Charge a second battery while driving

[Chatham]

Let me explain.
Every 15 days I hit myself 700km by car to go to work.
My idea is to connect a second battery to an alternator, which once charged will provide me with electricity to power the lights in the house. It is true that this makes a manipulation take out the battery of the car and connect it to the light network of the house.

FYI, the electricity produced by the alternator is not free: it consumes fuel (in continuous operation, it represents ~ 1/2 liter per hour)
When driving during the day, the alternator only outputs a very short time to recharge the battery after starting (150Ah for 1 or 2 seconds), the engine consumption is very low (injection + ignition), the lighting remains consumed a bit more ...
An alternator which is not excited does not consume power ...
To connect a 12v battery to the network of a house you need a converter / regulator that costs the asshole: this type of assembly is only interesting if you have an energy production installation on the house ( or the boat) with solar panels, wind turbine, stirling group, etc ...

[Christophe]

Yes chatman, especially that the alternator efficiency of a few years ago is around 50% and about this kk1 knows if there have been improvements in this area and what is the efficiency of modern alternators?

It is a bit like the controversy of 2005 of those who loudly claimed that the lighting of the daytime running lights did not lead to overconsumption .... It is not because we are unable to see overconsumption at the pump (margin of error / measurement) that it does not exist.

This is the kind of rather dangerous pseudo-scientific reasoning ...

[Other]

Hello

In certain cold countries, a second battery is installed in case of boosting in the event of non-starting
the auxiliary battery and connected with a diode on the +12 volt of the auto system
normally the alternator goes up to 14,4 volts with a diode that goes down to 13,8 volts but that is more than enough to recharge it

Now it's more expensive than charging it on the sector
little to gain.
to gain (a few hairs) it would be necessary that the recharging of this battery is done exclusively during the decellations
therefore a relay which puts it in contact only when you let go of the accelerator. Again at slowed it requires that although at idle the alternator flows little, but in decelleration descent it flows sufficiently.

Andre

[Christophe]

to gain there (some hairs) it would be necessary that the recharging of this battery is done exclusively during the decellations therefore a relay which puts it in contact only when one releases the accelerator.

I think that's precisely what bmw serie offers across its entire range ...
https://www.econologie.com/forums/bmw-effici ... t4303.html

[jonule]

not stupid, would need an electrical system as said André which activates the battery charge on decelerations! excelent!

FYI, the electricity produced by the alternator is not free: it consumes fuel (in continuous operation, it represents ~ 1/2 liter per hour)
When driving during the day, the alternator only outputs a very short time to recharge the battery after starting (150Ah for 1 or 2 seconds), the engine consumption is very low (injection + ignition), the lighting remains consumed a bit more ...
An alternator which is not excited does not consume power ...
To connect a 12v battery to the network of a house you need a converter / regulator that costs the asshole: this type of assembly is only interesting if you have an energy production installation on the house ( or the boat) with solar panels, wind turbine, stirling group, etc ...

well I ride free oil so the electric is free but good ...
finally what causes other overconsumption?
the radio?
car radio amplifier?
Heated seats ?
all the other electronic gadgets that push manufacturers to switch their alternators to 42V ... a good bastard voltage! ....... which would save copper, but I don't need nor want heated seats

the regulator can be welded yourself there are plans for pseudo sinus 500W, if not on ebay a 2000W 200 to 300 € at auction (150 made in hong kong), I get them in computer maagsins!
these are pure sinuses ...
ditto the batteries of the floor washer-style are recovered from the winders! by regenerating them (see link above), we avoid buying them from the skin of the buttocks, so that there are some left (from the skin)!

Well I repeat this solution is viable in autonomy (not nuclear), at low prices! and for isoéls sites it helps out, like I am helping out a friend with this technique right now ... it is not to save money on EDF, while waiting for prices to go up ...

[Chatham]

this battery should only be recharged during the decellations
therefore a relay which puts it in contact only when you let go of the accelerator. Again at slowed it requires that although at idle the alternator flows little, but in decelleration descent it flows sufficiently.

Andre

There is a car that has long used this principle efficiently (it runs electric at low speed): it's called a Toyota Prius ...

[Other]

Hello

Finally, how many km does it take to recharge a battery?
let's put 100 km max? let's put horrible consumption 10L / 100 max? or 10L of fuel? either € 12 in diesel, or € 7 in oil? (me it's zero € because filtered restau oil)

I also drive recycled oil on the diesel vehicle
but you forget to say that apart from the free side, you have to go and get it. store it decant it filter it, not counting the number of gasiol filters which clogs up which must be changed more often,
It is almost as free as the one who takes the trouble to cut his firewood in the forest.

To operate a 30 kw electric generator with recycled oil is more trouble than using the network circuit
there is the noise, to be profitable you must exploit the heat of the engine to heat the house, calculate the oil consumption and the tank to supply it.
Personally, hydroelectricity is difficult to beat in terms of price and clean energy.

[chatelot16]

the efficiency of a car alternator is bad: rarely more than 50% and there is no progress: the manufacturers seek rather to reduce the price and the weight than to improve the yield

overconsumption due to the charge of a battery seems low to you because a car consumes a lot: but there is no miracle the charge of the battery you pay it well in consumption

the only case where you could hope for a profit would be to put a bigger alternator with a special regulator to charge stronger when you want to slow down and not at all when you accelerate: the mechanical energy for the alternator will not be added to this that the engine must push but subtracted from what the brakes must lose: but the profit is low

the worst part is that car batteries are pierced baskets: they only return a small part of the energy that you put in them: you would absolutely need traction quality batteries, like wind turbines or photovoltaics

even if your oil is free it would be better to burn some in a good small diesel generator

and in winter the heat of this generator makes your heating which is better than in the car where the heat is lost

[jonule]

Yes, by the way, if I have a battery to charge it will be charged by wind turbine we agree, it's just that there are no small profits ;-) and with used oil one does not fear much ... the blow of the automatic recovery of the braking remains interesting, and a "stationary" battery can very well be connected in //, I recovered one of them of seat for electric wheelchair they are more profitable it is clear that the "starter" batteries ;-)

concerning the output of an alternator on diesel engine I also had as a figure 30%, the rest being much better restored in the form of heat, this is why I mentioned the principle of cogeneration to use a plate exchanger; - )))

I also drive recycled oil on the diesel vehicle
but you forget to say that apart from the free side, you have to go and get it. store it decant it filter it, not counting the number of gasiol filters which clogs up which must be changed more often,
It is almost as free as the one who takes the trouble to cut his firewood in the forest.
.

but that's what I mean ;-)

[Christophe]

the efficiency of a car alternator is bad: rarely more than 50% and there is no progress: the manufacturers seek rather to reduce the price and the weight than to improve the yield

Damn then, I was hoping for an improvement in performance in recent years ... but how to explain the good performance of group or power plant alternators and the bad of car alternators? Technology doesn't have to be so different, does it?

Is it due to the fact of a variable speed (therefore of a "smoothed average" performance for cars?) While the speed is constant on the groups?