How long would it take to charge 1 deep cycle battery with an 850W generator?

Hi REdbac

It should take about the same length as with any other generator
as pretty all all can deliver more current than the battery can accept for long life.

Ball park - couple of hours for a useful top up and 4-6 hours
for optimum.


(I assume the battery is charged via an appropriate 240v to 12v charger)

This is one of those typical "how long is a piece of string?" questions.

It depends on how flat the battery is; exactly what type of deep cycle battery it is etc. There are different "types" of battery that claim to be deep cycle. Some are true deep cycle, others are hybrid (they can be used for starting and or running accessories).

True deep cycle batteries need to be charged slowly (to avoid long term damage to the plates). I wouldn't consider hooking a deep cycle (or any other battery for that matter unless it was an emergency) up to the 12 volt output on a genny (any genny).

Instead, I would use a proper 3 stage battery charger on the 240 volt output side of the genny and charge the battery "properly". If you do it this way, it depends on 2 factors: how big your 240 volt charger is (I have 2 x 15amp jobbies) and how low the battery/ies is when you hook it up.

Redbac, if you are using the gennie on 240V with a battery charger, it will have more to do with the size of the charger than the size of the gennie. And the time to charge using the gennie will be the same as the time with the charger plugged into mains power.

I guess my answer is about as good as 'how long is a piece of string', but that's the way it is sometimes.

The cheapie ALDI or GMC gennies are only good for about 6 amps.

Hi Redbac, I see that from post 55212 you are looking at doing a 6 month trip with an on road jayco. I will make the assumption that the majority of the time you will use caravan parks but you would like to use bush camping when available. The genny that you are thinking of using is cheap, which is fine but you may (will) find it unreliable when using for extended periods. The smart chargers that Roachie mentions are really good but expensive.
Another option that you have is to have a second battery(deep cycle) in the van (battery box on the A frame or in the side boot) and have a "arrid"? style of solenoid with the appropriate wiring from the vehicle so that when you are driving you will be charging the battery slowly (which they like) and you can run the caravan fridge on 12 volt and then swap to gas when you have no power or 240 volt at the caravan park. The battery will be well charged to run the small stuff which I assume is 12 volt? Silly question but you never know.
You will need a good size deep cycle battery and make sure that the fridge works well as you van is 20 years old and swapping from 12 volt to gas may be a long process. If you need to charge the battery, start the car.
Something to consider

Regards

Mark

Redbac

How about a bit more info. How big is the battery. Are you using the 240V OP and charging the battery with a proper multistage charger? Are you using the 12V op straight onto the battery?

If you are using the 240 V OP and a multi stage battery charger, the time will be dependent on the battery size, the size of the charger and the depth to which you have discharged your battery.

If you are using the 12 V OP then see Site Link. Some forum members will reckon this a joke, but remember this was written by an engineer who is well versed in control circuitry and has measured these devices.

PeterD