Lights Don't Work On Battery

[Banjoman-SUN]

I have a 1982 Sunline T-1650. I have had it for several years now and it has been trouble free except for the water heater, but that's another story. This year when opening from winter storage, hooking up the battery, etc. I noticed that the interior lights don't work when the camper is running on battery. The water pump works, the exterior light by the door works, and the fan over the stove works but no lights. If I plug into AC now all the inside lights work. It did not have this issue last fall when I was putting it away for the winter.

I have Converter Systems CS-835 power converter and the instructions indicate that if AC is not available the converter will switch all DC circuits to battery. Apparently it switches some but not the ones for the light. I am afraid something may have gone wrong in this converter. Any advice from the experts will be greatly appreciated.

 

[JohnGB]

Hi Banjoman,

I tried to find a manual on your model converter, and not having much luck. They have been discontinued long ago.

Many of the really old converters had an internal relay that would connect the battery when the battery was needed. That said, if yours has the relay feature since part of the 12 VDC system works, there are high odds a relay would be working.

Since your 12 VDC lights work on shore power (120 VAC), this points to a board-level problem in the converter on that specific circuit. Since the lights work when the system creates 12 VDC power when on shore power, the lighting circuit wiring and fusing back to the power converter itself appears to be working. The problem is then within the DC control portion of the old converter used to switch the power to the battery.

In the late 70s and early 80s, I worked with hard-wire solid-state control systems for machine automation for my job. The days of AND/OR gates and JK Flip Flops, using TTL logic with "wire wrapped" connections on the back of the master rack for connections for those who remember that era. If you have a buddy or yourself who knows older printed circuit board design and troubleshooting, they may be able to test and back into which board component failed. That would tell you where the problem is. Then, it comes to the hunt to find the part to replace. It is a lot harder than it used to be to find these old solid-state parts pending what they are in low quantities. The days of running down to the local Radio Shack, who did sell ones and twos of many board-level parts, are long gone.

You may be into upgrading your power converter to correct the problem. This is a common thing to do on older power converters, and you gain the benefits of modern-day power converters. Many of the older power converters where not very good battery chargers or maintainers. They were nick-named battery killers as they had no true float mode once the battery reached full charge. They just kept pumping in too much charging power, boiling out the battery, and then early battery death came.

For a new system, I would recommend that you give this place a call. Ask for Randy, the owner. I have bought several power converters from them to replace older Sunline power converters that died. https://www.bestconverter.com/

You will see that their website has many power converter brands to help you get closer to fitting your upgrade. Sunline used many different brands of power converters as the years went by, and the technology kept changing and replacing the prior ones. Many brands went out of business along the way, forcing a change.

I understand that you're facing an issue with your power converter, and I hope this information can provide some direction in resolving it. Please don't hesitate to share any findings you have, as this can be beneficial for others who might encounter the same problem. Your contribution to the community is greatly appreciated.

John

 

[Banjoman-SUN]

JohnB, I found the problem and I am embarrassed to reveal that the problem was due to my carelessness. I am a retired electrical engineer which makes my stupid mistake all the worse. However, in the odd chance it might serve to amuse, or to help others this is what happened.
I noticed that the original light bulbs worked on battery power and the LED lights did not. I was testing one of the LED bulbs with another battery and I noticed that the LEDs are polarity sensitive. I didn't know this before, and suddenly it dawned on me to check the battery. Sure enough I had hooked it up backwards. Switching the wires solved the problem.
The good that came from this was I learned a lot about my power converter. I didn't know, for example, that it contains fuses behind a pull down door on the front. I didn't have any fuses of this type so I obtained some to carry as spares. I also found that this is where the battery charger is located and that it was an optional feature. Owners over the years for this camper carefully saved all the instructions manuals for pretty much everything and there was one for this power converter. If you like I can copy it (only 4 pages) and send it to you. I would just need to know how to do that.
By the way, I just finished installing a new Dometic water heater and very much appreciate your post on how to do it. It was not an easy task and I had to fix a a few issues such as a rotted out floor underneath and the copper tube for the propane hookup that broke at floor level. It is certainly a job I never care to do again.

 

[JohnGB]

Hi Banjo,

I'm glad you sorted it out. Please don't beat yourself up too badly; it happens! Your human and simple mistakes happen. I have done it, and I'm sure it will happen again.

We all learn from each other. Yes, LEDs are polarity-sensitive many times. Years ago, when I first started to convert our Sunline from the 921 incandescent to LED, I found several light fixtures that would not work on LED, but some did, and all worked on the 921 bulbs. H'mm, OK, why? They have a blocking diode to at least not burn up, but they will not work hooked up backward. I had to pull down the fixture and switch the wires to the light. The old incandescent never cared, but the LEDs do. The shop person at Sunline just hooked up the two black wires on the light and called it good.

That four-page cut sheet you mentioned on your power converter is a goldmine of information. If you could scan it to a PDF or any other format, and upload it or send it to me, it would be incredibly helpful.

To upload a file, navigate to the FILES section, click ADD, and follow the prompts. Once you've done that, add the file to the folder titled 'Sunline Electrical, Lighting, and Charging Systems.' The file will go through a moderator review before being posted to the section. The FILES section is the tab at the top of the forum; click it, and it is a tab/hotlink.

OR, just PM me through the forum message system, and we can exchange emails, you can send it to me, and I'll upload it.

Thanks for reporting back.

John