48 replies to this topic

[Ronanmd1]

HI guys - wondering if any of you can help me with a charging issue on my camper.  Background = I have a 2013 Ram 2500 diesel with a 2013 FWC Hawk camper.  The Hawk has 2 AGM batteries and a Sure Power controller/isolator installed from factory.  It also has the IOTA Q4 system for shore charging and an 85W solar panel (although it is shadowed a bit by my ski box).

 

I don't think the truck is charging correctly.  On my current road trip, I seem to use up a fair bit of my battery charge over night using my Dometic 80L fridge and one of the inside lamps (on for maybe an hour per night).  Each day the charge in the batteries loses a bit more ground.  First night batteries start at 12.5V and then are 12.1 in the morning.  After driving about 6 hours they increase to about 12.3 and then are 11.7 by the following morning.  Charge up to 12.1 with 4 hours of driving and then drop to 11.4 overnight..etc.  It seems like I am limping along with my batteries getting a fairly useless charge from the truck and are only getting what small amount of power I can provide with my solar panel and the 1-2 hours of generator time at camp (Honda 2000 W).

 

The solar panel shows an output of about 2.4 max amps at the solar controller with maximum sunlight (this is probably b/c the ski box shadows the edge of the panel).  The shore power seems to work correctly.  Plugged in last night.  Was reading 13.5V at the batteries.  By morning, both batteries fully charged.

Some observations:

1. The Ram has 2 batteries in the engine compartment.  At idle after start up, both read 13.5V.  A bit lower than what I expected (I thought they would be around 14.2V).  Also, I am not sure which battery the FWC tech ran the wiring to during the install.  If it is the accessory battery, then maybe this has a voltage controller?  Not sure if that would affect things.

 

2. At idle, the batteries in the camper are only getting 12.5V through the Sure Power.  It looks like the wiring from the truck is 4 gauge wire.  Maybe this is leading to my voltage drop from the truck?

 

3. I am not sure that the Sure Power is working right.  When I start my truck up, and the camper batteries are at 12.1V, the isolator keeps disconnecting and isolating the camper.  Voltage at the batteries are at 12.5V for about 10 seconds, then the isolator clicks and the voltage in the battery drops back to 12.1V.  10 After a 10 sec delay, the isolator reconnects and the voltage at the campers jumps back up to 12.5V.  This cycling just seems to continue.  I expected that the isolator would engage based on the voltage at the truck battery?  It seems to be sensing the low voltage at the camper battery and then isolating the system to protect the truck charging system.  Is this functioning correctly?  Maybe wired backwards?  

 

I am a tool when it comes to electrical diagnostics...hoping you guys may be able to point me in the right direction.  With 2 truck batteries, 2 camper batteries, a solar panel and generator I still can't seem to keep my beer cold!  lol

Thanks,

Jason

 

[DesertDave]

I imagine you will get a lot of input.  I'll start.

 

ANY shading on a solar panel virtually kills any charging you get.  I tested my factory 100W panel in full sun.  Just the single crossbar of the Yakima rack knocked off at least 50% when I located it where it could shade the panel.  Full shade on a sunny day knocks off about 97% of the charging capability, based on my playing around with a portable panel.

 

Charging from the alternator is probably the least successful means.  It is controlled by the truck electronics, which are aimed at charging the starting batteries and then providing the power to run the vehicle.  They are not designed to provide the charge profile of deep-cycle AGM batteries and even when optimized are probably only going to provide a decent bulk charge.  The Sure Power has interesting logic that will disconnect the camper batteries from the alternator if the camper battery voltage is too low.  I'll bet that you often are trying to charge too-low camper batteries and the Sure Power is cycling the connection on and off.  If you truly have 4 gauge wire you have done a lot to eliminate voltage drop from alternator charging.  I think the factory installs a 10 gauge wire.

 

Many 12V batteries are 'fully charged' when their resting voltage is 12.6V.  They are not well-suited to deal with multiple deep discharges below 50%, which is something like 12.1V or 12.2V.  The numbers you quoted make me thing you have damaged your batteries by discharging them way too deeply.   Once you have damaged batteries they won't charge up as well or as quickly, they won't hold as much energy and will discharge more quickly, and so on. 

 

The Iota Q4 system seems to be quite a good charging system for the type of batteries most of us use.

[Ronanmd1]

Ok. Closer inspection of the sure power instruction manual states that the isolator will disconnect when it senses 12.2 - 12.7 from main battery. Since my voltage drops from 13.5 at engine bay to 12.5 at sure power isolator I suspect this is a big part of the problem. The isolator is working as it should. Looks like I need some bigger gauge wire

[Bwht4x4]

So, I have the same truck but a 2005 model and also a 2013 Hawk.  While driving the truck will barely charge the battery and I do not consider the truck as a source to charge the camper's battery.  On one road trip the battery was at 78% and after a 3 hour drive it went to 82% (I have a Tri-metric battery monitor).

 

I have an 80L compressor refrig and depending on the outside temps the batteries are usually between 90% - 85% the next morning with the refrig running all night.  The batteries are usually 100% again (if it's sunny) in 3-5 hours.  I run a 160 watt panel with a SunSaver MPPT and can say that I would not want a panel any smaller than the 160 watt.  From my own experience I can only imagine that your 85 watt partially shaded panel is the issue.  IMO move the ski box and put a larger panel on the roof.

[Ronanmd1]

Bwht. Totally agree with the solar comments. I will likely move the box. Still surprised that the truck can't charge those batteries. Have you checked your voltage at the camper battery with truck running? Do you notice the drop I am seeing as well? I spoke with a guy today at sure power. He reaffirmed that if the isolator is only seeing 12.5V it will not allow charging of camper batteries. Maybe your issue is same as what mine appears to be. Increasing size of wire to isolator may also fix your issue?

[PaulT]

Jason,

 

If you have 4 ga wire, look at connectors under the hood, in the camper battery compartment, and in the camper to truck plug and socket for possible bad connections.  I have a 2010 Tundra with 2014 Hawk and factory 100 watt Zamp solar with the factory twin AGM 75aH batteries. FWC installed the camper about a year ago using 10 ga wire. The following are my voltage measurements. Sun was NOT shining on the solar panel but it was partly cloudy with some sun breaks. My batteries were indicated fully charged by the Zamp controller.

 

Truck     engine      Off         On

   battery                 12.51v   13.81v

   circuit breaker      12.51    13.79

 

Camper

   Zamp indicated     13.0      13.6

   battery                   12.98    13.46

   rear wall solar        13.04    13.52

 

   isolator 

       white top             12.48    13.66

       white bottom       13.04     13.65

       Red                     13.07     13.66

 

 

Because my batteries are indicated fully charged, there is not much voltage drop as little current was flowing.  You can use one of the voltage drop apps on a iPad/iPhone or equivalent for Android to compute your expected voltage drop for your measured current flow and the length of the wire between the truck battery and the Marinco Trolling connector used to attach the camper to the truck electrical. With 20 amps, 10 feet one direction, and 4 gauge wire, you should see about 1% voltage drop. 10 gauge would drop about 4% with the same conditions. You are seeing more than 1% so I suspect connections are not tight or are corroded.

 

Remember to measure twice and cut once. Check your voltages at each connection point from your truck to the camper with engine off and with it running to get some ideas of where your problems might be located. I would look closely at where the ground wire is attached to the truck.

 

Paul

[Ronanmd1]

Paul. Those numbers will come in handy to use as a reference when I get home. Thank you

[Bwht4x4]

Bwht. Totally agree with the solar comments. I will likely move the box. Still surprised that the truck can't charge those batteries. Have you checked your voltage at the camper battery with truck running? Do you notice the drop I am seeing as well? I spoke with a guy today at sure power. He reaffirmed that if the isolator is only seeing 12.5V it will not allow charging of camper batteries. Maybe your issue is same as what mine appears to be. Increasing size of wire to isolator may also fix your issue?

 

Ronanmd1,

 

I haven't checked the voltage at the batteries.  My solar system works so well that at this point I'm fine with using solar as my main/only power source.  I plan on buying a small 2000 watt generator for an upcoming deer hunt where there will be a lot of trees and limited sun for my panels.  I'll continue to to follow this thread to see how it ends up.

 

Thanks

[Ramblinman]

I had a problem similar to yours. After much hair pulling and tire kicking I found that the sure power was wired backwards - from the distributor.I learned that the distributor in Wisconsin (????) used a different plug. And subsequently the wiring was changed. Something to consider.

BTW my truck charges my battery full. I suspect yours should to. I will defer to those in the know on this forum.

Good luck with this keep us posted.

[LookyLou]

As you said the camper will disconnect from the truck at some point as the voltage drops.  It will reconnect as the solar panel brings the voltage back up.  The truck should charge your batteries especially after 6 hours of driving.  I count on it.  I'm not sure about everyone else but my truck actually has 2 alternators and it tops my house batteries off in pretty short order.  

 

I am removing my 90W hard solar panel and adding 2x 100W flexible panels (200W total).  Change the solar controller out last week from a SunSaver6 to a 30A ViewStar. Hope to get the panels on this week before going to Lassen.