The EUC MPPT solar charger&inverter project

[xiiijojjo]

Edit: Save time and go to my latest post to see what I've come up with at this point. 

Okay so I've been talking about this for years in and out of this forum and I've decided that this will be the year where I buy an EUC, CIGS solar panels and use the EUC to live nomadically, charging it with solar.

Now to do this I've needed solar panel tech to improve and it has, to the point where I now have found the kinds of solar panels that would be required for living nomadically with an EUC. These are long-lasting, light-weight and most importantly can be rolled up into a tube.

Next up I could just buy a LiFePo4 powerstation that can take 600-800w of solar, buy 3-4 of these solar panels and be fine. However, I'd prefer to not carry around a heavy powerstation (spefically the battery part) because of the weight and size, and I'd only have a 100L backpack to store everything I would need. 

So what I want your help with is basically building a powerstation WITHOUT any battery that can be connected to the EUC to use its battery, kinda like the experimental gotway 1000w 134v inverters, but I need the added feature of an MPPT solar controller to be able to not only output 1000w but to also have the ability to input 600-800w at least.

I am not completely idiotic when it comes to electrical stuff, but I'd certainly need some help.. From bringing up this same idea a couple of times I've come to understand that I would need a DC-DC step-up/puck converter, as well as an inverter.

 

I imagine I'll be using the Veteran Lynx for this project. I'll also be using the BougeRV panels, so their voltage is probably important specs:
https://www.bougerv.com/products/200w-flexible-solar-panel

 

Which parts would I need and could you please link them? Also, can you give me some pointers to how I must wire things together?

I would really be grateful for any input! It's happening this year!

Edited February 16 by xiiijojjo

[RagingGrandpa]

21 hours ago, xiiijojjo said:

what I want your help with is basically building a powerstation WITHOUT any battery that can be connected to the EUC to use its battery,
but I need the added feature of an MPPT solar controller

Are you accepting that you will not be able to ride your EUC during daylight, with this approach?

 

Anyway, you "just" need a solar charge controller, but the problem you'll face is that most home & RV commercial products are intended for a much lower voltage battery bank (48V or less). 
You want the same functionality, but with a battery charging output at 151V (Lynx EUC).
With no commercial option available, now we're deep into DIY territory.

If you're really ready for all this hassle, I'd envision it looking like this:

1. One 10A 24V solar charge controller per solar panel.
2. Some small 24V battery, to make the charge controller happy before connecting the EUC.
   Sealed lead-acid will be about 10 pounds; hopefully you could find a robust small LFP pack instead. Its job is to stabilize surge currents, but not really to store energy. 
3. A boost DC-DC converter with an adjustable current limit.
   Since 151V is a rare output voltage, you might be forced to put multiple of these 40W converters in parallel. You can connect their output directly to the EUC.

Don't buy anything until you've estimated the size and weight of the whole apparatus, and decided how you're going to transport it and what to do with it while you're off riding the EUC. 
 

Edited January 29 by RagingGrandpa

[xiiijojjo]

Yeah, if I would need all that stuff, then weight and size may be an issue... If I could simplify from here, it may still be a worthwhile effort. 

So far this is what I would have to beat for it to be worthwhile: https://eu.ecoflow.com/collections/delta-series-portable-power-stations/products/delta-2-portable-power-station

It has 1kwh of LFP, small enough, 12kg/ 26.5lbs, 1800w ac output, 1200w ac input, 500w solar input.

So with this powerstation fully charged, charging at 500w from 4 200w solar panels in series-parallel, for 2 hours straight while charging the wheel at ~1kwh I could charge it from 700wh back to the full 2700wh, if the sun gods are with me that is.

Safety is also a lot better with this I imagine..

Edited January 30 by xiiijojjo

[xiiijojjo]

!OUTDATED READ LATER POSTS!

 

What If I use one of these: 

PV: for solar 
BATT: 12-48V priority charge anything plugged in here
LOAD: 12-48V passthrough I can connect to, that only pass power when the battery is full, I could use those for running peltier modules for my DIY food cooler box.

 

 

Now I just need to find a small capacity, light-weight 12,24 or 48v battery Preferably LFP, with a high output rating to be able to provide extra power incase of spikes, right? What spikes can I expect with a 2000W inverter turning on, and a 1000W EUC charger? I can always plug the EUC charger in after powering up the inverter to avoid stronger spikes.
 

any 2000w 230V pure sinewave inverter with programmable low voltage disconnect would do, but I can find that one myself. I just have to be sure to get a small battery pack(or maybe capacitors?) that can supply power for the inverter producing spikes when turning it on or plugging in EUC charger. This battery can be up to 48V.

I also need to identify the specific DC-DC converter to use for the Lynx. 151.2VDC - 12-48VDC depending on which battery I use.

 

So first thing first, we need to find what battery (or maybe capacitors?) could be up to the task (No lithium-ion please) It should have the lowest weight possible while able to handle the spikes produced when connecting a good charger running 151.2V @ 6.6A for 1KW charge rate, using the 2KW inverter. 

 

Edited February 4 by xiiijojjo

[RagingGrandpa]

59 minutes ago, xiiijojjo said:

What If I use one of these: https://www.youtube.com/watch?v=XK6GIh0RA8Q

Sure. That's the same as what I outlined: 

21 hours ago, RagingGrandpa said:

One 10A 24V solar charge controller per solar panel.

 

59 minutes ago, xiiijojjo said:

need to find a small capacity, light-weight 12,24 or 48v battery Preferably LFP
high amperage rating

You asked for 1kW output to the EUC. That's about 42A @ 24V. Pretty tame for any LFP pack sold as a "motorcycle battery," such as below (two in series). 
https://www.ebay.com/itm/235396927094 
Starting a motorcycle engine takes about 100A...

 

59 minutes ago, xiiijojjo said:

2000w 230V pure sinewave inverter
plugging in EUC charger

Why add an AC step? The inverter is not needed...

You're suggesting an energy path of:
100VDC (solar) -> 24VDC (MPPT to LFP battery) -> 120VAC (inverter) -> 150VDC (EUC charger) -> EUC

Instead, I'm suggesting: 
100VDC (solar) -> 24VDC (MPPT to LFP battery) -> 150VDC (boost converter) -> EUC

 

20 hours ago, xiiijojjo said:

this is what I would have to beat
https://eu.ecoflow.com/collections/delta-series-portable-power-stations/products/delta-2-portable-power-station

That seems much more durable and weatherproof, easy to use, easy to buy... just get it  
 

Edited January 30 by RagingGrandpa

[xiiijojjo]

On 1/30/2024 at 8:23 PM, RagingGrandpa said:

Why add an AC step? The inverter is not needed...

You're suggesting an energy path of:
100VDC (solar) -> 24VDC (MPPT to LFP battery) -> 120VAC (inverter) -> 150VDC (EUC charger) -> EUC

Instead, I'm suggesting: 
100VDC (solar) -> 24VDC (MPPT to LFP battery) -> 150VDC (boost converter) -> EUC

!OUTDATED READ LATER POSTS!

Oh because I would still need the functionality of a 230VAC 2000W inverter for other purposes, considering I'd be living out there. I'd like to use an inverter for charging laptop, phone, LED camping lights, starlink (will probably be the easiest way to get a somewhat reliable internet connection while moving all over the world), and for offsetting burning alcohol in my alcohol stoves, if spare electricity is available I will use it to boil water/ cook. 

(this one is 2600W), with a big enough inverter that's one hour of cooking on a full lynx charge. If you're emptying the lynx battery in the morning for breakfast to save on burning alcohol in the alcohol stoves, you can just sit around for 2½-4 hours(depending on sun) if using 6 panels in series-parallel, and you'd have another full charge.

On 1/30/2024 at 8:23 PM, RagingGrandpa said:

 

That seems much more durable and weatherproof, easy to use, easy to buy... just get it  
 

 

I'd want to utilize the EUC battery instead to reduce weight WHILE having a powerstation capable of more than the Ecoflow Delta 2(only 500W of solar but my system has 200-1200W of solar in, depending on # of panels available), also I want to carry an adjustable amperage EUC charger with me for potentially charging at 15A in private businesses or gyms or certain places in public, that I'd be using while on the road whenever possible.

Powerstations are just too heavy and big just for taking 500W of solar in. I can build a smaller perfectly rectangular box, minimizing space use in my backpack, for this EUC powerstation/ solar charger contraption kinda like this box but without the batteries instead it should have a gx 20-5 male plug (I think the lynx uses that) to tap into the euc battery.
 

Ultimately I'd rather carry extra solar panels than extra LFP with my limited encumbrance, and having only a 100L backpack space is important too.
This project is just one piece of the puzzle. I've spent years testing camping equipment in preparation to living nomadically on EUC, countless hours going over the camping gear I'll be using, along with how much space and weight it takes up to get an idea of my final ride weight, and to have an idea of IF I can even fit everything I need in a 100L backpack. This is 5D tetris.

but thank you so much for helping me get creative @RagingGrandpaI'm getting closer to being able to make a wiring diagram in PS.
I'm getting excited! 

Edited February 4 by xiiijojjo

[RagingGrandpa]

1 hour ago, xiiijojjo said:

one hour of cooking on a full lynx charge

Scope creep alert!

Now you're talking about discharging  the Lynx.
You can't discharge it through its charging port, so now you're considering internal wiring modification to the EUC too??

[xiiijojjo]

On 1/30/2024 at 10:21 PM, RagingGrandpa said:

Now you're talking about discharging  the Lynx.
You can't discharge it through its charging port, so now you're considering internal wiring modification to the EUC too??

!OUTDATED READ LATER POSTS!

Couldn't I just use an XT90 Y Splitter cable (or whatever XT it uses) to tap into the battery?

 

How about Gotway? are their charge ports still hot & can you tap into those using the gx charge port?

Edited February 15 by xiiijojjo

[RagingGrandpa]

44 minutes ago, xiiijojjo said:

Couldn't I just use an XT90 Y Splitter cable (or whatever XT it uses)

Lynx uses single-pole battery connections, not XT-series. 

You could split them, but you should not recharge the battery from this, because it can defeat important safety features of the BMS which are meant to disable recharging during fault conditions.

 

44 minutes ago, xiiijojjo said:

How about Gotway? are their charge ports still hot

Yes, you can discharge through the charging port in modern GW/BG/EB models. 

That's why they're able to offer an EUC-powered AC inverter.

(And we couldn't use such a thing with today's Leaperkim EUC's.) 

Edited January 30 by RagingGrandpa

[xiiijojjo]

On 1/30/2024 at 11:23 PM, RagingGrandpa said:

Yes, you can discharge through the charging port in modern GW/BG/EB models. 

That's why they're able to offer an EUC-powered AC inverter.

(And we couldn't use such a thing with today's Leaperkim EUC's.) 

!OUTDATED READ LATER POSTS!

Thanks, that means that for this type of project I would be better off getting something from GW/BG/EB.

 

Welp... I'm kinda stuck looking for a 134.4VDC to 12-48VDC adjustible charger on Aliexpress. The only adjustable chargers I can find seem to all be VAC to VDC 

Edited February 15 by xiiijojjo

[RagingGrandpa]

Nearly all switching power supplies rectify their AC input to DC immediately... so you could just as well feed ~130VDC into a standard battery charger designed for 120AC. People have done it.

[woke rider]

What about if you make one of these, just up the voltage and change the adapter for your personal wheel?

https://www.electrifybike.com/products/solar-200-watt-ebike-battery-charger-sun200

That one can charge all the way up to 84v! So you just need to get an 84v wheel and make an adapter for your wheel.

Or, maybe get an ebike for going off grid and buy that one. Either way, me thinks this would be great fun.

Edited January 31 by iwantmymtv
typo and one more thing

[xiiijojjo]

 

On 1/31/2024 at 1:01 AM, RagingGrandpa said:

Nearly all switching power supplies rectify their AC input to DC immediately... so you could just as well feed ~130VDC into a standard battery charger designed for 120AC. People have done it.

!OUTDATED READ LATER POSTS!


Will it work with ~130VDC -> 110VAC? or even better ~168VDC -> 110VAC???!

If that is the case I can make this mod work for any voltage wheel 

Man, you are a wealth of knowledge! Thank you so much for helping me learn!

 

Edited February 15 by xiiijojjo
Fixed my post in the next post

[xiiijojjo]

!OUTDATED AND FULL OF MISTAKES READ LATER POSTS!

 

This charger is 100-120VAC -> 0-60VDC 50A, I'd need this even if I can only use it for discharging the 134V OR 168V EUC

https://www.aliexpress.com/item/1005004410604062.html?spm=a2g0o.productlist.main.5.4670524ciEkwDN&algo_pvid=f6db5932-04a8-4008-80d7-bd62347fe017&aem_p4p_detail=202402011433441415731146758360000820599&utparam-url=scene%3Asearch|query_from%3A&search_p4p_id=202402011433441415731146758360000820599_3&gatewayAdapt=glo2deu

Next up is the inverter.

Considering I can discharge the EUC battery @ 20A, 2000-2400W, a 2000W inverter should be fine.

So now I'm looking for a 2000W 230VAC pure sinewave inverter, with programmable low voltage disconnect, as I'd rather not mod that myself: 
(update: looks like I have to)

Assuming the inverter already has programable low voltage disconnect the wiring diagram should look like this right?

*mistakes in picture fixed in later posts

I know it ultimately comes down to the cells used, but what discharge rate could I expect out of a 48V 6Ah 13s2p bicycle battery?
Surely something like 6Ah x 0.5C = 3A constant recommended discharge rate? Ideally I'd want a 48V battery that can output at least 13.4A discharge rate. 
With full solar 20A + EUC battery 50A, with another 13.4A from the battery I'd be able to power full 4000W peaks. 
It's only 1.3kg so I hope that it would be enough. 

Gonna have to do this with an ET MAX because of the 20A charge ports allowing me to fast discharge this at 100-120VAC 20A too, for a perfect 2000-2400W output. 
 

Total weight of the Solar charger + inverter + 1.3kg battery + charger + wires and connectors = ~10kg
Still 3kg lighter than the delta 2 but with a 200w bigger inverter (that can handle 4000w spikes), and over 200% the solar input AND it's fixable/upgradable.
So far I'm leaning towards the mod. 

Edited February 4 by xiiijojjo

[xiiijojjo]

!OUTDATED READ LATER POSTS!

UPDATE: Found a possible solution, a 110-169VAC 26a -> 60VDC 41.6A charger https://www.idealplusing.com/index/product/detail/id/868

I don't actually want to carry around a battery, that was the entire point of this mod, so I altered the design to not include a battery that handles spikes, which I realistically won't be dealing with a lot, if at all.

 

 

 

Edited February 15 by xiiijojjo
updated wiring diagram and post

[xiiijojjo]

@RagingGrandpa

!OUTDATED READ LATER POSTS!

Spend the past two days looking all over Aliexpress. Do you think I could use this?:

Specifically the IPS-PFC3000-60
https://www.idealplusing.com/index/product/detail/id/868

It's:
110-169VAC 26A input!! Sounds perfect for a 168V EUC.

If I limit the output to 60v 35A I would never reach above 20A from the EUC charge port, installed a breaker there to make sure to never draw more than 20A potentially damaging the EUC.

 

Edited February 15 by xiiijojjo

[RagingGrandpa]

8 hours ago, xiiijojjo said:

I altered the design to not include a battery that handles spikes

... then you should investigate the "Load" output from your MPPT, to use instead of the "Battery" output.
The trick will be making the MPPT happy and active, if there is no voltage detected on its Battery output.
(Don't assume it will be happy.)

Otherwise, sure, your apparatus of 4 separate power converters could work? 

And I think it will be borderline to get 20 amps out of an EUC from its charging connection... be sure to parallel both connectors if you try it. 

[xiiijojjo]

On 2/4/2024 at 1:40 AM, RagingGrandpa said:

... then you should investigate the "Load" output from your MPPT, to use instead of the "Battery" output.
The trick will be making the MPPT happy and active, if there is no voltage detected on its Battery output.
(Don't assume it will be happy.)

Otherwise, sure, your apparatus of 4 separate power converters could work? 

And I think it will be borderline to get 20 amps out of an EUC from its charging connection... be sure to parallel both connectors if you try it. 

!OUTDATED READ LATER POSTS!

Sorry I already updated my older posts, and wire diagram in this thread to correct mistakes I had made. I have updated this thread waaaay too much.

I will investigate the "load" output from my mppt. I assume it will be able to output up to 60V. But even if it can only output 57.6V (adjustable in app), I could just set up the charger to output the same 57.6V to the busbars, the inverter takes 48-60V. 

 

Well the ET MAX charge port/ports (haven't seen how many yet) is rated for 20A in/out, so as long as the wires and breakers are sized correctly for ampacity, which I believe they are in my most recent version of the wiring diagram posted below, everything should be good as long as you think I can safely use the type of 110-169VAC charger.

 

Updates:

* voltages/amps fixed, all wire AWG stated, all circuit breaker specs stated, all voltages and amps stated.

* Decided to go for an all circuit breaker build as they can double as on/off switches.

* Added a 48VDC -> 12VDC converter, and busbars for the 12V circuit, to connect more things to in the future.

* Added 2 super efficient Peltier modules to be able to produce ice cubes, and to refreeze the cooling elements for my small cooler box.

Edited February 15 by xiiijojjo

[alcatraz]

I don't quite understand the project but one idea was to have three smaller 48v packs connected in parallel when hooked up to the solar panels and then when you want to ride to set them to serial (144v) and ride on them.

It's inefficient to move charge from one battery to another (you lose a lot of the energy) so maybe you should try to keep the majority of your capacity with the panels and only have a smaller internal capacity. 

Obviously you need to figure our a circuit that prevents the external pack from charging the internal (avoid rapid equalization of voltages). 

[xiiijojjo]

On 2/4/2024 at 12:18 PM, alcatraz said:

I don't quite understand the project but one idea was to have three smaller 48v packs connected in parallel when hooked up to the solar panels and then when you want to ride to set them to serial (144v) and ride on them.

!OUTDATED READ LATER POSTS!

I'd rather keep the battery packs firmly inside the EUC, plugging in the 110-169VAC -> 60V 35A charger into the EUC charge port to discharge
the ~110-168VDC EUC battery directly into the 48-58V busbars.

On 2/4/2024 at 12:18 PM, alcatraz said:

It's inefficient to move charge from one battery to another (you lose a lot of the energy) so maybe you should try to keep the majority of your capacity with the panels and only have a smaller internal capacity. 

The 110-169VAC -> 60V 35A charger is 89-91% efficient so I'd only lose around 300Wh on a full 100-0% discharge (on an ET MAX).
But this was my first thought too, to have an internal pack to handle spikes, but realistically I'm not gonna draw that much current, and all my 1500W+ devices have a way of slowly ramping up their output to avoid breakers going off, so I don't really need it, and considering that I'll be travelling with the EUC, it'll right next to me 24/7 so It's always easy to plug it into my contraption. 

On 2/4/2024 at 12:18 PM, alcatraz said:

Obviously you need to figure our a circuit that prevents the external pack from charging the internal (avoid rapid equalization of voltages). 

I updated my wiring diagram, to exclude the battery pack from earlier posts, I'd much rather keep all my batteries in one place (the EUC) = lower weight, fire risk, price.

Edited February 15 by xiiijojjo

[alcatraz]

I meant the efficiency of the cells themselves. Charging and discharging generates heat, on both the source and destination pack.

You'd be lucky for the wheel to get ~60% of whatever your solar panels generated. About half (~20%) can be saved if you avoid one charge+discharge cycle by riding the solar pack. Even a bit more than half (over 20%) because slow solar charging is more efficient than faster transfer charging.

So perhaps 85% vs 60% efficiency by eliminating a charger, two cycles and keeping the slow charging.

[alcatraz]

If you have an abudant solar generation, you don't need efficiency. But the size of that kind of solar setup is maybe 2-3 times the size of what you'd need for a ride pack.

I'm not sure how important portability is in this project.

Edited February 5 by alcatraz

[xiiijojjo]

On 2/5/2024 at 12:35 AM, alcatraz said:

I meant the efficiency of the cells themselves. Charging and discharging generates heat, on both the source and destination pack.

!OUTDATED READ LATER POSTS!

I'm not sure if I understand what you mean. I know that charging and discharging generates heat, on both the source and destination, but if the EUC charge ports are rated at 20A and the inverter is rated at 83.4A, then as long as all the cables, lugs and breakers are sized correctly heat shouldn't become an issue unless I've missed something in my wiring diagram...

On 2/5/2024 at 12:35 AM, alcatraz said:

You'd be lucky for the wheel to get ~60% of whatever your solar panels generated.

I understand there will be some loss from the solar charge controller-> inverter -> EUC charger -> EUC battery but that's a loss that I'm willing to take, for a setup this light, compact and capable.

On 2/5/2024 at 12:35 AM, alcatraz said:

About half (~20%) can be saved if you avoid one charge+discharge cycle by riding the solar pack. Even a bit more than half (over 20%) because slow solar charging is more efficient than faster transfer charging.

So perhaps 85% vs 60% efficiency by eliminating a charger, two cycles and keeping the slow charging.

I don't understand what you mean by "riding the solar pack"

I will primarily be solar charging, as in I will be using solar panels to input power into the solar charge controller which converts that power into 58V for the busbars, which distribute that power to the inverter, allowing me to plug in a charger for the electric unicycle to charge "directly" from the solar panels. While also giving me 220-240VAC for European appliances, and USB A and USB C charging.

However if I need power when the sun is no longer there, and I can no longer provide power directly from the solar panels into the inverter, I have the option of plugging in the EUC via the charger/converter to supply 58V to the busbars instead of the solar charge controller. 

Also I don't know what you mean by me being able to eliminate charge cycles. Are you talking about keeping the EUC battery life longer by charging it slowly and not discharging it too much? If that is the case don't worry, I don't care about the battery lifespan of the EUC and will be charging it as fast as possible and discharge it at a maximum rate of 2100W, which should be safe for the contraption in the wiring diagram and also for the EUC and its batteries.

On 2/5/2024 at 12:38 AM, alcatraz said:

If you have an abudant solar generation, you don't need efficiency. But the size of that kind of solar setup is maybe 2-3 times the size of what you'd need for a ride pack.

I'm not sure how important portability is in this project.

I will start will 3 solar panels in series with the specs mentioned in the wiring diagram. 

I'm not sure what you mean by a "ride pack". I think starting with 3 panels would be fine, especially since I haven't calculated the full weight of my camping gear yet, there is a limit to how much weight I can carry in a backpack and also the EUC has a limit to how much weight it can carry.

So far the entire contraption + 3 solar panels weigh 19.5kg/42lbs.
I could save some weight looking for a different inverter or charger/converter potentially... or maybe by getting a different solar charge controller and only bringing 1-2 panels, but that doesn't sound like the right move to me... I could remove the 12V system completely but I need the ability to keep food fresh and to make ice.

Edited February 15 by xiiijojjo

[xiiijojjo]

!OUTDATED READ LATER POSTS!

At this point it would seem that all I need is some level of confirmation that this charger won't blow up my EUC battery. If it's safe I'll start building this thing soon.

Specifically the IPS-PFC3000-60
https://www.idealplusing.com/index/product/detail/id/868

 

Could I really use simple 100-240VAC -> VDC converters, instead of having to get the huge charger/converter in the link above? 

 

Edited February 15 by xiiijojjo

[xiiijojjo]

!OUTDATED READ LATER POSTS!

Omg I just had an idea. What If I just used the MPPT solar charge controller instead of getting a heavy adjustable converter/charger.

I would just need to get an MPPT that could take up to 168VDC input so something like this 250VDC 60A MPPT solar charge controller could be used to input solar OR EUC battery albeit not at the same time(technically possible but inefficient), which is not a problem at all. I can plug solar into PV+/- in the daytime and plug EUC into PV+/- after sunset. 

*update added a portable freezer, for freezing cooling elements to keep food fresh, and to make ice cubes.
Running it while the sun is out should be fine, the cooling elements can stay frozen for over 24 hours in my other, lighter, insulated cooler. Much better than the peltier module idea I began with.

Only thing about this version, is that I don't know if the ET MAX limits its own charge ports at 20A, I hope it does.
In any case this MPPT is limited at 3440W output or 20.5A @ 168V, but that's still 34.4A @ 100V if the charge ports are not limited, so let's hope they are. 

Honestly a lot smarter of a solution if this works how I imagine it will.

I'm not sure if I can connect strings with different voltages to this charger considering the multiple PV inputs, and can't find anything in the original documentation, but maybe I could use the one PV+/- for EUC and the other for my solar panel array with a different voltage? 

I can connect the EUC and solar panels at the same time but unless I'm getting 100-168V of solar input it would be terribly inefficient. Also I don't see myself traveling with more than 4 panels weighing in at a combined 12.7kg/28lbs. For this reason I will plug solar into PV+/- in the daytime and plug EUC into PV+/- after sunset.

 

I know that I could simply buy a 2nd smaller MPPT solar charge controller like the 100/20, purely for solar input, but total cost/size/price is more important than that luxury feature.

Edited February 15 by xiiijojjo