Victron MPPT vs solar panel with own controller - 2023 Tab 400

aquadgolf13 · December 13

Hi, 2nd owner of a 2023 Tab 400. Looking to add a portable solar panel. Previous owner installed an SAE port near the cargo bay with the battery disconnect switch. I believe he had an additional MPPT installed, but removed it prior to sale. The cables from the SAE port end after about a foot inside the cargo bay. I understand I have two options: One - install an additional Victron MPPT either 100/30 or 100/50 or wire the SAE directly to the battery if I purchase a panel with its own solar controller (the easier route).

What is the benefit(s) of going the more difficult Victron MPPT route?

pthomas745 · December 13

You can use another Victron controller with a portable panel and not "mount" it anywhere, and simply connect the SAE port to the battery distribution block and connect the new controller to it.

Or: mount the new Victron somewhere in the space there near the disconnect switch, connect the SAE port wires to the "PV" inputs on the controller, and plug the solar panel cables into the port. Then wire the controller "Batt" outputs to the battery distribution block.

The 100/30 controller would allow you you plug a 300 watt panel to that setup.

Grumpy_G · December 13

The MPPT controller is the better option because it has a maximum input voltage of 100V which allows use of more powerful panels or daisy-chained panels. It also maximizes charging. Downside is that many portable panels come with a charge controller that you would have to remove before connecting to the MPPT charge controller.

rcarlson1957 · December 13

Really depends on your power requirements and usage. I like flexibility. I didn't have built in solar panels or a charger on my 2018 Tab 320. I ended up installing a Victron shunt, temp monitor and solar controller in the tub for the battery with an outside connection and got 2 portable panels. I use 1 for the camper battery (100ah lithium) and 1 in conjunction with a portable solar battery with a built in controller when boondocking. In addition, I installed an alternator charger in my truck that I can use to either charge my camper battery or the portable solar battery when I'm traveling down the road or run it for a bit on cloudy days when solar won't work very well. The other thing to keep in mind with installing a 2nd Victron controller. You can monitor all of it very easy.

Marceline · December 13

Grumpy_G said:

The MPPT controller is the better option because it has a maximum input voltage of 100V which allows use of more powerful panels or daisy-chained panels. It also maximizes charging. Downside is that many portable panels come with a charge controller that you would have to remove before connecting to the MPPT charge controller.

It seems like it's a lot easier to find portable panels without a built-in controller than it used to be. Probably because sales of portable power stations have taken off, and the input for these stations is panel without a controller.

donmontalvo · December 13

I have a Rich Solar MEGA 200W suitcase solar panel. I didn't expect it to come with a PWM controller. I immediately took the PWM controller offline, since I have a Victron 100|30 connected to the SAE port in the Nautilus compartment of my T@B 320. My 12V 2x100Ah LiFePO4 parallel array quickly charges up, whereas the PWM was iffy.

Good video on PWM vs MPPT:

https://www.youtube.com/watch?v=fTvNqxLCkJc

I recently also bought a Renogy 220W folding solar panel. I made sure it did not come with a PWM controller. Lucky that it didn't. My JLUR has a Renogy DCC30S (DC to DC with MPPT) so it's 12V 100Ah LiFePO4 is charged whether I'm camping or driving.

FWIW I've never been a fan of PWM controllers.

Image: https://us.v-cdn.net/5021717/uploads/editor/78/g1nlbvqmkirv.jpeg

tphaggerty · December 14

Have basically this same setup. Rooftop solar to a mounted MPPT controller. Added an SAE port (used the vent port on the side for mounting since the battery compartment doesn't need venting with LFP) connected to the batteries. Also have a 100w Renogy solar suitcase with a PWM controller.

I only use the suitcase for longer stays and for sites with lots of shade, nice to be able to pick up some solar by moving things around. Seems to work fine. As far as I can tell, the solar production from the 2 systems "adds up". Some online sources say that the lower (or higher) voltage/current source blocks out the other one but that hasn't been my experience. I've confirmed the charging current via the battery BMS. It would probably work better if I moved the suitcase controller to the battery compartment to compensate for cable voltage drops, but I haven't gotten around to it yet. Not sure how much difference it would really make anyway.

I think a portable panel is a great option. The advantage to one with an attached controller is flexibility, you can use it for other things. A controller in the T@B gives better options for controller choices as well as a bit better efficiency especially with long cable runs. Not sure which wins for cost...

Just make sure you test & match the polarity of the SAE port to your external controller and/or panels!! I believe it is the opposite of what is "normal" for an SAE setup (like for motorcycle battery charging setups).

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Victron MPPT vs solar panel with own controller - 2023 Tab 400

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