Does a generator need a battery charger

Yes, this is what I have been told as well, so bit the bullet and just installed a 30a 3 stage smart charger to hook up the battery bank to the Geni. Apparently it is the way to go. Cheers Tony

Hi there, Don't know size of battery - it's second battery to run a 35 l Engel - plus - i think it's about 75 amp - Nos on it are N7022MF also 730 CCA and 160 RC. Do any of these tell the size?

Loris,

Those numbers mean it is a start battery, not a deep cycle one, however is quite a large start battery.

Start batteries are not ideally suited to cycling, but, given that your fridge is not large it may well work well for a while.

The trick is not to drain it too much. Rather than run it down and give it one big charge once a day, keep it topped up with gennie 2 or 3 times a day.

Another thing to do: whilst you are running the gennie to charge the battery, plug the fridge into 240 volts from the gennie (use a power board) and crank the fridge up to full on the thermostat. This way you will drag the fridge temp way down whilst the battery is being charged without any draw on it.

Then when you switch the gennie off and run off the battery you turn the thermostat back down it will be a while before the fridge draws on the battery again.

Hope this makes sense and helps.

Jim.

Hi,

I just had both batteries replaced here in Darwin -- so that means I now have two start batteries and not one deep cycle, one main. Why would the auto electrician do that? Guess I have to ask him...plus, what you say makes sense when charging - still have to know what charger to get for this system.

I think the fridge in his car is an auto fridge - which does run off a main if I remember correctly from TLCC newsletter. At least, I know there is one fridge that doesn't need a deep cycle battery.

Loris,

I'm not saying your auto elec has done anything wrong. Whilst the generally accepted theory is that Deep Cycle Batteries should be used for running a fridge, there are a great many on this forum who swear by the "Exide Extreme" start battery for this purpose.

The Extreme is a very good quality, large capacity, start battery and seems to successfully break the rule that start batteries should not be used for running a fridge.

It is also possible that your auto elec has used the type of battery he has supplied you with success over many years. Or it is possible he has little experience in such matters and has simply supplied you the wrong battery (this would seem unlikely). Personally I would give him the benefit of the doubt and ask him.

This 12 volt stuff is not an exact science and you will get a lot of conflicting opinions.

One thing that is never disputed is this: discharging a battery shortens its life. The deeper you discharge it shortens its life dramatically. So whatever you end up with, keep the charge up to it regularly.

Jim.

"However you may have problems running a charger from the generator"

Not with the Honda inverter you won't....mine works fine.

I can second that mine is working just fine as well running a 30 amp charger

I can third that !
Willie

I did say "may" not will. It is possible that the inverter types are OK but the slip ring types are not.

PeterD

Another way , if you are stuck, you can put a resistive load in series with it....i.e..... on the positive leg say, put a 60 watt 12v globe....this limits the current to 5 amp max( 60/12 =5)....the lamp should be bright at first but then grow dull as the battery voltage comes up...I have and still use this method with good success....it too is safe and simple.....using a 18w 12v lamp you limit the current to just over 1 amp for example.

730 cold cranking amps = 730CCA
160RC....???? anyone.

160 RC is the reserve capacity in minutes at 25 A current draw (ie until the battery is buggered.)

160 minutes is 2.66 hours times 25 A equals 66.66 A/H (amp hours) however I would suggest drawing no more than 30 A/H out of it between full charges if you wish to get more than a dozen or two full cycles out of it.

PeterD

Correction - that should be minutes a battery will maintain 25 amps load at a useful voltage.Therefore 160 RC will maintain 25 Amps for 160 mins

Don't worry about damaging that battery with the honda charger.
Unless your battery is really really full and you run the generator for hours, it will not overcharge.
If your battery is say 1/2 discharged, it will take something like 6 hours running before you even approach a full charge.
Having said that, to quickly bring it up to full charge you will need a high current charger and plug it into the 240V side. A 20 amp charger will still take a quite few hours though.
Cheers

Hi Loris

He (HL) is talking about limited use of the honda generators internal charger , the 12v output on it.

Use of a seperate charger - speeds up the charging process , because it has more output than the internal honda charger.

Interesting subject and got me thinking.

I have a good Ctek 20 that I charge with the 240 volts.

How would a cheap 2 stroke ($99 at local Hardware) hooked up to my Ctek 20 go charging batteries. ? Seems good value for less than $100 !!.

Bill

Bill,

I believe there have been cases of those cheap gennies blowing battery chargers up.

From memory, Lucy destroyed two chargers before ditching the gennie and buying a decent one.

Jim.

There can be bad combinations of products as Jim says but in your case it will work remarkably well Bill .

The odd one of those gennies has had poor speed control etc , however you would have to be very unlucky and the Ctek handles a large range of inputs.

Whenever I buy low cost things like that I ensure that I can both check them out and return them easily.

Sounds lke you hooked up the Engels to the charging output without a battery as a buffer....you can't blame the cheap gennie for that!
Cheers