I have an "onboard battery charger" so when I hook up to power it automatically charges first my starting battery and then my house battery through a solenoid setup, I was told by a wandering expert, whom shall remain nameless, that I am better off running my 300 watt inverter whilst driving and feeding the power through my on board battery charger to recharge my batterys. my question is (1) does this make sense at all (2) wouldnt the current draw of the inverter and charger overule the benefits it creates (3) is there a chance of the battery charger "fighting" with the alternator of my vehicle. I know the people in the know recommend leaving the solar panels hooked up to do the charging but is this the same principle or not, your views please

1st we need to know how many batteries and what type. What are they used for and the size of the alternator in ya vehicle to be able to give a qualified answer.

Grrr!!!

the house battery is a 100 amp hour, alternator standard toyota whatever they are??? it just doesnt sound right to me, running all that gear, but what do I know

I'd reckon that runing an inverter to power a chager would be self defeating in as much as inverters are no where near as efficient as we are led to believe. In my Jack there are 2 humugous batteries one is deep cycle the the other is for starting. They are set up in parrallel with an isolating diode that can be switched to allow the second battery to start the car if necessary. The vehicle charging system "sees" one 500 Ah battery (the 300ah starter battery and the 200Ah accessories) and charges both together. It does take a while to charge them both, Like 10 hours on the road if they are both flat as you can only charge them at around 10% of the total capacity, if that makes sense. If I stop near power I just put a 10 amp DSE charger across them for top ups that is ok.
I think from memory the alternator in the Jack is around 75 amps capacity but the charging regulator limits the current to a safe level, if you were to allow 75 amps to charge the batteries they would boil and sulphate up, a sign of overcharging...And would cost you heaps to replace....
Yes I've replaced them both, quoted $1200 for them but got the two from NRMA batteries for $380.....
Hope all this makes sense I know what I'm trying to say but get lost in context...

ah hah!!! Basil's out of his corner, yep fully agree with that doesnt make any sense to me, far too complex too many plates in the air

I have asked to owners of this site for the ability to upload files and diagrams for which I have many to do with this subject but there appears to be a lack of willingness to allow for that to happen so I am affraid I cannot get the info and drawings for you. It is sad as I can do this on every other site bar this one...

Oh well ... such is life - sorry people...

Grrr!!!

This might help...

http://www.exploroz.com/Vehicle/Electrics/BatteryCharging.aspx


Grrr!!!

thanks Doug and Ian, I looked at that website and I am doing pretty much that already, I have a 100amp in house battery and it is a 60 amp alternator, the charger is an onboard "smart charger" variable charge rate of course. now because my alternator is 60 amp and the battery to charge is 100 amp does that mean that it will be charged in 2 hours?. it doesnt really matter because as I stated previously I have an 80 watt solar panel which keeps up to my needs anyway, but I am just curious as to this charger thing, it didnt (and still doesnt) sound right to me

dave06 wrote:

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thanks Doug and Ian, I looked at that website and I am doing pretty much that already, I have a 100amp in house battery and it is a 60 amp alternator, the charger is an onboard "smart charger" variable charge rate of course. now because my alternator is 60 amp and the battery to charge is 100 amp does that mean that it will be charged in 2 hours?. it doesnt really matter because as I stated previously I have an 80 watt solar panel which keeps up to my needs anyway, but I am just curious as to this charger thing, it didnt (and still doesnt) sound right to me

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I think you would destroy your battery if you chaged it in 2 hours.... Usually a 10% charge rate is optimal ie a 100Ah battery should be charged at around 14 Volts at 10 amps....