40 Amp Shore Power Charging, With A $12 Server Rack Power Supply

[lexio]

For some reason the Victron 100/30 doesn't like my bench power supply. It makes it hiss as it tries to find it's power point.

nasty ( strange), my self i use a 40amp epever works good on power supply

 

[A.Justice]

That means your powersupply isn't providing enough juice.

A 30A MPPT, with a battery which is at approx 13.3V, requires 400W of power. Take 95% as efficiency for the MPPT means it requires at least 420W at the primairy side.

Since a MPPT wil 'hunt' for the maximum available power, it potentially will try to pull that 420W. Using a 30V power supply makes you need it capable of providing 14A.

If it's only providing 10A, it needs to have current limiting, and not just shutting down on overload. However, due to the nature of a MPPT, it might be the MPPT algoritm interferes (/is faster) than the current limiting of the PSU, causing it to flap and never find a proper point to actually start working.

To be on the safe side, make sure the powersupply is capable of at least 30A x 14.6V (maximum on paper with all cells at 3.65V) = 440W, add 10% for the MPPT, so go for 500W.
Also, make sure the powersupply provides at least 20V, since the MPPT requires battery voltage +5V to start working.

Maybe you can limit the MPPT to a lower than 30A setting, that might work with a smaller powersupply.

That's correct, but I even tried limiting the Victron to 1 amp charging, and had the same issues. It might just be my bench power supplies, I know other people have done it with good results.

 

[DJSmiley]

That's correct, but I even tried limiting the Victron to 1 amp charging, and had the same issues. It might just be my bench power supplies, I know other people have done it with good results.

Maybe the powersupply can't coop well with the surge currents during the MPPT searching for its maximum point.

As a test you can try to hook up some capacitors on the output (1000uF or so), they will reduce the stress on the PSU during short highcurrent pulses from the MPPT. Might be just enough to get the MPPT to find its point and start working.
(The capacitors will provide the addtional current during the small bursts). The more capacity, the better, but I think you don't need to go that high)


Cheap solution is getting an old server/router powersupply from Ebay. An old Cisco one is deal, they provide 42V or so at high currents,

Ascom Cisco Power Supply 1300 W Max D-59494 Soest 34-0918-02 | eBay

Find many great new & used options and get the best deals for Ascom Cisco Power Supply 1300 W Max D-59494 Soest 34-0918-02 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

$14 for a 42V / 27.5A PSU. That's over 1kW of juice... and will allow you to run 2 100/30's in parallel

you only need to wire the poweron signal so it will start without the chassis it usually belongs to, but plenty of info how to do so.

 

[lexio]

Maybe the powersupply can't coop well with the surge currents during the MPPT searching for its maximum point.

As a test you can try to hook up some capacitors on the output (1000uF or so), they will reduce the stress on the PSU during short highcurrent pulses from the MPPT. Might be just enough to get the MPPT to find its point and start working.
(The capacitors will provide the addtional current during the small bursts). The more capacity, the better, but I think you don't need to go that high)


Cheap solution is getting an old server/router powersupply from Ebay. An old Cisco one is deal, they provide 42V or so at high currents,

Ascom Cisco Power Supply 1300 W Max D-59494 Soest 34-0918-02 | eBay

Find many great new & used options and get the best deals for Ascom Cisco Power Supply 1300 W Max D-59494 Soest 34-0918-02 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

$14 for a 42V / 27.5A PSU. That's over 1kW of juice... and will allow you to run 2 100/30's in parallel

you only need to wire the poweron signal so it will start without the chassis it usually belongs to, but plenty of info how to do so.

will this thing not blow-up your charge controller ? a victron 100/30 can only handle 440 watt input if you go over that one you will bow up your scc please don't do this. always stay under the max wattage of your charge controller. this psu will give 1155 watt. even if you connect two victrons 100/30= 880 watt max it will blow both of them

dc-dc chargers are current limiting takes let say 140 amp in and gives a lower amp out lets say 60 amp that is why your psu alway needs to be bigger in wattage then your dc-dc charger.

scc controllers are not limited by the input amps/watts so always take a smaller psu in wattage then your charge controller can handle and at least 3v higher then your target voltage .

 

[Short_Shot]

yes this is what i meant. sorry for my English.

but on the other hand why not use your scc and your lab power supply 10 amp at 30v gives you 21 amp at 14v also done that. set your float to 14v else your voltage and your current will drop to soon.
also make sure that you have a 30 amp mppt scc and your solar disconnected.

connect every thing together 60 amp dc-dc and 21 amp scc gives you 81 amp.
and suddenly i realise i want to charge with even more amp to charge these things.

My mistake. I was hung up on the "ah" statement

 

[A.Justice]

Maybe the powersupply can't coop well with the surge currents during the MPPT searching for its maximum point.

As a test you can try to hook up some capacitors on the output (1000uF or so), they will reduce the stress on the PSU during short highcurrent pulses from the MPPT. Might be just enough to get the MPPT to find its point and start working.
(The capacitors will provide the addtional current during the small bursts). The more capacity, the better, but I think you don't need to go that high)

I've got some very large caps that I can try next time. That would be a really convenient way to charge, and could even be charged with the 40 amp DC to DC at the same time.

 

[lexio]

I've got some very large caps that I can try next time. That would be a really convenient way to charge, and could even be charged with the 40 amp DC to DC at the same time.

charge controllers don't give off surge currents. on the input side.

 

[A.Justice]

charge controllers don't give off surge currents. on the input side.

Honestly this is a little bit above my pay-grade, I'll just stick with the DC-DC, it works great!