Mony Vs Poly panels.

[dfrank]

So, I had mostly decided that I wanted mono panels, then must have mis read the ones I pulled the trigger on, and ordered poly unintentionally to save a few bucks.

Does it matter?

I bought 2 Renogy 100 W poly panels to put on my TC. I think they were $115 each.

I can send them back and get the monos, but I'd be paying shipping and the extra 20 or so each.

The poly's seem to be a better size, but that hardly makes much difference in my application.

Also is the ten gauge wire they want me to use appropriate?

I have lots of scrap 12-3 extension chord that I like use as one wire. I think this makes it a 4 gauge or smaller, but don't know how to verify what that really translates to. The factory 10 gauge will be easier to plug and play, if they are sufficient.

Does it matter where I place the controller as far as the distance between the roof top panels and the battery?

They will be a pretty straight vertical run from battery to panel. I can put the controller up higher if it matters.

I still need a battery monitor, and possibly a new system of shore power charging.

I am not sure that my '98 vintage Magnatek charger treats my batteries as well as it should.

Batteries waiting to be installed are a pair of 6V T105's. THey'll be going in an underbody box beneath the new flat bed.

Thanks for any insight,

Dave

 

[john61ct]

Controller should be very close to the batts

 

[dwh]

IIRC Renogy polys are like 15% efficient, monos 18%. So your talking like 3w per hour difference per 100w panel

Max.

On a good day. Usually the difference will be even less. Not enough to notice until you get into installing a few thousand watts on a house.

The factory #10 wire is fine for the 10-15 amps that 200w of solar can produce.

What Verkstad said about charge controller placement. Electrically, PWM doesn't matter where it is. MPPT closer to the battery can be better, but doesn't really matter much with a small solar setup.

However...if the charge controller has temperature compensation and an internal temp sensor, then it should be somewhere close to the same temp as the batteries. Which usually means fairly close.

 

[john61ct]

Voltage drop can be an issue for either type.

Especially for those with no dedicated sensor wire.

That efficiency bit isn't right, the watts rating is after the difference is taken into account. But it does make a difference in watts per sq ft when space is constrained, as much as 20%.

And nitpick, no such thing as "watts per hour", in that example just watts is fine.

 

[dwh]

Voltage drop can be an issue for either type.

There is no voltage drop in that situation.

That efficiency bit isn't right, the watts rating is after the difference is taken into account.

15% of the energy is converted to electricity...or 18% is. Using 100w panels makes the math easy to give the newb an idea of scale.

And nitpick, no such thing as "watts per hour", in that example just watts is fine.

So no such thing as kilowatts per hour either?

 

[dfrank]

Maybe a kilowatt per week?

I was planning to place my 2 Trojan 105 6 V batteries in a box below the flat bed.

Should I instead make an insulated compartment up on the bed, and try to get some warmth from the truck?

Is it worth some trickle heat source on these, when it is parked in the driveway, which sadly will be 90% of its lifespan?

I do plan to keep it plugged in when I can, so the fridge can run on AC.

I suspect I'd be better off figuring out how to by pass the old converter charger, but I really dint know enough about that unit.

Maybe a 110 plug that only peers the fridge and a seperate trickle charger, or smarter charger in general?

Do you guys like the "Genius chargers"? I have a small one that I have been using to keep the yet to be connected trojans topped off.

The original converter charger is a Magnatek, I assume the original unit from '98. I can also just guess that this unit contributes to early battery demise, but poor battery management may be the main culprit (excess discharge).

Thanks,
Dave

 

[JaSAn]

xxx

IIRC Renogy polys are like 15% efficient, monos 18%. So your talking like 3w per hour difference per 100w panel . . . Max.
. . .
However...if the charge controller has temperature compensation and an internal temp sensor, then it should be somewhere close to the same temp as the batteries. Which usually means fairly close.

A 100W panel will produce 100W under standard conditions BY DEFINITION. The difference is that mono panels are smaller to deliver the same watts.
I read somewhere that poly panels are a little more efficient under low light conditions.

If your charge controller has an internal temp sensor then it needs to be as close to the same temperature as the batteries to correctly modify voltage. If the CC has a remote temperature sensor then it doesn't need to be at the same temperature as the batteries.

. . . I was planning to place my 2 Trojan 105 6 V batteries in a box below the flat bed.
Should I instead make an insulated compartment up on the bed, and try to get some warmth from the truck?
. . . I do plan to keep it plugged in when I can, so the fridge can run on AC.
. . .
Dave

My batteries are kept in my camper outside over the winter with the solar panels keeping them charged with no problems (low of -22ºF this winter). Batteries are 4 Y.O. GC2s and still hold a 1.27 specific gravity. Don't understand your wanting to heat the battery box.

I only fire up the refrigerator before trips; when sitting I just leave it open.

jim

 

[john61ct]

I just meant not factors in the PWM vs MPPT debate, obviously a given context may render some factors irrelevant.


An yes wrt to units, watts and kW are an instantaneous measure of **rate** of power output or consumption, like MPH wrt distance or GPH for water flow, may be constantly changing and already include a "per time" component. Same with amps.

watt-hours and amp-hours are required when talking about an average or total quantity energy **per time unit**, or static capacity, like miles or gallons.

 

[john61ct]

Small-amp chargers can be OK for keeping a full bank topped up. Not for in-use deep cycling, need much bigger amps and proper smarts wrt customizability. Good chargers usually cost more than the batt bank.

Unless you **know** its voltage profile in storage is healthy, best to just hook it up overnight every few weeks rather than all the time.

No need to rig a heated battbox, just bring them indoors in extreme conditions.

Arctic expedition vehicle maybe?