Recommendations for Mains Powered Smart Battery Charger

Rosscoe,

Check out the following URL
http://www.projecta.com.au/

They have Automatic, Manual & 3 stage MCU Units
These chargers should be available at most Battery Retail outlets.

I have a 10amp manual unit (about $130) and a separate controller (about $60)which stops overcharging and can be switched to Gel style batteries.

Plenty of options, depending on how deep your pockets are.

Hi Rosscoe,

I have the Bainbridge 3 stage smart charger. It can independently charge 3 batteries at 15A max. I have had this for several years and am very happy with it. It charges my 115Ah deep cycle battery on my van.

Theoretically it should be able to charge your gel cells in less than 6 hours, however, it will depend on how fast the battery can take the charge (gell cells much better than lead acid wet cell).

The charger is switchable between the type of battery (lead acid/ gell / etc...) to ensure the appropriate charge rate for that battery type.

Cheers

Captain

Hey Rosscoe we have one of these Projecta adaptors connected to our 8amp battery charger brilliant they are, turns your normal charger into a monitoring charger, it's on 24/7 now looking after our deep cycle battery in the camper.

Baz.

Rosscoe
I have a 115 amphr batt and if is nearly flat it probably takes over 24hrs maybe even 36 hrs to charge fully, it will accept 5-6amps for a while then tapers off to 2amps and less for the last 10hrs or so, not that i sit there and watch the charger but i was shocked as to how long it took it to recharge. This the big dissadvantage of a deepcycle batt. If you do not have solar pannels or a regular power top up source you would probably be better off with a normal batt or a optima or eQuivalant batt as the latter accept a lot of amps hence a very quick charge.

Mattie

Rosscoe,

Have a yarn to Anthony at Brown and Watson (distributors for Projecta) who can explain it better than any of us. Their number is 03 9730 6000.

Rosscoe, to do it in a reasonable time you'll need something that can deliver 10 amps or more, you said batteries so I assume more than one, so you'll probably need something close to 20Amps. Have a look at www.gsl.com.au, they have a 17A switchmode which you can get for about $250, australian made too. It charges until terminal voltage hit's 14.5 then drops back to a float of 13.8. Depending what sort of gell you have the 14.5 may be getting a little high, but it would certainly be fully charged. The 14.5 is good for any conventional wet cell but some sealed gells might start gassing up at 14.5.

Hi Captain, your batteries, cranking or deep cycle, should charge fully when being charged by your vehicle's alterator. The most likely causes of low battery voltage charging is either ( or both ) the wire to the batteries is to small or you are not opertaing the vehicle long enough at a siutable rev to get the batteries charge properly.
PS Bainbridge brand seem to be a much more reliable charger.
Regards.

Hi again folks, one important point when charging batteries. The charge current is controlled by the battery NOT the charger. A charger may be good for 50 amps but if the battery's maximum charge absorbtion rate is 10 amps then that is all it will take. Before buying a charger, find out from the battery manufacturer what is the optimum charge rate for the batteries you have.
regards

Hi again Captain.
If you are running additional gear off your cranking battery, the battery will take longer to charge.
The Redarc products are amongst the best available so the way to get the other batteries to charge is to remove as much off the cranking battery. Then when you start your vehicle, the Redarc will only have to wait for a short time for the cranking battery to charge up as it only has to have the drain from starting the vehicle replaced and then the other batteries can be charged.
Also don’t forge, if you are using anything less than 8 B&S cable to connect to the rear battery, you will both slow the charging rate and reduce the charge voltage getting to the battery.
I supply charge control gear to a number of motor home manufactures and there is little problem with charging the auxiliary batteries, no matter where they are located as long as there is thick enough cables run between the cranking battery or alternator and the auxiliary batteries.
And one more important point that is often over looked, you MUST run the same size cable for both positive and NEGATIVE.
Do not use the vehicle’s chassis for the earth return as this will reduce the charge and voltage getting to the auxiliary batteries.
Regards.

50mm2 is whopping big cable, you sure it's 50mm? I'm running 4GA stuff which is about 18mm2 and it's over 1cm in diameter with the insulation. What's the diameter of your cable?

Hi Captain, from your cable cross section size, sounds like you have at least 6 B&S which is heaps ( about twice the current capacity of 8 B&S ).
The flat 12 pin I take is a Brilite, if so I would recommend you use an set of Anderson Plugs instead ( careful when buying them as these are normally sold 1 at a time Not as a pair and you will need 2 ). Anderson plugs are used on things like the batteries on electric fork lifts. The most common size is a 50 amp but for a little extra go to the next size up which is 175 amp.
They are a mirrored connector or in other works, the plug and socket are identical. ( Great devices )

Connecting to the chassis is a NO NO.
The reason is that you may have checked to see if there was a voltage difference before you set up you wiring. Thats all good and well while there is no load.
The trouble is that there will most likely be a dirty or rusted or even a painted joint or two and with no load, no problem.
But once you start to apply a load, even a very small load, you will start to get resistance at the bad joints.
And the higher the load the worse the resistance gets.
This resistance now governs the amount of current and the voltage level that can be supplied to the battery.
As for the winch, You have fallen for one of the most common deceptions relating to alternators.
To get the maximum amperage out of an alternator, your motor has to be revving at 2000 rpm at the least.
And here is the problem, the alternator is putting out say 60 amps and the winch is pulling 150 amps, then the battery is still supplying most of the load and if you use the winch long enough, you can still flatten the battery with the motor running.
To give you a better idea of what I mean, here is another example of flattening a battery with the motor running.
This one is a common occurrence, vehicles driving slowly over rough terrain at night for long periods often have there lights go very dull because they have not had the motor revving high enough to allow the alternator to produce enough current to replace what the head lights ( and other electrics ) were using.
Hope this all helps.
Regards.

drivesafe,

I'll answer your question in a number of ways.

The vans sits outside the house for two to three months at a time with me folornly wanting to hit the road. During this time I monitor the battery for both Open Circuit Voltage and Electolyte SG and put it on a cheapy mains charger every now and then but especially before I go on a trip.

When we travel we typical do not camp in unpowered sites for more than about three days. The van battery is then normally only used at night to run lights (halogen for bedtime reading and 1 amp fluro for outside if necessary), TV via a 300W inverter for news and the odd footy match and bit of music. I also have an electric water pump. The van fridge runs on gas while we are camped. With an 85 AH attery fully charge before I leave home I get the three days on the first stop before the battery reaches about 50% discharge. I don't take the battery lower than 50% discharge.

When we do hit the road it would be normal for us to drive for at least 4 hours but more often than not for 6 or more.

Regards,

Rosscoe

Hi captain.
If your systems working well, and it sounds like it is, the earthing to the chassis is not an issue in your situation.
But for the benefit of someone else who might be considering wiring up a dual battery system, the industry standard is to install both positive and negative wire of the same type all the way between the batteries.
As for your battery dropping to 12 volts while winching, DON’T TOUCH A THING. Your battery is in pretty good shape as most batteries drop to 12 volt just by turning on the headlights. When winching, it’s common for batteries to drop to or even below 11 volts.
Your system is working and working well.
Happy motoring and regards.