FHU - Solar - Battery Charging

There was a question if shore power was expensive. It is extremely expensive when boondocking

pianotuna wrote:
Any time I have shore power I'm going to use it. Even if you pay for the power it is better for the battery bank to remain fully charged.

How about this? Use your shore power at night and your panels during the day when they'll cover the loads and batteries won't discharge? You'll save a little power and not cycle the batteries.

CT_WANDERER wrote:

westend wrote:
You shouldn't lose any appreciable water (more than usual, you will lose some) in the batteries if the controller is set up correctly. What controller are you using?

I am using Morningstar TS45 PWM controller. Running it on their program #4 (Aborp 14.4V, Float 13.4V, Equal 15.1V) So far, from what I can tell, it seems to be working out Ok for me. Gary

Yeah, that's a good controller and your settings should be OK for Texas. If anything, with 6V batteries you can raise the absorption V in the Winter.

You'll probably have time this Winter to observe what the batteries are doing and adjust your controller voltages to a point where you get full charge by afternoon. I know some guys on here that have their controllers set to almost total absorption. Since we'll have 15-16 hrs of night, the batteries just drift down with nighttime use.

Any time I have shore power I'm going to use it. Even if you pay for the power it is better for the battery bank to remain fully charged.

westend wrote:
You shouldn't lose any appreciable water (more than usual, you will lose some) in the batteries if the controller is set up correctly. What controller are you using?

I am using Morningstar TS45 PWM controller. Running it on their program #4 (Aborp 14.4V, Float 13.4V, Equal 15.1V) So far, from what I can tell, it seems to be working out Ok for me. Gary

smkettner wrote:
Are you doing this full time? For the winter? One week?

I would probably do a week on then a week off for solar/converter balance.
Almost need a grid tie inverter :B

I am in Mission,Tx for the winter. I am very happy with what I am seeing on the solar controller monitor system. At home in the NE there is a lot of trees and I have never got these high output from the solar panels. I only finished installing them this late this summer before leaving for the winter. Still waiting to see just what will be the max output of the system. Thanks Gary

Is shore power all that expensive? FHU Park?
Agree with Tom M, I keep # cycles to a min to save the batts.

When on shore power I disconnect my batteries from the rest of the trailer and let the solar controller maintain them. Every morning the controller does an almost instantaneous bulk (mppt) and absorb phase (14.8V) and then sits at the float voltage (13.1V) for the rest of the day. Unless I equalize (15.9V) a lot, or boondock more than I am now, I just need to add water once a year.

Makes no sense to have your converter on, especially if it costs you, unless its dark and your batts are not as full as you want them, morning or evening. All your controller settings for bulk, abs, float should be set higher than the usual converter settings. Therefore, the converter will be shutout and will not be able to get a charge in edgewise anyway. Experiment a little bit and see what fits your current situation and remember to change it back (or less) when circumstances change like in storage. Go 3-4 days at 14.8v bulk with 2-3 hours of abs at the same then drop to 13.6v or 13.8v for float. Last day, do a hydro dip in the late afternoon and check for excessive bubbles. If that is too “hot” drop to 14.6v and repeat.

In the long run water is cheap. Just be aware of it.

I also have grid power and choose to cycle my battery often, as I want to see how it performs being cycled heavily, as it interests me.

I could easily plug in and never cycle the battery and claim a 12 year life for it, But I take pride in not having to use the grid too.

The water usage depends on the amount of time held at absorption voltage. Note most charge controllers do not hold this long enough with their stock settings. Also many do not hold it high enough.

Once again the Hydrometer is required to know if your batteries are indeed full when the solar controller drops to float voltage. Do not just believe the amp hour counter or any blinking green light, or claims from the 'just fine' head in the sand brigade.

It has been shown time and again that float voltage is almost always prematurely allowed by most controllers and that more time at absorption voltage is required for a true restorative 100% recharge.

The time at absorption voltage is a moving target dependent on depth of discharge, the charge rate upto absorption voltage, and temperature. It will also change as the battery ages, and water use will also increase as the battery ages.

If you really want to get the most from your battery bank, you need to determine what Absorption voltage and what duration to hold it until specific gravity rises to within 0.005 of maximum. Whatever water loss occurs from this is a secondary consideration as it is more important to fully charge the battery than worry about 0.01 cents of distilled water escaping to the atmosphere every day.

Some claim the Hydro caps or Water miser caps do work as advertised and reduce water usage. If I bother ever getting a trojan T-1275 I will consider getting them, but right now I am questioning my need for a house battery at all. My Dual purpose TPPL AGM easily starts my engine depleted to 30% state of charge and can accept huge currents and appears quite happy as long as it gets fully charged each day and gets a 40%+ charging rate often.

That said it is cloudy today, afternoon, and I am 45AH from full. Time to plug in, or drive.

Leave the converter operational. My PD plays well with the blue sky controller.