Roughly How Much Drain on Battery?

[jopparocks]

I'm going away at Easter and will be staying in a couple of sites which don't have hookups and so I have a power capacity query. It might be cold as we'll be going to the top North of Scotland (outside John O Groats).
I have two 110 amp batteries and two 75 amp solar panels. We will want to use the blown air heating from my Truma heating system on my 1997 Hymer S650.
We'll no doubt be putting the telly on at night (a12v Avtex) as well along with led lights and will want to run the heating maybe sometimes in the day too. There's a fridge which will be running and possibly charging my phone through a small invertor as well. We like to be comfortable
On this set up how long do you think the batteries will last? Will be going for lithium if my set up is not up to it.
Cheers Martin

 

[Richard n Ann]

Very difficult to say. How old are the batteries? They were 110ah when new but won't be now

 

[EzeeRider]

Also depends on how much sunshine hits your solar panels. If you are happy with your batteries, best bet is to try it and be prepared to run the engine as a contigency.
ezee

 

[jopparocks]

Very difficult to say. How old are the batteries? They were 110ah when new but won't be now

Good point. Guy I bought the van from just over a year ago said they were new. Hardly been used since then except of one trip last September.

 

[Jimbohorlicks]

Will you be running your fridge off the battery or gas?

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[stevewagner]

in case you are not aware if they are standard leisure batteries you only have 50% usable capacity ie 110 amps in total. Also I expect you mean 75 watt solar panels which I doubt will be putting back what you will be using unless it is very sunny all day every day.

 

[acropolis22]

We have Truma heating. The fan has 2 settings. Eco and high. On high the fan draws 0.7 amps as measured by the Victron battery monitor. In total we never draw over about 4 amps with lights, router etc, but we don't watch TV......

You won't actually be running the fridge off the battery will you? Most fridges run off EHU, gas, or 12V when the engine is running.

 

[jopparocks]

Will you be running your fridge off the battery or gas?

Battery Jim

 

[acropolis22]

Battery Jim

Ok, if that's the case your battery will be getting more of a caning. Others more knowledgeable will give you the details.

 

[jopparocks]

in case you are not aware if they are standard leisure batteries you only have 50% usable capacity ie 110 amps in total. Also I expect you mean 75 watt solar panels which I doubt will be putting back what you will be using unless it is very sunny all day every day.

Steve yes they are 75 watt - daft mistake on my part. I'm aware of the 50% thing for batteries which is why Lithium is being considered in future when I some spare money.
Not really expecting the solar panels to do much at this time of year. Really just wondering how long I can have on the batteries before they will need charging. Wouldn't need more that 2 nights on battery power with some driving about inbetween.

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[jopparocks]

Ok, if that's the case your battery will be getting more of a caning. Others more knowledgeable will give you the details.

Suppose in April in the north of Scotland I can put the milk outside to keep cool

 

[stevewagner]

Steve yes they are 75 watt - daft mistake on my part. I'm aware of the 50% thing for batteries which is why Lithium is being considered in future when I some spare money.
Not really expecting the solar panels to do much at this time of year. Really just wondering how long I can have on the batteries before they will need charging. Wouldn't need more that 2 nights on battery power with some driving about inbetween.

Have you got or considered fitting a B2B charger? Much faster recharge with a B2B.

 

[jopparocks]

We have Truma heating. The fan has 2 settings. Eco and high. On high the fan draws 0.7 amps as measured by the Victron battery monitor. In total we never draw over about 4 amps with lights, router etc, but we don't watch TV......

You won't actually be running the fridge off the battery will you? Most fridges run off EHU, gas, or 12V when the engine is running.

Its an old system which only has a thermostat and switch for heating and/or hot water. Quite efficient at heating the van up.
I'm assuming the fridge is electric only as I don't see any option for switching to gas. Seems to run nicely on 12v when not on hookup.

 

[jopparocks]

Have you got or considered fitting a B2B charger? Much faster recharge with a B2B.

I'm pretty sure there's a B2B charger but can't check as van is in body repair shop getting fixed. But there is a system for charging that means my starter battery will never be run down when not on hook up.

 

[Speve]

I would just give it a go and that way you will definitely find out what the system is capable of we have two 90w panels and two 95a leisure batteries and we didn’t have problems with it over five nights without hook up but driving a couple of days between stops.Used Fridge heater and tv

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[funflair]

Assuming it is a compressor fridge it will still take a fair amount out of your batteries, if it's a three way running on electric = no chance.

 

[Tombola]

what Fridge is it ?
could poss use min 8a per hour (averaged)
truma fan, 1a
lights 2-3a
inverter 1 amp
so look at around 14-16a per hour,
then other bits?
you have 100 ish usable amps, 7 hours max...probably less, your solar isnt going to touch it. B2b yes,
if only one night before then getting on hook up then you may be able to get away with it by turning fridge off and hardly opening it. Ive kept my chilled food in the garage before now when in cold places.

do the fridge on gas if you can then all esle becomes better

have fun is the main thing

 

[Jimbohorlicks]

Battery Jim

I think that's going to cause you issues unless you get lots of sunshine and you don't watch your TV for long and your in bed for 7.30 pm with everything switched off.

 

[acropolis22]

what Fridge is it ?
could poss use min 8a per hour (averaged)
truma fan, 2a
lights 2-3a
inverter 1 amp
so look at around 14-16a per hour,
then other bits?
you have 100 ish usable amps, 7 hours max...probably less, your solar isnt going to touch it. B2b yes,
if only one night before then getting on hook up then you may be able to get away with it by turning frdige off and hardly opening it. Ive kept my chilled food in the garage before now when in cold places.

do the fridge on gas if you can then all esle becomes better

Agree about running the fridge on gas. I know this is splitting hairs, but where do you get 2 amps for the Truma from? I know for a fact ours draws 0.7 amps on the high setting.

 

[Tombola]

Agree about running the fridge on gas. I know this is splitting hairs, but where do you get 2 amps for the Truma from? I know for a fact ours draws 0.7 amps on the high setting.

yeah sorry, I said 2 as literally today I was in mine and the truma fan was running for no reason, so I flicked on the bluetooth monitoring and it was showing 2 amps coming out, but I had lights on aswell, duh?
bad guess, Ill edit the post
but rememeber it can booost at first for a while

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[jopparocks]

I would just give it a go and that way you will definitely find out what the system is capable of we have two 90w panels and two 95a leisure batteries and we didn’t have problems with it over five nights without hook up but driving a couple of days between stops.Used Fridge heater and tv

Sounds promising for us then

 

[jopparocks]

what Fridge is it ?
could poss use min 8a per hour (averaged)
truma fan, 1a
lights 2-3a
inverter 1 amp
so look at around 14-16a per hour,
then other bits?
you have 100 ish usable amps, 7 hours max...probably less, your solar isnt going to touch it. B2b yes,
if only one night before then getting on hook up then you may be able to get away with it by turning fridge off and hardly opening it. Ive kept my chilled food in the garage before now when in cold places.

do the fridge on gas if you can then all esle becomes better

have fun is the main thing

We are so looking forward to getting away in Easter I'm feeling like a kid waiting for Christmas. Sounds like we will be ok.

 

[Tombola]

We are so looking forward to getting away in Easter I'm feeling like a kid waiting for Christmas. Sounds like we will be ok.

youll be fine, if all else fails, find a site with ehu.
keep us posted how it goes

 

[pappajohn]

300 to 400 watts of solar MIGHT keep the batteries charged
What you have now .....expect a very cold second night.
Don't use an inverter just to charge a phone, use a 12v cig lighter USB adaptor.

 

[Jamesh]

Take 2x 2l milk frozen....

Don't put warm cans of beer in the fridge.....

Open the fridge as seldom as possible buy some frozen food and let it thaw....

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[jopparocks]

300 to 400 watts of solar MIGHT keep the batteries charged
What you have now .....expect a very cold second night.
Don't use an inverter just to charge a phone, use a 12v cig lighter USB adaptor.

Its just a wee inverter that plugs into one of the 12v cig sockets

 

[Reallyretired]

It really doesn't make sense to convert 12v dc to 240v ac and then back to 5v dc to charge a phone.

 

[berni109]

Why not try it overnight on the drive (if you have one).
It can only be worse in the frozen north.

 

[jopparocks]

It really doesn't make sense to convert 12v dc to 240v ac and then back to 5v dc to charge a phone.

Yes now its pointed out to me it does seem daft. I'll get there in the end!

 

[jopparocks]

Why not try it overnight on the drive (if you have one).
It can only be worse in the frozen north.

We have a drive so good advice.