Towing Trailer - Charging Lithium Trailer Battery

[Midwest Duo]

We are looking at a new trailer that will have a lithium battery and a CTEK Battery Charger/Controller. The trailer builder says that, “the CTEK D250S battery charger optimizes the recharging of your trailer battery. It includes the functionality of a battery isolator and a solar controller. The D250S DUAL automatically selects the best connected DC energy source (from tow vehicle or solar) for the purpose and switches between them to achieve high efficiency multi-stage charging.

So I’m very challenged on this subject…. I have read that a vehicle’s alternator can be compromised when connected to a trailer running on lithium. I understand the LC doesn’t have an alternator. Is there anything else on the LC that I should be concerned with when 7pin connected to the trailer? The write up mentions the CTEK includes “the functionality of a battery isolator”… Is that protecting the trailer or the LC?

Do I need an isolator (or something) to keep the LC from charging the trailer?

 

[EOD Guy]

Not quite sure what you are asking......

If you want to prevent the LC from providing 12v to your trailer 100% of the time .......... you could disconnect the "Black" wire from the trailer's plug.

If you want to selectively prevent the LC from providing 12v to your trailer ............. you could install a battery selector switch inside your trailer to switch (black wire) between "12v from the LC" or "Off" or "Solar".

I'm not positive, as I've never checked, if the LC's system times out after engine shut off and doesn't provide 12v to the tow connector. If that is the case, it serves as a isolator and I don't think there's anything additional you need to do.

An isolator is intended to prevent overcharging and/or parasitic drain between two or more batteries.

Briefly glancing at the C-Tek's manual, I would think the Trailer's builder has done their homework by including it in their build specs and there's nothing to worry about.

 

[Midwest Duo]

Not quite sure what you are asking......

If you want to prevent the LC from providing 12v to your trailer 100% of the time .......... you could disconnect the "Black" wire from the trailer's plug.

If you want to selectively prevent the LC from providing 12v to your trailer ............. you could install a battery selector switch inside your trailer to switch (black wire) between "12v from the LC" or "Off" or "Solar".

I'm not positive, as I've never checked, if the LC's system times out after engine shut off and doesn't provide 12v to the tow connector. If that is the case, it serves as a isolator and I don't think there's anything additional you need to do.

An isolator is intended to prevent overcharging and/or parasitic drain between two or more batteries.

Briefly glancing at the C-Tek's manual, I would think the Trailer's builder has done their homework by including it in their build specs and there's nothing to worry about.

I wasn’t really sure what to ask! I suppose I’m trying to make sure that I’m not putting my LC electrical system at risk by commingling with a Lithium system through 7pin… because I’m paranoid.

The trailer builder is Camp-Inn out of Necedah, WI. They do teardrops. There’s some factory tour vids on YouTube. Two engineers got together 20 years ago and started this company. We drank the kool-aid on this one and we’re going forward.

Anyway, I appreciate you taking some time with this, EOD.

 

[EOD Guy]

No worries, honestly I think you'll be fine. The only time a Li battery is picky is when it's depleted to a very low level, the chargers designed for lead-acid won't charge the Li battery. However if you sister a charged 12v battery to the dead Li battery (via jumper cables/wires) it will fool the non-Li charger into start charging the Li battery and once the Li has charged enough to sustain the process, you can remove the jumper wires. Li chargers have a different logic in the charge process.

I have resurrected many 20v cordless batteries using the jumper method.

 

[ultane]

I have resurrected many 20v cordless batteries using the jumper method.

I need to do this today. A small 20v battery that powers a Craftsman back pack sprayer (vinegar for weeds) is DEAD, not responding to the charger. Relatively new set up, but after the last use, I left the switch on the sprayer turned on, while I fired up the grill to cook supper. Now, I just have to figure out how to do so. I am sure Duck Duck Go will help me find out how to do this.

 

[ultane]

I have resurrected many 20v cordless batteries using the jumper method.

It worked! I found an article on ‘Popular Mechanics’ that set me straight.. Then used an older 18V lithium Milwaukee battery to wake up the 20 volt lithium Craftsman battery for the lawn sprayer. Connected for five minutes, then charged it for a couple of hours. Worked beautifully! The weeds are dead!

 

[EOD Guy]

Yepper, I have a side project I'm currently working on.......... I purchased a super el=cheapo deWalt charger and gutted it, I'll run some parallel wires from my quick charger so in the end it'll just be plug and play without the loose wires etc........ I own too many 20v batteries that are used nearly every day and several times after a hard fast drain, I forget to drop them into a charger and they need a little help to start the charge process.