Solar Charging D/C cell battery directly

[Religious Shooter]

I have some solar panels with MC4 connectors, Rockpals and Jackery solar generators. I use the pass thru charging feature on the solar generators and charge my D/C cell batteries through the AC port.

I read that this can cause the solar generator to degrade faster due to the heat, etc.

How can I set it up so that I don't need an intermediate battery (solar generator) to charge D/C batteries directly from the solar panels?

I tried this:

https://www.amazon.com/Cutting-Edge-Power-Adapter-Directly/dp/B07HNB3TTS/ref=sr_1_4?dchild=1&keywords=usb%2Bmc4&qid=1618038171&sr=8-4&th=1

It stopped working. When it did work it took forever since it is only 5V 2A USB.

I have a renogy charge controller with a sacrificial battery and use it to charge my USB battery banks and AA/AAA batteries. But again, it takes forever to charge 4 D/C batteries via USB.

Any suggestions?

[envelope]

I've concluded you either need a completely solar setup, or your current batteries are the sacrificial lamb. I'm about to experiment with the sustainability of the same mc4 to USB after siphoning/splitting one mc4 connector into 2

I picked up the 100w version in case I needed to scale up. 50w would not have met my needs

[broadside]

If I am understanding you correctly, you just need a solar charge controller like https://www.amazon.com/Controller-Ba.../dp/B072MMDY4F

But the sizing depends on the battery config (12 vs 24) and total solar putput and its wiring setup

[envelope]

If I am understanding you correctly, you just need a solar charge controller like https://www.amazon.com/Controller-Ba.../dp/B072MMDY4F

But the sizing depends on the battery config (12 vs 24) and total solar putput and its wiring setup

I was looking at that before settling in the cutting edge mc4 to USB converter I assumed the solar controller you linked required a battery, which then fed the USB output. If my assumption was wrong, then for sure your recommendation is the better way to do it!

[broadside]

You'd have to read the manual to see if the load side is isolated from the input or not. I don't have that unit so I'm not sure.

[brassburnz]

I have some solar panels with MC4 connectors, Rockpals and Jackery solar generators. I use the pass thru charging feature on the solar generators and charge my D/C cell batteries through the AC port.

I read that this can cause the solar generator to degrade faster due to the heat, etc.

How can I set it up so that I don't need an intermediate battery (solar generator) to charge D/C batteries directly from the solar panels?

I tried this:

https://www.amazon.com/Cutting-Edge-Power-Adapter-Directly/dp/B07HNB3TTS/ref=sr_1_4?dchild=1&keywords=usb%2Bmc4&qid=1618038171&sr=8-4&th=1

It stopped working. When it did work it took forever since it is only 5V 2A USB.

I have a renogy charge controller with a sacrificial battery and use it to charge my USB battery banks and AA/AAA batteries. But again, it takes forever to charge 4 D/C batteries via USB.

Any suggestions?

There are solar kits for backpacking and placing in your car windshield that have a USB A port for charging. They are only 10-20 watts or so, so I think it would take several hours to charge a phone. I've thought about getting something like this, but I don't really have a need.

https://smile.amazon.com/XINPUGUANG-Portable-Foldable-Compatible-Camouflage/dp/B08LGWKVNW/ref=sr_1_14?dchild=1&keywords=50+watt+folding+solar+panel+kit&qid=1618799139&sr=8-14

I'm not familiar with the USB power adapter.

I don't usually charge my iPhone with the Jackery 500, but when I do it charges as quickly as if plugged into AC. The passthrough capability of the Jackery lets me charge from my panels or AC and charge my phone at the same time. The 5w DC pull is so small I don't think it does any damage to the Jackery.

I've run a mini-fridge pulling 54 watts running/5 watts resting through the Jackery for 28 hours while it was receiving 45 watts of solar from a BougeRV 175 watt panel. The Jackery never dropped below 85% so it could have run for a while as long as the sun cooperated.

Hobotech runs cooking appliances with his "solar generators" while charging through the pass through circuit all the time. He's never mentioned anything about the battery cells degrading.

[unusedusername]

You really don’t have to worry about NI-MH size C and D batteries hurting a solar generator. They hold so little power compared to modern batteries that it is almost nothing. I wouldn’t even worry about it.

If you want to be sure, charge them with a really slow charger. Slower chargers put less draw on their power source. A charger takes USB (A, not C) input will be slow since USB does not have much power in its max spec.

Here is a suggestion for a slow charger:

https://www.amazon.com/dp/B07Y5ZB8Z5/

A Jackery 500 holds 500 watt hours. The biggest “D” cell is a little over 10 watt hours. You can recharge 40-ish of them, including loss in the charger, before the Jackery goes dead, and that assumes you have no power input to your Jackery. That also assumes the D cells are completely dead, which you don’t want to do to NI-MH cells. If you assume a more saine “recharge when half full” process then you’ll get 80-ish D cells out of your Jackery.

[tigerpan]

It don’t have enough information, what’s max voltage input? Amps max wattage input?

[tigerpan]

If I am understanding you correctly, you just need a solar charge controller like https://www.amazon.com/Controller-Ba.../dp/B072MMDY4F

But the sizing depends on the battery config (12 vs 24) and total solar putput and its wiring setup

The max input voltage for 12v system is 23v. You can only used 1 100w panel.

[unusedusername]

If I am understanding you correctly, you just need a solar charge controller like https://www.amazon.com/Controller-Ba.../dp/B072MMDY4F

But the sizing depends on the battery config (12 vs 24) and total solar putput and its wiring setup

That charge controller is set up for sealed lead acid batteries. Please don’t try to use it on a NI-MH D cell. Bad things will happen if you try to change a battery using a chemistry significantly different from what the charging circuit is expecting.

Normally, it will just fry the battery and you’ll have to throw them into the garbage. If you are extremely unlucky, it could start a fire.

[brassburnz]

I'm using a Jackery 500 to charge a 3.7v, 3000mAh, 11.1 Wh, lithium ion camcorder battery. The charger was only pulling 7 watts from the Jackery. The Jackery is at 83%. I'll have to check it again when it's finished charging. I'm not using pass through.