How do you keep the trailer backup battery charged. (or do you)

[RancherGuy]

Like most people here, over the years, I have had several trailers. Some have proven to be good and some have not. But every trailer that has had a backup brake battery has been a problem. Every battery has gone bad ...

I took the time to read every posting, but I never saw any mention of what I am about to write.

I have 2 GN trailers, each with those little brake batteries. I read the entries where someone says they didn't change them for 7 or more years, but I don't believe they were good for anything close to that long. Most are SLA, meaning they are just like your drive vehicle, thus should never be expected to last more than 4 years under optimal conditions. But they are not in optimal conditions --

For my trailers, the battery had no method of being charged. The battery is isolated from any electrical source or load until the "pin" is pulled, then it is supposed to power the brakes. Thus if it is isolated, with no chance of being charged, how long would you expect it to be good? Yep, maybe a year if you cross your fingers. And no, unless something special is done in terms of circuitry, even connecting the trailer to your vehicle with the brake lights on, does not charge the battery. If you don't believe me, do this and use a voltage tester on the battery.

Here is what I did. First, my tow vehicle (GM pickup) has one of the seven connector pins for +12V power full-time. However when I went to test it, there was no power. The manufacturer decided they could save a few pennies by leaving out the fuse for it in the fusebox. I researched and found that was all I needed to do. Now I have power at the connector.

Next, on both of my trailers, I again tracked that power line. On both trailers, that full-time power (when connected to the tow vehicle), was connected to nothing. So I wired it so that the power wire now goes to the trailer's safety brake battery.

Now when my trailer is connected, that little battery is being charged with the same voltage as my tow vehicle's battery. I can rest assured that even if I don't use the trailer for months, the battery gets recharged when hooked up for use.

 

[ROUSTABOUT]

Like most people here, over the years, I have had several trailers. Some have proven to be good and some have not. But every trailer that has had a backup brake battery has been a problem. Every battery has gone bad. Every year. So before long, I quit checking it. I live in Missouri which requires a backup battery to last enough to apply brakes on both axles for 15 minutes.

When I bought my new Kubota tractor in 2017, I also bought a new trailer. Best trailer so far. But hauling heavier equipment really makes you want to comply with all the laws. That meant I had to do something about the battery.

My new trailer also had one of those new worthless little weenie batteries. It went bad the first summer. I threw that thing away. Then I did the following.

• I purchased an AGM battery from Menards. Cost $80
• I purchased a small pelican case to hold new battery and charger/maintainer. $60
• I put both in the Pelican case and wired the battery to the original box connections.
• I used Anderson Connectors in case I needed to disconnect any part.
• I purchased a MPPT solar controller, Victron 75 watt. $120
• I purchased a solar panel, SunPower Flex, 50 watt. $110
• Wired it to the controller – 3 connections, battery, solar, and load. The load terminal is used to power the GSP unit.
• The battery maintainer is if I want to charge via 120v extension cord. But I have never used it yet.

I have used this system for 4 years. NOW THE QUESTION – I have not seen any trailer using solar. How many of you guys do something like this, and If not, how to you manage that stupid little worthless battery?

I bought a trailer over twenty years ago. Put a big winch on front and a full size battery box. Haven't had those problems.

 

[ScottK]

I just charge the battery when I need it or replace if necessary. I freely admit negligence regarding the backup battery. I am far more conscientious when it comes to my safety chains.

In my mind the chains are “an ounce of prevention”, and if some event occurs where the chains come into play and they fail; then I’m having a really bad day.

How do you charge it?

 

[fried1765]

I pull the battery if it’s going to be a long time between uses. I store the battery hooked up to a battery tender, not a cheap harbor freight one, battery tender brand. Some people don’t believe they help but my batteries in my rv, motor cycles, and equipment last a lot longer.

Battery Tender (brand) or Battery Maintainer (brand) chargers, absolutely do extend battery life!

 

[Smily0]

I took the time to read every posting, but I never saw any mention of what I am about to write.

I have 2 GN trailers, each with those little brake batteries. I read the entries where someone says they didn't change them for 7 or more years, but I don't believe they were good for anything close to that long. Most are SLA, meaning they are just like your drive vehicle, thus should never be expected to last more than 4 years under optimal conditions. But they are not in optimal conditions --

For my trailers, the battery had no method of being charged. The battery is isolated from any electrical source or load until the "pin" is pulled, then it is supposed to power the brakes. Thus if it is isolated, with no chance of being charged, how long would you expect it to be good? Yep, maybe a year if you cross your fingers. And no, unless something special is done in terms of circuitry, even connecting the trailer to your vehicle with the brake lights on, does not charge the battery. If you don't believe me, do this and use a voltage tester on the battery.

Here is what I did. First, my tow vehicle (GM pickup) has one of the seven connector pins for +12V power full-time. However when I went to test it, there was no power. The manufacturer decided they could save a few pennies by leaving out the fuse for it in the fusebox. I researched and found that was all I needed to do. Now I have power at the connector.

Next, on both of my trailers, I again tracked that power line. On both trailers, that full-time power (when connected to the tow vehicle), was connected to nothing. So I wired it so that the power wire now goes to the trailer's safety brake battery.

Now when my trailer is connected, that little battery is being charged with the same voltage as my tow vehicle's battery. I can rest assured that even if I don't use the trailer for months, the battery gets recharged when hooked up for use.

Good points. My truck did have the +12v active, but, the Diamond C trailer did not have the battery connected to any incoming power, so as you mentioned, it would never charge. As I mentioned, I added a solar panel and the Hopkins charger specifically for this purpose. They say it prevents over charging the trailer battery from the vehicle. I'm not sure that it really needed that protection, but for the $6 they wanted for it, I decided it wasn't worth thinking about/debating over and just put it in anyways.

 

[kpsp50]

I use a regular car battery on my flatbed trailer with a maintainer the battery is over 12 years old and still going good on my welder generator I use battery with a battery tender and it is 15 years old still going on my gen set I use a harbor freight battery maintainer those batteries are 8 years old and on my motorcycle I use a battery tender and it's 5 years old and still going strong that should give you an idea of how good the battery maintainers are and how long they will last good luck on your venture

 

[Golden Rocket]

Personally - the battery is never an issue unless it will not take a charge because of an internal short etc - then it gets replaced - for regular use, once a year even, the battery will charge from the vehicle running (as long as you wired it to a source thru the 7 pin connector) and typically takes 20 mins - so by the time you get there - same for the battery onboard for a hydraulic power unit - it if aint charged enough, just let the tow vehicle run

 

[buckeyefarmer]

My trailer gets used once or twice a year.
Need to use it soon, Just put new taillight on. Planning to get new battery.

 

[Goodwinch]

I wouldn't call anyone crazy because of how they treat their batteries. I didn't call the guy crazy that claimed to have poured snake oil in crankcase and driven a car 250,000 miles without as much as checking oil,much less changing it but i wouldn't be following his example.

Reminds me of an elderly guy who came to the shop with an engine issue. Think it was an early 60's mopar station wagon. Had one of those oil filter canisters that attached to the engine with hoses. I pulled the lid off and found a roll of toilet paper inside. Gentleman swore by the toilet paper; I swore by the bill for overhauling the engine! Still makes me smile after all these years later. My philosophy was like yours Jaxs in that I never called him crazy!!

 

[dodge man]

That toilet paper filter was a real thing and my understanding was it was pretty effective.