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Solar Charging a Duel Battery system (New Solution?)

Eclectic

Regular
Joined
Aug 6, 2012
Messages
316
Location
Southern California (San Gabriel Valley)
I have a Meet One Tour, a duel motor duel battery trike. The goal is to add a solar panel to extend the range…but duel batteries make it complicated. I assume the batteries use a Dual-Battery Equalizer on the output side but they still need to be about the same voltage. They are the same batteries (48v 15ah). The ideal would be to charge and discharge at the same time but I can’t figure out how to do that. The alternative would be to charge a second set of batteries and swap them. To complicate things, I have a single “BougeRV Arch Pro 200 Watts” panel [Voc (V) =36±5% V , Vmp (V) =31±5% V, Imp (A)=6.46±5%A] because 2 100w panels do not fit and the 200w is near the perfect size. How can I charge 2 batteries with a single panel and keep them the same voltage. So far my best idea is to use a second set of offline batteries, charge the 1st battery with a boost mppt charger and then use a “Victron Orion‑Tr Smart Isolated DC‑DC Charger” to charge the 2nd battery from the 1st. A very expensive solution that I am not sure would result in 2 batteries with same voltage.
 
Nobody?...I guess I ask tough questions. It’s been years since I posted here (long story). I was hoping to chat with humans but I ended up chatting with GPT. After spending the day with chatgpt (incredibly frustrating) this is what we came up with. Basically using Ideal Diodes to prevent back-feeding while making a pseudo-parallel connection.

Diagram01.png

It starts with the single solar panel, mppt controller and a disconnect switch (to turn off power while changing batteries). It then splits into two streams. An Ideal Diode to prevent a back-feeding surge if the there is a SOC (State Of Charge) difference in the batteries. Then a fuse for safety, a volt-amp-watt meter for info and then the battery. This design requires a second set of batteries. One for discharging and one for charging. Since each pair of batteries will be kept together, discharged and charged together they should maintain similar SOC. While the battery pairs maybe different sizes, (15ah or 25ah) they would all use the same mounting plate (these are standard Hailong style batteries). For the charging system I plan on using the mounting plates to hold the batteries and use the discharge connection for charging. This keeps the connection more agnostic (the charge connectors tends to be all over the place but the 5 pin blade discharge connector seems common). Because they discharge through a Dual-Battery Equalizer, the battery pair should have similar voltage after discharging but if they aren’t, the diodes should keep them from surging to equalize. The lower voltage should take most of the current until the lower voltage catches-up to the other battery when they would start to share the current, keeping them somewhat balanced. Since the system is limited by the 200w panel, even if a single battery was taking all the current for a while, it should not exceed the max rate of the batteries. I should be able to plug in a 2nd 200w array and mppt controller (something to deploy when stopped or camped) without fear of over-charging. This way the spare batteries just sit there just slowly charging. When the discharge batteries get low enough, I swap the batteries.

The idea is to turn the Meet One Tour into a long range adventure machine (maybe I should do a post on how I ended up with this trike). This should “Go a Long Way” towards achieving that.

I have passed this design through GPT and Claude and they like it but they tend to hallucinate a lot so I really want confirmation from a smart human, so please somebody respond.

Thanks
 
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If the packs are BMS protected and you trust the BMS, I would put them on the same solar charge controller in parallel. If you can program the charge controller max voltage, you can set it slightly below the BMS cutoff voltage. If your batteries are in parallel without diode protection on the charge side, they will hold the same voltage and distribute the charge current however it must divvy up to do that.
 
Thanks for the response........These are generic packs so I don't really know about the BMS. I added the diodes just to keep it safer in case the SOC is off or something else goes wrong and I don't think they are that big of a voltage drop to matter and they aren't that expensive. I barely know what I am talking about so I could be wrong but I think the diodes are just some insurance against smoke and fire. Thanks for the tip about charging just below the BMS cutoff, that makes sense and I hadn't thought of that. I ran for years on LiPo packs (no BMS) that I only balanced every couple of months...so what do I know? They are basically in parallel except I added the diodes but if that causes problems, please let me know. Thanks again
 
If I plug a 48 V 400 watt panel directly into my 48 volt battery that uses a 2amp charger that would burn it up correct? I need a smaller panel? Just curious.
 
If I plug a 48 V 400 watt panel directly into my 48 volt battery that uses a 2amp charger that would burn it up correct? I need a smaller panel? Just curious.
Use an MPPT charge controller that can regulate to the voltage you want or need. I charge my bikes on sunshine most of the time now.

 
Use an MPPT charge controller that can regulate to the voltage you want or need. I charge my bikes on sunshine most of the time now.

I have a Victron 450/200 and I also have 1 EG4 XP 6000 and I have 3 Schnieder XW PRO's. Just bragging is all. I want to do it straight plugged in with a real simple circuit to meter 2 amps. Thanks.
 
I have a Victron 450/200 and I also have 1 EG4 XP 6000 and I have 3 Schnieder XW PRO's.

My gang of Victron 75/15s can not step up to ebike battery voltage so the choice for me is to plug into the inverter or to use a battery specific MPPT. I do the latter.
 
My gang of Victron 75/15s can not step up to ebike battery voltage so the choice for me is to plug into the inverter or to use a battery specific MPPT. I do the latter.
Do you like the Victron stuff? I bought a 450/200 because Will Prowse said just buy it because it was the best charge controller you could get.
 
They are the same batteries (48v 15ah).
Below is not a recomendation, just what I do.

I charge my (48V nominal) home bank w/Victron 150-35, and use a smaller 48V Victron 100-20 for vehicles. Utilizing the Victron MPPT software, I turn OFF equalize, then set maximum absorption voltage. I primarily utilize Ego batteries and usually charge separately... then parallel when they are below 100mV difference. I have, however, charged two paralleled packs simultaneously if they were already connected (and fused) to each other . The 100-20 Victron MPPT output can be set to around 57V max (assuming, at least, 60V controller input source). About every 3 or 4 trips, I'll charge with the OEM 120Vac charger to assure balancing.
 
The Chinese are really giving them a run, everybody loves the new XP 12000, I bought Schnieder and Vic because people say they are proven but with for the EG4 price you just get 2 and way easier to set up. They were running those ECO Worthy batteries the big ones for cheap on sale. Solar I think has bottomed out on price and will be going up so you may want to get it now if you need stuff.
 
Below is not a recomendation, just what I do.

I charge my (48V nominal) home bank w/Victron 150-35, and use a smaller 48V Victron 100-20 for vehicles. Utilizing the Victron MPPT software, I turn OFF equalize, then set maximum absorption voltage. I primarily utilize Ego batteries and usually charge separately... then parallel when they are below 100mV difference. I have, however, charged two paralleled packs simultaneously if they were already connected (and fused) to each other . The 100-20 Victron MPPT output can be set to around 57V max (assuming, at least, 60V controller input source). About every 3 or 4 trips, I'll charge with the OEM 120Vac charger to assure balancing.
Thanks...Our situations are different. I am looking to charge in the field and not at home so partial charging would be common and I would not have the luxury of charging each battery to a full state before pairing them. That is why I would keep them in parallel all the time while charging. If that is dangerous, please let me know. I think this setup will keep them close. The diodes should keep them from back-feeding if there is a slight difference when charging and the Duel-Battery_Equalizer (OEM from the manufacturer, it is a duel-battery trike) should keep them from back-feeding on the discharge. I think
 
Can't you just get a panel and make slight changes to it to work in the field? It seems like it would be simpler? I don't know I am dumb about this.
 
Can't you just get a panel and make slight changes to it to work in the field? It seems like it would be simpler? I don't know I am dumb about this.
The idea is to use a solar canopy on the trike to charge a second set of batteries while I am riding (see the "Sun Trip" races). Then when the first batteries run low, just switch to the 2nd set and start the first set charging. I might deploy additional panels when stopped or camped but I plan on being out adventuring for days at a time. If it was my own build, I would have just paralleled the output from the charger with the discharge of the battery..but this is a factory trike with dual motors and dual batteries and I don't want to void the warranty. When I saw that it had 2 standard Hailong style batteries, i thought it was a blessing, but when I started designing the solar charging I realized that it made it more PITA. Trying to manage charging all those batteries 1 at a time and keep them balanced while riding does not seem practical. I don't have space to add a second charging system and that might end up with voltage differences anyway. So parallel charging seems to be the best way to go. There is a problem if the battery voltages are different when you parallel them, they want to balance the voltages really fast which can lead to very bad things. I think adding the diodes should keep the batteries from back-feeding. My problem is I also barely know what I am talking about. My degree was in computer programming 50 years ago not in electronics, so I tend to make mistakes. The smart people on this forum have save my backside many times in the past. So I am hoping to get feedback because hooking up batteries the wrong way can easily result in smoke and fire
 
Sounds really cool what you are doing, good luck. I think you will get it figured out.
 
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Can you run on just one battery at a time with your current set up?

Then you could do the charge-and-swap trick without any changes to your existing power system - the charge and discharge systems would remain air-gapped.

Or, maybe better...

I'm gathering the kit to put a solar roof on my trike (or it's trailer). On paper, my two 160W panels can easily deliver more than the flat-road power needs of my trike. The battery then is to provide a power sink and to provide for the hill climbs needed.

Yes, I can imagine riding in an area that requires serious battery capacity due to hills, and no sunshine, but apart from that, I need only a small battery, or to use less of a larger one (more practical). Grin discusses schemes to use multiple panels to charge a battery while in use, and also sells the bits to do it. I would imagine using this approach to charge to only 80% on my large battery to leave room for regen.

This, too, relies on only needing to charge one battery at a time - can your trike run this way?
 
Thanks for responding. Like you I have been following everything that Justin has to say since I built my first e-bike in 2012. I have been dreaming about this project since then. Life got in the way but now I am trying to make it happen. I am planning on going to the alpine regions of the eastern Sierras and the Rockies (9,000-10,000ft, Sonora Pass Rd has places with 24% grade). I know from past experience that I could be pulling 1500w+ especially since I want to pull a trailer. So I was excited about a dual-motor dual-battery AWD trike. It comes from the factory as a dual battery system. It can kinda run on 1 battery but its not happy and forget about anything steep. Yep...a single large battery, that, I know how to deal with. Thought this was going to be easy and then I started to think about the real-world details and went oh-****, this might harder then I thought.

I am interested in what you are doing to add a solar canopy and trailer.
 
I am interested in what you are doing to add a solar canopy and trailer.

Me too. :cool:

I am moving slowly. Unfortunately, I have retired to an area that is indifferent-to-hostile towards ebikes. It is quite hilly, and also there is a very sparse economy so that there are only small towns connected by two-lane roads - one in each direction, and the roads have no accommodation for bicycles, let alone trikes (see my signature). The local economies here rely on people towing camping trailers on holidays. This means large vehicles piloted by city people at high speed on narrow roads often with no shoulder, let alone bike lanes.

I have some reasons to be here for a while. I'm investigating whether the next state over (Victoria) might be better for a bicycle life. Also, current world events may change circumstances in ways that make the situation more accommodating for me, but the possibility of widespread electric cars would not necessarily help - they still travel at high speed and don't increase the IQ or the integrity of the operator.

My trike has a footprint of approximately 2 meters by 0.8 meters, which matches two gleaf solar panels I have, each at 160W nominal, when mounted together. I'm thinking of making the frame to mount them like that, and then separately make a frame that holds that as a roof for the trike, or the top of a trailer. The rest of the trailer could then be low to only carry cargo beneath the panels, or higher to permit sleeping inside.

I have a Wike trailer kit which relies on me buying square tubing rails locally to define it's size. It may not be strong enough for what I arrive at, but does let me do the experiments before welding something up if needed for strength.

I also have one of the last 170W SunPower panels Grin sold before they became unavailable. If I'd bought a second, I wouldn't have also bought the gleaf panels, but this gives me options. I might mount the SunPower as the sun/rain shade for the trike, while pulling the gleaf panels on the trailer.

Local laws (Australia) don't permit me to use a motor rated for more than 250W continuous. I could manage this with a mid-drive motor using the gears, or the scheme I'm using now with a hub motor and a step-down ratio to the rear wheel (again, see my signature). My set up is simplified this way - only one motor, only one battery at a time.
 
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The idea is to use a solar canopy on the trike to charge a second set of batteries while I am riding
Beware the wind off passing trucks. Even on a heavy motorcycle I move right over when a long semi is coming towards me. It's the sudden crosswinds that are the worry, they can push me a foot or two off course easily and that's without a square meter or more of sail up top.
 
I have a Meet One Tour, a duel motor duel battery trike. The goal is to add a solar panel to extend the range…but duel batteries make it complicated. I assume the batteries use a Dual-Battery Equalizer on the output side but they still need to be about the same voltage. They are the same batteries (48v 15ah). The ideal would be to charge and discharge at the same time but I can’t figure out how to do that. The alternative would be to charge a second set of batteries and swap them. To complicate things, I have a single “BougeRV Arch Pro 200 Watts” panel [Voc (V) =36±5% V , Vmp (V) =31±5% V, Imp (A)=6.46±5%A] because 2 100w panels do not fit and the 200w is near the perfect size. How can I charge 2 batteries with a single panel and keep them the same voltage. So far my best idea is to use a second set of offline batteries, charge the 1st battery with a boost mppt charger and then use a “Victron Orion‑Tr Smart Isolated DC‑DC Charger” to charge the 2nd battery from the 1st. A very expensive solution that I am not sure would result in 2 batteries with same voltage.
my eyes suck but looked a bit at responses and have something so add,
The real need for me is a battery charge splitter that uses the 3 conductor plugs MEETONE and others use. You will want diodes inline to assure no crossfeed issues but the BMS's may manage this already. once you have that then there are many "Solar BOOST controllers" see ebay 400W MPPT Boost Controller Solar 24V-85V Voltage Regulator Waterproof LED | eBay and Amazon Amazon.com : MPPT Solar Charge Controller 15A for 24V/48V Battery Systems, 400W Solar Panel Regulator with LED Display & IP66 Waterproof Enclosure : Patio, Lawn & Garden these are waterproof and easy to adjust. [no affiliate links]
Also for fast tracking known reliable MPPT boost controllers see GENSUN, I would contact these guys before ordering as you want it optimized for your needs. Amazon.com : MPPT Solar Charge Controller 15A for 24V/48V Battery Systems, 400W Solar Panel Regulator with LED Display & IP66 Waterproof Enclosure : Patio, Lawn & Garden

Here is a example of a improved compatible 5amp (better used for this dual charge concept) charger for the MEETONE Trikes.found on ebay, Powatechnic™ 54.6V 5A 3-pin Fast Charger for 48V Meetone atoubd $99

as for DIY stuff aliexpress should haVE SOME CABLE OPTIONS FOR YOUR NEED.

iF SOMEONE MAKES THE CHARGE CABLE SPLITTER POST A RESPONSE HERE PLEASE.
 
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