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oldjohnt

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    Indiana
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    RV Travel, Antique Tractor Shows, Bluegrass Festivals, Snowbirding

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  1. If it sanitizes and sterilizes as it claims there's a good chance it draws considerable MORE (Subject to how long it operates and at what power) energy (heating water or steam etc) then the CPAP. The 200 Watt is sounding better all the time lol I have no idea how much energy it consumes, throw that meter to it n let us know John T
  2. Birdman, I have to agree as any solar is good solar but more solar is better lol I often find myself camped under a total shade canopy and/or its rainy n cloudy for days in which case I don't harvest anywhere near what I would iffffffffff the sun was bright n shiny PLUS the panels were tilted and pointed to the sun throughout the day. Even if two of us calculated (based on your figures) the 100 watt panel will suffice I SAY GO FOR 200 and I bet you wont regret it VERY FUN CHAT YALLJohn T
  3. Birdman, now that you gave us ACTUAL ENERGY use we can size your battery bank NOTE that below is using the figures you provided above, earlier you indicated "the CPAP draws 0.81 amps at 120 VAC" which equated to 71 Amp Hours over eight hours THOSE TWO FIGURES ARE QUITE A BIT DIFFERENT ??? I cant say from here how often or how long the tank heat and humidity function draws energy, perhaps that could explain the big number difference from your two posts ???? 1) 0.18 KWH/1000 = 180 Watt Hours 2) Using 12 battery volts, 180/12 = 15 Amp Hours of energy drawn from your battery bank (Battery full charge is 12.6 but as it discharges voltage drops) 3) Using two CPAP's and assume they draw near the same energy that's 30 Amp Hours but the Inverter is NOT 100% efficient so if it were say 85% efficient that 30 Amp Hours equals 34.5, at 90% efficient it equals 33 Amp Hours drawn out of your battery bank 4) Since if using AGM or Flooded Lead Acid you don't want to draw down over 50%, you need to start the CPAP's with at least 70 rated Amp Hours of energy storage and to be on the safe side Id prefer at least 100 when the CPAP's start 5) You spoke above using a pair of deep cycle 6 volt batteries. If so and if they were similar to Trojan T-105 that series combination would give you 225 Amp Hours (112.5 USEABLE) at 12 volts so ifffffffffff you actually used 34.5 Amp hours total per night, you can get around three nights of use. Of course lesser Amp Hour batteries would give you less 6) INVERTER The brick converters you posted were rated at 90 watts but lets use say 200 Watts total for two CPAP's so to be safe and allow for expansion Id suggest say a 400 Watt or larger AND I HIGHLY RECCOMEND A PURE SINE WAVE INVERTER. Some equipment has problems with MSW (cheaper to buy) but most ALL equipment does fine on PSW 7) SOLAR You mentioned a 100 Watt Panel. Ifffffff it is exposed to good bright sunlight at a direct angle (ideal best condition but NOT typical) using say 13.6 charging volts, that would equal around 7 battery charging amps and over lets use 4 hours that's 28 Amp Hours of energy (42 Amp Hours over 6 good sun hours) which is close to that 30 Amp Hours you use up each night NOTE this is ONLY an approximation NOT exact or typically practical. Unless the sun was bright direct angle to the panels I more often saw 5+ never 7 the theoretical and on many days I didn't see 6 good hours of sun...…….. Hope this helps, you have asked good questions and we have tried to help the best we can based on the info?? you provided. NOTE It appears mpt and I agree (a good thing right) HOWEVER we have based our analysis on the figures you gave us so we are only correct if your figures are. They seem on the low side to me but if they arent correct let us know ……….. John T Longgggggggggg retired n rusty Electrical Engineer and NOT any Solar expert so nooooooooo warranty lol Post back any follow up questions and we will be glad to help
  4. With big enough cables and heavy duty high current rated quality connectors (IE low resistance and voltage drop), you get MUCH MORE charging amps, that a WELL DUH LOL If you want to use an energy source such as an alternator or battery charger to pump energy into a battery, its best to dissipate that energy into the desired load NOT waste it as I Squared R heat losses in the wiring. That's all basic conservation of energy. Then if you want to balance the charging into multiple batteries its best if they are the same type and design and if connected according to http://www.smartgauge.co.uk/batt_con.html. Take care yall John T Dry camped in the Ocala Natl Forest but under full shade and cloudy days I'm not harvesting an abundance of solar energy...
  5. Birdman, the Kill A Watt meters I've seen DO HAVE A FUNCTION THAT RECORDS "ENERGY" IN KILOWATT HOURS (I cant say if yours does or not) and that's the best figure to show HOW MUCH ENERGY THEY CONSUME OVERNIGHT. Once you tell us the "energy" (that's X watts for X time, IE Watt Hours) they use overnight we can size how many amp hours of stored battery energy you need to power the CPAPs while sleeping. To your specific question " I can take the .81 times 8 hours and get 6.48. Does not sound right, how do I figure out how much I use nightly?" If the CPAP draws 0.81 amps at 120 VAC and if it ran say 8 hours, that's "APPROXIMATELY" .81 X 11 = 8.91 12 VDC battery amps for 8 hours OR 71 Amp Hours and if you have two running that's approximately 142 Battery Amp Hours used up overnight If you required 142 Battery Amp Hours and don't what to draw the batteries down over 50% you would need to start off when you go to bed with at least 284 or lets say 300 Amp Hours for good measure. Since you will use energy from say 5 PM to bed time when the solar isn't producing it keeps looking like 400 Amp Hours of stored battery energy is where you may end up BUT ONLY THE EXACT FIGURES WILL DETERMINE THE ANSWER. As I told you often my running ONE CPAP and a small 120 VAC fridge overnight works with 450 battery amp hours and you may come in at less, but at this point and based on what you have said I dont envision you getting by with too much less then 300 Amp Hours to allow for safety and other night loads (water pump or vent fans or especially a furnace!!!!) Remember, Amps is current flow, Amp Hours is a measure of ENERGY. Typical Deep Cycle Batteries are rated at Volts and Amp Hours since we need to know how much "energy" they can store ………… Your meter may well have a function to tell you how many Watt Hours or Kilowatt hours the appliance draws over time...……. Fun chat glad to help, let us know John T
  6. Pretty much LOL A teeny wire ran back maybe 20 or 30 or more feet is a darn poor "booster cable" yet it can keep a toad battery trickle charged while towing to "some" limited extent...…….. When dry camped I don't allow my RV engine battery nor any toad battery in the house battery circuit...…….. John T
  7. AMEN Kirk no argument from me...…...I see more and more AGM use nowadays (and even some factory installed Lithium, RVX) to reduce worry and hassle of adding electrolyte PLUS the latest series of "drop in" Lithium battery technology with built in protection and in reduced frame sizes such as Battle Born and others is making it simple n easier to go the Lithium route, but darn they are expensive up front even if over the long run considering cost per life cycle they are great. They still have some cold temperature issues. Hey as one gets older they don't even buy green bananas let alone invest in batteries that may perform 10 plus years to recoup their huge initial investment lol IE at my age AGM was my choice... FWIW We are also on the same page regarding your statement "In practical application, if the batteries are all flooded cell most of us would opt to charge them all together" I SURE DO When I had four flooded lead acid I charged them all together and now when I have three AGM I again charge them all together. Might I dare to say GREAT MINDS THINK ALIKE No correction from me on that for darn sure...…….. FWIW Ive primarily been talking above about letting the RV engine alternator charge the house batteries when driving down the road, although sure one can also configure the house charger/converter when plugged to shore power to also charge the engine battery if desired. Although its not rocket science the easy and simplest way to achieve better charge balance when batteries are separated is the use of bigger cables, but that could prove expensive and cumbersome As always great chatting with you Kirk John T
  8. YES you can configure what's called a "series parallel" HOWEVER the two 100 AH sixes in series still equals 100 AH at 12 Volts, and if you parallel that combination with another two sixes in series you end up with 200 total AH NOT 400...……... In the past I used four Trojan T-105 (225 AH) in series parallel to achieve 450 AH at 12 volts not a problem. Now I converted to multiple 12 Volt 200 AH AGM's Frame size 4D 129 lbs in parallel to get more AH. Its what Amp Hours you need and the room to place them that matters, there's all sort of combinations out there YES you can connect batteries located in your truck to your RV that's no problem HOWEVER use big cables to reduce voltage drop PLUS you need good quality high current rated connectors. If the cable is too small and/or the length to great of course there's more V = I x R Voltage Drop but such a system is certainly manageable and doable .. Its a GOOD idea, I would size the solar array such that its possible to achieve 100% SOC by mid morning to noon where possible and reasonable subject to sunlight and angle of sun to the panels and room.... Great questions Birdman, you're getting there yayyyyyyyyyyyyyyy John T Live in the RV from Alexander Springs dry camping in the Ocala Natl Forest Florida
  9. Good morning sundancer, Even if the house and engine batteries are lead acid they will NOT "charge the same". That's simply because in the wiring back to the house battery there is resistance and voltage drop and its NOT the same as the factory wiring from the alternator and its voltage regulation scheme and where voltage is monitored to the engine battery. YES the house battery will still receive "some" charge and that depends on the wire size and distance and relay but the two batteries although still "charging" will NOT "charge the same" Of course, the fact that BOTH are lead acid is MUCH better then if they were mixed which could make proper charging and balanced charging even worse lol YES indeed I sure agree both being lead acid means they have the same preferred charge algorithm and charge profile and will "charge the same" PROVIDED all else is equal ….. Good plan, the charger or solar charge controller should indeed be set to match the battery!!! YES when plugged to shore power a quality "smart charger" maintaining the batteries is great and the same method I use at times Fun chatting with you Sundancer, best wishes n God Bless John T
  10. That's so because OFTEN (not always depends on batteries) a big heavy duty full deep cycle 6 volt such as a Trojan T-105 which has 225 Amp Hours still (with two in series for 12 volts) yields MORE amp hours then a cheaper dual purpose 12 Volt RV/Marine Battery like sold at Walmart which may be less then 100 Amp Hours at 12 volts. But they do make a single 12 volt which has around 200 AH BUT THATS A HUGE FRAME LIKE 4D and 129 pounds. They also make a smaller frame (like Group 31 or similar in size, 60 to 70 pounds) 12 Volt deep cycle but those are around 100 up to maybe around 135 Amp Hours. I suspect people who made statements like you referred to knew 6 volt batteries like Trojans etc are true Deep Cycle while the twelves they were talking about weren't IE they professed its better to use two sixes if they were comparing deep cycles to non deep cycles as that series sixes combination may ??? yield more energy storage. For dry camping to maximize the amp hours of energy storage USE WHATEVER COMBINATION that you can fit into your available space. That may be two sixes in series orrrrrrrrrrrr it may be two twelves in parallel HAVE TO COMPARE APPLES TO APPLES Im running three 12 Volt AGMs in parallel now for 520 Amp Hours but that's a lot of space n weight ya know. But remember I run a CPAP all night plus a 120 VAC compressor fridge 24/7 and like enough capacity so I don't draw down near 50% overnight. Sure Lithium are much lighter and can be drawn down deeper if that's what you prefer John T
  11. Great question, it gets a bit complicated but I will try my best to provide some degree of insight and will post a link where you can get a more detailed answer about charging multiple batteries in parallel which is basically what you're asking about. 1) If say you're driving down the road and you have EITHER a mechanical isolation relay that parallels your house and engine batteries together OR a solid state battery isolator THE ENGINES ALTERNATOR WILL LIKELY PROVIDE "SOME" CHARGING CURRENT to your house battery bank but its NOT near the quality nor quantity nor completeness a proper smart charger set to match your battery type (lead acid or AGM or Lithium) can provide. HOWEVER that all depends on the wire gauge and distance back to the house batteries and any other resistances plus the voltage regulation circuitry of your engines alternator and the type or relay used. If you used light gauge wire several feet back to the house bank and expect the engines alternator to charge it very well, you could be disappointed... 2) A problem if you try to charge different batteries in parallel even with a so called smart charger IS DIFFERENT BATTERY TYPES CHARGE BEST AT PARTICULAR CHARGING ALGORITHMS (Voltage, Current, Time etc) . A lead acid prefers one rate while AGM or Lithium is different. Again you can still get 'some" degree of charge but its nowhere near or perfect to what similar batteries would receive connected to one common charger AND FURTHER MORE if the proper series/parallel wiring arrangement isn't used still one battery may not charge as much or as well as the other See: http://www.smartgauge.co.uk/batt_con.html 3) YES two different groups should be charged separate with a charger to match their type FOR BEST RESULTS but as I explained you can still get some degree of charge (albeit not near as good or full or proper) into both if not. For example I let my smart 4 stage charger (set for AGM not Lead acid) OR my MPPT Solar Charge Controller (set for AGM) charge my AGM house bank and engine alternator charge my starting battery BUT I do have a 100% duty cycle mechanical relay so the engines alternator can provide some current to my house bank IFFFFFFFF I turn it on when driving like if its night or cloudy etc where solar isn't contributing. Hope this helps, theres lots more but consider this a NON exact NON perfect start and if you ask I will add more John T
  12. Neighbor Ray, that's correct, if you put two 6 volt batteries in series do get a 12 volt bank AMPS ARE NOT ADDITIVE yayyyy lol John T
  13. Of course if multiple batteries are connected together its best for charge and load balance if allllllllllll are same type and design and even brand and age, HOWEVER it remains true as I posted "Batteries in series add voltage" While correcting a post believing two batteries in SERIES yielded double the Amp Hours, I responded "Batteries in PARALLEL maintain the same voltage, while the amp-hours add" THAT RESPONSE CONCERNED A QUESTION REGARDING TWO I ASSUMED IDENTICAL BATTERIES. IE voltage of the two in parallel stays the same but AH does double. Its true batteries in series add voltage and that's true REGARDLESS if they are the same voltage or not !! A 6 in series with a 12 yields 18 volts,,,,,,,,,a 6 in series with a 6 yields 12 volts Fun chat yall, hope this helps Right on Lou, its mostly about lead and acid and plates (basically weight) and surface area etc and you can put more lead n acid n plates in a bigger case. John T
  14. If "things on the battery" don't work there's EITHER a) A dead battery OR b) Circuit breaker of fuse(s) that are tripped or blown or an open wire between the battery and 12 VDC distribution system input HOWEVER when plugged to shore power ifffff you have a working??? Converter/Charger that's ON with 120 VAC present on its input (IE no tripped 120 VAC input breaker) and ALSO ifff there no tripped breakers of fuses or an open wire/circuit between its DC output and the batteries,,,,,,, "things on the battery" 12 should work unless there's a serious battery problem Years ago (past used RV dealer and 49 year RV owner) I saw RV's with changeover systems between the battery and Converter so you could select Converter OR Battery to feed 12 VDC loads but I haven't seen that in a long time If NOOOOOOOOOOOOO 12 VDC loads are working even with a good working and connected (no breakers or blown fuses) Converter/Charger, Id be looking for an open wire or bad loose connection or tripped breaker or blown fuse between the battery + output post up to the DC distribution fuse panel. On many RV's theres a fairly large wire from the Battery + up to the DC distribution panel (also needs a good connected -) and there should be a breaker or fuse in the circuit/wires FROM battery up to 12 VDC distribution/fuse panel. You need to see if the battery is charged and reads like12+ Volts ???? If the Converter/Charger is working when plugged to shore power battery voltage could rise from say 13 to 14+ volts does it ?????????? IFFFFFFFFFFF the battery is charged and if the Converter/Charger is working but still no 12 volt loads operate I suspect a bad or broke or open wire or a tripped breaker of blown fuse FROM the battery up TO the 12 VDC distribution/fuse panel. No 12 VDC there means no working 12 VDC loads. You say NO 12 VDC loads (lights or vent fans or water pump etc) work right?? and Even on shore power with a working powered up Converter/Charger still no 12 VDC loads work right ?? CHECK BATTERY AND WIRES AND/OR FUSES/BREAKERS from battery to 12 VDC distribution/fuse panel and also insure there's 120 VAC to the Converter/Charger input (no tripped 120 VAC breaker feeding it) and its output is connected to the battery )no open circuit or fuses or tripped breaker) John T
  15. Good plan Birdman, run the audit and we can see exactly how much battery storage capacity you need to run both CPAP's overnight without discharging more then 50% SOC. If you're lucky, you may get by with 200 battery Amp Hours and those are available all over the place (Renogy, FullRiver, Lifeline, Trojan, etc etc) in a huge Frame size 4D 129 pound unit,,,,,,,,,,,,,,BUT you may need more ??? ONLY will your energy audit tell. FWIW I needed more then only a single 200 Amp Hour (one CPAP and small dorm size 120 VAC compressor fridge) but a CPAP consumes less then my fridge...………. John T
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