off grid cabin/ home

Re: off grid cabin/ home

Voltage wise, it sounds more like a 20% discharge (~0.2 volt drop). But estimating battery capacity purely by voltage is difficult (i.e., was that resting or loaded voltage on the battery, or started at resting and the -0.2 was when you were drawing a load, etc.).

By the way--What "heat was running"?

Yes, both your charging voltage and current seem low when using the generator.

So--Back to basics. What is the present battery (voltage/AH/more than one/series-parallel or what)?

And what is the AC charger you are using (or inverter/charger)?

Some voltages:

~12.7 volts at 75F / 25C resting voltage ~100% state of charge
~13.6 to 13.8 volts for "float charging" (if you don't have grid voltage, you are not going to "float" with an AC charger on a genset--waste of fuel)
~14.5 to 14.8 volts for fairly aggressive charging of a flooded cell lead acid battery
~12.0 volts with light loading--Battery is getting pretty near 50% state of charge
~11.5 volts with very heavy loading--Battery is pretty much near 50% state of charge
~12.2 volts or so with 3+ hour of no charging/discharging is ~50% state of charge

Do you have a Hydrometer (if flooded cell batteries) and an AC/DC Current Clamp DMM of some sort?

If you are planning on a "well instrumented" DC off grid power system--You should probably look at some sort of Battery Monitor like the Trimetric or Victron or some other brand/model. It will help you answer a lot of questions about how much power you use and how well everything is charging.

Battery Monitors are not perfect--But they sure can help answer the basic questions and are easier to understand if you have guests/spouse/kids taking care of the cabin while you are not there.

-Bill

Re: off grid cabin/ home

wellbuilt wrote: »

The battery was a Interstate G 27 pro sealed lead acid wet cell.

Even these "sealed" batteries can usually have the caps popped off and be checked with a hydrometer for specific gravity.

Generally, these types of batteries are not true deep cycle batteries but really "Marine" type--Sort of between a starting battery and a deep cycle.

The battery is new and kept on a trickle charger and used a few times a week in a dump trailer .

1 amp trickle charger? Generally, these are not very good at recharging a cycled battery and not even very good at floating one either (I have had more trickle chargers boil a battery dry than be killed by a "regular" car charger).

The battery was resting 12.5( Off charger for 6+ hrs ) After I ran my loads over night they where turned off for 6 hours+.
When we tested the battery at rest it was 12.3( No load)

Sounds like the battery is not fully charged (~12.7 to 12.8 volts) or is becoming sulfated (not uncommon failure)--Possible from poor charging practices. Roughly, a 0.2 volt drop is around a 20% of battery capacity used... You may have started at ~75% State of charge and gone down to 55% SOC (these numbers--not much better than pure guessing--Measuring battery voltage as State of Charge is not very accurate--However, it does sound like the battery was undercharging).

The converter is a Triad Ultiad TV 331w ) 30 amp max 14.1 max voltage Its from 1974 .

That is an OK voltage for a converter that has lots of time on the AC mains... If you are going to be spending a lot of time dry camping, you probably want to charge the battery bank more towards 14.5 to 14.8 volts (for a fast charge, and a limited amount of time--Depending on current and how discharged the battery bank is).

The trailer has a 12v hot air heat propane fired unit about 8 years old .

Many of these heaters draw significant amounts of power (around 8 amps or close to 100 Watts). On cold nights, sometimes can run upwards 50% of the night.

I was testing 1 Interstate pro G27 12v flood battery The amp hrs are not stated .

A good sign that the battery is not really a deep cycle... Probably around 90 AH or so.

The battery compartment is very small The g27 sticks out with the door open .
Could I keep the new batteries out side in a battery box ?

RV--You are stuck with what the mfg. has left for room. Many people will mount batteries externally because of lack of space in the RV box.

Weight/Balance is important when mounting more/new battery location. Also, you want to keep battery cables relatively short (to AC inverter, to various battery chargers).

And temperature--Ideally, the batteries should be around 75F/25C... For every 10C/18F increase, battery life is cut by 1/2. And batteries below 50F will have less apparent AH capacity (when cold).

Charged batteries are very hard to freeze (below -70F or so). However batteries near dead will freeze closer to 32F. AGM batteries are relatively damage resistant if "frozen" (AGM batteries should not crack the case--But they will will not charge/discharge if frozen).

I have 5 hot leads should I junk the old converter and run a new panel to the battery with solar panels for charging did not want to start a new project .
Could I just add a 30 amp car charger and run it with the weak converter .

Go back to your loads--How many AH/WH per day? Solar or no solar? How much storage (over night, two days, maximum 50% discharge?).

Im trying to stay with the smaller 1800watt generator because I can carry it, or just leave it in the generator house , If it gets robed I can buy a new one .

Not happy when anyone gets their stuff stolen. It sort of comes down to cost/benefit analysis. If you have a "cheap" generator stolen every three years? Do you get a nice (expensive) Honda eu1000i or 2000i ($800-$1,000 or so) which is smaller/easier to take home (and quieter).

Could I try a 45 amp iota charger on my small 1800watt generator and see if it will start ?

It should work OK on a reliable genset.

I could all ways get a larger generator , I will have one up buy the house any way .

You probably will end up with two (or more) generators. One small one for minimal loads (and charging a relatively small battery bank). A larger one (perhaps "cheaper/noisier" to run shop tools, well pump, etc.

Im buying 2 GC 215 to day for next week end and will charge them with my generator or bring them home until I get set up .
I don't want to sit in the dark . Thanks guys .

You can use between a 25 and 45 amp battery charger on your 2x 6 volt @ 215 AH batteries.

A 10% rate of charge means a smaller generator running for 5-7 hours to most recharge the battery bank. A 20% rate of charge means a couple hours less.

Are you going to have any solar at all? In general, run the generator to recharge from 50% to ~85% or so State of charge (high current until around 80-90% state of charge, and use solar to finish the charging (5%-10%-13% rate of charge).

-Bill

Re: off grid cabin/ home

Please ask if any of the tech talk is confusing for you... It is difficult for us to know when a reader gets lost in the explanations because there is no body language/feedback--Unlike face to face conversations.

-Bill

Re: off grid cabin/ home

Assuming these are Vmp~30 volt 250 Watt panels on a 24 volt battery bank, you would have to put two panels in series for Vmp-array~60 volts and then the two strings in parallel. Vmp~30 volts for an array is too low of voltage for charging a 24 volt battery bank.

A good quality MPPT charge controller can run with an "over-sized" array--It just "clips" the output current to rated value, safely and reliably. My standard recommendation for an over paneled "cost effective" usage of MPPT controllers is:

30 amps controller * 1/0.77 panel+controller derating * 29 volts charging = 1,130 Watt array

So--Your configuration would pretty much max out the "cost effective" output of a 30 amp Kid controller.

Of course, if you ever plan on adding to the array, you would need another controller, or replace it with a larger controller.

-Bill