Battery Protection from alternator.

[dsswerwe]

I have an aftermarket additional alternator (24v, 100A) installed in vehicle for charging 24V battery bank without external voltage regulator sometimes my load and battery bank takes current from alternator simultaneously.

Connection Details:

Additional Vehicle Alternator -> Battery Bank -> Load

Normally its voltage cutoff at 28.5 volts, but we have observed that they went up to 32v which can damage our load. I need protection (overvoltage/over current) for my equipment and batteries from alternator.

I think Victron Energy Smart Battery Protect 24 V 100A will fulfill my requirement. The datasheet shows that it protects the device/load when input voltage exceeds from 32.6v, I need it to be maximum 28.8V. Can anyone tell me that its input voltages are adjustable/pre-set or not? If there is something else please suggest.

https://www.victronenergy.com/upload/documents/Datasheet-Smart-Battery-Protect-65-A--100-A--220-A-EN.pdf

 

[danadak]

The over voltage condition, is it pulse or more of a DC condition ?
If pulse any details, like timing limits......

Pulse conditions possibly :

High Power | TVS Diodes | High Power Diodes - Littelfuse

www.littelfuse.com

https://www.mouser.com/new/bourns/bournsPTVS/

https://www.mouser.com/new/eaton/eaton-high-power-tvs-diodes/

If DC condition any problems simply dropping V using high power zener or series high power diodes ?

Does our DC-DC charger has a protection for input over voltage and if it has a protection what is the input over voltage limit?​

Why not directly contact them at [email protected], with a question like is Vmaxin a full current
spec or is spec load dependent....? And other questions.

Have you looked at Over V condition with a DSO to capture event, if pulse condition ? Eg. is this a load
dump situation ?

https://www.ti.com/lit/an/snva681a/snva681a.pdf?ts=1690281680868&ref_url=https%253A%252F%252Fwww.google.com%252F

https://m.littelfuse.com/~/media/electronics/application_notes/littelfuse_tvs_diode_meet_automotive_load_dump_standard_application_note.pdf.pdf

https://www.analog.com/en/technical-articles/loaddump-protection-for-24v-automotive-applications.html

Regards, Dana.

 

[bidrohini]

From the datasheet, it looks like you cannot preset the cut-off voltage to 28.5V. Anyway, to be more sure it's better to contact victron energy. I can see their email id given in the datasheet.

 

[kellys_eye]

You seem to be very nervous of an over-voltage situation! Not the first post you've put here on the subject.

The device you link to does what it does to protect the batteries - not your equipment. If you want your equipment to be protected then ensure it is capable of either operating at the 'dangerous' voltages or has it's own input protection. Properly designed equipment does.

 

[kellys_eye]

I have an aftermarket additional alternator (24v, 100A) installed in vehicle for charging 24V battery bank without external voltage regulator

Give us the spec of this alternator. Surely it has an INTERNAL regulator? If it hasn't then what are you using to regulate the output anyway?

It's output can only exceed 28.8V if it's either not working or you momentarily disconnect the battery (when you might see a surge higher than 28.8V due to the speed at which the regulator operates i.e. not quickly enough).

 

[danadak]

Of course jump start can also be an issue :

https://m.littelfuse.com/~/media/electronics_technical/application_notes/varistors/littelfuse_suppression_of_transients_in_an_automotive_environment_application_note.pdf

Regards, Dana.