I have a 120w mono crystal solar panel.The rated output of 120w is calculated at 17v.5 out put at 7amps from memory. I run it through a digital regulator to charge 12v 100ah sla battery in my camper van. My question is how are you using that pannel to charge the batterys on the go ?
My pannel should be able to charge my 750whr 36v battery easy in one day of good sun.
BUT!
The only integrated way I could think of to charge my pack as I ride or park would consist of the following.
* 120w solar panel
* small digital regulator set to charge 12v sla to enable 12v 5ah sla to charge
* compact power unit consisting of 12v 5ah sla, 200w 240v inverter all built into one unit weight 2kg.
* My 80w 2amp 36v 240v charger plunged into inverter.
This is what it would take to charge on the go at around 65w or around 1.5amps you would also need the regulator in the bottom pic
On the left is my 36v lifepo4 in the middle is a 80w 36v charger and on the right is a 200w inverter with built in 5ah 12v sla behind is the big 120w panel
I have tyred this set-up in my back yard and the inverter dose run the charger but you must insure that the panel is at least putting out 80w or more like 100w because there isn't much head room in the little 5ah sla you need to be feeding power in almost as quick as its coming out. This sounds easy but the 120w rating for the panel is at 17.5v at 14.5v sla charging voltage its more like 100w max. I think if I had a 40w charger perhaps 65w max I could charge the battery's on the go at 1 to 1.5amps. Park the bike in the sun for 2 hrs and you could put back 3ah back into my 20ah pack.
I don't think its practical to charge the bike on the go as the panel is 15kg + 2kg for the inverter/sla pack. But over the coarse of a short bike ride the extra weight of the panel wouldn't be worth it for just 40 to 80 whrs max you would get back on a 1hr bike ride ride . The fact you cant tilt the panels for ideal output when mounted on the bike is a problem. Not to mention having a crash on your bike and smashing $750 worth of solar pannel.
I can see integrated solar charging on the go being practical on a electric kayak.You have plenty of space. Your outboard electric trolling motor is 12v. So you can charge the big sla pack directly from the solar regulator and weight isn't a a big issue on the water. 100% doable and practical.
What I do think is practical for the electric bike and I might do soon is. Buy a 2nd lifpo4 36v battery . Keep the solar panel at home tilted up at the sun giving out max output charging my big 100ah sla battery and simply charge one pack from it throughout day with the 2amp charger plunged into the inverter. Each evening you would have a fully charged 750whr 20ah pack ready to go from the sun for free.
This is the 100ah sla I would prefer to charge from at home.
Solar Regulator reg charging at 4.8a 14.5v 69w low output because panel was laying flat on ground and not tilted to the sun
you never get the full rated output or in my case 120w from your panels. Unless you can charge your battery at the 17.5v its rated at.
Kurt.
(9/10 wh/km)
