Morocco Truck

Problems with solar panels

Solar problem in the Sahara?. Our brand new Tenesol TE2000 solar panels were underperforming, giving only 27.4 open circuit volts instead of 33, which wasn’t enough to charge up our system. Even in the Sahara where sun is never a scarce commodity. And solar is important to us because we keep Abigail’s insulin in our fridge to control her diabetes and no fridge means no insulin which means no more Sahara. Time to go north anyway. We had a technician contact Tenesol but they have not been able to help us yet.

Quick fix? I wired the panels in series rather than parallel (technicians suggestion). That doubles our voltage which I hope our system will handle, and it gives us the load amps of a single panel. If anyone out there thinks this is a crazy solution, please let me know.

10 replies on “Problems with solar panels”

Yes, found it!
Its about a MPPT (max power point tracker) controller. This one searches for the right voltage of the solar panel it witch it produces highest current. (in your case example 18v 25A =450W)
And converts this to 28V 16A =450W !
This is a magnificent finding since it not only brings the highest power to you batteries. (independent on what voltage they need to be charged) But also does not care about what voltage your solar panel is. It can be for ment for 12-24-48V it all works on the battery voltage you adjust it to.
The controllers are a little more expensive, but they are your solution and bring the best result.


Hi family!
I am in El Moreon now (Spain). Living for some time with my new girlfriend and she is expecting a baby!
Later, when i was in Aurir with Alesh, i met the same seller of solar panels trying to sell the same 18V panels to a new victim. A dutch couple. I informed them about the 18v specifications and confronted the seller man about it.
He didn’t like it of course and quickly packed and left. Later on they bought new panels for a good price at the factory in Morocco.
I now am working in El Moreon in servicing solar panels and just heard now of a special regulator that converts the voltage of the solar panel to that of the batteries. This would be perfect to have your panels working on the power they should deliver. (now they are working only on about half power) If i know more i will tell you.

CU and good journeys. I read your blogs now and then.

Hug to you all,

i mean only charging the batteries with the panels, not use generator, or house power to charge them…

you have my mind a buzzing, i will see if i can find his blog and post to see if it is useful to you…


how are the solar panels going? i saw your page and got me to thinking about another blog. the guy has been running solar for 6 years, charging batteries, powering alot…with having used a generator or house/campground power to charge them. i will see i can find the site again. very useful information.

sorry guys. i am a bit stupid here and dont understand. if the panels say they should give 33 volts without load but only give 27, am i not missing 6 volts?

this store sells the tenesol te2000 them for 12/24 volts. link

it doesnt mention 18 volt. are these different? i dont understand.

Hello Kevin,

You are right.
I was reading the same specifications, but was’t keen enough to pay attention to the nominal voltage…

I was testing the solar panels and concluded that without load it they had only 27 volt. It was really open circuit without load.
This in full sun, directly aimed, both panels the same voltage. They should just give the 33 volt. They just don’t match the specifications.

But with a 18volt nominal they indeed would have problems with the 24v batteries.

Pretty stupid they got this panels to them sold. They are just useless in this way.


thanks Kevin. Appreciate your help. I have sent you an email with the details of the solar installation guy (Hassan) and the garage, and the controller (prostar 15) and other info.
Our technician said if we were getting 33 open circuit volts instead of 27.4, then there would not be a problem. Look forward to hearing your advice.

Dear Andrew

Thank you for your comments. The TE2000 is an 18v Nominal solar panel designed for use with grid tied systems. The voltage at maximum power is approximately 27 volts and the open circuit voltage is 33 (No load) as such are not suitable for battery charging. From your description the modules sound like they are infact working as they should.

Who advised you on the system configuration?

How is your system configured?

Who did the installation?

Please can I have further information regarding your charge controller. Is it a MPPT regulator?

You can connect the panels in series so long as the open circuit voltage (66 volts) does not exceed the input voltage of the charge controller otherwise you wil blow that.

Your feedback would be greatly appreciated

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