Should Trojans go this fast??

[rclark]

I bought two new Trojan T-105's and installed in MH, I will keep it plugged in for a day and then unplug it for a day or two because my MH has the unfriendly converter !! The only things that are on is the lights in the bays where the tanks are (2) and the frig plus the propane detector. According to the charts that have been posted here the Trojan's are down too about 30 or 40% in just 36 to 48 hours when unplugged from the electric..

Does this sound right to you all ????

Thanks Randy

 

[Karl]

Randy,

Quite possible. Not sure how many watts the lights in the bays are, but the heating element in the fridge will draw a significant amount of juice. It's better to run it on propane unless hooked up to shore power.

 

[Gary RV_Wizard]

You may not have the T105's fully charged yet - they need 48 hours on the charger to get to 100%, even though they are new.

One 12v light is typically 1.0-1.2 amps per hour, so just two bay lights for 36 hours is about 80 amp-hours of use.  48 hours would be about 100 AH.  A pair of T105's has about 200-220 amp hours, so 40% is in the right ball park for that load.

 

[carson]

One possibility, maybe???

    Have you checked to see if your "unfriendly" charger is actually "charging"?

I used to have one like that and much to my surprise, one day I discovered that it had had zero output to the battery for some time. I never noticed it as the engine alternator kept them reasonably charged. The DC (hi-amp) supply was working perfectly.

When plugged in to shore-power the battery terminals (12V) should read between 13 and 14+ Volts, approx. If not, thats your problem.

carson FL

 

[Ron]

Our Trojans are 9 plus years old and still going strong.  But then we have a good three stage chargers and the batteries have never been neglected.

 

[rclark]

Thanks for the replies!!

Karl, I have the frig set on auto and when genset or shore power isn't available it automatically switches to gas.. I've never seen it try to run on electric with just the battery power available!! Also you were assisting me on another problem with my furnace, turns out the blower motor wasn't getting up enough speed to activate the sail switch according to the tech..

Gary, what you compute is about what is happening. When first installed I left plugged in till batteries give me a 13.6 V reading without shore power!! Maybe I was expecting to much!!

Carson, when shore power or genset power is present the reading at the batteries is 13.6 - 13.85..

Ron, I hope mine last that long!! I bought a 3 stage charger that will get hooked up when we get back from the Redskin game Sunday. The MH won't be used again until the end of March!!

Thanks Randy

 

[John From Detroit]

No matter what the power source the fridge eats 12 vdc for the control power.

How long the batteries last per charge is the same for Trojans as any other brand for the same given capacity, though I understand trojan's have a very nice discharge curve

But to computer take amp-hour capacity of battery (NOTE: if you have 2 six volt think of them as one 12 volt and take just one amp-hour rating, if you have 2,6,8 six volt take one from each pair, if you have 12 volts add them together)

230 amp hours (Common six volt pair size)

Divide by 2 (115 am hours)

Add up load  Lamps are, for example, 1 amp each (About) There is a chart in the files section here IIRC.

Divide 115 by amps and that's how long they will last

You said 2 lamps plus fridge (say 1  amp) plus static loads (another 1 amp) times 48 hours  that is  192

It appears I'm being overly generous with the fridge and static loads as I came up with 16 percent left after 2 days.

 

[Karl]

Randy,

Karl, I have the frig set on auto and when genset or shore power isn't available it automatically switches to gas.

Make SURE it's switching to gas. If you have an inverter and it's turned on, chances are it's powering the heating element of the fridge too - regardless of shore power or genset power! :

 

[Gary RV_Wizard]

I have the frig set on auto and when genset or shore power isn't available it automatically switches to gas.. I've never seen it try to run on electric with just the battery power available!!

It won't do that, unless you have an inverter and it is wired to provide 120VAC to the fridge circuit (some are, others are not) OR if you have one of the 3-way fridges that works directly on 12VDC as well as propane and 120VAC. That's a feature on the smaller size fridges and those are rarely found in large motorhomes.

You may, however, have a small heater built into the door edges that evaporates condensation. Those are 12v powered so they work in both LP and electric mode.  If you have an on/off switch inside the fridge that is labeled something like "high humidity" or "power miser", you probably have this sort of heater. A few, like my Norcold 1200 series has the door heater and no switch to turn it off. The door heater will suck and amp or two.

 

[John From Detroit]

You keep forgetting he claimed to have two compartment lamps on all the time too,

Typically these are 15 watt (a bit over an amp) bulbs. so that's 96 of his 115 amp  hours right there!

 

[rclark]

Gary, the MH does have the humidity switch and I do leave it on when the frig is turned. So there is some more of my power going away!!!

Karl, I'm certain that when the genset and shorepower are absent it switches to gas. I don't have a hard wired inverter, but hope to get one sometime in the future!!

John, I'm not sure of the wattage on the bulbs but when it gets down to 30 degrees or so I can check the thermometer in the bays and it is usually around 42 to 46 degrees in there!! The bays seem to be very well sealed and insulated on the Pace Arrow.

Randy