small battery for emergency brakes?

[chriscowles]

I have a Shamrock 21DK with a dealer-supplied Deka group 24 marine battery. I plan to buy another like it and store both at home for maintenance reasons. I don't camp as often as I'd like so I don't go to the trailer as often as the batteries might require.

I keep the trailer at a storage lot elsewhere. When preparing for a trip I park in front of the house for loading. I don't necessarily want to haul the batteries back and forth. It's easier to mount and dismount them directly from my garage to the tongue.

While towing, it needs a battery to serve for an emergency brake in case of decoupling. In that case it only needs power for a minute or two. I'm thinking a much smaller capacity 12V battery would serve that purpose.

Am I way off base? If not, I'll get a very small battery and leave it on the trailer. When camping I'll connect up the others, in addition, then take them off before I return the trailer to storage.

Comments? Education? If this isn't a bad idea, what size battery should I get? If inadvisable to have the small battery hooked up at the same time as the dissimilar larger batteries, I can just unplug the SAE connectors I plan to install.

Thanks

[rana]

You're on base. Just about any sealed 12v (like the gel's you can pick up at Walmart for childrens power riding toys) can be used if you don't have far to go. $15-$20. It would probably need to be wired into the switch wiring though.. not through the main house cables. Your house parasitic draw might run it down too quickly.

For longer hauls they sell kits pretty inexpensively over at etrailer.com that can be used with dedicated battery and dedicated charger that works off the power pin on your 7 plug. In that type of a setup you can just leave the battery completely independent from your house batteries.

[TURBS]

E trailer has brake away kits.

[chriscowles]

Originally Posted by TURBS

E trailer has brake away kits.

I'm not sure if that's a misspelling or a pun. [emoji4]

[OldCoot]

Originally Posted by chriscowles

I'm not sure if that's a misspelling or a pun. [emoji4]

Remember, FT Turbs was kicked out of the entire Iowa school system his first day of kindergarten.

[Paulie1138]

If you go get the power toys battery, be sure you get one that is 12 volts, as they come in 6v and 12 volt versions!

[TURBS]

Originally Posted by chriscowles

I'm not sure if that's a misspelling or a pun. [emoji4]

Play on words!
Make no mind to oc, he's old and senile.

[OldCoot]

You can also use a sealed battery for a lawn tractor or motorcycle.

[geotex1]

Originally Posted by chriscowles

I have a Shamrock 21DK with a dealer-supplied Deka group 24 marine battery. I plan to buy another like it and store both at home for maintenance reasons. I don't camp as often as I'd like so I don't go to the trailer as often as the batteries might require.

I keep the trailer at a storage lot elsewhere. When preparing for a trip I park in front of the house for loading. I don't necessarily want to haul the batteries back and forth. It's easier to mount and dismount them directly from my garage to the tongue.

While towing, it needs a battery to serve for an emergency brake in case of decoupling. In that case it only needs power for a minute or two. I'm thinking a much smaller capacity 12V battery would serve that purpose.

Am I way off base? If not, I'll get a very small battery and leave it on the trailer. When camping I'll connect up the others, in addition, then take them off before I return the trailer to storage.

Comments? Education? If this isn't a bad idea, what size battery should I get? If inadvisable to have the small battery hooked up at the same time as the dissimilar larger batteries, I can just unplug the SAE connectors I plan to install.

Thanks

The only way you are off-base is in that your breakaway battery must be able to provide and maintain 15 continuous minutes of activation for the brakes. That's the letter of the Federal DOT requirements. That said, a kit like this one gets it done:

50-85-302 - Bargman Breakaway Kit System #50-85-302 - RedTrailers.com

I have used the Bargman kits quite a bit, and generally buying the kit is cheaper than the battery holder and battery independently unless you have a local trailer supply that buys the components in bulk. You can get them with the on-board charger for charging from the tow vehicle, or without. I personally have two batteries on a trickle charger in my garage at all times and just drop them in when needed when I couple my non-camping trailers.

[chriscowles]

Originally Posted by geotex1

The only way you are off-base is in that your breakaway battery must be able to provide and maintain 15 continuous minutes of activation for the brakes. That's the letter of the Federal DOT requirements.

Thanks for that fact, and to others responses and references.

With regard to wiring to the TV to allow recharge, how do I isolate it from the house circuit so as to avoid parasitic drain? If power from the 7-pin connector connects to both the house batteries and to the brake battery, does that not connect the brake battery to the house battery? Or does some circuitry in the charger prevent outflow back through the charging power source?

[geotex1]

Originally Posted by chriscowles

Thanks for that fact, and to others responses and references.

With regard to wiring to the TV to allow recharge, how do I isolate it from the house circuit so as to avoid parasitic drain? If power from the 7-pin connector connects to both the house batteries and to the brake battery, does that not connect the brake battery to the house battery? Or does some circuitry in the charger prevent outflow back through the charging power source?

Absolute cheapest way - install a simple toggle switch disconnect for isolation. Use the "on" position when you are hitched and charging, and flip it to "off" when you unhitch. OK, that's not THE cheapest - you can pull the terminal off the cell - but it is one of the cheapest and cleanest!

[chriscowles]

Originally Posted by geotex1

Absolute cheapest way - install a simple toggle switch disconnect for isolation. Use the "on" position when you are hitched and charging, and flip it to "off" when you unhitch.

I'm likely to forget. If there's a reasonably cheap way to accomplish it that doesn't involve my memory, that would work better.

[geotex1]

Originally Posted by chriscowles

I'm likely to forget. If there's a reasonably cheap way to accomplish it that doesn't involve my memory, that would work better.

How electrically savvy are you? It can be accomplished with isolation by relay, solenoid, or diode simply enough. Basically, these would be switches triggered automatically with a current sensing setup.

[chriscowles]

I correctly wired a major renovation on my house. I have the tools and skills but not the knowledge. Given a parts list and diagram, I could do it.

[geotex1]

Ok, then tell me if you tow vehicle provides +12VDC all the time or only with ignition on.

[chriscowles]

Originally Posted by geotex1

Ok, then tell me if you tow vehicle provides +12VDC all the time or only with ignition on.

Dunno. Will measure tomorrow.

[chriscowles]

Had a thought that might make this non-workable. I have a power jack. Am I correct in thinking the 5 watt battery can't handle the ups and downs?

[geotex1]

Originally Posted by chriscowles

Had a thought that might make this non-workable. I have a power jack. Am I correct in thinking the 5 watt battery can't handle the ups and downs?

As long as you park coupler high and drop on the ball, it's enough. If you were really looking to replace your house battery, it won't. However, you can always just back close enough to attach the trailer umbilical and use TV feed to adjust the jack and then couple/uncouple.

[rana]

Originally Posted by geotex1

However, you can always just back close enough to attach the trailer umbilical and use TV feed to adjust the jack and then couple/uncouple.

Double checking that your plugs power pin is wired and hot, keep your TV running, and it should be fine. I'm sure you're jack also has a manual socket as well.

[chriscowles]

Originally Posted by geotex1

As long as you park coupler high and drop on the ball, it's enough. If you were really looking to replace your house battery, it won't. However, you can always just back close enough to attach the trailer umbilical and use TV feed to adjust the jack and then couple/uncouple.

I'm not looking for the 5W to serve as house battery. I'll drop the 12V group 24 in place when I bring the trailer to my house to prep for a trip.

Your suggestions make my plan workable.

Thanks