Community Forums

rarebear.nm · 11-22-2019, 12:17 PM

I was wondering if anyone has seen anything about replacing trailer axle/brakes with a regenerative braking system, like used on EVs? The power generated could be used to recharge the house batteries as opposed to wasted heat. Best if used with lithium or lithium hybrid batteries.

I'm not really thinking about adding a boost from the trailer, just braking. So the motors would only be used in their reverse mode for power generation. I know a company is doing regen braking for semi trailers now.

Old-Biscuit · 11-22-2019, 12:25 PM

Isn't that what the 'charge' line from tow vehicle does?

jcussen · 11-22-2019, 12:36 PM

Quote:

Originally Posted by rarebear.nm

I was wondering if anyone has seen anything about replacing trailer axle/brakes with a regenerative braking system, like used on EVs? The power generated could be used to recharge the house batteries as opposed to wasted heat. Best if used with lithium or lithium hybrid batteries.

I'm not really thinking about adding a boost from the trailer, just braking. So the motors would only be used in their reverse mode for power generation. I know a company is doing regen braking for semi trailers now.

Excellent idea. Electric retarders have been used for years, but changing the design slightly to a generator type application would be great. Slowing a 20000 lb trailer would produce a lot of power to recharge your batteries. Yes, Lithium Ion would be best because they can take the high charging rate.
https://en.wikipedia.org/wiki/Retard...ctric_retarder

TonyMac · 11-22-2019, 12:52 PM

How much does it cost?

Soppy · 11-22-2019, 12:55 PM

It sounds like a good idea , but there are a few things to consider . The first is the added weight as well as the initial cost. I'm sure a system like that would work well to charge batteries. If your looking for payback on the investment, it probably won't happen. Semi trucks put on lots of miles so payback is an option.

rarebear.nm · 11-22-2019, 02:00 PM

The question was posted just as a curiosity.

The "charge" cable for a variety os reasons frequently does little to recharge the house batteries in many TV-trailer combinations.

From my reading lithium hybrid (lithium + supercapicator) can accept the high rate of power generation from regen systems much better (nearly 100%) than standard lithium batteries. I think common lithium batteries can only capture about 20% of the power produced from regen systems.

Cost payback? What about RVs is cost effective? For many of us they are our toys and an escape mechanism. Just seems like that standard brakes (drum or disk) are such a waste of energy.

TonyMac · 11-22-2019, 02:04 PM

Quote:

Originally Posted by rarebear.nm

The question was posted just as a curiosity.

The "charge" cable for a variety os reasons frequently does little to recharge the house batteries in many TV-trailer combinations.

From my reading lithium hybrid (lithium + supercapicator) can accept the high rate of power generation from regen systems much better (nearly 100%) than standard lithium batteries. I think common lithium batteries can only capture about 20% of the power produced from regen systems.

Cost payback? What about RVs is cost effective? For many of us they are our toys and an escape mechanism. Just seems like that standard brakes (drum or disk) are such a waste of energy.

I could not possible care less about wasting energy. I care about wasting money.

jcussen · 11-22-2019, 02:25 PM

Lithium ion batteries have a 1C rate, meaning if you have 300 ah's of battery, you could theoretically charge at 300 amps. Lead acid is .2C which means a max of 60 amps into 300 ah batteries. Have never seen one for sale, but probably one could be made from parts from a wrecked ev.

LAKnox · 11-22-2019, 10:27 PM

Nice idea, but where does all that juice go when the batteries are fully charged after the first 2 or 3 braking events? Might as well add on a braking grid off a locomotive to dissipate the resulting heat...and the fans needed to cool the grids?

Lyle

rarebear.nm · 11-23-2019, 12:05 AM

Any real numbers for power produced from regen braking? Total Amps/sec or other use full units? Lookup "Hybrid Supercapacitor Battery" if unaware what I'm talking about here. Your point about excess power is good, thanks.

Hey, non of this is about a real functioning product, just a concept, so I could care less about the money issue at this point. If you attach money to many products too early in concept development they would never scale up from research concept to a marketable product.

jcussen · 11-23-2019, 07:11 AM

Quote:

Originally Posted by LAKnox

Nice idea, but where does all that juice go when the batteries are fully charged after the first 2 or 3 braking events? Might as well add on a braking grid off a locomotive to dissipate the resulting heat...and the fans needed to cool the grids?

Lyle

Actually just like all EV's, regular disc or drum brakes will take over. If you are not putting any load on the generators, they will just freewheel and not produce any power or heat. Don't think cooling is a big factor even when current is being sent to the batteries. because generators will be on the axle and out in the air flow.

jcussen · 11-23-2019, 07:33 AM

Quote:

Originally Posted by rarebear.nm

Any real numbers for power produced from regen braking? Total Amps/sec or other use full units? Lookup "Hybrid Supercapacitor Battery" if unaware what I'm talking about here. Your point about excess power is good, thanks.

Hey, non of this is about a real functioning product, just a concept, so I could care less about the money issue at this point. If you attach money to many products too early in concept development they would never scale up from research concept to a marketable product.

Very interesting technology. Believe the tesla can supply up to 40 kw when regen braking. this battery would be ideal for quick acceptance of that charge.

IC2 · 11-23-2019, 01:34 PM

Thinking about how a towable is used, can't see any payback to a regenerative system. Most trailers are used at a CG and usually stay static for long periods of time vs being on the road. This means that you have an expensive battery charger that isn't used for a good part of the time, making you rely on another charging means - pedestal hookup or solar. Lots of money for no real advantage, Good idea to think about but pretty impractical for the normal/average RV owner

rarebear.nm · 11-23-2019, 02:30 PM

I would take exception with how you think most towables are used. When traveling with our 5th we seldom stay put anywhere for more than a couple of nights, many one night setups. I installed solar and it has provided 100% of our 12 volt power needs for several years. Converters are turned off. I know plenty of TT owners who move frequently.

As I said above I could less about the money side of this, it's only a concept. Could it be done and not why not.

In the years I ran software development projects I liked to hire younger people because they did not know something could not be done and then we got it done. The older folks usually told me why not.