Trying to understand battery usage - help?!

[chockswahay]

I have found that if the leisure batteries are fully charged then they ‘charge’ the engine battery until parity is reached. This of course won’t happen if the car is not driven OR max charge is selected.

So on a general ‘drive and forget’ basis the entire battery system sits at 80% is capacity. In real terms this means only 30% (45 amps) of the leisure batteries are useable.

The only way round this (excluding solar) is to drive with the max charge permanently selected.

As it happens, I fitted a 100w solar panel 5 weeks ago and the leisure batteries are holding up very well in view of the fact that the fridge is permanently on and the van has been driven very little in that time.

 

[Vinnie]

Is a possible solution to use the fridge intermittently when running on leisure battery and effectively as a cool box (obviously depends what you are trying to keep cold). Would sustain the leisure battery longer. Seems to work for us

 

[Lambeth Cali]

Is a possible solution to use the fridge intermittently when running on leisure battery and effectively as a cool box (obviously depends what you are trying to keep cold). Would sustain the leisure battery longer. Seems to work for us

If you set it to 1 that’s pretty much what you’re doing.

 

[CampervanOwner]

Thank you everyone for all your replies. Much appreciate!

 

[Wannabecamperman]

Thank you everyone for all your replies. Much appreciate!

Solar is your friend. Once you go there, you may wish to do as many (myself included) and start investing in solar generators too, which allow air fryers and hair dryers, etc - all off grid all summer long with just 200w.

 

[GreatResigner]

You have 2 x 75 amp batteries giving a total of 150 amp hrs.
Good practice for AGM leisure batteries is not to run them below 50% capacity which gives you a total of 75 amp hours usable power.

You stated that the display showed between -1 and -4 amps and the ambient temperature was quite warm.

When the display showed -1amp , probably due to just lights you could have run them for 75 hrs ( 3 days ).

When the display showed -4 amps this was the fridge running. So at that current draw you would have had 20 hrs usage. Fortunately the California compressor fridge runs intermittently to maintain the temperature BUT the warmer the ambient temperature the more often it will run.
In winter the fridge might only run for 10 mins/hr so using 4/6 amps/ hr = 0.7 amps/hr.
So your battery will last a 100 hrs.
In a hot summer the fridge may run for 30 mins/hour = 2 amps/ hr so your battery will only last 35 hrs.

NB: because of the Smart Alternator system the leisure batteries are only charged to 80% actual capacity although the Control Panel shows 100%.
Use the Max Charge button on the dash an hour or two before site arrival and this will ensure the Leisure Batteries are fully charged

Would a T5 have included the “Max Charge” button you mention above WelshGas?

 

[WelshGas]

Would a T5 have included the “Max Charge” button you mention above WelshGas?

No, but easy to fool a smart alternator, used in the BlueMotion regenerative braking system.
1. If you have heated seats, Level 1.
2. Headlights On.