What is a good solar controller?

[Hubert]

I have a boat lift that can lift 6500 lbs. It has a powerful motor. I attempted a DIY solar panel system to charge it but I admit my ignorance has led to an issue. I have a 50w solar panel. My problem is that the motor draws HIGH AMPS. So both 10A solar controller I bought off Amazon (tried 2 different ones, one was Renogy Wanderer, another was some Chinese name) both think they short circuited since the motor draws a ton of amps. These cheap controllers can handle 10 amps of charging from the solar panel, but can't handle high load amps. I don't know how many amps, but I have heard these boat lift motors need something like 750 watts. I have a 24 volt battery (2 x 12 volt batteries in series). I want to buy a controller that can handle a high amp load. When shopping, most controller don't even specify how many amp load they can handle, which is why I am reaching out. Thank you

 

[gnubie]

Are you trying to run your motor through the solar charger's load output terminals? That isn't practical, they are only intended for small loads. Your motor should be wired off your central bussbar or off the battery terminals, not the charger.

A 50 watt panel isn't going to do much towards charging your battery unless you only use that lift sparingly.

 

[Hubert]

THANK YOU! Your comment made me realize my mistake in simple mindedly following the directions that were provided with the solar controller: I had connected each of these to the controller directly: 1. battery 2. load 3. solar panel. Instead I followed your direction and kept the battery connected to the motor. I spliced in a connection to the solar controller to the battery. I then connected the solar panel to the controller. I did NOT plug anything into the load terminals on the solar controller. I got a reading of 18 volts on the SV and my lift works. Very pleased. Thanks a lot

BTW most boat lifts on my lake have 10 watt panels. 50 watts is plenty. The motor only works less than minute every time it lifts or lowers. Most people use their lift twice a day when they are at the lake, and for most people, these lake homes are not used on the weekdays. The boat lift companies sell solar set ups they install on the boats and they charge about $400 for a 10W solar kit. I am not sure they even include a solar controller because they say the voltage is too low to overcharge the battery. I did this myself (clumsily) for less than $200 USD. Since I have a bigger panel, I have peace of mind I can use the lift as much as I want without worrying about not enough charge, and I have controller that should extend the life of my batteries by preventing overcharging.

 

[John Frum]

BTW most boat lifts on my lake have 10 watt panels. 50 watts is plenty. The motor only works less than minute every time it lifts or lowers.

The question is how much amperage is required to get the rotor spinning?
This is called LRA=locked rotor amps.
Also how much energy in watt hours does the lift use in the minute that it is running?
The battery has to satisfy both requirements and the panel has to replenish the battery.