Extra power in January (1 Viewer)

[deleted-member02]

I will be off grid for a week in January and am trying to work out the best way to manage my electrical supply.
I have a decent 180 amp battery, all LED lights, don't watch too much telly. The main drain will be the blow air heating and charging phones/tablets etc.
Now I also have a spare 90amp battery that's just sat in my garage. Can I use this to my advantage by temporarily connecting it to the 180amp battery ?
Would it be better to connect them both fully charged, or better to connect the 90amp once the bigger battery had drained.
If possible, don't want the hassle of physically swapping batteries / resetting panel and so on - was intending to use small cable run and croc clips. Hook it all up on arrival, disconnect, before moving on, so as not to create any charging issues.

Any advice appreciated.

 

[JeanLuc]

I'm not an electrical expert but here are a few thoughts that occur to me.

• If the temperature falls very low in January, I'm not sure that 270 Ah will last a week. I have drained 2x110 Ah in a weekend when it was well below freezing. Remember the battery(ies) will give less than their rated power at low temperatures and ideally, you don't want to take more than 50% out of your good 180Ah battery anyway.
  
• You refer to 'resetting the panel' so I assume you have a later model Schaudt system with the LCD control panel (mine is the old two meters with needles version - nothing to reset). Because the EBL is more than just a charger - it controls and fuses all 12V circuits - you might find that adding a battery would still require a reset as the EBL would suddenly be confronted with a change in capacity whilst it was monitoring 12V supply - I'm not certain about this.
• If you add a charged 90Ah battery in parallel with a disharged 180Ah battery (using croc clips in your example) will the discharged battery not pull down the charged one, obviating the benefit?
  
• If possible, I would stick with the existing 180Ah capacity and hire/borrow a small inverter generator to run for a couple of hours every other day. I realise this may not be possible in the location you will be in, but it would be my choice.

 

[Chockswahay]

The power killer will be the heating fan, especially if it's really cold! If you are staying in one place then I think you will be lucky to get past 2 days, on the other hand if you are touring and charging on the road then no problem.

In real terms you can only really rely upon an operating range of 85% max and 50% minimum so 35% will give you just over 90 amps to play with....

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[jonandshell]

The power killer will be the heating fan, especially if it's really cold! If you are staying in one place then I think you will be lucky to get past 2 days, on the other hand if you are touring and charging on the road then no problem.

In real terms you can only really rely upon an operating range of 85% max and 50% minimum so 35% will give you just over 90 amps to play with....

That is a very good point about maximum charging levels. Many standard split charge circuits wont even achieve that much due to inadequate wiring and voltage drop.

Another good reason for a B2B or A2B charging system. Of course, traction batteries help here to due the ability to discharge reliably down to 20%. You get more power from a similarily rated battery.

 

[Barclaybasher]

Would running the van engine a couple of times a day help?

Engine heater would also help with heating the van

The fully charged spare battery should be carried but may not be needed

 

[deleted-member02]

Last time we went off grid in Jan the cold absolutely nailed the battery, couldn't believe the difference.
Hence better planning this year....
I figure that I'll use between 20-30 amps a day. I can borrow a generator , there are no noise issues and it would be lighter than an extra battery, just seems overkill to run a genny for a few amps of electric...

I did have a b2b charger on my last van and yes a quick drive would help. I haven't fitted one to this van, mainly because I haven't noticed a sharp drop in charging rates( previously had Nasa battery monitor now use the EBL digital screen).

Thanks to all

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[JeanLuc]

I would suggest caution if considering a B2B charger with an EBL-equipped van. I know people do fit them but they can cause problems - see here (point 2 in their list):
http://www.aandncaravanservices.co.uk/schaudt-elektroblock.php

 

[jonandshell]

I would suggest caution if considering a B2B charger with an EBL-equipped van. I know people do fit them but they can cause problems - see here (point 2 in their list):
http://www.aandncaravanservices.co.uk/schaudt-elektroblock.php

No problem so long as you fit an isolating relay between the EBL and leisure battery.

The only thing that wont work is the counting of the amps going in during charging.

It depends if you are interested in minor details or decent charging.