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diy solar

Getting 100W solar panel and a charge controller to work together

Arbee

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Dec 16, 2020
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First, I want to apologize if my referring to products here is considered an "affiliate link." I simply own them and have questions on their use. I'm not endorsing nor suggesting avoidance of their use. : - )

Ok...here goes : - ) I have this 100W solar panel of the roof rack of my Jeep Wrangler https://www.eco-worthy.com/collecti...00w-12v-extremely-flexible-mono-solar-panel-1 Sorry, I only saw the moderator's Youtube video on the ills of flexible solar panels after I bought it!!!

I would like to use it for two purposes. The first is to charge this 10ah battery. https://www.eco-worthy.com/collecti...n-bms-3000-life-cycles?variant=37586593349820

Perhaps TMI: my vehicle's dash camera, which is currently energized by my vehicle's factory batteries (yes, there are two in parallel, long story, part of the Engine Start Stop system to save gasoline at traffic lights) has a parking mode setting that I have configured to shut off the camera at 12.3V, so as to not drain these batteries from successfully cranking the engine. Despite these batteries being hooked to a Deltran 3 amp Battery Tender connected to shore power, on cold nights the camera shuts off because the composite battery voltage of these 2 batteries drops. So I was thinking of powering the camera during parking mode, to the previously linked Lithium Iron Phosphate (LiFePO4) 10amp battery---less susceptible I'm told to voltage drops with temperature..... and charging this battery with the aforementioned solar panel, so I can run my dash camera in parking mode even when I am away from home (where shore power for the plug in Deltran 3 amp charger may not be available.)

With the same 100W solar panel, I thought it would be cool of I could also trickle charge the vehicle's batteries, two AGM's, using this Deltran Brand solar controller: https://www.batterytender.com/Battery-Tender-Solar-Controller .

I like the fact that it has the same technology to charge these AGM batteries differently, depending upon their condition, as does the plug in Deltran controller I have, but this solar controller is limited to 45W panels. Supposedly Deltran promotes battery life with its across product segment charging algorithms.

What is the best way to hook this up? I was thinking about splitting the two leads off the solar panel each into two, one side going to this nothing special PWM charge controller, to charge the dash cam's aforementioned LiFePO4 battery: https://www.eco-worthy.com/collecti...h-paremeter-adjustable?variant=37685431435452 .

And on the other side of the split I'd like to put the aforementioned Deltran solar controller.....but that device can't take in more than 45W as input without frying. Is there something I can put between the solar panel wire split off, and this Deltran product to make sure that the Deltran product doesn't see more than 45Watts?

Maybe I am approaching this all wrong. Maybe there is a better product to stick between the split off of the solar panel wires and my vehicle's battery, like, price notwithstanding, an MPPT controller.

Many thanks for your patience with this newbie! : - )
 
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I never heard of splitting a solar panel to two different outputs and can't really see anything good coming out of it. I would wonder what would happen to voltage and amp output as the two different devices fight over the one input. Maybe it would not make a difference.

I assume that the dash cam has the same voltage range that the battery does, to include charging. Some DC items might not like higher voltage. I charge everything in my trailer at 14.7 and have not had problems. So, the dashcam can hook to the Charge controller. Notice I mention charge controller because the panel will put out very close to 19 volts, so something needs to regulate that voltage which is too high for most 12 volt devices.

If I were to charge a second battery as you suggest by trickle charginf the battery, instead of splitting the output, you could get a 12 volt DC to 12 Volt DC charger. I'm looking into something similar for my set up, but this Amazon.com: Victron Energy Orion-Tr Smart 12/12-Volt 30 amp 360-Watt DC-DC Charger, Non-Isolated (Bluetooth): Automotive Victron device at 360 watts is probably more than you want. Better yet, a small solar panel with some sort of device to regulate the current would help: Amazon.com: SP-3 SolarPulse 12V Battery Solar Charger Maintainer, 3W: Automotive. Not recommending that one, but I used something similar on my truck until I started to park it inside and after being away for up to six months, it started fine.
 
Thanks chrisski.

The dash camera hooks up to 12volt batteries and consumes no more than 4.2W, so yes, I guess one could say it has the same voltage range as any of the 3 batteries I mentioned in my OP. I'd be hesitant though about hooking the dashcam to the Charge controller simply because (and maybe I'm missing something) there would be no energy to run the dashcam at night.

I do appreciate how you've expressly said that hooking the dash camera directly to the solar panel would be a no no, given the voltage output of the solar panel. Thanks.

I think you are saying sir (but could completely wrong) that I might be able to charge a single battery, and then use that battery to charge both the batteries under my vehicle hood with a DC-DC controller, perhaps in additional to running the dash camera in parking mode off of that battery directly connected to the solar panel. Might I get you to confirm that?

I might need a bigger battery (hopefully not solar panel) and charge controller to do that but okay....what I've bought in error can be returned.

Final question. I read another post about a member deliberately creating heat around his LiFePO4 battery, itself part of a cold weather exposed setup. It was my understanding the LiFePO4 batteries were much more resilient, at least to voltage drops, in colder weather than Lead Acid batteries. Is that wrong, or have I overstated just how much more resilient things are that someone in the know would take such battery warming strategies?

Thank you. : - )
 
I'd be hesitant though about hooking the dashcam to the Charge controller simply because (and maybe I'm missing something) there would be no energy to run the dashcam at night.
I mispoke on that one. I meant to say there‘s some sort of bus bar that you hook the smaller battery to, the charge controller to, and the dashcam. If you were going to trickle charge with that smaller battery, the DC to. DC charger would hook on the busbar also.
creating heat around his LiFePO4 battery, itself part of a cold weather exposed setup. It was my understanding the LiFePO4 batteries were much more resilient, at least to voltage drops, in colder weather than Lead Acid batteries. Is that wrong, or have I overstated just how much more resilient things are that someone in the know would take such battery warming strategies?
You’d need to check the specs on the lithium battery. The ones I looked into putting in my RV could not get charged below freeing, so that might be what the heater pack is for to keep the batteries warm enough to receive a charge. If these low temps are a problem for where you’re at and the battery you chose, there’s have to be some way to shut the temperature off.
I think you are saying sir (but could completely wrong) that I might be able to charge a single battery, and then use that battery to charge both the batteries under my vehicle hood with a DC-DC controller, perhaps in additional to running the dash camera in parking mode off of that battery directly connected to the solar panel. Might I get you to confirm that?
Although that DC to DC charger is an option, I don’t think it is a good one.
 
Thank you sir. I think I need to resubmit my question in a more open ended manner, stating my desired goal and the tools I have so far to accomplish it for recommendations on what else is needed.

I may be unintentionally constraining your answers: appreciated and well received though they are. : - )
 
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