High Output Alternator

[CaMeLeOn]

I have a Ford Focus Mk2 1.8 petrol from 2006 and i have on it an 1500w Rms subwoofer, 1300w Rms amp, another amp 4x80w Rms, 1 Farad capacitor, 4 Speakers of 100w Rms each and 4 tweeters.

The alternator was changed last year to a bigger one (supposedly 140amp) and a 60Ah battery. My problem is that i still don't have enough current for everything, lights dim very bad, every light inside is dimming when the bass hits. I was thinking about installing a second battery but that will only stress the alternator even more in my opinion. Where could i find an online shop in UK or something that sales high output alternators ? 

[isetta]

Not sure if this is really to do with alternator or thickness of cables, where is the power to audio equipment cables connected to the car. If you have not run power cables direct from battery terminals to the audio equipment it might help if you do. 

[mjt]

I agree with Isetta. This won't be an alternator problem. To be honest if cost isn't an issue your best bet would be be to fit a second battery dedicated to the audio system and install a split-charge system. That will prevent dips in voltage on the second battery from being seen on the car's systems.

I'm just glad you're in Ireland - I wouldn't want you driving past my house every day with that kit!

[JW1982]

The Focus MK2 has the alternator capacity configured into the PCM. Most PCM types have 3 different configuration settings. 105 Amp, 120 Amp and 150 Amp. The PCM controls the alternator (Smart Charge System) based on the configured type of alternator.

Installing a higher capacity alternator (for example 150 Amp) can be done without any problems as long as the PCM configuration is also changed. Without changing the PCM configuration the PCM will not use the full capacity of the alternator. 

[CaMeLeOn]

On 6/29/2018 at 9:14 PM, isetta said:

Not sure if this is really to do with alternator or thickness of cables, where is the power to audio equipment cables connected to the car. If you have not run power cables direct from battery terminals to the audio equipment it might help if you do. 

Cable is running straight from the battery terminals to the cap in the boot, it's a 11.8mm thick cable of pure copper rated for 240amps. I've tested with a multimeter and with the car running and sound sistem disconnected it only shows 13.7 volts (normally should be above 14)

 

 

 

[CaMeLeOn]

On 6/30/2018 at 10:45 AM, mjt said:

I agree with Isetta. This won't be an alternator problem. To be honest if cost isn't an issue your best bet would be be to fit a second battery dedicated to the audio system and install a split-charge system. That will prevent dips in voltage on the second battery from being seen on the car's systems.

I'm just glad you're in Ireland - I wouldn't want you driving past my house every day with that kit!

But wouldn’t that put more stress on the alternator having to work more ? Didn't had enough time lately to go around and try and solve this mistery.

 

 

PS: I don't think my neighbours love me too much either 🙂

[CaMeLeOn]

On 6/30/2018 at 11:53 AM, JW1982 said:

The Focus MK2 has the alternator capacity configured into the PCM. Most PCM types have 3 different configuration settings. 105 Amp, 120 Amp and 150 Amp. The PCM controls the alternator (Smart Charge System) based on the configured type of alternator.

Installing a higher capacity alternator (for example 150 Amp) can be done without any problems as long as the PCM configuration is also changed. Without changing the PCM configuration the PCM will not use the full capacity of the alternator. 

Didn't know that, thank you, i will look more into it.

[mjt]

22 hours ago, CaMeLeOn said:

wouldn’t that put more stress on the alternator having to work more ?

The alternator's built-in regulator will prevent it being overloaded and the second battery will absorb the peaks. I know that's what the capacitor is supposed to be doing but it's obviously not sufficient. There are intelligent devices called battery-to-battery chargers which are simply connected between the vehicle battery and the second battery. I won't risk breaking forum rules by advertising a particular make but if you do a search for "battery-to-battery chargers" you'll find them. The advantage of this type is that it gives the vehicle battery charging priority and only diverts surplus charge to the second battery once the vehicle battery comes up to full voltage. It uses a multi-step charge profile, actively boosting the voltage by converting to AC, transforming up and rectifying and its design means that loads on the second battery don't get reflected back to the vehicle electrics.

Some split-charge controllers have their own regulators that have to be connected to the alternator, bypassing its own regulator. These would not be suitable for use with the smart-charge system on the Focus. The battery-to-battery charger avoids this problem.

If you still have the problem once you've got your car configured correctly for the uprated alternator this might be worth considering.

[CaMeLeOn]

11 hours ago, mjt said:

The alternator's built-in regulator will prevent it being overloaded and the second battery will absorb the peaks. I know that's what the capacitor is supposed to be doing but it's obviously not sufficient. There are intelligent devices called battery-to-battery chargers which are simply connected between the vehicle battery and the second battery. I won't risk breaking forum rules by advertising a particular make but if you do a search for "battery-to-battery chargers" you'll find them. The advantage of this type is that it gives the vehicle battery charging priority and only diverts surplus charge to the second battery once the vehicle battery comes up to full voltage. It uses a multi-step charge profile, actively boosting the voltage by converting to AC, transforming up and rectifying and its design means that loads on the second battery don't get reflected back to the vehicle electrics.

Some split-charge controllers have their own regulators that have to be connected to the alternator, bypassing its own regulator. These would not be suitable for use with the smart-charge system on the Focus. The battery-to-battery charger avoids this problem.

If you still have the problem once you've got your car configured correctly for the uprated alternator this might be worth considering.

Thank you so much for all the info provided.