Using a MPPT solar charge controller as a bulk charger

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motomech
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Using a MPPT solar charge controller as a bulk charger

Post by motomech » Dec 05, 2017 6:15 pm

I'm building a sm. tracking solar generator to use w/ my toy hauler when boondocking that can be used in 2 ways.
1)To top off the toy hauler's 12 V deep cycle battery.
2)To charge my LiPoly 12S/20 Ah main pack.

The details of the panels and how the tracking system works I will post later when I have the system up and running, but it will use 2) 50 Watt/12 V panels connected in series as one 24 V panel.

For job 1), the panel will feed a MPPT solar controller, which will function as a "buck" converter, taking the 24 V input down to the RV battery's charge Voltage

For job 2).the panel will feed the second solar controller, which functions as a "boost" converter, taking the 24 Volts up to my 12S charge range(42 V to 49V). For this I will be using this new, inexpensive controller;

https://www.amazon.com/gp/product/B01HC ... UTF8&psc=1

Here I am bench testing it, powering it w/ a 12 V server power supply and using 2) 6S bricks as a load;
SAM_1195.JPG
SAM_1194.JPG
As you can see, it's no power house, but it is sm. and weighs nothing . The power supply's 12.48 V output gets pulled down to 12.08 V under load putting 1 Amp (50 Watts) into the batteries. With a 24 V input I should see a 2 Amp output of 100 Watts, (somewhat less depending on the Sun and the panel efficiency. The MPPT controller is very efficient, in the mid to high 90% range).

I understand that at that rate, will take quite bit of time to put back the 10 Ah that I typically use from my main pack, but I don't see any other way to recharge it off the grid. While most of my packs can be broken down and charged using my RC balance charger running off my RV or truck battery, this main pack is built in the bike w/ no way to "break the string".
I could, of course, run the boost controller off one of my batteries overnite @ 50 Watts as the toy hauler requires little power at nite. I will test to see how much that scenario drains the lead-acid batt over an 8 hr. period.

I should have everything together for testing in several days and will relay how this works within the week.
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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Re: Using a MPPT solar charge controller as a bulk charger

Post by tomjasz » Dec 06, 2017 1:57 am

Thanks for the post, 8 have the same controller, just not gotten around to setting up sith a 100w panel.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Using a MPPT solar charge controller as a bulk charger

Post by motomech » Dec 06, 2017 5:29 am

I have a little more Sun to play with. :D
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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Re: Using a MPPT solar charge controller as a bulk charger

Post by fechter » Dec 06, 2017 9:30 am

You might try removing the MPPT and hook the boost converter directly to the panels and compare. Most of the boost converters have adjustment for voltage and current. I think you could tweak the current to get the maximum power (manual MPPT). This would eliminate any losses in the MPPT unit.
"One test is worth a thousand opinions"

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Re: Using a MPPT solar charge controller as a bulk charger

Post by motomech » Dec 06, 2017 10:32 am

The MPT-7210A solar controller IS the step-up boost converter. That's what is unique about it as I think it's the only one of it's kind. At least in that price range. It does make for a simple system.
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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Re: Using a MPPT solar charge controller as a bulk charger

Post by Hwy89 » Dec 06, 2017 11:46 am

I've been a full time RVer for about 3 years now. I carry a 180 watt panel, 27V open circuit through a simple non mppt controller always feeding my house battery bank. I use an RC balance charger occasionally but mostly bulk charge with a Meanwell plugged into an inverter. Not the most efficient way but it works. I have found that my house batteries are usually full by noon and On a sunny day I can top off the bike battery in about an hour an a half and still have a full house battery.
Thanks for posting the boost controller I wasn't aware of them and will be buying one to try out. In reading the reviews it seems that these reset a lot if the input voltage drops so the best way to hook one up would be to use the house battery as the input.

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Re: Using a MPPT solar charge controller as a bulk charger

Post by tomjasz » Dec 06, 2017 12:26 pm

motomech wrote:
Dec 06, 2017 5:29 am
I have a little more Sun to play with. :D
You do, but I find that folks here don't realize how much sun we actually have. Solar is still a win!
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Using a MPPT solar charge controller as a bulk charger

Post by madin88 » Dec 06, 2017 1:10 pm

Hwy89 wrote:
Dec 06, 2017 11:46 am
Thanks for posting the boost controller I wasn't aware of them and will be buying one to try out. In reading the reviews it seems that these reset a lot if the input voltage drops so the best way to hook one up would be to use the house battery as the input.
I don't own such controller, but a few month ago i did some research for a future project.
What i found out is this ebay mppt controller is really slow in tracking the maximum power point.

Genasun controllers should be top regarding user reports:
https://genasun.com/
only problem is battery voltage should be less than 60V.

here is another one for even 72V battery:
http://www.eastgem.net/solar-controller.html

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Re: Using a MPPT solar charge controller as a bulk charger

Post by motomech » Dec 06, 2017 2:07 pm

Hwy89 wrote:
Dec 06, 2017 11:46 am
I've been a full time RVer for about 3 years now. I carry a 180 watt panel, 27V open circuit through a simple non mppt controller always feeding my house battery bank. I use an RC balance charger occasionally but mostly bulk charge with a Meanwell plugged into an inverter. Not the most efficient way but it works. I have found that my house batteries are usually full by noon and On a sunny day I can top off the bike battery in about an hour an a half and still have a full house battery.
Thanks for posting the boost controller I wasn't aware of them and will be buying one to try out. In reading the reviews it seems that these reset a lot if the input voltage drops so the best way to hook one up would be to use the house battery as the input.
I'm really trying to keep the weight down, toy haulers are kind of heavy to start with. I could easily add another battery, a bigger inverter and charge my ebike pack with my wonderful Mean Well HLG LED power supply. But that would add another 70-90 lb.s and since I don't need another house battery or inverter to be comfortable, I'm reluctant to do that.
Appearently, inexpensive MPPT controllers, whether they be buck or boost, lag a bit in tracking when clouds interrupt the input. As you probably know, clouds can be a blessing here in the South West, so I can deal w/ any vulgarities in my solar gen. It's just for one of my Ebikes, and only one of it's two packs at that..
Last edited by motomech on Dec 06, 2017 3:13 pm, edited 4 times in total.
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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Re: Using a MPPT solar charge controller as a bulk charger

Post by motomech » Dec 06, 2017 2:27 pm

madin88 wrote:
Dec 06, 2017 1:10 pm
Hwy89 wrote:
Dec 06, 2017 11:46 am
Thanks for posting the boost controller I wasn't aware of them and will be buying one to try out. In reading the reviews it seems that these reset a lot if the input voltage drops so the best way to hook one up would be to use the house battery as the input.
I don't own such controller, but a few month ago i did some research for a future project.
What i found out is this ebay mppt controller is really slow in tracking the maximum power point.

Genasun controllers should be top regarding user reports:
https://genasun.com/
only problem is battery voltage should be less than 60V.

here is another one for even 72V battery:
http://www.eastgem.net/solar-controller.html
Nice controllers for sure, but they are buck controllers and wouldn't be useful charging my Ebike. The MPT-7210A is CC/CV, something I need for my LiPoly.

To charge my house(RV) battery, I'm using the EP Solar MPPT 20A/30A/40A Tracer which has seen a price reduction. Both Julian Ilett and Adam Welch gave it "2 thumbs up" on their Utube reviews;

https://www.ebay.com/itm/EPEVER-Tracer- ... 2749.l2649

I especially like the Ebox-WIFI attachment that allows the system to be monitored and adjusted from inside the trailer without running any wires in.;

https://www.ebay.com/itm/eBox-WIFI-01-R ... 2749.l2649
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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Re: Using a MPPT solar charge controller as a bulk charger

Post by madin88 » Dec 08, 2017 1:06 pm

motomech wrote:
Dec 06, 2017 2:27 pm
Nice controllers for sure, but they are buck controllers and wouldn't be useful charging my Ebike. The MPT-7210A is CC/CV, something I need for my LiPoly.
That's bullshit.

https://genasun.com/all-products/solar- ... ontroller/

They have boost converters suitable for Li batteries up to 60V (can be adjusted even a bit higher in factory from what i was told).
Of course with CCCV charging.
Genasun is many times better as the MPT-7210A (if you can live with 60V max charge voltage).

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Re: Using a MPPT solar charge controller as a bulk charger

Post by tomjasz » Dec 08, 2017 1:11 pm

madin88 wrote:
Dec 08, 2017 1:06 pm
motomech wrote:
Dec 06, 2017 2:27 pm
Nice controllers for sure, but they are buck controllers and wouldn't be useful charging my Ebike. The MPT-7210A is CC/CV, something I need for my LiPoly.
That's bullshit.

https://genasun.com/all-products/solar- ... ontroller/

They have boost converters suitable for Li batteries up to 60V (can be adjusted even a bit higher in factory from what i was told).
Of course with CCCV charging.
Genasun is many times better as the MPT-7210A (if you can live with 60V max charge voltage).
"3.55V per cell, which is suitable for most LiFePO4" I don't find an Lion version?
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Using a MPPT solar charge controller as a bulk charger

Post by madin88 » Dec 08, 2017 1:37 pm

tomjasz wrote:
Dec 08, 2017 1:11 pm
"3.55V per cell, which is suitable for most LiFePO4" I don't find an Lion version?
The float/CV voltage can be specified by the customer (check specifications the column far right) .
As this is a charger and not a BMS, the cell voltage by itself doesn't matter.

If you have 14s LiIon battery for instance, the float voltage would be than 4,2V x 14 = 58,8V (if you prefer a 100% charge).
I was told the GVB-8 can be set even a bit higher as 60V.
In terms of lifespan or if you plan to let the MPPT charge controller 24/7 attached to your LiIon or LiPo battery it would not be wise to charge to 100%.
I personally would than set to 4,1V per cell or lower..

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Re: Using a MPPT solar charge controller as a bulk charger

Post by motomech » Dec 08, 2017 3:23 pm

madin88 wrote:
Dec 08, 2017 1:06 pm
motomech wrote:
Dec 06, 2017 2:27 pm
Nice controllers for sure, but they are buck controllers and wouldn't be useful charging my Ebike. The MPT-7210A is CC/CV, something I need for my LiPoly.
That's bullshit.

https://genasun.com/all-products/solar- ... ontroller/

They have boost converters suitable for Li batteries up to 60V (can be adjusted even a bit higher in factory from what i was told).
Of course with CCCV charging.
Genasun is many times better as the MPT-7210A (if you can live with 60V max charge voltage).
That's bullshit.
Hey, I wasn't aware they could do that, I wasn't trying to bullshit anybody. I learned something, which is what I thought this forum is for.
No need to be rude and foul-mouthed.
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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Re: Using a MPPT solar charge controller as a bulk charger

Post by Samson » Dec 08, 2017 4:00 pm

I use the MPT-7210A with a 120 Watt 24 Volt peak (18 Volt MPP) panel to charge my 14S 18650 e-bike battery at 57.5 volts. I see output from the MPPT in the 95 Watt range in full high sun normally though it does hit 106 Watts at time. The MPT-7210A is a boost converter and can supply up to 60 Volts. The only thing I do not like is when a cloud goes over then clears it takes a couple of minute to ramp the voltage back up again. On a day with frequent scudding clouds this wastes a lot of usable charge time. Changing the recovery time constant would be a good thing but it is not programable.

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Re: Using a MPPT solar charge controller as a bulk charger

Post by madin88 » Dec 09, 2017 5:36 am

Samson wrote:
Dec 08, 2017 4:00 pm
On a day with frequent scudding clouds this wastes a lot of usable charge time. Changing the recovery time constant would be a good thing but it is not programable.
Yes thats the main problem.
It might be good enough for stationary use, but installed on a vehicle which is moving it would have poor output power most of the time.
The genasun GVB-8 feature 15Hz MPPT tracking, but i have seen now that it won't be cheap.
The Li 56,8V costs 190 USD and custom float voltage costs 250 USD.
motomech wrote:
Dec 08, 2017 3:23 pm
Hey, I wasn't aware they could do that, I wasn't trying to bullshit anybody. I learned something, which is what I thought this forum is for.
No need to be rude and foul-mouthed.
I only have wondered that you overseen "Solar Boost Charge Controller with MPPT for Lithium Batteries" in the name of the product. :)
It wasn't meant rude.

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Re: Using a MPPT solar charge controller as a bulk charger

Post by Hwy89 » Dec 10, 2017 10:24 pm

Samson wrote:
Dec 08, 2017 4:00 pm
I use the MPT-7210A with a 120 Watt 24 Volt peak (18 Volt MPP) panel to charge my 14S 18650 e-bike battery at 57.5 volts. I see output from the MPPT in the 95 Watt range in full high sun normally though it does hit 106 Watts at time. The MPT-7210A is a boost converter and can supply up to 60 Volts. The only thing I do not like is when a cloud goes over then clears it takes a couple of minute to ramp the voltage back up again. On a day with frequent scudding clouds this wastes a lot of usable charge time. Changing the recovery time constant would be a good thing but it is not programable.
This is why I suggested using the house battery as a buffer on the input. The battery will stabilize the input voltage.

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Re: Using a MPPT solar charge controller as a bulk charger

Post by motomech » Dec 11, 2017 1:05 am

Yeh, but the big advantage to this controller is the ability to go straight from array to load, making for the lightest, most simple system possible.
Let's not forget that the 7210A is $43. For that price, I think it exceeds expectations
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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Re: Using a MPPT solar charge controller as a bulk charger

Post by heathyoung » Dec 12, 2017 12:29 am

This MPPT charger will supply 82V at least, I've got it charging a 72V nominal battery bank, from a 50V 250W panel.
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