Please tell me: How to SIMULTANEOUSLY charge EB3A from solar AND from car 12V cigarette lighter?

Product Discussion BLUETTI EB Series
1

Hello,
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Please tell me: How can one SIMULTANEOUSLY charge the EB3A, from BOTH solar power AND from a vehicle’s 12V cigarette lighter power outlet?
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Background:
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-1.-I have a 2006 minivan I camp in, here in the USA, and the Bluetti EB3A is great for camping.
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-2.-I have a 100Watt rigid solar panel, permanently mounted on the roof of the vehicle, and it charges the EB3A at anywhere between around 10W and 70W, depending on the angle of the sun, and the current cloud cover.
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-3.-I have a Bluetti 12Volt cigarette lighter adapter with the DC7909 connector, which charges the EB3A at about 30W to 50W, through the EB3A’s DC input port.
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-4.-Currently, I manually plug in EITHER the solar panel, OR the vehicle cigarette lighter adaptor, into the EB3A’s DC input port… Thus, when I prepare to drive on a cloudy or rainy day, I plug in the vehicle’s 12V charger to the EB3A… and when I stop to park the vehicle in sunny weather, I plug in the solar panel power to the EB3A.
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-5.- Ideally, I would like to have all electrical connections fully connected, at all times, and not need to manually change the connectors, depending on when I drive, and when I park the vehicle.
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-6.-One thought I had, was to try charging the EB3A with the solar panel through the EB3A’s DC input port, and simultaneously charge the EB3A from the vehicle’s 12V power through the EB3A’s AC input port, by using an inverter… so… I tried setting the EB3A to “Silent” (100Watt) charging mode, and tried using a pure sine wave inverter (rated at 300W), powered by the vehicle’s 12V cigarette lighter, to provide 120VAC power to the EB3A’s AC input port, but the inverter cycles on and off, and does NOT seem to charge the EB3A…
EDIT: This inverter approach now seems to be working, at least for today. I removed a 12V splitter cable, which had been providing power from the 12V cigarette lighter port, to the inverter’s power input. Apparently the splitter cable had been causing an unwanted voltage drop (a “brown out”?), which had apparently caused the inverter to turn itself off and back on. Plugging the inverter directly into the cigarette lighter port seems to have gotten this working. I do not know if this will continue working, or if there is a more optimal solution.

Note: I had set the EB3A to “Silent” (100Watt) charge mode in order to prevent the EB3A from pulling more than 100Watts through the inverter, because the cigarette lighter uses a 20Amp fuse, and I want to avoid blowing the cigarette lighter’s fuse…
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Summary: How can one SIMULTANEOUSLY charge the EB3A, from BOTH solar power AND from a vehicle’s 12V cigarette lighter power outlet?
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Thanks in advance!
Kevin

1 Like
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If you want to do it Proper Install a solar system in your van
(ideally with a “24V” LFP battery.)
This system can be charged via Solar or via a DCDC charger from your 12V system if the ignition is on.

From a 24V system you would get close to 200W to your EB3A

1 Like
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Thanks, bernad.
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I’m not sure if I fully understand… I’m not very experienced with these sorts of electrical systems, and I’d like to keep my build as simple as possible, while satisfying my goals.
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Did you mean to recommend that I should setup a LFP (LiFePO4) battery, which would be charged by both solar and the vehicle’s 12V cigarette lighter port, and then this LFP battery would charge the EB3A?
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Cool idea, but then I wouldn’t need the EB3A, as the LFP battery would be my battery system… assuming I understood correctly.
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I’m really looking for a simple and easy way to charge my existing EB3A, using both solar and the vehicle’s 12V cigarette lighter port. And since I’m putting this in a minivan, I need to keep the system small so it will fit in the small vehicle
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Thanks,
Kevin

4

All, FYI:
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The inverter approach (item #6 in the original post) now seems to be working, at least for today. I removed a 12V splitter cable, which had been providing power from the 12V cigarette lighter port, to the inverter’s power input. Apparently the splitter cable had been causing an unwanted voltage drop (a “brown out”?), which had apparently caused the inverter to turn itself off and back on. Plugging the inverter directly into the cigarette lighter port seems to have gotten this working. I do not know if this will continue working, or if there is a more optimal solution.
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I’m still very interested in learning a better (i.e., smaller, cheaper, simpler) solution… so please share your suggestions.
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Thanks,
Kevin

5

Yes.
Yes you would need both. but you would have the Capacity of both

The other Other option is to get a CC/CV DCDC charger and Diodes
The DC/DC charger gets set to around the same voltage as your solar Panels voltage.

Via Diodes the DC/Dc as well as solar feed the solar input of the EB3A

6

Thanks, bernad.
There is a lot for me to learn… I didn’t know about CC/CV chargers… I’m very new at this.
Is there an introductory textbook on the subject of setting up these sorts of systems, that you could recommend, please?
Thanks,
Kevin

7

Mobile Solar Power Made Easy!: Mobile 12-volt off-grid solar system design and installation. RV’s, Vans, Cars and boats!
by William Errol Prowse IV May 15, 2017, available on Amazon
He also has a YouTube channel with good content.