Best way to charge car batteries......some advice please.

Greetings

A search of this site may assist. As well Camper Trailers. If you flattened your batteries you should read this Battery FAQ. As a guide only 50% of a batteries stated amp/hours is available for use.

Other perhaps more qualified will also reply and I expect the answers to be many and varied.

Generators - usually equate with noise and there are many camping spots you either cannot use them or use is restricted. Still probably the most cost effective method of supplying reliable power.

Solar Power - Quiet and pollution free in use. Expensive and performance is subject to the vagaries of weather and geographic location ( sun hours). Good if you stay in the one spot for a few days.

Vehicle alternator - Limited and subject to similiar noise problems as a generator if you attempt to charge when stationary. Many standard vehicle alternators can barely charge a second battery in less than 2 hours running above idle.

You will need to calculate your power usage per day.
Calculate youre vehicle alternator output and how long it takes to charge you second battery (and trailer batteries) from 50% discharge.

Then you will be able to decide how your are going to replace the energy consumed based on how long you wish to stay at unpowered locations.

As an example

I run a 39 litre engel fridge and 2 x 1amp camp lights. I have dual batteries in the vehicle with only the fridge plugged in. I use a seperate ( small) battery for the camp lights.

I can stay without power, for a maximum 3 days arriving with full batteries. I obtain a powered site at caravan parks and recharge batteries using a 240volt 3 stage charger and run the Engel on 240volts.

Alternativley I need to drive for around 4 hours on the 4th day to get the vehicle alternator to recharge the batteries to the full state.

Regards

Paul

G'day Outa Bounds,

This is well answered by Paul so I only want to add that I found a Honda and a 3 stage charger the ideal situation. We run 2 x 50 litre Weacos via a 75 AH battery this way. Also the genie can provide clean power to run the lappie, charge batteries and run my welder in the bush. When it is running, usually avo and early evening it is used to provide lighting etc.

Kind regards

outa bounds,

a mate has a new generation honda inverter generator and I have never come across anything like it to date. I want one........

You can use a generator to power a battery charger if you like. The trick is to use the most powerful (Amperage) battery charger suited to your batteries.

For example if you are charging 200AH worth of batteries you might be able to use a 30amp or 40amp battery charger. You would be looking at 4-5 hours using a 40 amp charger to re-charge the batteries. (Check with someone at Batterywold for advise, they do a lot with RV's and Motorhomes etc)

My Kipor Generator runs for around 5 hours on a tank of fuel , around 5 litres. It is very quiet, you wouldn't hear it much if it were positioned 20-40 yards away etc. Good battery chargers include Xantrex (www.xantrex.com) .

I run 2x 220amp 6 volt deep cycles in camper. Run same as most, fridge, lights etc.

I use a BP Solar panel in 80 watts & can use Honda 650 Genny if needed. Thats if the big light in the sky goes out for more than a couple of days. If i arrive with fully charged batts i am good for 4 days before charging is needed..

Good luck

If you connect up your camper to your car after you have flattened the batteries in the camper, you will simply drain the aux in the car very quickly. Then when you start the car, your alternator will be flat out keeping up with 3 batteries and whatever accesories you may be running, and it would take days of driving to get back up to a decent level of charge, but still not fully charged.

Firstly, try to keep the all your batteries the same type - wet cell, dry cell, agm, deepcycle type, cranking type etc - (they charge and discharge at different rates)

Try to charge them as often as you can. Discharging them big-time stuffs em up.

If you run a gennie, you can put a loaf of bread on while you're at it.

Outa Bounds, you have had some good advice so far. If you are looking for a generator, consider the Kipor. I have one and I think it is very similar to the Honda. Very quiet and so far, very reliable. It's main attraction is it is about $400 cheaper than the Honda and Yamaha and has similar features. Hasn't proven it's longevity yet, but OK so far.

When you run your cable via Anderson Plug, use the thickest cable you can manage. It will reduce voltage drop and give a better charge. I used 25mm squared double insulated welding cable (from electrical wholesaler). A number of others on this forum have used the same thing, or similar.

Even if you don't get a generator initially, it is well worth getting a good multi stage charger. I have a CTEK 25 Amp, which is very good, but there are a number of other good brands as well. If going away for a few days or more, I always fully charge off 240 V before heading off. When on a big trip, we do the same whenever we have access to 240V (occasional CP, drop in on friends etc). We only run the gennie when necessary.

I run a 105AH Deep Cycle and two 120AH AGM Deep Cycles. They run a 70 Lt fridge (with freezer compartment), water pump, up to 6 lights and an inverter for charging laptop, camera and other batteries. If ambient temp is not above mid 20s, we get about 6 days, but this includes a bit of driving (say average one hour per day) that helps a bit on the vehicle mounted DC. If ambient temp is well into the 30s (often is, I'm in Qld), this can cut time down to 4 or 5 days due to extra cycling of the fridge. I mention this to ensure you have a realistic view of what your batteries can achieve.

Well worth the time and investment to get this sorted well.
Good luck.
Norm C

Hi OB,

I have seen advertised in magazines, a small motor with a 50 amp (maybe more?) alternator attached to it. You would use it like a genset but you would be pumping 50 amps in at any one time as opposed to the smaller amps a gennie or charger could put in. Therefore less time would be required running the noise box to have full batteries again. I can't remember names or prices for these things (others may help here) and I understand their limitations compared to the genset but it may be worth looking in to as this may suit your requirements and budget better than an expensive 3 stage charger and gennie ???
Plenty of advise on best way to go so I won't comment on that as you already have enough ammo to get you thinking for days.

Cheers Trevor.

Yo Outa Bounds,

Where you from?

I live in Cairns and have just started a campertrailer group up here (no membership-fees etc just agroup of people camping and swapping ideas etc) that could probably assist you to get things sorted.

This forum is really great - listen to the old hands - they have the experience - don't take too much notice of the jibes - they are mostly in fun - we are all fair game on this site. I was so impressed with the site and the respondents I joined (couldn't afford to buy it though). If you are interested let me know thru here (email address) and I will get the info to you.

Yes we are all interested in probs like this and the focus of one of our weekends away will to be to swap ideas along this line...

Hope to talk soon....

Grrrr!!

Kippor 2000 genset, and a three stage smart charger will do the job. ebay has both at huge savings.ie genset =$895 and charger =$200. use these and you will last forever.

"I imagine this should get us one weeks worth of power (at least)"

- this is not a good way to PLAN on using your batteries if you want a long life. Whenever a battery is less than 100% charged, sulphate is building up.

You should PLAN on totally recharging your battery every day. If the sun doesn't shine etc etc and you occasionally leave them uncharged for several days, it won't have a major impact.

Mike