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[c-fut]

Hello all. My buddy built a solar charging array that consists of 2 solar panels rated at 37.93v / 9.09a  / 345w each. These 2 panels will be wired in paralled to get 37.93v / 18.18a / 689.56w for the 2 panels. These 2 panels will charge 2 lithium phosphate batteries rated at 12v x 100ah=1200wh each. The 2 batteries will be wired in series to get 24v x 100ah=2400wh. The inverter is rated for 2000watts at 24v. Would I be able to plug my onboard charger to the inverter to charge my zero s that has a 13kw battery with this setup? Thanks in advance.

[TheRan]

I don't see any reason why that wouldn't work, Andy Kirby (on Youtube) has a similar setup that he uses to charge his Twizzy and e-bikes. I assume this is stationary setup at your buddy's home, if so and you're going to be charging from it regularly I'd up the battery capacity if it's not too costly.

[Crissa]

Well...

...Not really, since you're only producing <0.7KWh per hour the sun is up.

Maybe if the batteries were fully charged, and you plugged in while the panels were in full sun, you could charge using the default charger.

But you'll want an inverter with a capacity 50% more than the wattage of the bike's charger.  The peak power an inverter can produce is different than the throughput power it can produce for the hours needed to charge the bike.  The electronics will heat up and become less efficient at what they do and need to shed that heat somehow.

That's not to say there might not be a way to trickle-charge the battery.  I dunno.

-Crissa

[TEV]

Assuming that the inverter will be able to sustain the 1300W (1.3KW) that the onboard charger will need, then you will be able to put back about 2000W (2KW) in your 13KW pack. You are limited by the capacity of the storage battery because the solar panels can't provide the 1300W for the charger. So after charging for about 1.5 hours your storage pack will be empty, and your motorcycle  SOC will be about 10% more than before you started charging from that 2400W storage pack, and only if it was fully charged.

[Crissa]

If the array and the batteries are connected, you'll get a little bit further, but yes, TEV's basic math is what I was meaning.

-Crissa

[Doug S]

You're making a couple of naive errors that many new solar converts make. First, your "345W" solar panels will never deliver that. They may approach "rated" voltage unloaded; "rated" current into a short circuit; together, never. That's just how they rate them. You'll be doing well to deliver 250 actual watts on a good day in direct summer sunshine, or around 500 watts (0.5kw) between the two.

Your primary mistake, however, is conflating kwh and kw. A battery's capacity is rated in kwh, power is rated in kw. You're saying you want to charge a 13kwh battery (your bike) from your buddy's 2.4kwh battery. Do you see the problem with this? You could gain a partial charge, but only very partial. The solar array's ~0.500kw will help, of course, but only slowly.

Sure, you could do it, but only over the course of many hours and/or several days.

[c-fut]

I don't see any reason why that wouldn't work, Andy Kirby (on Youtube) has a similar setup that he uses to charge his Twizzy and e-bikes. I assume this is stationary setup at your buddy's home, if so and you're going to be charging from it regularly I'd up the battery capacity if it's not too costly.

I was thinking of building a set up like he has. I would be charging mostly from the batteries as the sun will be going down when I'm plugging in.

[c-fut]

Well...

...Not really, since you're only producing <0.7KWh per hour the sun is up.

Maybe if the batteries were fully charged, and you plugged in while the panels were in full sun, you could charge using the default charger.

But you'll want an inverter with a capacity 50% more than the wattage of the bike's charger.  The peak power an inverter can produce is different than the throughput power it can produce for the hours needed to charge the bike.  The electronics will heat up and become less efficient at what they do and need to shed that heat somehow.

That's not to say there might not be a way to trickle-charge the battery.  I dunno.

-Crissa

The inverter is rated at 2000 watts and 4000 peak. Do you think that would be ok since the stock charger draws only 1.3-1.4kw?

[c-fut]

Assuming that the inverter will be able to sustain the 1300W (1.3KW) that the onboard charger will need, then you will be able to put back about 2000W (2KW) in your 13KW pack. You are limited by the capacity of the storage battery because the solar panels can't provide the 1300W for the charger. So after charging for about 1.5 hours your storage pack will be empty, and your motorcycle  SOC will be about 10% more than before you started charging from that 2400W storage pack, and only if it was fully charged.

Sounds like I would need more batteries if I wanted to fully charge my Zero without sun

[c-fut]

You're making a couple of naive errors that many new solar converts make. First, your "345W" solar panels will never deliver that. They may approach "rated" voltage unloaded; "rated" current into a short circuit; together, never. That's just how they rate them. You'll be doing well to deliver 250 actual watts on a good day in direct summer sunshine, or around 500 watts (0.5kw) between the two.

Your primary mistake, however, is conflating kwh and kw. A battery's capacity is rated in kwh, power is rated in kw. You're saying you want to charge a 13kwh battery (your bike) from your buddy's 2.4kwh battery. Do you see the problem with this? You could gain a partial charge, but only very partial. The solar array's ~0.500kw will help, of course, but only slowly.

Sure, you could do it, but only over the course of many hours and/or several days.

That makes sense. Trying to fully charge a 13kwh battery with a 2.4kwh battery will definitely not do it. I thought a battery's capacity is rated in aH?

[Starpower]

If you have utility power, then I would simply get a couple of AC modules (grid tie solar panels with a micro inverter integrated) or integrate your own for savings. Connect that to your utility service (with permission of course, wink) and that 500W (real output) will produce an average of 2.5 kWh/day or about 12 days to fully charge from dead. This is much cheaper, easier, more efficient and useful (if no need for charge you still make use of the PV power). A new secondary battery will be about 90-95% efficient each way so you lose 10-20% of your energy moving power in and out of the solar battery. The utility is a massive and 100% efficient "battery" use that! "Charge" the utility with solar and take it back as needed. If you fully deplete your 13 kWh battery daily then you'll need about 3.5kW of PV power, every other day then it will require 1.75 kW for offset and so on. Calc for your needs.

I charge off of my 4.8 kW solar system but I've been off-grid for 40 years and I'm stuck with the secondary batteries for the home (14.6kWh at 1300 pounds!). However, I only charge during the day when my house batteries are only consuming under 2 kW leaving enough solar surplus to charge the Zero without actually taping the house batteries, in effect solar-direct charging. I typically return home with a 10-20% SOC and can be fully topped off in 2 days. Zero refers to "fuel" costs for me!

[Starpower]

And now you know the meaning of my profile name...

[BrianTRice@gmail.com]

Mind the minimum input rating of the original equipment. 100V minimum input in particular seems notable.
https://zeromanual.com/wiki/Gen2/Calex_Charger
https://greenwattpower.com/product/1300-watt-evc-li-ion-charger-series/

It is my understanding that the Calex/onboard charger has no inrush protection, so you may need to built in an external safety to the circuit as well.

[heroto]

The OP had an optimistic power output from 2 solar panels (or he or she is in Arizona?).

[ZEROfreak]

I have this solar charge controller. And you can step up the output voltage.