EB70 panel woes . . . struggling to run my fridge / power outages ??

[richsolar]

Hey Folks,

Def a newbie/beginner in the Solar World . . .

Starting with a small Bluetti EB70 power station thought it would be pretty straight forward, but two 230W used panels I bought were too high voltage, pic attached.

So I'm currently borrowing a smaller panel (120W - but inputs seem capped at 90W) from a neighbour, but with my fridge running, a Dometic CDF-36 (12-24V 60W), if we have a few days of partial sun it drains the battery.

I figured I'll move the fridge to a cooler place in the house and make a cover for it to improve insulation, but also a bigger panel will charge more on those cloudier days and guarantee full charge on a sunny day with the fridge running.

My questions are can I run one of those bigger panels using an external solar charge controller capable of higher voltage, or I've seen 'buck converters' mentioned but not sure what those are?

Or do I have to buy a newer 12-24V panel closer to 200W? There is a used 29V panel going on Marketplace but that's just outside the 12-28V OCV range for the EB70? I also wondered about connecting the two diff panels I have in parallel (one of the 230W used ones and 120W neighbours), if the voltage will be restricted to the lower of the two (my neighbours one), thus will work with the EB70?

Look forward to hearing your responses folks and becoming a part of the Community.

Ta,
Rich

 

[12VoltInstalls]

we have a few days of partial sun it drains the battery

One 120W panel is not enough - worse if using lead acid batteries. That’s 60Ah at 12V nominal so a tiny lithium battery.

Starting with a small Bluetti EB70 power station thought it would be pretty straight forward

Do you need convenient, carry-around power? Because at the typical bluetthi purchase prices you can get components and batteries about twice the available power for the same money- typically less- that WILL accept your small 440W panel array. And even expand it, scale it up, as required.
In fact, since it isn’t enough power anyways, spending ~$150 more would give you almost double the battery power (watt-hours), a decent inverter, and a charge controller capable of 150% of the battery needs.

In practical terms that will let you use a lot of power all day long while still permitting the battery to recharge fully.

You basically have a 60Ah system with barely enough solar capacity.

FWIW- picture #4 is one of the coolest photos of an offgrid location I’ve seen in a while

 

[mikefitz]

The EB70 is good for USB charging and short time AC loading but has limited power storage and solar panel limitations due to the 28 volt 8 amp panel limit.
My suggestion is to add a 12v 100Ah battery, lithium would be ideal but lead acid would be a medium term solution, and a solar controller. Whilst a MPPT controller would get the most power from the panels, a low cost PWM would yield 16 amps maximum from the two 230 watt panels in parallel. Run the fridge direct from the battery and charge the EB 70 using the car charger from the battery during daytime.
Your fridge/cool box is very efficient and will consume around 300 to 400 watt hours a day. Since the EB70 has 700 watt hours of storage, fridge operating from the EB70 alone, for more than 2 days of poor solar, will have issues as you are experiencing.
By being able to use the two 230 watt panels, the low yield on cloudy days should still be enough to keep up with fridge demand.

Mike

 

[12VoltInstalls]

Your fridge/cool box is very efficient and will consume around 300 to 400 watt hours a day.

Small storage though, and ergonomics?
My 120V ~7.5CF top freezer model is a blessing to me. 60W running is 5A at 12V at roughly 60Ah ~750Wh / day is more attractive to my way of thinking than living out of a cooler. YMMV

The fridge at $215 purchased new leaves a fair number of $ to add some panels if one needs to as compared to the refrigerated cooler cost up front. While that pretty much eliminates practical use of low cost suitcase batteries like bluetthi I don’t think that’s much of a compromise when a 1000W+ system runs so well at practically the same upfront price of entry.

When you can buy the MPPSolar 1012LV for ~$450 it’s hard to justify the little bluetthi that struggles at 400Wh. Yes it costs more for the battery (batteries) but you will actually function with it and not have to bend over and fetch stuff from a cooler.

 

[richsolar]

thanks for the feedback folks, it sucks without a fridge, i just got used to it!

The EB70 is good for USB charging and short time AC loading but has limited power storage and solar panel limitations due to the 28 volt 8 amp panel limit.
My suggestion is to add a 12v 100Ah battery, lithium would be ideal but lead acid would be a medium term solution, and a solar controller. Whilst a MPPT controller would get the most power from the panels, a low cost PWM would yield 16 amps maximum from the two 230 watt panels in parallel. Run the fridge direct from the battery and charge the EB 70 using the car charger from the battery during daytime.
Your fridge/cool box is very efficient and will consume around 300 to 400 watt hours a day. Since the EB70 has 700 watt hours of storage, fridge operating from the EB70 alone, for more than 2 days of poor solar, will have issues as you are experiencing.
By being able to use the two 230 watt panels, the low yield on cloudy days should still be enough to keep up with fridge demand.

Mike

Really like this idea Mike! I can easily source a 12v 100ah battery, same as a car battery right? What PWM would you recommend for those panels/battery? I just have to alter some cables i.e. fridge to new battery (currently has a cig lighter connection), and Bluetti car charger would also have cig lighter connection I presume. Would I have to disconnect the Bluetti from the battery at night or?

Ta, Rich

 

[richsolar]

The EB70 is good for USB charging and short time AC loading but has limited power storage and solar panel limitations due to the 28 volt 8 amp panel limit.
My suggestion is to add a 12v 100Ah battery, lithium would be ideal but lead acid would be a medium term solution, and a solar controller. Whilst a MPPT controller would get the most power from the panels, a low cost PWM would yield 16 amps maximum from the two 230 watt panels in parallel. Run the fridge direct from the battery and charge the EB 70 using the car charger from the battery during daytime.
Your fridge/cool box is very efficient and will consume around 300 to 400 watt hours a day. Since the EB70 has 700 watt hours of storage, fridge operating from the EB70 alone, for more than 2 days of poor solar, will have issues as you are experiencing.
By being able to use the two 230 watt panels, the low yield on cloudy days should still be enough to keep up with fridge demand.

Mike

@mikefitz let me know on the above when you get a chance . . . I'm keen to order the bits . . . cheers

 

[richsolar]

could I use an external MPPT to reduce the voltage and charge my Bluetti eb7o that way? From my two 37v (ocv) panels . . .

 

[tammons]

Hey Folks,

Def a newbie/beginner in the Solar World . . .

Starting with a small Bluetti EB70 power station thought it would be pretty straight forward, but two 230W used panels I bought were too high voltage, pic attached.

So I'm currently borrowing a smaller panel (120W - but inputs seem capped at 90W) from a neighbour, but with my fridge running, a Dometic CDF-36 (12-24V 60W), if we have a few days of partial sun it drains the battery.

I figured I'll move the fridge to a cooler place in the house and make a cover for it to improve insulation, but also a bigger panel will charge more on those cloudier days and guarantee full charge on a sunny day with the fridge running.

My questions are can I run one of those bigger panels using an external solar charge controller capable of higher voltage, or I've seen 'buck converters' mentioned but not sure what those are?

Or do I have to buy a newer 12-24V panel closer to 200W? There is a used 29V panel going on Marketplace but that's just outside the 12-28V OCV range for the EB70? I also wondered about connecting the two diff panels I have in parallel (one of the 230W used ones and 120W neighbours), if the voltage will be restricted to the lower of the two (my neighbours one), thus will work with the EB70?

Look forward to hearing your responses folks and becoming a part of the Community.

Ta,
Rich

The 120 watt panel is not capped, it is efficiency. 90 watt max sounds about correct.

If you want to run the larger panels you need to get the voltage and watts down to the EB70 max which should be (max solar input for my EB70s and I assume yours) is 200 watts, 12-28V, 8A. That would max out the EB70 solar charging.

I have the EB70s and I am currently testing a Change Moore fridge 45 with an internal battery to see if it will run continuously. I bought the kit with the Bluetti 200 watt folding solar panel and it maxes out at maybe 150 watts on a sunny day if everything is perfect. I tried a 100 watt panel and it was not enough power to keep building the EB70s charge while running (or charging the fridge)

A 200 watt panel is barely enough in sunny weather and it has been running for a couple of days now, but the weather is clear right now.

The way my fridge works with the internal battery is, the power source whatever it may be, car, 110v, solar panel plugged directly into the fridge, or a power station, charges the internal fridge battery and the fridge runs off the internal battery. So the solar panel is charging the Eb70s which in turn is constantly charging the fridge battery, until it is dark. Then the EB70s charges the fridge battery and draws down the EB70s. The fridge battery is about 173 watts.

If the EB70s runs down and turns off during the night, the internal fridge battery will continue to run the fridge. I think it is rated at 12 hours, but that is probably in fridge only mode and perfect conditions.

Hooked everything up, and by yesterday morning my EB70s was dead and turned itself off. By that night solar charging all day and running the fridge (freezer too at 40/0df) the EB70s battery was at 80%. Today when I woke the EB70s was at 20% and it its charging via solar at 138 watts.

So the EB70s + 200 watt is barely keeping up with charging the EB70s + the power requirements of the fridge if it is sunny. And the EB70s carries it through the night.

However if it is overcast partly sunny etc, it wont keep up.

I dont know the full power draw of my fridge over time, as I am hunting for a cumulative power meter to test it.

To run it full time in most any weather, I am thinking of setting up a 100 amp 12v lipo battery (1280 watts) and have two 200 watt solar panels.
200 watt panel in sunny weather. 400 watts for partly cloudy and overcast.

Dont know if that helps but maybe it will.

 

[Tomthumb62]

Small storage though, and ergonomics?
My 120V ~7.5CF top freezer model is a blessing to me. 60W running is 5A at 12V at roughly 60Ah ~750Wh / day is more attractive to my way of thinking than living out of a cooler. YMMV

This is exactly what we do. So great. Only downside is needing a small fan inside tire fridge to circulate cold air. Under $300 for our 7.5cf Avanti fridge, going strong for 5 years now (used seasonally). Can be found at Home Depot for about $650, ours was a scratch and dent model from Amazon Warehouse.

 

[12VoltInstalls]

Under $300 for our 7.5cf Avanti fridge, going strong for 5 years now (used seasonally). Can be found at Home Depot for about $650, ours was a scratch and dent model from Amazon

I got very lucky on an Element ~7.5
It was a ‘warehouse’ clearance at walmartha and it was marked $145 but at checkout it came out $115. I had to go next door to hahbah fweight and buy a hitch haul rack to take it (I was 150 miles from home!)

Either way, the money makes sense compared to other options, never mind that the RV fridges aren’t great efficiency-wise on electric in general, and replacement cost…

 

[Tomthumb62]

never mind that the RV fridges aren’t great efficiency-wise on electric in general,

Those three way fridges are great on propane, okay on 12v and really really bad on 120v. Like so bad I’ve read they’ll use 400-800W. That’s the regular load, not the startup surge.

Our 120v Avanti uses 45-80w, less in cool weather, more in hot weather. 600-800W startup surge for less than 2 seconds.

 

[12VoltInstalls]

Those three way fridges are great on propane, okay on 12v and really really bad on 120v.

I’ve never seen one on battery or 120V do well with consumption. Propane fine.

They basically all work great- the costs to run them whether in dollars or watts is a big issue in my head.

 

[tammons]

I just picked up a CIGS 200 watt panel and that upped the efficiency and is charging my EB70s running a fridge a good bit faster than the Bluetti 200 watt folding panel I was using.

 

[12VoltInstalls]

that upped the efficiency and is charging my EB70s running a fridge a good bit faster than the Bluetti 200 watt folding panel

Huh. ?

 

[tammons]

Huh. ?

The Cigs panel is producing more watts than my bluetti panel. Maybe 9-10% more. Not really sure about the actual amount since I havent run them side by side and done a cumulative power test. I have read that CIGS panels are more efficient. And they are way lighter and supposedly last longer, but they roll up so bulkier in a different way. But you could stack several and roll them up together.