Solar - The Perfect Match

GaryKelly · Guru

Solar - The Perfect Match

bill12 · Guru

Not if the solar reg is a good one. It will just stop charging when the battery is full. I like the more is better style, and have 2 - 120amp/hr batteries, and 2-80 w panels, with an mppt reg. Works for me. Bill

Yuglamron · Guru

Not being a sparkie my input is my view only.

I have always been of the opinion it's better to drive a big V8 at low revs that a small four at high revs.

It seems to me(I will probably be shot down in flames) that a bigger wattage panel would be better than a small one.I would thing that the solar regulator would determine the charging rate etc for your system to avoid overcharging etc. If the difference in cost is not too prohibitive.

GaryKelly · Guru

Thanks bois. Yep, there is a regulator. Dunno if it's a good one or not - can't see a brand name, but it includes a voltage meter and it's working - the battery has been fully charged for a whole year because I've never used it except to test a few things. The regulator automatically stops charging when the battery is full.

So I guess my question is this: If I only have the one 100ah battery, and it's down to say 50% charge, will a 200W panel charge it more quickly than a 100W? Or does the rate of charge remain the same no matter what the wattage?

bill12 · Guru

Mine seems to charge more when there is more draw, more being used. Sounds like you have a good solar reg. How many volts in the battery.Mine gets up to 14v when nothing is being used. Bill

GaryKelly · Guru

Same here, Bill. The voltage meter goes up to 16 but it's presently showing 14.

DeBe · Guru

Yes Garry, a 200W panel will charge your battery quicker than a 100W. You have double the current avalable, also if you have cloudy conditions then you will apreciate the larger panel.

GaryKelly · Guru

Thanks, DeBe. That settles the matter. A 200 watter it is! Or will be. I'll stick with the old 70 for the time being. No rush.

beiffe · Guru

If you have the room you can leave the old one there and just add more, but if you are restricted in space then perhaps the replacement will be better.
I prefer as much as I can get.
Portable panels are a good option if you have somewhere to carry them as they will give approx 30% more if you take the time to move them 3 or 4 times during the day, plus you can move them to the sun where it is hard to get your RV in the sun all the time.
The portables can be setup to feed the same regulator so no extra cost and I prefer that method myself. I usually disable the regulator on the panels and then replace the cables with thicker cables and then wire through your current regulator.
Regards
Brian

patrolst · Senior Member

GaryKelly wrote:
G'day assorted geniuses and techno tragics. I know this subject has been covered a million times before but dummies like me find it difficult to get their heads around it. So I need a simple answer.
At the mo, my camper is equipped with a 10 y/o BP solar panel, 60 or 70 watts, connected to a 12V car battery used as a house battery, and a 300W pure sine inverter. I'm going to replace the house car battery with a 12V AGM gel 100ah. I'll keep the old solar panel for a while for budget reasons. But when I do replace it, would a 200W panel be too much for a single 100ah battery? Or would a 100W be better suited?
My electrical needs are pretty modest... laptop, occasional TV, radio, recharging phone/camera batteries, lights and that kind of thing. No major appliances like the fridge (except when travelling - otherwise gas).

Gary before you upgrade the panel check the size of the regulator it may need to be upgraded as well.

nkrcs · Newbie

One thing I will say apart from going for the 200W will charge your battery quicker is that instead of going Gel may I suggest going going Dry AGM they can be mounted in any configuration, basically maintenance free, you can drag them down a lot lower than most deep cycles and they can be charged via a vehicle to full capacity, where most other deep cycles can only be charged to 70% via vehicle, but shouldn't really be charged by a vehicle at all