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tensch

Long Beach, CA

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Posted: 02/05/20 05:24pm Link  |  Quote  |  Print  |  Notify Moderator

I have a 100w Renogy solar panel that is used to keep the two 6 volt batteries (flooded) charged while dry camping. The controller that came with the trailer when I bought it was one of the cheap generic chinese models (blue) that sell on amazon for $15 or $20. The usb ports broke and I am looking to replace. My thought is that a PWM is fine for my needs. What amp size controller is recommended? And what are the optimum float, high voltage and low voltage disconnect settings, and load on setting for this setup? Thanks

BFL13

Victoria, BC

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Posted: 02/05/20 05:50pm Link  |  Quote  |  Print  |  Notify Moderator

tensch wrote:

I have a 100w Renogy solar panel that is used to keep the two 6 volt batteries (flooded) charged while dry camping. The controller that came with the trailer when I bought it was one of the cheap generic chinese models (blue) that sell on amazon for $15 or $20. The usb ports broke and I am looking to replace. My thought is that a PWM is fine for my needs. What amp size controller is recommended? And what are the optimum float, high voltage and low voltage disconnect settings, and load on setting for this setup? Thanks


First look up the charging voltage specs for those 6v batteries. Typically 14.8v absorption with 13.6 float at 77F, but higher with lower temps and lower with higher temps. If you get a temperature compensated controller, then just set for 77F and leave it.

100w at 6.2 amps Isc (which is what you see with PWM) is not much for keeping up a pair of 6s unless you hardly use any 12v and it is always sunny.

So in case you get more solar, go for more amps size of a controller with adjustable voltage settings ( even if you don't get more panel watts.)

The Grape 40 amper is often recommended here (Home Depot ISTR) for not much money.


1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
See Profile for House electronics set-up.

Lwiddis

Mojave, Kern County, California

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Posted: 02/05/20 06:26pm Link  |  Quote  |  Print  |  Notify Moderator

One hundred solar watts isn’t much. Standard is one solar watt per battery amp hour plus times 1.25 to 1.50 watts in the great Northwest.

“I bought it was one of the cheap generic chinese models (blue) that sell on amazon for $15 or $20”

Then you get a cheap generic charge. I’m all for saving money but I want my controller to work everyday correctly. BATTERIES cost a bundle. Penny wise, pound foolish.

* This post was edited 02/05/20 06:32pm by Lwiddis *


Winnebago 2101DS TT & 2020 Chevy Silverado 1500 LTZ Z71, 300 watts solar-parallel & MPPT, Trojan T-125s. TALL pole for flags. Prefer USFS, COE, BLM, NPS, TVA, USF&WS, state & county camps. Bicyclist! 14 year Army vet - 11B40 then 11A - (MOS 1542 & 1560)


Lwiddis

Mojave, Kern County, California

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Posted: 02/05/20 06:41pm Link  |  Quote  |  Print  |  Notify Moderator

100 solar watts is at best 5.50 amps per hour. Times, at best, five hours per day...27.5 amp hours to the batteries. Peanuts. Solar panels aren’t that expensive.

babock

Los Angeles, CA

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Posted: 02/05/20 08:38pm Link  |  Quote  |  Print  |  Notify Moderator

Lwiddis wrote:

100 solar watts is at best 5.50 amps per hour. Times, at best, five hours per day...27.5 amp hours to the batteries. Peanuts. Solar panels aren’t that expensive.
X2

Get another solarpanel and spring for an MPPT. They aren't much more money and totally worth it.

pianotuna

Regina, SK, Canada

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Posted: 02/05/20 10:35pm Link  |  Quote  |  Print  |  Notify Moderator

If you want a good charge controller that is pwm, it is hard to beat the Grape 40 amp unit. It is fully featured with a temperature sensor.

https://www.homedepot.com/p/Grape-Solar-........rge-Controller-GS-PWM-COMET-40/305498558

http://www.grapesolar.com/docs/GS-PWM-COMET-40%20large%20print%20manual.pdf

I have to agree that 100 watts is on the low side--depending on the time of year and the location.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp hours of AGM in two battery banks 12 volt batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

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