Need more power

Discussion in 'Tech/Mech General' started by errpaul, Oct 30, 2015.

  1. errpaul

    errpaul Funster

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    So getting to grips with being self sufficient when away in the motorhome.
    I have fitted a 150w solar panel and we have 2x 110ah batteries. In this October overcast weather that provides us enough power to keep going with a little use of the heating.
    We however plan to use the van throughout the winter, being static for up to a week. Obviously that means far less power from solar, and far more use of the heating (blown air ).
    As I see it the options are:
    - Larger battery bank (not ideal as current batteries are only aroumd a year old)
    - Additional solar panel
    - Battery to battery charger (could run engine as and when needed to charge batteries I think)
    - Generator

    Any advice or experience of systems would be appreciated
     
  2. funflair

    funflair Funster Life Member

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    I would certainly say more solar, at least the same again and then see how you get on, I don't see the point of bigger battery bank if you can't recharge it.
    As you have found the gain from solar is pretty low when the weather is grey.

    Martin
     
  3. Reallyretired

    Reallyretired Funster

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    Though I'm a fan of solar, theres no doubt its not a lot of help in a grey winter. I would recommend the B2B charger, it is always available.
    Generator much more expensive, heavy, noisy and a fairly low charging rate if you are just using the MH built-in charger.
     
  4. Peter A Forbes

    Peter A Forbes Funster

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    As said above, no point in having a bigger battery unless you have the means to charge it.

    We have fitted twin 225AH AGM battery sets, two sets of two 100W panels and twin controllers, but that still leaves you exposed on a cold wet week in the north of the UK with virtually no usable light.

    For these situations we have two 50A power supplies that are rigged to work as chargers and shore supplies, leaving you the option of pulling into a CL for a night to get the batteries charged up to 85-90% of capacity overnight, given that EHU is available.

    It is pretty much forgotten that a mains charger can be used as a shore supply as well, and if you have the facility to charge up your batteries quickly, you won't get the walk-down on capacity that happens when they are not fully charged each day and start the new day with less capacity than the previous day.

    If you look on ebay for 13.80V Power supplies:

    13.80V 30A Switchmode power supply £19.99 Free postage

    13,80V 50A Switchmode power supply £53.00 Free postage

    These are all adjustable within 5% or so, even the ones sold as 12V output for LED lighting are adjustable up to 14V in most cases.

    We have two 26A in the trailer and two 50A going in the Mercedes. There is also a 24V 10A unit for the vehicle batteries plus a Durite B2B unit as well.

    Peter
     
  5. Allanm

    Allanm Funster

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    I would get as many solar panels as you can, you could add another battery or two, batteries a year old will have almost the same capacity as a new one, so, as long as your new batteries are the same size ( and make, if possible) they will work well together. I did that, no problems. Peters tips above are very good, but, when all else fails, use a generator. As long as you are far enough away from annoying other people, they can be a lifesaver, and they don't have to be smelly heavy or noisy if you buy a good make. We store ours in the van when not in use, and you would never know it was there.
     
  6. JeanLuc

    JeanLuc Funster

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    In winter, nothing beats 230V mains to the charger so I would suggest using sites where you can get a hook-up or carry a small inverter PSW generator such as the Honda EU10i (quietest) or perhaps one of similar spec (but probably a bit noisier).
     
  7. Jaws

    Jaws Funster Life Member

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    At the very least 300w of solar panels.. But more would be better ( of course :) ! )

    Blown air heating systems are REAL power hungry.
    The other option is to look at a diesel powered heater,
    They are cheap to run but having said that, most will draw about 2 to 3 amps anyway.

    A third option is to do what we did in the Miller. I bought a flu-less catalytic heater.
    It was not perfect as it was only a small one, but used virtually bugger all gas, NO electric, and kept the chill out of the van at night so we were not freezing when we got up in the morning :)
     
  8. eddievanbitz

    eddievanbitz Trader - Funster

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    Or frankly all of them
     
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  9. Boringfrog

    Boringfrog Funster

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    Have you got any eBay links to the said power supplies? Thanks.
     
  10. fastpat

    fastpat Read Only Funster

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    We have two leisure batteries and a solar panel Truma blown air heating (6E), up north off grid we can last 3 - 4 days. We purchased https://www.machinemart.co.uk/shop/product/details/jump-start-4000 I look upon it as another battery - it provides that fall back position and being totally isolated form everything else if I do draw a bit from the engine battery at least I know I can always get started.
     
  11. jonandshell

    jonandshell Funster

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    A2B or B2B is the best suppliment in my opinion.
    We go skiing and stay stationary for up to a week at temperatures as low as -20. Inside the van, the diesel fired Webasto dualtop heater maintains T-shirt weather!
    The A2B charger keeps the 345 Ah traction battery bank topped up with an hours run of the engine each day. Charging current is about 90 amps under these circumstances.
    We don't have solar or a generator.
    The final 2 days we just run the battery down and recharge for free on the descent back down the mountain.
     
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  12. jdk62

    jdk62 Funster

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    Kryptonite...... :D
     
  13. Gromett

    Gromett Funster

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    As Eddie says if you are using your van all winter then having a choice of power sources is advantageous.

    A B2B will put 50 Amps in. Sterling do a 60Amp battery charger.

    If you go with a generator get the biggest charger you can afford that is suitable for the battery bank size you have. This means you run the generator for less time. If you are driving about then the B2B can keep you topped up. More battery bank means you last longer before needing to charge. More solar even in winter can help a little. I can get up to 20AH back into my batteries in winter on a bright day (last time I tested).

    I have a rule of thumb that says have as much solar (Watts) as you do in batteries (AH). I currently have 180W of solar and 220Ah of battery.
    I would like to have more and when I build the new van will have more roof space and payload so will try and get up to 500W and 500Ah.

    On my second van I had 1000AH of batteries and 240Watts of solar. I could go for 10 months of the year without hookup. In Dec and Jan I had to hookup once every 2 weeks.
     
  14. peterc10

    peterc10 Funster

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    What's and A2B please? Do you have a link?
     
  15. Gromett

    Gromett Funster

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  16. peterc10

    peterc10 Funster

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    Thanks for that and the link. Just looked at both A2B and B2B and I am not sure I understand the difference! So if I just want one, which should it be?
     
  17. TerryL

    TerryL Funster

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    B2B - it charges your vehicle battery first - which doesn't take long - then any spare alternator capacity is used to charge the leisure batteries. The Sterling we've got fitted also has an intelligent charging system that protects and revitalises the batteries.

    Warning though - either system will put a load onto the alternator higher/longer than they were designed for so make sure whatever you get has an alternator overheat sensor/cutout - I know the Sterling offering does.

    I'd go for the B2B first, rather than additional solar panels or batteries simply to avoid the additional weight.
     
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  18. jonandshell

    jonandshell Funster

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    A2B wipes the floor with the B2B product.

    It is a more difficult installation however. Many auto electicians will run scared.

    I have installed the A2B product due it's better performance.

    Most will go for the B2B product for simplicity and the avoidance of base vehicle warranty issues.
     
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  19. Peter A Forbes

    Peter A Forbes Funster

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  20. peterc10

    peterc10 Funster

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    So there you go ......... as clear as mud :D
     
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