Solar charging 84v battery packs

[SolarCurious2874]

Google searches have left me empty handed as well as scrolling through this forum briefly.
I'm trying to figure out the viability of directly charging my 84v personal electric vehicle through a solar array. Obviously I would need a controller that is capable of an 84v output and I'm assuming I would need to wire up a sufficient number of panels to get above 84v. I know that there are a lot of mppt solar controllers that will accept input up to at least 100v but I'm finding only 12 or 24v outputs. Obviously, these are the most common battery bank voltages.
Is there a controller that would do what I'm looking for?

Thanks,

Keith

 

[gnubie]

I know you can get 96v chargers, Google will find them for you, but as to any of them being suitable for your purposes, good question. Does your EV actually take 84v DC in? Can you link to any tech details for the EV? If the EV just has DC in and all the smarts for the charge process are external you'd have to look at the fully charged voltage for the EV and then look into one of these 96v chargers being suitable.

 

[Fred S]

Are there electronics protecting the vehicle batteries, or are you connecting straight to them?

 

[Supervstech]

Is this a home built EV?

 

[SolarCurious2874]

I'll try to answer all 3 questions. This is an electric unicycle with 84v packs. I have a fast charger that displays the amps going into the battery. It runs whatever amps setting you put it at until the battery reaches 80 to 90% then backs off the amperage progressively until the battery is full. I'm not at all certain if there is a built in bms but I believe that there is some sort of battery management when the unit is on and operating. I'm guessing this because at full charge, going downhill has caused some shutoffs to occur to other riders in a forum along with warning beeps. The wheel regenerates downhill so the system protects the batteries by warning then shutting off. Not ideal for the rider, might I add.
My best guess is that this built in protection may not work while the unit is off and charging from the charger.

 

[SolarCurious2874]

So, you may be wondering why not just charge off an inverter? Well, the solar charger has losses, the inverter has losses and the charger, reportedly, has large losses. Obviously, charging directly from a solar charge controller would take two units, and their losses, out of the mix.

 

[Supervstech]

So, you may be wondering why not just charge off an inverter? Well, the solar charger has losses, the inverter has losses and the charger, reportedly, has large losses. Obviously, charging directly from a solar charge controller would take two units, and their losses, out of the mix.

Losses with modern stuff is minimal really. Figure less than 2% in many cases.

 

[SolarCurious2874]

Losses with modern stuff is minimal really. Figure less than 2% in many cases.

I think not. I'm finding, more and more, that losses are huge, not in the 2% range.

How much energy is lost due to the conversion from DC to AC power in PV solar panels?

Answer (1 of 9): If you only look at the Inverter losses you would lose about 30% in a 95% efficiency inverter. This is because a 95% efficiency inverter has a MAXIMUM efficiency of 95% only if the load and the input power and ALL parameters are perfectly matched. It can be as low as only 5% effi...

www.quora.com

 

[Supervstech]

I think not. I'm finding, more and more, that losses are huge, not in the 2% range.

How much energy is lost due to the conversion from DC to AC power in PV solar panels?

Answer (1 of 9): If you only look at the Inverter losses you would lose about 30% in a 95% efficiency inverter. This is because a 95% efficiency inverter has a MAXIMUM efficiency of 95% only if the load and the input power and ALL parameters are perfectly matched. It can be as low as only 5% effi...

www.quora.com

I have seen real world 2% to as high as 23% losses.
It depends on use, brand,type etc.

 

[gnubie]

As a rule of thumb I work on 85% for typical buck/boost and 75% for full transformer switching designs, works out reasonably well for typical, ie highly variable, use.