I have 600w solar panels, 3x120amp AGM batteries, a 40amp DC to DC Controller (Redarc), a 25amp Projector Battery Charger, a battery monitor inside the van, and the van has heavy duty wiring.
I run a 215 Waco Compressor Fridge, a 60 Engel Freezer, a Sleep Apnea Machine, plus I charge a laptop, phone, tablet, camera, kindle reader and an Ipad. Lights are all LED.
The van is 3 years old and usually we are camped up north with long sunny days every day. We camp in nature based places and rarely go to Caravan Parks. We are up North of WA for about 5 months every year and when we are home everything is turned off and the batteries are on trickle feed from a small solar panel.
The Problem
At sunset the battery monitor shows 13.7volts. By about 2pm the battery protector cuts the power out. I have had to run the generator for a few hours in early evening this trip to keep everything going. If I turn the freezer off for the night it copes better.
The Question
Have I enough in my set up to cope with the above. I have been told to re-condition my batteries? I have been told that some controllers (Redarc V other brands) are better and put in more - 20amps verses 25 amps. Any ideas as to what I need to change would be appreciated.
I do not know the details of the power requirements of the items you mention, but making some assumptions it looks as if you would have enough of both solar and battery. The adequacy of the solar is backed up by the fact that you are sitting on 13.7V as the sun goes down.
With your three batteries, you should have about 180 usable amp hours to keep you going through the night. Your three main power consumers would be your fridge (estimate 4ah per hour), your freezer (estimate 2ah per hour, assumes well insulated, and left shut), and your CPAP (say 2.5ah per hour, based on devibes add, and assumption of no heater or humidifier), the other items are relatively small.
Starting at say 6pm I would expect a drain rate of say 9ah (fridge, freezer, chargers etc) up until say 9pm, then move to fridge, freezer, and CPAP, still assume 9ah. Thus by 2am you should have used about 72ah, and still have plenty left to see you through the rest of the night.
Do you know what voltage is left in the battery when the battery protector cuts in ? Is it possible the battery protector is set to too high a voltage (I do not use one, so not sure if they are adjustable).
Are you able to monitor how much current is being drained from the battery, then connect and disconnect each of the major items to see if any of them are drawing exceptional current?
The next thing I would be doing is trying to get your batteries, cycled and tested.
I am not holding myself up as an expert, just trying to suggest things you can investigate.
Thanks for your comments. The battery protection unit (Solar Force) that Retreat put in has not got any settings that I can see to alter the cut out voltage. It cuts out at 10.20v, but the batteries still show 80%. I have been testing it at home without using the sleep apnea machine, and it still cuts out at the same voltage etc. When we are camping, and the battery protector cuts the power, we can turn off the compressor fridge (Waeco 215ltr) and we can turn the lights on again.
Sorry, I have also had the battery charger on reconditioning, which was recommended now, and that made no difference. I am yet to have the batteries tested. Maybe we need a bigger charger, 25amps may not be enough to charge a low battery.
Thanks for your comments. The battery protection unit (Solar Force) that Retreat put in has not got any settings that I can see to alter the cut out voltage. It cuts out at 10.20v, but the batteries still show 80%. I have been testing it at home without using the sleep apnea machine, and it still cuts out at the same voltage etc. When we are camping, and the battery protector cuts the power, we can turn off the compressor fridge (Waeco 215ltr) and we can turn the lights on again.
Harry, if it's this particular one, it does have an adjustable cut out voltage, but it's still too low at a maximimum of 11.0 VDC. 12.0 to 12.2 VDC would be a better level.
the battery protector is situated just above the batteries.
The 60 ltre Engel runs on Freeze all the time and the compressor Fridge, (Waeco 215 ltr fridge with a 40 litre Freezer) runs on level 3.
I do use the heater on the sleep apnea machine.
I have been reading about Lithium batteries, which are supposed to last one third longer than the AGM batteries, are less weight, and a 200 amp lithium battery is supposed to be equivalent to my 3 batteries. Might need specialized chargers for them I guess.
The battery protection unit is similar, but not the same - does not have the cut out voltage bit. I think that the voltage drop should be much higher than what it is, given that I get up to 13.33 during the day.
Charging voltage is NO Guide to actual Amphr capacity
Batteries will constantly loose some of that capacity with use
A100Ahr battery can appear to be fully charged by voltage, but all that really means is that the actual remaining Ah capacity has fully charged, even though that actual capacity may only be very low [like 20Ahrs]
The FIRST thing you should do is have the batteries CAPACITY tested
If the voltage drops quickly down to around 10V it is very likely they are stuffed Lost capacity, probably due to being regularly OVER discharged
When you get NEW batteries make certain you have a GOOD LOW voltage cut out[adjustable to 12V] fitted as close as possible to the batteries The LA Batteries should not be taken below 12V IF you want them to last!!
-- Edited by oldtrack123 on Monday 5th of October 2015 03:45:48 PM
