Charging a 36 volt Ping battery directly from photovoltaics.

[shawname]

I use a 36 volt Ping battery to power my electric bicycle. The charging steps look like this:
Photovoltaics to charge controller to battery to inverter to battery charger to battery management system to battery. A lot of steps, a lot of inefficiency.

I'd like to experiment with simplifying to: Photovoltaics to BMS to Battery.

Mr Ping does not want more than 42volts going into his little ping. I am using a 5 amp battery charger right now. I am thinking about assembling a 42 volt 3.5 amp panel out of eighty four 3x6 cells. A diode will prevent discharge.

Anyone tried this, or know if it will work or not?

cheers,

Shawn

 

[dogman dan]

I would think the main issue would be regulating the voltage. A 36v charge controller would be nice.

An alternate solution might be three 12v bms's. Then charge using the 12v charge controller.

 

[neptronix]

An RC charger that can do 10S-14S can simplify this. an iCharger 1010b+ can push out 43v tops.. the hyperion 14S can put out quite a bit more.

Most RC chargers are designed to run off 12V batteries. You can skip the inverter stage and the end result will be more efficient. It will cost you, but yeah..

 

[Lebowski]

would it be possible to put so many panels in series that you get over 100 V
out of the solar panel ? If your charge setup is like mine (eFuel 18V30A into iCharger 1010),
probably your power supply will accept the 100V DC directly. A modern
switch mode power supply does not need AC but will work of DC too.

 

[shawname]

I would think the main issue would be regulating the voltage. A 36v charge controller would be nice.

I was thinking that if the photovoltaics put out 42 volts max, that as the Ping battery charged, the voltage would also increase, until no current could flow into the battery.. Wishful thinking?

I did look for 36 volt charge controllers and fund this:

PT 36-5A, 36V here http://www.altestore.com/

It is a 36 volt mmpt charge controller with a 42 volt cutoff!

Thanks!

 

[shawname]

would it be possible to put so many panels in series that you get over 100 V
out of the solar panel ? If your charge setup is like mine (eFuel 18V30A into iCharger 1010),
probably your power supply will accept the 100V DC directly. A modern
switch mode power supply does not need AC but will work of DC too.

Hmm, interesting. It would take 200 solar cells as each one puts out .5 volt. That's a lot! Thanks, but hopefully I can find a simpler solution.

Shawn

 

[nechaus]

iv made a few solar panels in my time.

its alot of soldering man, and its a pain in the ass.

i recommend to not use the 6x6 cells as they break really easily

 

[dnmun]

ping uses 45V for the charging voltage on his 36V lifepo4 packs, not 42V.

42V is for the 10S limno4 packs.

 

[shawname]

ping uses 45V for the charging voltage on his 36V lifepo4 packs, not 42V.

42V is for the 10S limno4 packs.

Yes, I have measured the voltage at the charger. But in a personal email with Mr Ping he recommended that I limit the voltage to 42 to avoid overcharging.

I did find this Mppt charge controller:

http://www.altestore.com/store/Charge-Controllers/Solar-Charge-Controllers/MPPT-Solar-Charge-Controllers/Solar-Converters-MPPT-Charge-Controllers/Solar-Converters-PT-36-5A-36V-MPPT-Charge-Controller/p1380/

Which seems to be custom made for the application.. The cut off voltage is 42..