66788 said:
I honestly don't know how you can get by without a house battery. You must be an occasional van user and not a full timer, as my solar system/electrical system for the house is the very heart of my home.
I run CPAP, 2 fans, ARB 50qt fridge, lights and charge my electronics all from the house battery. One GP31 AGM and 205 watts of solar does all this quite well, and is charged in less than 3 hours the next day.
I don't mind living small, but I don't want to give up certain aspects of modern living, and I don't have to with a good house battery setup.
I get by because I can plug into the grid nearly anytime I want. I'm fairly stationary with a private level legal parking spot and a sleep in my van every single night. When I am travelling I use a fraction of the battery power overnight compared to what I use when I am at my spot, unless the Van is party central, which does not happen often enough.
I cycle this battery deeply 4 or 5 nights a week minimum, so I can see what it can handle, and since I can high amp recharge it and fully recharge it after each deep cycle, I do not fear overdischarge or not being able to start my engine, and if I were to deplete it to the point where it could not start my engine, a few hours of sunlight would rectify that situation, or perhaps even a few minutes of my 40 amp charger, and my thickly wired alternator can put 100 amps into this AGM battery if the rpms are there.
I used to carry 345Ah of battery capacity for the warm and fuzzies and bragging factor. Realizing i can get by with just 90AH, at least in summer time, with a high quality AGM charged properly, has been enlightening.
I will be getting a Trojan T-1275 before winter sets in, and my AGM will be returned to primarily engine starting and emergency capacity duties, but I know that I can manage to get by on a single 90AH AGM battery. I would not try the same with a 100Ah wet/flooded battery They can't produce enough CCA when only 25% charged to easily start the engine, like this AGM can.
Having a battery monitor which shows me nearly exactly how much I have removed from my battery, and how much various charging sources have returned, and having monitored this battery monitor through out many different battery lifespans, since 2007 gives me that confidence.
When one has little idea of how much they remove from their battery, or how much their charging sources return, then it is much wiser to carry more capacity. Also While some seek to get the maximum timespan out of their batteries, I seek to get the maximum number of deep cycles. So I cycle deeper than most, as I view each battery lifespan as a test of the battery itself, and there is no point in testing a battery if it is not worked hard, so i work it hard to help me better understand what a battery can do, especially when properly recharged, promptly and fully.
I do not even need to discharge this battery, I can plug in and let my Meanwell adjustable voltage power supply hold my battery at 13.6v and power all my DC loads all night every night as long as I am not out travelling. I cycle this battery to better learn what a lead acid battery can handle when charged properly.
I'm not recommending others follow this method, just mentioning what is possible when a quality AGM battery is properly and promptly recharged, even if it is discharged well below the recommended 50% level.
So far, so Good. It is hard to notice any performance/capacity loss in the 23 months and approximately 200 deep cycles it has been subjected to.
Big T has the same brand AGM as me, but only 75Ah capacity instead of my 90. His can suck huge amounts of charging current from the alternator being located in the engine compartment, and he has a higher solar to capacity ratio than myself. While he does not know exactly how much he is consuming from his battery, he can take ~ 50AH from it each night, as long as it is returned to 100% charged the following day, and he can likely do this for 500 deep cycles. With 200 watts of solar, if he awakes to a battery so depleted it cannot start his engine, a few hours of sunlight will allow him to start and drive and high amp recharge the battery and the solar can finish the task, if the sunlight is available.
A house battery system is great, it is practically mandatory in this lifestyle, but one can also live life a little closer to the edge. A high quality AGM such as a Northstar or Odyssey recharged properly can allow one to get away without a house battery. It is all in the recharging, and not going below ~11 volts and having high amp recharging available in addition to low and slow solar. A capable grid powered charger is also mandatory if one does not drive daily, but of course having access to grid power is another matter.
66788, if your 205 watts of solar is fully charging your 31AGM battery in 3 hours of sunlight, you certainly have a huge buffer and are not really even drawing the battery below 80%. Nothing wrong with that. Shallower cycles = longer battery life. I'm choosing to cycle deeper with little to no buffer, as an experiment.
But, when I do get the Flooded Trojan T-1275 installed , my abusive AGM experiment is basically over. I'm just glad the NS AGM battery and my electrical system has been able to allow me to easily get away with no dedicated house battery for the last 3/4 months, as my finances have not been healthy enough to get that T-1275 yet. When my previous flooded battery lived out its cycle life, if I did not have this AGM battery, that has both very high CCA ratings and ability to be deeply cycled, I would have been in a much worse position.
I would not trust a flooded marine battery to handle what this AGM has shrugged off. No way could a flooded marine battery handle cycling to 20 or 30% or 40% state of charge and still start my engine, no way could it accept 100 amps from my alternator, and no way could its capacity seem to have not degraded in 4 months of cycling to 30 to 40% 4 to 5 nights a week. I do not carry a jumper pack, or even jumper cables.
BigT might not want to live this close to the edge, I am relating to him, that his battery, can.
It is all about the recharge, and his alternator can meet the high amp requirement, his 200 watts of solar can meet the recharge to 100% requirement if the sunlight is available. It is all about how much he consumes from the battery, and the 50% rule can be broken more safely with a high quality, high CCA AGM. Drive for long enough and have enough sunlight and taking it down to 20% charged night after night, and the battery should be able to deliver, where as most other batteries would give up much quicker.
Of course the cycle life will be shortened with deep discharges, but if it comes down to $ spent for the amount of cycles, he will likely come out ahead compared to having a huge house bank properly wired with enough solar to properly feed it.
The warm and fuzzies of having a large buffer, can cost a lot of money.
I've whittled my buffer to the near minimum, without issue. It makes me reluctant to get the trojan t-1275 house battery and have that buffer back, but I miss dipping my hydrometer too.
I had to clean the tubing and all at least twice a week or I started sneezing and my nose would run. I said to h*ll with the humidifier and have not used it since. Is my throat and mouth dry the next day? Sure. I just drink a glass of water when I get up and get the coffee started. Did it take me a little while to get used to sleeping with the dry mouth and throat? I think a few weeks was all it took. That was a looong time ago. I only need to clean my pillows and mask tubing every two weeks or more. To clean the pillows/tubing (only the short piece connected to the mask part, not the long hose) I get hot water and antibacterial soap in a pan, just enough to cover the tubing and use my little finger in the pillows and swish the water in the hose. Re-assemble everything and run water through the hose and pillows to rinse. Hang by the pillow end after shaking excess water out to dry over a towel bar. Ready to use that night. I bought the 12v adapter for the machine itself and it seems to use very little power but I have 375 amps worth. Can go a whole week running everything (TV, laptops, lights and cpap) and not use even 40% of it.
