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Post by molly2 on Dec 2, 2016 0:53:58 GMT
How do you keep your batterys topped up this time of year when solar power is at a minimum and battery output is at a maximum ? .
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Post by stonedaddy on Dec 3, 2016 11:14:38 GMT
Take em down the pub and top em up with some Guinness.  .. .... Tom .... |
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Post by molly2 on Dec 3, 2016 11:50:16 GMT
Take em down the pub and top em up with some Guinness. .. .... Tom .... I was hoping for more tecky answers, trust you 
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Post by daven on Dec 3, 2016 21:18:07 GMT
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Post by stonedaddy on Dec 5, 2016 10:28:57 GMT
Take em down the pub and top em up with some Guinness. .. .... Tom .... I was hoping for more tecky answers, trust you
Well i was close to a tecky answer but ended up with a tacky one. I suppose if they don't like Guinness you could try them on whiskey or brandy but they might end up burping and pumping all over the country. .... Tom .... |
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Post by molly2 on Dec 6, 2016 17:49:32 GMT
I was hoping for more tecky answers, trust you
Well i was close to a tecky answer but ended up with a tacky one. I suppose if they don't like Guinness you could try them on whiskey or brandy but they might end up burping and pumping all over the country. .... Tom .... Think I will buy a very, cheap, smelly, noisy ,genny run it all night while in the pub ,drinking whisky . |
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Post by molly2 on Jan 14, 2017 13:59:54 GMT
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Post by blueadept on Feb 3, 2017 15:32:14 GMT
Let me introduce myself (1st post, lol!) here by detailing what I have done so far on this front... I always loved power supply systems design, and I have viewed the van as a test bed for different ideas...
I have a 24v system in the van, comprising about 320Ah of decent deep cycle batteries, and a 4000w inverter... which allows me to shy away from gas for almost everything.... I also have 840w solar capacity... but as you say, when there's no sun, the solar output is very small...
I have a 2 way interaction with the vehicle battery as well as external mains hookup capability.
1) I built a small maintenance charger powered off the 24v system to keep the vehicle battery ticking over... just a 13.3v regulated supply with a 5Amp current limit. It has a button to up the voltage to 14.4 for absorption charging the vehicle battery in an emergency (say I left my lights on and killed the vehicle battery).
2) I built a unit which switches on a relay if the engine is running... basically just powered from the ignition "run" setting, and checking the status of the alternator (the charging indicator on the dash)... This turns on DC-DC split charge system (see 3)
3) My DC-DC split charge system is made from a 1000w inverter, strapped to a large battery charger for the 24v system (25amps)... that pulls about 800w max.... but the vehicle has a 180Amp alternator, so it should be fine. This system is cheaper than a dedicated DC-DC charger, more powerful, and more flexible (see 4).
4) I have 2 separate automatic 240v changeover switches which use external power instead of both inverters if there's an external hookup... this means that the DC-DC split charge system now becomes an AC-DC charge system and tops up from the hookup, while the AC outlets also come from the hookup, not the 24v inverter.
This gives me 3 separate ways to charge the 24v battery system (Solar, Engine and Hookup)... all selected automatically based on availability.... I rarely hook to external mains except if I want to leave a dehumidifier on in the van etc... and honestly it's really hard to kill my batteries.... I don't cook a lot, but I have a kettle, a microwave and an induction hob, and I make the occasional coffee, bacon sandwich or ready meal and I've never had a power issue.
Hope that's techy enough in terms of an answer... I wonder what other people have done, I'd love to hear what people think of my solution.
James
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Post by molly2 on Feb 8, 2017 22:04:32 GMT
Sounds great as you say very tecky ,you must have a huge van ,and very power hungry.my problem is my van has a smart alternator and is very unreliable at charging my leisure battery .I can do 3 three knights heating then I need hook up.
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Post by caz on Feb 9, 2017 15:37:57 GMT
I reckon 3 nights is about it unless you put in more battery power. I can do 3 nights - 150w solar but only one battery and I think it's only an 85aph. I keep the eberspacher on all the time but turn it to lowest setting overnight and when I'm not in the van.
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Post by blueadept on Feb 10, 2017 12:41:11 GMT
Sounds great as you say very tecky ,you must have a huge van ,and very power hungry.my problem is my van has a smart alternator and is very unreliable at charging my leisure battery .I can do 3 three knights heating then I need hook up. The van is not that big (converted MWB sprinter), but I have devoted a lot to getting the most solar capacity possible... I'm not sure exactly what spec of heater you are using, but looking at the options, some Eberspächer ones claims a draw of up to 10A@12v, while Propex claim a load of 1.4A in continuous operation... I think probably 10A for Eberspächer is a worst case during startup, and probably it's less in operation... but still considerable. Under ideal conditions in perfect weather you can probably get 50Ah in 1 day from a 150W panel, but in reality it's going to be half that at best.... There's a lot of assumptions here, but I think it should be close to what's happening. Heater load= 5A 1 Night = 10 hours Daytime charging = 25Ah Starting with a fully charged ~80Ah battery, after each night, and the following day to recharge, you will be down by 25Ah, so after 3 days you will be down by 75Ah, and the days recharge will not be enough to cover your next night. You can only solve this by increasing solar capacity, or reducing load.... so there are a few solutions. 1) Increase solar capacity to 300W... so as to cover the full night time usage.... this should increase your endurance to "almost indefinite"... depending on what other loads there are. 2) Reduce your use of the heater by half, perhaps with a timer? 3) Use a heater which uses less power... Propex does appear to use less... and obviously some catalytic propane heaters which use no electrical power, although those may not be an option since they will cause condensation and the risk of CO poisoning. As you can see, increasing the solar capacity has much more effect than you might expect... hence my giving priority to that over efficiency. |
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Post by blueadept on Feb 10, 2017 13:47:47 GMT
Oh, also... as regards how "Techy" something is... I don't know that it needs to be that way. Admittedly I am building some custom devices for my application, but that's really only because I can, and it allows me to have them potted in epoxy so there is no issue with moisture or vibration etc... you could definitely do it with off the shelf items.
Once you break it down into a block diagram it's really quite simple.... "This box turns on when the engine is running", "This box turns 12vDC into 240vAC", "This box charges a 12v battery using a 24vDC supply"... it's not that much different to Lego.
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Post by caz on Feb 13, 2017 18:36:54 GMT
My Eberspacher handbook gives power useage as 8 watts on low (850 watt heat output) up to 34 watts on high (2,200 watts heat output).
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Post by blueadept on Feb 13, 2017 22:22:03 GMT
My Eberspacher handbook gives power useage as 8 watts on low (850 watt heat output) up to 34 watts on high (2,200 watts heat output). OK, thats a lot better on the documentation front than I found online.... 8 watts from your 12v battery should clearly be ~650mA so you should, conceivably run at that power for somewhere around 100 hours from your 85Ah battery.... Even 34 watts is only ~3A and so you should be able to run for 20 hours or so... (I'm under-rating your battery because you obviously should not run it completely flat)... Are you running on high or low for those 3 nights, on high it sounds about right 8x3 hours is 24 hours..... but I'd be surprised if you needed 2200w heat for 8 hours in such a small space. Can you give me some more details, becaue if you're running on "low", and only managing 3 days then either they lied about the power consumption, your battery is not holding charge, you are using a lot of charge during the day... OR, there is a voltage cutoff in the heater which is a bit over-sensitive. |
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Post by caz on Feb 14, 2017 20:59:34 GMT
As I said, I turn it the thermostat to low overnight and when I am away from the van, back up (to about halfway) when I need more warmth. If it gets too hot I turn it to about a quarter. It's impossible to be totally scientific about it, too many variables. Outside temperature, wind chill factor, how long a walk I go for, whether there's a pub nearby, have I remembered to pack my PJs, is the dog with me .................  |
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Post by blueadept on Feb 14, 2017 23:26:47 GMT
As I said, I turn it the thermostat to low overnight and when I am away from the van, back up (to about halfway) when I need more warmth. If it gets too hot I turn it to about a quarter. It's impossible to be totally scientific about it, too many variables. Outside temperature, wind chill factor, how long a walk I go for, whether there's a pub nearby, have I remembered to pack my PJs, is the dog with me ................. I hear ya!... it's hard to know what's going on without data tho!... You could consider connecting one of these in line with the heater temporarily to find out how much energy it uses over those 3 days... since this would help you determine if you have a battery problem, or if it's using more power than expected. www.ebay.co.uk/itm/RC-150A-DC-Watt-Meter-Voltmeter-Power-Analyzer-with-Backlight-LCD-0-150A-/282200710596?hash=item41b4791dc4:g:Wl4AAOSwmLlX7lmAIt not only reads current and watts, but calculates watt hours, and amp hours used over a period of time, as well as max min voltage, and peak current, so you can really find out what's going on. You could also try putting it in-line with the solar panel to find out how much energy you collected over a day etc..... it really depends how much faffing you want to do.. If you're stationary for the period, in a relatively secure location, you could also consider setting up a second portable solar panel in the ideal south facing angle to collect the most power, here is a 160w folding panel I own, charging a battery at almost 10 amps in very modest sunlight.... this panel is quite large, but it folds into a nice protective case which can be carried like a suitcase... photos.google.com/share/AF1QipOn8LyOTiHmx_HIh1Z8O5AnTcUcDy08JREoI3kyhOsrl2CnWEIkThAx5zW4RWRmZA/photo/AF1QipOfI8jI1aiPW6EeWmpPQJkXpXU8UeX1k4Fa4_B8?key=TExIcXlPcy1FTmc4bGxMdmNYMmFqR2o4YlpzQ193 |
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Post by caz on Feb 17, 2017 20:29:23 GMT
Sorry but I can't be bothered with all that. I really don't care whilst it's working!
I never go away for more than 3 days at a time without EHU in winter - have to use a site every 3 days so I can wash my hair & empty the loo.
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Post by blueadept on Feb 18, 2017 0:02:23 GMT
Sorry but I can't be bothered with all that. I really don't care whilst it's working! I never go away for more than 3 days at a time without EHU in winter - have to use a site every 3 days so I can wash my hair & empty the loo. Most people aren't interested in messing around to find out what's actually going on with electrical things if it's not a huge problem... that's understandable, it might however interest you to know that I'm currently trying to put TEGPower, in touch with some of these heater companies... since TEGPower make a thermoelectric generator that produces 45watts of power from the difference in temperature between the top of a log burner and the air, moved by a fan... this sounds very much like it would be a good fit for this type of heater... producing it's own electrical power, and charging your battery as it runs. |
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Post by molly2 on Feb 19, 2017 23:07:17 GMT
My truma gas heater uses .6 amps on low 1.2 kw 1.2 amps on high 2.4 kw .I have a 50 w solar panel but is useless in winter about 200 m amps if I fitted a 100 w sp I would expect double ,no more than an 1 to 2 amps a day . Nov to march . No room for more solar.i use a 100 amp Lb +70 amp Lb for winter . in winter i could use 20 amps a day heating lights and TV .Way above what solar can supply .As they say when it's gone it's gone .Up to now I have used the van for 3 nights in minus temps .My van has a smart alternator that plays havoc with engine to LB charging .
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Post by molly2 on Feb 19, 2017 23:15:37 GMT
My Eberspacher handbook gives power useage as 8 watts on low (850 watt heat output) up to 34 watts on high (2,200 watts heat output). OK, thats a lot better on the documentation front than I found online.... 8 watts from your 12v battery should clearly be ~650mA so you should, conceivably run at that power for somewhere around 100 hours from your 85Ah battery.... Even 34 watts is only ~3A and so you should be able to run for 20 hours or so... (I'm under-rating your battery because you obviously should not run it completely flat)... Are you running on high or low for those 3 nights, on high it sounds about right 8x3 hours is 24 hours..... but I'd be surprised if you needed 2200w heat for 8 hours in such a small space. Can you give me some more details, becaue if you're running on "low", and only managing 3 days then either they lied about the power consumption, your battery is not holding charge, you are using a lot of charge during the day... OR, there is a voltage cutoff in the heater which is a bit over-sensitive. |
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Post by molly2 on Feb 19, 2017 23:17:16 GMT
My Eberspacher handbook gives power useage as 8 watts on low (850 watt heat output) up to 34 watts on high (2,200 watts heat output). OK, thats a lot better on the documentation front than I found online.... 8 watts from your 12v battery should clearly be ~650mA so you should, conceivably run at that power for somewhere around 100 hours from your 85Ah battery.... Even 34 watts is only ~3A and so you should be able to run for 20 hours or so... (I'm under-rating your battery because you obviously should not run it completely flat)... Are you running on high or low for those 3 nights, on high it sounds about right 8x3 hours is 24 hours..... but I'd be surprised if you needed 2200w heat for 8 hours in such a small space. Can you give me some more details, becaue if you're running on "low", and only managing 3 days then either they lied about the power consumption, your battery is not holding charge, you are using a lot of charge during the day... OR, there is a voltage cutoff in the heater which is a bit over-sensitive. |
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Hi we nearly always freecamp - old age pension gives loads of leisure time but too little money to pay camp site fees. 
The van has solar panel, large water tank So we are pretty self sufficient. Jon
Nov 18, 2016 20:22:15 GMT
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Hi we nearly always freecamp - old age pension gives loads of leisure time but too little money to pay camp site fees. 
The van has solar panel, large water tank So we are pretty self sufficient. Jon
Nov 18, 2016 20:22:15 GMT
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Jan 29, 2017 12:30:47 GMT
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Jan 29, 2017 12:30:47 GMT
