How to eliminate voltage sags in your car

Fighting with voltage sags

So, with the problem of voltage sagging in the hot yes to include voracious consumers are faced in one way or another a lot of owners of priors (and not just them). This trouble did not bypass me. When cold, the voltage is 14.3 on the generator, 14.2 on the battery, 13.9-14 on the onboard engine, which is very good. All this at idle. But when I drive in heavy traffic, with the air conditioner on and heated mirrors (in the rain) the voltage drops to 12.8-12.6. On the highway, everything comes back to normal, that is, the problem is only when driving in heavy traffic. The first thing that popped into my brain was to duplicate all possible wires, both plus and mass. But after thinking for a while, I decided to make some measurements beforehand, namely to measure voltage drop in different parts of electric wiring in different operating modes of the car. All measurements were made at idle, which is not quite fair to the generator and wiring, but nevertheless. Only the parking lights were on. I measured the voltage drop between the alternator stud and the positive terminal of the battery. The voltage drop is about zero, which is good. I turned on high beam, heated mirrors, heater on 4 speed. The voltage drop in this area is already 0.4V. This is a lot. Then I measured the voltage drop between the plus terminal of the battery and the red wire coming from the same terminal in the wiring block with the same load. The voltage drop is zero. Then I measured the voltage drop between the “mass” wires. The voltage drop between the battery’s minus terminal and the metal bracket above the mounting block is zero. The voltage drop between the battery minus terminal and the mass on the engine in load mode is less than 0.1V. This is not much, which is good. Where then comes the voltage drop, as the engine warms up, and with the included consumers? I measured the voltage at the alternator – 12.8V. This is the main culprit for the voltage drop. Either the voltage regulator is drizzling from overheating or the alternator. The alternator is new, 100A. Voltage regulator is “new sample” praised Orbit. Thus the only part of electrical wiring with relatively large voltage drop of 0.4V is the section from the stud of the generator to the plus terminal of the battery. Here it was decided to lay an additional wire. In fact, from the alternator stud, there are two wires with a diameter of 4 or 6mm^2 (I don’t remember now) in the same corrugation. The wires are pink and go each to a fuse rated at 60A (both blue) in the main fuse box, a black box under the hood near the battery.

Panel rebuild from VAZ 2110

To this box and laid a stranded wire cross section of 10mm^2. There are two regular wires, and I laid one, but much thicker than the regular ones. I decided to connect the laid wire to one of the regular pink wires. Here came the question: how to connect? You can, of course, throw the wire to the + terminal of the battery through an additional fuse, but my battery terminals already have so much stuff on them, it’s hard to figure out. So I had to drag it all the way to the black box.

I could not get the connector with the pink wire directly out of the plastic case. These connectors are very powerful. So I decided to simply bite off one of these wires.

Then, I terminated the wire from the fuse with the terminal with press jaws and connected it with a bolt to the terminal of the new wire.

And lastly, I took good liberty of bolting both the bolt contact and the bitten off old wire on the alternator side with xb duct tape.

So, I simply replaced one of the existing, regular, smaller cross-section conductors running from the alternator to the main fuse box with a much larger cross-section conductor. The voltage drop with the included consumers is now less than 0.1V in this section. This is the most important section of the wiring responsible for charging the battery. And here is how the fuse box looks like from above

The two parallel wires from the alternator come each to its own 60A fuse, and after the fuses already come to the plus terminal of the battery.

The wire that connects this fuse block directly to the battery positive terminal is crazy cross section and no voltage drop was found on it, of course.

So, if you are concerned about voltage sags, you first need to figure out their nature. Also, before you decide to run the extra wire, look at the contacts. They may simply be oxidized or dirty. If the oxidation is very bad (inside the terminal), and it’s impossible to clean it, then maybe it will be enough to bite off the oxidized terminal, clean the wire well, and press it into a new terminal, having previously poured technical Vaseline into it. I repeat that laying additional wires is the last resort If you still decided to lay additional wires, then turn on any voracious consumers and the moment when the voltage has dropped, measure the voltage directly on the generator. If the alternator voltage is OK, then we measure the voltage drop on the section: alternator pin – battery terminal. Next, we measure the voltage drop on the section: plus the battery – the fuse box (red wire with a cross section of 4 or 6 mm^2). Next, we measure the voltage drop on the mass between the battery minus and the engine.

Inverter for capacitor charging

Get rid of the voltage drop (80A alternator and doubling wires)

I would like to start with the fact that on Monday, the 16th of May I turned 2 years old, which means that my studies slowly coming to an end, graduation soon, and subsequently I will be able to fully earn “green papers”, so they can tell you all their “perversions” made with it onboard my 9. Plans abound, gradually ending with the stories of the old improvements, moving on to the new realization of the goals, there is not much left. :)

That is why I decided to carve out some free time to write another record, which will certainly be useful to all experienced tazovodami, as well as beginners who have just started to sink into all this swamp! =) This entry decided to divide into 2 parts, as much information which wants to share and one record, most likely, will not fit. Let’s move closer to the point – this time let’s talk about improving the car power supply – we will get rid of all sorts of voltage sags from various sources of energy consumption.

And as always, a little backstory, how did it all begin? Not everything is as simple as it seems at first glance. One beautiful summer day the generator decided to fuck up – on the dashboard, barely visible, the control light of the battery light turned on, signaling that the battery is not enough charge from the generator. It kind of hints: – “Why the f*ck are you doing other things in the nine and completely forgot about the power? That won’t do! “. If I, at that time, approached this case with a sober mind and a solid memory, you could understand that the car has long since left the dealership and this phenomenon, after 15 years, is quite normal. But, no – I am a poor student, who does not like such tricks of the car. Why exactly at this point decided to “command the long life” of the alternator? There was a lot of foul language, especially in those moments when I had no idea what could possibly go wrong. At first I gave up on this light: “Well, it burns and let it burn! “. Drove around for a while, it went out. Later, it began to flicker intermittently and finally lit up, as they say, at full power. I had to take the alternator off and figure out what the problem was. It turned out very simple – worn brushes of the alternator, which I replaced the same day. But, since I took it off, why not give it a full inspection? Together with my father we replaced the bearings, checked the integrity of the diode bridge, the winding and the armature. The first time I drove myself, everything was fine, no problems.

Solid state relay for turn signals in cars, two simple schematics

Then it came to the music, because of which I had to think about purchasing a more powerful alternator and the choice fell on the 80Amp alternator with 2112 injector. I scoured all the usual scrap yards in my “village” and found some good options, but the money was not satisfied. It was decided to look through available options on the Internet. In looking for scrap cars in Yekaterinburg turned up a good option pretty quickly. The next day I went to the city on business and came to buy an alternator. The seller was a good guy, Yury, who buys broken cars, disassembles them for parts and what is whole goes on sale. Agreed with him on the following: 1) alternator KZATE 2112 – 14B 80A 2) pulley drive alternator 3) Fixing the generator to the engine block As a result: 1500 rubles. I think the purchase is very profitable, because only one generator, without mounts and other nuances, in my city is the same money. Just a cast-iron pulley generator drive costs 700 rubles, not to mention the mounting of the generator to the engine block.

As always, the most interesting thing happens during installation. After inspecting the alternator, it was decided to replace the plastic cover, since the old one had two of the three fasteners broken. Also, during installation I found that the alternator pulley was a little bent. Of course it could be straightened with a few blows of the hammer on it, but there was no time to risk it. And the nine had been already disassembled and was on elevator – what could I do. On their own went to the nearest store, which bought: 1) pulley of the generator (n / o, D17) ~ 1) The pulley of the generator (n / o, D17). 125 rubles. 2) The alternator belt BRT. ~ 360 rubles. 3) alternator cover ~ 70 rubles. 4) Regulator relay (brushes) ~ 180 rubles . 5) Alternator belt tensioner bar ~ 140 rubles .

How to correctly photograph a car.

It was decided to replace all the necessary details immediately with new ones, so as to be fully confident in the performance of the generator and subsequently not have to disassemble it to fix any bugs. After installing the generator, made the first run, took a small measurement – the instrument showed 13.9 volts without load. Then we did not measure anything else, because there was no such a goal. The generator worked and on this well! :)

I drove myself for a while, but suddenly something prompted me to go back to the power supply in the nine. Namely: I had a problem with small brownouts at full load: the dipped headlight, stereo, heater on 3 and heated rear window. It took a few evenings to look up all the information I needed on the drive. It was decided to rewire part of the underhood, namely: remove shabby wires coming from alternator to battery, from battery to starter and engine block, replacing them with more productive cables, also add minus wire from body to alternator. Having written everything I needed on a sheet of paper, went shopping, were bought: 1) Cable KG 1×35 (3 meters) ~ 142.67 rubles/m = 428 rubles. 2) Copper ferrules (8 pieces – M8 and one M6) ~ 21 rubles/piece = 168 rubles . 3) Active battery terminals (+, -) (n/a, from vaz 2114) ~ 200 rubles . 4) Heat shrink tube (20/10) ~ 61 rubles . 5) Hose for cables ~ Free because I bought it in summer to bring in a more respectable form wiring car under the hood. The price tag, unfortunately, I do not remember – but one thing I can say for sure is that it is not expensive.

Why did you choose KG? I could have picked up some good brand cable, which would come out to me at least 4 times more expensive for exactly the same cross section, but the choice fell on the “Soviet” welding cable (KG – cable flexible). Find one you can almost at any electro-shop, there are different cross-sections of 8 and up to 120 KG-35 was chosen due to the fact that in the near future planning to start building a good music system, respectively, will need a good power supply, without dips. As protection for the KG insulation was selected corrugated, as cable insulation leaves much to be desired, in severe frosts can crack, which is not desirable for power cable. Also, I prefer to use a corrugated tube under the hood, so as to protect the cable from moisture and dirt.

Removal of creaks and noise isolation panel of KIA Cerato III. Comfort mat materials

That same day went to the box, in order to engage in the manufacture of wiring. What we need to make I have already described above, then proceed! =) For convenience I used the help of my best friend – vice. We clamp the wire in a vice, take a saw on the metal and neatly cut off the insulation from the wire, pre-measured on the terminal how much we need, not forgetting about the allowance of 2 mm. Then twist the wires in a pigtail and put it on the terminal / lug. Since we do not have clamps, we will use what we have – again, the vise helps us. I want to warn you right away that you can break your head. We carefully clamp the tip in the vice, hold the wire and squeeze the vice by smooth movements. It is not necessary to squeeze too hard, as soon as you feel that you are about to reach your limit – tie it off. Now it is necessary to protect the wire with an insulating tube. Then pull it through the corrugation and also insulate it with thermal tube at the edges, so the corrugation will sit exactly in its place and will not go anywhere. All, the wire is ready to be installed in the car! The rest of the wires are “assembled” in the same way and installed in the car. All the wires were run in the factory places, instead of the factory flimsy wires. This time I also didn’t made any measurements, all by impressions: the dipped beam was normalized (got brighter, at full power load), I could listen to music louder, at the same full power load – no dips were felt. It even seemed that the heater began to blow faster and more steadily at all speeds, without the slowdowns that were previously, though rare.

And don’t forget that bad power leads to bad things! )

The next step in power improvement was my choice of . Read on in the next part of the power improvement (part 2 of the post) ;)

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