Solar charging

[Hemi]

Dear Members

Can I use a solar panel to charge my evolution mount.
Is it as simple as connecting the mc4 plugs from the PV to the mount via a mc4 to 5.5x2.1mm jack adaptor?

I was thinking of using a 30w panel which outputs a max 2.2amps. Is there a restriction on PV panel size? I.e. Could I potentially supply too much current....The PV panel is rated at 12v but can have up to 18v. Will that fry the evo battery?

Thanks in advance

Hemi

[Star Catcher]

Hi Hemi

From what you say, the panel is quoted as being 12V output, so I assume there is an attached regulator that drops the open circuit voltage (18V) to 12V. The regulator is attached to the back of the panel. It typically has outputs for charging a battery and also outputs for a load e.g. like a fridge.

There is no restriction on panel size you can connect. A bigger panel will charge your battery faster. If the battery in your mount is 10AH then your 30W panel in theory (full sun, perfect temperature, 100% efficient controller etc) should charge it in 4.5 hours. A 60W panel will charge it in half the time, all being equal.

You can connect from the regulator's battery output terminals to the terminal/socket on the mount. I have assumed the battery in the mount is a 12V lead acid type, however it could also be a lithium type? If lithium, the charging profile from the panel's controller may damage the battery over time if maximum charged voltage level exceeds what is recommended for the particular battery type. If the controller applies a higher than normal voltage for extended periods, it will shorten the life of the battery.

More expensive solar charge controllers are smart enough to know if the battery is a wet cell, AGM, Gel, Cadmium and even lithium types. Some cheaper controllers can be manually switched to different battery profiles. It is highly unlikely this type of controller is integrated into your 30W panel.

Hope that helps.

Ted

[Hemi]

Thanks Ted,

The battery is the lithium phosphate built into the evolution mount.

Hemi

[acropolite]

The panel will be 18v open circuit, they are almost universally not regulated and the majority of add on solar regulators are Pulse Width Modulation type and don't regulate to a constant 12volts. The manual specifies 12V power supply, achieving a constant 12V from a (nominal) 12 v panel will be difficult without using a low dropout regulator.

I'd be measuring the voltage of the existing plugpack under normal charging conditions, it may be that the voltage used has a fairly wide tolerance, if so then adding a solar regulator and an additional external 12v battery to smooth the output from the panel/regulator would probably be the easiest solution and you would have the bonus of an additional standby supply.

[Hemi]

Thanks Phil,

My original charger from Celestron went the way of the DoDo. I'm using a super cheap battery/jump starter thing to charge the evolution mount. Works fine. Would that have good regulation to 12v. Reading stuff elsewhere suggests some tolerance to 14 and 15v, with some saying the mount works better at a slightly higher voltage.

I'm certainly in unfamiliar ground and don't want to hammer my battery so your advice is greatly appreciated.

Thanks


Hemi

[issdaol]

Thats true mainly if you buy a "raw" panel.

Many portable panels now have inbuilt MPPT modules built on usually in the 10, 20 or 30 Amp range for the MPPT)

Just need to check if the MPPT module that comes with the portable panel has a LiFePO4 charge profile which a lot do nowadays.

Most of these portable panels can be purchased from 4wd or camping stores.

[Hemi]

I bought a cheap raw 20w panel from Jaycar. And a cheap solar Regulator which prevents overcharging, again from Jaycar