has fitted an NDS SCE 360 MPPT but looking over the paperwork we took away, I also see reference to a Redarc BCDC1240 being fitted as the B2B. Both this and the NDS unit appear to be suitable for lithium and I thinkthe NDS charges both batteries so no need for a Battery Master. I'll also fit a Smart Shunt

The current mains battery charger is a CBE516-3 which doesn't appear to have a setting ideal for the Fogstar so I'm going to fit a Victron IP22 30/1 I have spare. The vehicle currently has 2x100ah lead batteries but we want to be able to off grid for upto 5 days and camp all year round so hence happy to invest in a lithium.

I have 2 questions (I will ask the dealer but also interested in the view of this forum so I am prepared);

1) I have a Fogstar 300ah lithium to fit. My understanding is that with the above equipment and I'm told appropriate cabling already installed, it's just a drop in swap out?
2) As the Redarc is also an MPPT, am I better off using that and by passing the NDS unit?

Thoughts welcomed. Have a great long weekend all

 

[1 Cup]

Nice

 

[wildebus]

Good afternoon all,
We had a quick look over our new Rapido today which we will be collecting on 1st September. I arranged to have a couple of solar panels fitted which are made by NDS and I think we have about 360w, which was the most that could be accommodated. The dealer has fitted an NDS SCE 360 MPPT but looking over the paperwork we took away, I also see reference to a Redarc BCDC1240 being fitted as the B2B. Both this and the NDS unit appear to be suitable for lithium and I thinkthe NDS charges both batteries so no need for a Battery Master. I'll also fit a Smart Shunt

The current mains battery charger is a CBE516-3 which doesn't appear to have a setting ideal for the Fogstar so I'm going to fit a Victron IP22 30/1 I have spare. The vehicle currently has 2x100ah lead batteries but we want to be able to off grid for upto 5 days and camp all year round so hence happy to invest in a lithium.

I have 2 questions (I will ask the dealer but also interested in the view of this forum so I am prepared);

1) I have a Fogstar 300ah lithium to fit. My understanding is that with the above equipment and I'm told appropriate cabling already installed, it's just a drop in swap out?

No such thing as a Drop In Lithium. You have some chargers that can be configured to Lithium so you are in a fairly good shape though.

2) As the Redarc is also an MPPT, am I better off using that and by passing the NDS unit?

The Redarc BCDC1240 is a good charger but there is something you MUST be careful of. It has a very hard upper voltage cutoff for the solar panel input.
I don't recall precisely what it is, but in essence, if you have "12V" panels, which output around 20V or so, you should be ok.
But if you have "24V" panels, which output around 40V (or you have two 12V panels in series, which is the same thing as a 24V panel) you WILL blow up the Redarc and they are not repairable due to their method of manufacture.

Also, is it a BCDC1240 or a BCDC1240D? It sounds like you are getting a brand new van so I would expect it was a 1240D, but Redarc may still make the old 1240 (the difference is the older 1240 will use EITHER Alternator OR Solar to charge the battery, whereas the D (Dual) will use solar when available and top up with Alternator power to the charger limit when the engine is running, so is theroretically more efficient.

The fact the dealer consciously fitted a seperate Solar Controller suggests that the panels are not compatible with the BCDC1240 (overvoltage maybe?), it is an older controller (the non-Dual 1240 needs an extra bit of kit which he may not know about?), or he disb't know the Redarc was a Combo Charger? I'd probably leave it as it is unless you have a good reason to change it around.

Thoughts welcomed. Have a great long weekend all

 

[GMLS]

No such thing as a Drop In Lithium. You have some chargers that can be configured to Lithium so you are in a fairly good shape though.


The Redarc BCDC1240 is a good charger but there is something you MUST be careful of. It has a very hard upper voltage cutoff for the solar panel input.
I don't recall precisely what it is, but in essence, if you have "12V" panels, which output around 20V or so, you should be ok.
But if you have "24V" panels, which output around 40V (or you have two 12V panels in series, which is the same thing as a 24V panel) you WILL blow up the Redarc and they are not repairable due to their method of manufacture.

Also, is it a BCDC1240 or a BCDC1240D? It sounds like you are getting a brand new van so I would expect it was a 1240D, but Redarc may still make the old 1240 (the difference is the older 1240 will use EITHER Alternator OR Solar to charge the battery, whereas the D (Dual) will use solar when available and top up with Alternator power to the charger limit when the engine is running, so is theroretically more efficient.

The fact the dealer consciously fitted a seperate Solar Controller suggests that the panels are not compatible with the BCDC1240 (overvoltage maybe?), it is an older controller (the non-Dual 1240 needs an extra bit of kit which he may not know about?), or he disb't know the Redarc was a Combo Charger? I'd probably leave it as it is unless you have a good reason to change it around.

Thank you for your comprehensive reply which I need to digest but its not the "D" version

 

[Nabsim]

@wildebus instead of changing the mains charger could he not change output from battery bank to mppt? Seem to think it was an idea I got from you quite a while ago but I could have wrong end of the stick

 

[wildebus]

@wildebus instead of changing the mains charger could he not change output from battery bank to mppt? Seem to think it was an idea I got from you quite a while ago but I could have wrong end of the stick

I think what you are suggesting is this .....

Connect the existing DC output of the charger to an MPPT Input where the Solar Panel would usually be connected. Then you can use the Smart Charging design of the MPPT to present a charging profile that is suitable for a Lithium Battery and save the need to invest in a new Smart Mains Charger?

That concept certainly can work and I know of at least two forum members who have that kind of setup, where they switch from a Solar Input to the MPPT controller to a Power Supply input instead when they are hooked up.
There may be a problem with using the existing Mains Charger as the voltage is quite low compared to a solar panel, for example, this approach would absolutely not work with a Victron controller as a 12V mains charger is too low a voltage to turn on the MPPT. But if you got a 24V or an 18V Power Supply - for example like this:- https://amzn.to/3sBm7ne - you could do it (I used one of those to connect to Solar Controllers so I could test them withput having to rely on solar panels).
Connecting via the Redarc might work as that expects a wide range of voltages (within limits of course!) and will reduce or boost it as appropriate within the charger.

I remember having a conversation on these lines with Ablemail discussing the option of using one of their AMS (B2B+MPPT Combos) and a 24V Power Supply rather than buying a much more expensive Smart Mains Charger. The Power Supplys are cheap (which is why you see them in so many Sargent units with a fixed 13.8V output rather than a proper Battery Charger) and the AMS with the MPPT is not much more expensive than the AMC B2B Charger, but gives you all the Smart Charging intelligence of a quality MPPT.

 

[GMLS]

The plot thickens The unit is clearly marked 1240 which I understand was released before the 1240D dual input version, however the front of my unit looks like the pictures of the 1240D with a solar led rather than the 1240 version.Checking with the importer as maybe mine was been mislabled.