Boost MPPTs

[sunshine_eggo]

It comes up from time to time if there's a way to use lower voltage PV to charge higher voltage batteries:

Here are a few options:

https://www.amazon.com/SUNYIMA-Controller-Electric-Charging-Regulator/dp/B0B7WWY5S3

https://www.amazon.com/dp/B07Z9F6729/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B07Z9F6729

https://www.amazon.com/dp/B0B4SL5C2X

Not an endorsement. Just some options.

 

[Ellcon123]

I've used the MPT-7210 in the past and it does its job. Limited to 10A so higher battery voltage is the way to go. With one panel I could get 1kWh a day on a 24V system. They power of the solar so they will start to charge a flat battery. Fan is noisy but this all comes from the mesh. Cut it out and all silent.

 

[pollenface]

I use these, they're awesome ?

 

[Ellcon123]

You can also use as a charger upto 72V.

 

[efficientPV]

I'm quite fond of the ECO WORTHY https://www.amazon.com/dp/B0B4SL5C2X It can actually work without a battery connected when you want a battery less system, something I'm fond of. It can output up to 90V. Lithium voltage can be set in .1V increments for full range.

 

[MisterSandals]

I use these, they're awesome ?

Which one in particular? Is it configureable and/or have a custom battery profile?

I could see getting one of these in the future. I didn't think they were really viable.

Do any of the tier 1 makers sell something like this? Maybe something in blue, and smart.

 

[efficientPV]

This is the inside of the ECO

and this is the RENOGY Rover proving once again that RENOGY is crap. They put a 30A fuse in series with a 10A hall effect current sensor. It blew the wires right off.


The ECO has a switch settable lead acid battery of 48, 60, and 72V. The lithium range is determined by switch settings and is fixed voltage charging. You can set it from panel voltage up to 90V in 0.1V incroments.

 

[pollenface]

Which one in particular? Is it configureable and/or have a custom battery profile?

It's just one off ebay, generic i guess. 5a charging power. You adjust the mpp voltage manually (17-18v) and set the output voltage to suit the battery

 

[AlpineJoe]

and this is the RENOGY Rover proving once again that RENOGY is crap. They put a 30A fuse in series with a 10A hall effect current sensor. It blew the wires right off.
View attachment 182492

What blew right off? I see electrolytic cap C15 is gone but the leads were cut. The leads inside of an aluminum electrolytic are not terminated that way.

 

[400bird]

I was unaware there were so many options for boost charge controllers.
This one is significantly more expensive, but US made.

Amazon.com

 

[atatistcheff]

I already have the Victron 100/20 MPPT, hate to buy another charge controller. What about something like this to boost the PV voltage?

https://www.amazon.com/Converter-DROK-Numerical-Adjustable-Regulator/dp/B08PV5YY55

 

[400bird]

Charge controller pull as much as then need from the panel. Output is controlled by the input.
Boost converter, like the one linked above, work the other way around. Output is the driver, so input is controlled by the output.

If you did get it to work, it would defeat the purpose of the MPPT

 

[MisterSandals]

What about something like this to boost the PV voltage?

Why do you feel you need to boost the voltage? Boosting the voltage won't help your solar watts, in fact the conversion might actually be another layer of loss. If you double the voltage, the amps will be halved so multiplying volts x amps will be the same (less conversion loss).

What are you doing and what do you hope to accomplish?

 

[atatistcheff]

Why do you feel you need to boost the voltage? Boosting the voltage won't help your solar watts, in fact the conversion might actually be another layer of loss. If you double the voltage, the amps will be halved so multiplying volts x amps will be the same (less conversion loss).

What are you doing and what do you hope to accomplish?

I have a 100W portable panel that it would be nice to use to charge a 24V battery. The panel Voc is 22.6V which isn't high enough to charge it. I was wondering if putting the boost on the PV output would give the MPPT enough voltage to work. Ya, I know it's not very efficient, just thinking out loud.

My assumption here (which may be faulty) is that the Victron MPPT is not a boost converter. That is, it will take a higher voltage and convert it to charge the 12, 24, 48V battery but it won't take a lower voltage and boost it to do so.

 

[MisterSandals]

I was wondering if putting the boost on the PV output would give the MPPT enough voltage to work.

This is all new to me but i think your use case is what these are made for. Go for it and please post results.
I suspect it might be cheaper to buy a big cheap panel to harvest sun at the voltage your MPPT needs. Unless portability is an important aspect of your solar array.

 

[sunshine_eggo]

I already have the Victron 100/20 MPPT, hate to buy another charge controller. What about something like this to boost the PV voltage?

https://www.amazon.com/Converter-DROK-Numerical-Adjustable-Regulator/dp/B08PV5YY55

I have a 100W portable panel that it would be nice to use to charge a 24V battery. The panel Voc is 22.6V which isn't high enough to charge it. I was wondering if putting the boost on the PV output would give the MPPT enough voltage to work. Ya, I know it's not very efficient, just thinking out loud.

That device expects a sufficient power supply to provide its maximum output, so the moment the panel can't supply the set voltage and current, it shuts down. There will also be no MPPT function whatsoever.

If you set it to a voltage and current that is < 50W, then it will work when the panel can meet those needs. It will never output more than 50W, and if the panel can't supply 50W, it shuts down.

For $10 more for the ECO-WORTHY, it makes a lot more sense to go with a MPPT charger designed to boost.

My assumption here (which may be faulty) is that the Victron MPPT is not a boost converter.

Correct. Almost none are. That's why I started this thread.

Victron MPPT require +5V (0A, Voc) above battery to START working. PV must remain +1V above battery voltage to continue operating.

 

[atatistcheff]

For $10 more for the ECO-WORTHY, it makes a lot more sense to go with a MPPT charger designed to boost.

Yes, that is a good point. It's not as much fun, but more practical. ;-)

 

[Nobodybusiness]

I was unaware there were so many options for boost charge controllers.
This one is significantly more expensive, but US made.

Amazon.com

That’s the one Scott Hunt uses..Engineer775.

 

[DougfromdaUP]

I bought a Genasun to play with charging 48 volt LiFePO4 batteries using Peltier devices. When I was done with that project, I sent them an email asking what I could do to use it to charge from an unlimited current source, like a 24 volt alternator. They responded within days, I sent it back and the installed custom firmware (for a fee of course.)
But how’s that for unbelievable customer service?