Just a general question of the techy type people here, I've just bought a s/h Jayco Journey Outback...lucky me some will say...It has the standard electrical syhstem fitted, the house battery as usual is a basic 100amp AGM, the charging system is through jayco's BMPRO J35-B Battery Management System.
The J35-B has a maximum solar input of 320w, and the van already has a 160w panel on the roof. The system will charge the single house battery via a 15amp charging system when on mains power, and via the solar panel when no 240v input. All good if you spend most of your time on powered sites as the battery would always be charging. I do have a gen set but have only ever pulled that out when in trouble as prefer to use quiet solar.
We do mostly off grid camping, and I know a 1 x 100 amp battery won't cut it over several days pulling power for lights, water pump, charging phones etc...even while running the fridge on gas when enduring some badly overcast days...and as we all look for some shade cast by trees the roof mounted panel isn't likely to get a lot of useful sun anyway.
In my last camper set up I ran 2 x 140amp AGMs, and used 2 x 200w folding solar panels wired in series through an MPPT controller which was good to run a fridge and a freezer as well as lights, water pump, and the necessary coffee machine through a 1500w inverter for as long as we were camping out...often a couple of weeks.
Anyway, just wondering what the collective thoughts here are on running the solar input from the folding panels separately...ie adding a separate MPPT via an external Anderson plug connecting direct to the batteries, bypassing the existing Battery Management System as it does not have the capacity to take an additional maybe 350w solar input. I am replacing the 100amp house battery with a 140amp battery and adding another 140amp to give me 280amps....and will be fitting an inverter.
I would need though to work out how hopefully I can set up the existing BMS so that the battery charge condition will show up on the charge monitoring already fitted to the van.
Does any one see an issue doing this? I can't see any potential problems at all, maybe somebody here can?
I did a quick experiment with my two Victron MPPT bluetooth controllers 100/20 & 75/10. Is was sort of ok.
You would need to measure the voltage while charging & then go into the menu & adjust the cut off voltage as precisely as possible, otherwise one cuts off the other controller too soon.
In my situation the smaller controller was turning off the larger one. So either get the voltage exact or a whisker in favour of the larger controller.
Both my controllers were close to the battery with very heavy wiring, so long wire run from controller to the battery was not another factor.
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Thanks for that tip, yes you are right, both controllers will want to go to float at some point and as you point out will likely fool the other in to thinking the batteries are full when possibly not...cheers
Dean,
Perhaps you should bear in mind that solar panel ratings are lab-test ratings and in real life you can only ever get about 75% of the panel's rated output under the very best operating conditions. Secondly, if a solar controller unit has more solar input than it is meant to handle, it will just restrict output to its rated limit, in your case 350w.
Cheers,
Roy.
Very true Roy, thank you...hence my thoughts that I'd maybe have only 350w in total anyway from the two "200w" panels on a good day...outside of the theoretic 160w already in place.
One of the panels I have I was suckered in to purchase as it was advertised as 250w, but on receiving it the physical size and cell count is the same as the alleged 200w I already had! Caveat Emptor...EBay sellers are not known for truth in advertising...
The fitted BMS only will take 320w input, and as the van already has 160w on the roof theoretically at least, it only has spare capacity of another 160w. I am keen to utilise as much solar as I can as there will be occasions I will want to run an additional freezer (an extra 35 amps a day) on occasion.
The two panels I have have been giving me up to 42v at the MPPT connected in series, with output voltage of up to 14v and amperage output varying as required by the 280amp battery bank. I was pulling up to 80 amps a day with the set up I had and the 280amp battery bank would be on float usually by mid morning with the two panels.
(I have just fitted the two 140amp batteries in to the van, and have removed the 100amp.)
The fitted BMS I have I cannot find any info whether it uses a PWM type built in controller or an MPPT. With what they cost they should be MPPT but who knows. For short 1 day stays I would certainly get away with the 1 x 160w panel, but for extended stays I need to be sure I have plenty of power....especially to pump power back in after using the inverter.
My concern is how I should run the two battery management systems effectively side by side with out any drama...has anybody done similar?
I reckon i am over thinking this installation.
I am going to wire a new Anderson plug input for the panels outside then cabled inside, then hard wire the new 30 amp MPPT controller to the batteries.
I'll only ever be adding the extra panels when off grid anyway, so the rest of the time the fixed existing panel will operate, or the mains input. I am sure the respective controllers will sense battery condition and charge accordingly.
I will come back to this thread in a few weeks after I have used the set up a few times and report...
I have near double solar for my 30 amp controller . I makes a buzzing noise when it restricts voltage . It doesnt happen very often . Two X 120 AGM in parallel. VSR to starter batteries to charge while motor is running also .
I reckon i am over thinking this installation. I am going to wire a new Anderson plug input for the panels outside then cabled inside, then hard wire the new 30 amp MPPT controller to the batteries.
I'll only ever be adding the extra panels when off grid anyway, so the rest of the time the fixed existing panel will operate, or the mains input. I am sure the respective controllers will sense battery condition and charge accordingly.
I will come back to this thread in a few weeks after I have used the set up a few times and report...
Cheers
Hi Hitting the road, How did you go after setting up your system. I have a Redarc Manager 30 and there are no issues with running a a seperate solar controller. I use a an EPEver Triron Which I have wired directly to my batteries so that I do not forget to connect it which I did for all of about 5 minutes one time .
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