RE: Battery Charger

[whitestar505]

 Can anyone tell me anything about batteries and charging? Is it better to charge with a smaller charger than a larger one. ie: 1.8 watt vs a 5 watt. Now I know you have to conver the wattage to volts. But I am sure larger wattage is more voltage.
 
 Anyhow, will the larger voltage damage the battery from charging so fast?

[SactoCampers]

 whitestar505

Can anyone tell me anything about batteries and charging? Is it better to charge with a smaller charger than a larger one. ie: 1.8 watt vs a 5 watt. Now I know you have to conver the wattage to volts. But I am sure larger wattage is more voltage.

 Not exactly. Since wattage = amps x volts   you could have higher wattage by raising the amps and keeping voltage constant.
 
 A few basic statements:
 
 1.) Electricity is like water in a hose:
 2.) Voltage is the water pressure
 3.) Amperes (amps) are the current (i.e. water volume coming out of the hose).
 4.) Wattage is a combination of the two.
 5.) Unrelated to water, Amp-hours is a measurement of energy storage capacity in a battery. The term " watts"  is not generally used when talking about charging, and energy consumption with trailer batteries. It carries with it the extra variable, volts, which is already known and assumed (12). Therefore, the terms " amps"  (i.e. the current drawn by an appliance) and " amp-hours"  (storage capacity of battery) are used to keep the language simple. Consider the following example:
 
 The fan from your furnace uses about 3.57 amps of energy (and technically 43 watts). If you run your furnace for 5 hours, you have consumed 17.85 amp-hours (3.57 amps x 5 hours) of that battery s capacity. Each light bulb uses about 1.5 amps. Turn all 5 of them on for four hours and you have used 30 amp-hours (1.5 amps x 5 bulbs x 4 hours). You can see why we all conserve energy while dry camping!
 
 Now that we have a basic understanding of electricity, let s figure out what you need for a charger.
 
 Let s look at it this way (you have to read carefully and concentrate hard. It s not easy to " get"  at first. Lord knows it took me a while):
 
 A typical group 24 battery (size of a car battery) has about 50 amp-hours of energy. Now, remember our equation: watts = amps x volts. An electric charger takes 110-volt AC power coming from your household plug and converts it to 12-volt DC power (because your trailer battery is 12 volts, not 110). So, if for example, you buy a 6-amp charger you are using 72 watts (6 amps x 12 volts) to charge that battery and will take over 8 hours (50 amp-hours / 6 amps) to fully charge that rather small group 24 battery. A 10-amp charger reduces the charge time to 5 hours. So if it takes 8 hours to charge with 72 watts (6-amp charger), imagine what it would take with 1.8 or 5 watts from a solar charger. It won t even begin to charge your battery. The general consensus is you need a minimum 40 watt solar panel to recharge your battery while camping.
 
 Therefore,
 
 If Solar: 1.8 watts to 5 watts should only be considered a " maintainter"  of a fully charged battery not a " charger."  As stated, if you want to recharge via solar while camping, general consensus is you need 40 watt panels or more to recharge your battery after frugal use. These can be found at various places for ~$300-$350. If recharging at home, you re much better off using the converter/charger in your trailer than a 1.8 or 5 watt solar charger.
 
 If electric: Electric charger output is generally measured in amps not watts. Some people have 6 amp chargers, others 10 amps, others higher than that. The higher the number of amps the faster it can charge your battery. The general hierarchy of battery chargers from worst to best are manual, automatic, and 3-stage automatic. If you have only a passing interest in batteries and charging, you can get a fully automatic 10 amp deep-cycle charger for around $30 at Wal-Mart.  Others will try to convince you to get a 3-stage charger which cost around $100 and up, but I don t think it s cost effective. I have a $30 charger and it keeps my batteries charged well. Biggest benefit comes from upgrading from your trailer s converter/charger to a dedicated charger.
 
 I looked into solar panels but decided for my style of camping, it was more cost effective to buy a second battery and dedicated charger.
 
 Make sense? I hope this was helpful.

[whitestar505]

 SactoCampers
Hey Brian,
 
    Like your picture. [] I offen wondered if they were smarter then man.
 
 Thanks for the info. I guess what I was looking for was something to keep the battery up during the winter mouths while still sitting on the trailer. Do you think it might do that for me?[&:]

[SactoCampers]

 whitestar505

 

ORIGINAL:  whitestar505
 
 Hey Brian,
 
    Like your picture. [] I offen wondered if they were smarter then man.
 
 Thanks for the info. I guess what I was looking for was something to keep the battery up during the winter mouths while still sitting on the trailer. Do you think it might do that for me?[&:]
 

 
 Yeah, it should. I don t think the wattage matters. It s not enough to harm your battery.

[cowboy]

 whitestar505
SactoCampers,
 
 I would like to ask a quick question since it seems that you have this battery thing down pat.
 
 I often read about using a dedicated battery charger instead of the factory provided charger/converter.
 
 How has this been managed, is everyone using a battery selector switch or just disconnecting the battery leads from the battery to the charger/converter. It just doesn t seem right to have both connected to the battery at the same time.
 
 I have a  01 Viking Sega 2107 and the charger/converter will top the battery charge to 12.86 volts every time, am I lucky or do I need to learn something I don t understand. This is a new Group 27 190 AH reserve Deep Cycle from West Marine and it would be nice to hear the best and proper way to keep it alive.

[Campntime]

 whitestar505
Glad this whole battery question come up as I am about to purchase a charger for our PU.  Automatic Charger from Walmart fits my bill...and thanks to SactoCampers....I even know why.  Thanks for thread!

[MtnCamper]

 cowboy

 

ORIGINAL:  cowboy
 
 How has this been managed, is everyone using a battery selector switch or just disconnecting the battery leads from the battery to the charger/converter. It just doesn t seem right to have both connected to the battery at the same time.
 
 

Not SC, But if you are plugged into shore power, Why would you need to charge your batteries. If you are worried about standard charging while the converter is in the circuit, (not powered), just unplug the battery connection, or add a toggle switch to the " hot"  wire and break it that way. The switch works good when the camper is in storage too. Doesn t run the LP detector, so the battery doesn t have a constant drain on it.

[whitestar505]

 Campntime
Campntime, Let me know how it works OK.
 
 Thanks

[SactoCampers]

 cowboy
Hi Cowboy, sorry for the late reply. I was out most of the weekend.
 
 

I often read about using a dedicated battery charger instead of the factory provided charger/converter.

 One of the limitations of the converter/charger in your popup, and Mike4947 is much more knowledgeable about these things than me, is that they generally don t produce the amperage output they claim. So, say for example you completely discharge your group 27 battery (good choice, bigger batteries are better if weight and size aren t issues) while on a camping trip. You may get a little bit of charge on the drive home and then you plug in your charger. The longer your battery sits not completely charged the quicker sulfation of the plates kicks in. Since the converter/charger is putting out very low amperage relative to their claims, the theory is that over time the battery will begin to deteriorate (i.e. lose its ability to hold charge) prematurely because of the length of time required to charge the battery. For example, most experienced " battery folks"  claim you will likely only get a couple years out of your battery using the converter charger (of course this depends on frequency of use and depth of discharge), whereas you will extend it with a higher amperage dedicated charger. My group 24 battery went dead after two seasons using the converter/charger and camping about once a month year-round. It was indicating a full charge (around 12.8 volts) but I checked the electrolyte and all 6 cells were bad. But that s just anecdotal information and your mileage may vary. Since your battery is new, I have no doubt that it is holding a full charge, but mine was a few years old. I figure that since a dedicated 10-amp charger is inexpensive relative to a new battery (the charger should last indefinitely), that I would get one and closely monitor my batteries  lifespan.
 
 

How has this been managed, is everyone using a battery selector switch or just disconnecting the battery leads from the battery to the charger/converter. It just doesn t seem right to have both connected to the battery at the same time.

 I connect my charger directly to my batteries using the clips that it comes with. The trailer is stored in my garage so it is very easy for me to monitor my batteries and top off their charge.
 
 Refer to Mike4947 for more detailed information on batteries and chargers. He s very knowledgeable.

[Bearnkat]

 whitestar505
Hi All,
 
 Since we re on this battery thread. Here s what we do and let me know if there is a problem. Our popup is stored in the garage and we just keep it plugged in and the inverter trickle charges the battery to keep it charged. At least this is what our Coleman dealer told us. We never do that much " dry-camping" , we re always plugged in where ever we go, normally to one of our Texas State Parks.
 
 Any comments on our procedure? I also check the battery monthly to see if water needs to be added.
 
 Chuck

[Camper Dan]

 Bearnkat
Bearnkat[],
 
 That sounds about right!
 
 About charging with my Sears Charger/Starter...I ve got one that is a 12/2/75 Amp model.  When I charge my battery at home I start the charger on: 12VDC, " Deep Cycle Automatic" , 2 amps...and let it go over night, then the next morning I ll set the rate up to the 12 amp setting.  This unit cycles on an off some as the surface charge disapates near the end of the charging cycle.
 
 Doing it this way keeps the water from gassing off during the initial charging and switching to the 12 amp charging rate speeds up the charge, if needed, and doesn t gas off because...even though the charger is set for 12 amps the partically charged battery requires less...like maybe 4 to 7 amps.[]  I got tired of charging, topping off, recharging.[] (when set at 12 amp setting for the entire charge cycle).

[Bearnkat]

 whitestar505
Hi All,
 
 We were at Costco last night and we went on and picked up a battery charger, one of those 12/2/75 Amp models. We noticed that the same model was $38 at Sam s and $32 at Costco. Pretty good savings. The reason I got the cahrge was because the inverter was " under-charging"  the battery. With the inverter the charge voltage was 13.1 volts. According to all my sources it should have been a minimum of 13.5. I don t know if the lower voltage would make that much difference, but the $32 was a small investment.
 
 C & T
 

[mike4947]

 whitestar505
C & T , Good to see someone doing the right thing for their battery. You hit the nail on the head about the Converter in your PU. It s voltage is made run 12 volt equipment and is indeed not high enough to fully charge a battery.

[Bearnkat]

 whitestar505
Hi All,
 
 The sad thing about it all is that I work for an internationally based battery manufacturer and I should have known better. I started talking to one of my sales managers and told him what I was doing (letting the inverter keep the battery charged) and he looked at me with one of those :You know better than that"  []looks. I told him that I bought the charger and he said it was a very wise decision.
 
 C & T []

[chasd60]

 whitestar505
The auto industry is not too far from the 36/42 volt battery and charging system. Will take a lot smaller wiring for the same power output. I work for a semiconductor manufacturer and we have been making 42 volt capable parts for a little while now with a lot more to come. I suppose we will be using a DC to DC converter before too long. Yep, we make those too!!