100W Simple Set Up

[FosterWV]

Searched & Read up on basic setups and had few questions I couldn’t find. Also open to any recommendations Thanks in advance

Battery Bank is a set up golf cart batteries that power a 1 gpm water pump, led lights, fan at night 8hrs, fridge, Wilson Phone Booster when working “from home”

Can I go from MC4 connector to SAE connectors needed to pass thru a trailer wall?

PWM vs MPPT for 100w panel ? Read that for 100w MPPT wouldn't do much good

Components and Cost I was looking at

 

[highwest]

From my limited experience only:

I’ve gone MC4 to SAE with no issues.

I’ve had MPPT controllers and the only issue I’ve seen is that they typically want to see from the solar panel >5V above the charging voltage of the battery, so you need to be sure the solar panel will output that level of voltage. The wattage of the solar panel will dictate the speed of the charge.

I have to constantly remind myself that amps multiplied by volts equals watts. In your case, 100W (optimistic for solar panels) / 5.56A = just under 18V… since your golf cart batteries will likely want to charge at/above 13.8V, an MPPT controller may not be happy with this situation.

Someone with more experience with both MPPT and PWM controllers should jump in here and fact check me.

 

[BagiMT]

I would use Anderson Powerpole connectors instead of the SAE connectors, they are rated at 30A if you ever want to add more panels. Both should be fine for 100W. Also make sure you use an appropriate wire gauge for the length of the cable and the amperage to avoid voltage drop. Besides that, I run a the same controller with a 12 V AGM battery and it works fine.

Sent from my LM-G820 using Tapatalk

 

[FosterWV]

Appreciate the replies, I’ll go w the PWM controller. I originally thought about the Anderson connectors but can’t find a way to pas it thru the trailer wall. The panel won’t be permanently mounted and the cables will need to be disconnected.

Also don’t have room to store/transport a full-size panel, hence the reason for the folding panel and seems like renogy was most popular.

 

[jonyjoe101]

Just make sure you double and triple check the sae connectors before connecting them. I was going to use them but found it was very easy to wired incorrectly. In some situations the positive wires can be black or vice versa, to me it was too easy to screw it up, all it takes one mistake. For that reason I don't use sae connectors for any devices.
For 100 watt, pwm is good. 100 watt panel maxes out at about 21 volts, for mppt you need panels that put out 30 volts or higher. I had a 120 watt panel and tried both pwm (6 amps) and mppt (also produce 6 amps). But on a 240 watt 36 volt panel, pwm (produce 7 amps) and mppt (produce 12 amps) a big increase.
One thing to look for when you hook everything up is measure the voltage at the battery terminals, if they are never reaching 14.4 volts then you got voltage drop. Every controller I ever used had voltage drop. The controller can read 14.4 volts but the battery terminals might be at 14 volts or lower, it results in undercharging the batteries.

 

[john61ct]

power a 1 gpm water pump, led lights, fan at night 8hrs, fridge, Wilson Phone Booster when working “from home”

100W not enough even in ideal conditions.

If your GCs are 200+Ah shoot for 400W to get them to Full most days and keep them in the high SoC range that will ensure good longevity.

Unless you have a genset to run for an hour or two each morning

 

[FosterWV]

Just make sure you double and triple check the sae connectors before connecting them. I was going to use them but found it was very easy to wired incorrectly. In some situations the positive wires can be black or vice versa, to me it was too easy to screw it up, all it takes one mistake. For that reason I don't use sae connectors for any devices.
For 100 watt, pwm is good. 100 watt panel maxes out at about 21 volts, for mppt you need panels that put out 30 volts or higher. I had a 120 watt panel and tried both pwm (6 amps) and mppt (also produce 6 amps). But on a 240 watt 36 volt panel, pwm (produce 7 amps) and mppt (produce 12 amps) a big increase.
One thing to look for when you hook everything up is measure the voltage at the battery terminals, if they are never reaching 14.4 volts then you got voltage drop. Every controller I ever used had voltage drop. The controller can read 14.4 volts but the battery terminals might be at 14 volts or lower, it results in undercharging the batteries.

Thanks I’ll double check when wiring up the connectors, I’m still looking at other options to pass thru a wall and be able to disconnect etc

I’ll check voltage output etc as well

 

[plh]

You will need to figure out your daily energy need. 100W panel is going to really output 50% to 75% of lab rating for best case 4 hours per day when aimed properly. Maybe 25% for another 4 hours per day, and not much for the remaining sunlight. If you flat mount the output will be less.

 

[john61ct]

In ideal conditions a 100W panel will put 25-30Ah per day into a 12V system.

Not into the battery, that only gets what is left over after feeding any concurrent loads.

 

[FosterWV]

In ideal conditions a 100W panel will put 25-30Ah per day into a 12V system.

Not into the battery, that only gets what is left over after feeding any concurrent loads.

Good info, Thanks
I’m at avg 22.5 per day so even half that would help. I’m not expecting to fully recharge the batteries every day.

 

[FosterWV]

Thanks for the advice on the SAE wires after looking it over I’ve decided to run MC4 cables direct to solar controller. Then put a box on the outside of the trailer to store the cables.

 

[john61ct]

I’m at avg 22.5 per day so even half that would help. I’m not expecting to fully recharge the batteries every day.

Try to do so at least half your off grid days if you want decent longevity from the GCs.

Also do not let SoC% go much below 50% other than in emergencies.

If conditions are not ideal your deficit will accumulate. At least plan so adding more panels will not require replacing the SC.

1:1 ratio actually works well…

 

[FosterWV]

Try to do so at least half your off grid days if you want decent longevity from the GCs.

Also do not let SoC% go much below 50% other than in emergencies.

If conditions are not ideal your deficit will accumulate. At least plan so adding more panels will not require replacing the SC.

1:1 ratio actually works well…

Thanks again, I have a battery monitor have always kept above 50%

The batteries always kept up on 3-4 day trips but want some insurance and not worry about the fridge staying little extra colder or possibly extended the trips if possible. Seems we never have enough time tho

 

[john61ct]

Then maybe get that 2nd panel from the get go?

With 200+ Ah you really could go to 3-400W without increasing storage, especially for when conditions go suboptimal

 

[FosterWV]

Then maybe get that 2nd panel from the get go?

With 200+ Ah you really could go to 3-400W without increasing storage, especially for when conditions go suboptimal

We typically go for 3-4 days and the batteries have never went below 50% so 100W should be enough to maintain daytime usage. I know 100w won’t bring them back to full charge, once we get home I hook up a battery charger.

Ideally 200W + would be nice but I have no room for extra panels.