240v - 12v Rectifier

[Richard.C]

Found the galley fridge wasn't running from the 240v few weeks ago. It had a waeco mps-50 rectifier that wasn't giving any DC output. Bought new mps-50 online and worked fine for 2 weekends of use, now the compressor tries to kick in but stops and then just keeps trying, switched over to the batteries and the fridge works fine. So I assume the new mps-50 has crapped out already.

Anyone know of other 240v - 12v rectifiers that auto select and prioritise 240v when it's available?

Thanks

 

[Happy Dayz]

I fon't know the kit, i do have experience in electronics, and think perhaps your taking the wrong diagnostic.

Two units have now failed - that needs to be investigated, perhaps the compressor (which has a motor in it) has become worn, causing an overload and blowing your rectifier.

Check you have a fuse in line with the fridge of the correct rating, not uncommon someone inserts a higher rated fuse due to it constantly blowing.

Fuses are rated to protect the cable not the device, cable is rated to handle the expected current needed by that device.

So say a 5 amps fuse is replaced by a 15 amp fuse which may seem to cure it, but may simply mean the cable can't pass more than say 7 amps. The 15 amp fuse will not blow and the cable could actually catch fire as the pump pulls more than it is rated at.

Alan

 

[Richard.C]

Just to add fridge details here's the nameplate, 12 to 24vdc is okay. It shows 42w, I wonder if the mps-50 just isn't man enough?

http://s216.photobucket.com/user/cranstonr/media/20160723_163439_zpsx8041uh5.jpg.html

 

[Richard.C]

I fon't know the kit, i do have experience in electronics, and think perhaps your taking the wrong diagnostic.

Two units have now failed - that needs to be investigated, perhaps the compressor (which has a motor in it) has become worn, causing an overload and blowing your rectifier.

Check you have a fuse in line with the fridge of the correct rating, not uncommon someone inserts a higher rated fuse due to it constantly blowing.

Fuses are rated to protect the cable not the device, cable is rated to handle the expected current needed by that device.

So say a 5 amps fuse is replaced by a 15 amp fuse which may seem to cure it, but may simply mean the cable can't pass more than say 7 amps. The 15 amp fuse will not blow and the cable could actually catch fire as the pump pulls more than it is rated at.

Alan

Thanks, unfortunately left my clamp meter at home so don't have a super accurate current measurement, however with everything else switched off the battery monitor is registering 3.5A current draw when the compressor is running so I don't think it's far out.

I'm wondering with the fridge rated at 42w and the rectifier 50w maybe there's an inrush that the rectifier can't handle.

 

[Happy Dayz]

Just to add fridge details here's the nameplate, 12 to 24vdc is okay. It shows 42w, I wonder if the mps-50 just isn't man enough?

http://s216.photobucket.com/user/cranstonr/media/20160723_163439_zpsx8041uh5.jpg.html

3.5 amps is not imho excessive, you will likely have a large old style electrolytic smoothing cap, these are known to dry out. Could be worth replacing, but you will only know if you fit another rectifier.

If you going to try it, theres no harm in uprating the rectiyer block, i'd just check all fuse ratings first, watch for any excessive heat being generated, perhaps fit or a bigger heat sink.

might be cheaper to fit a later solar battey controller, i bought s cheapy SOLAR30 £10 delivered.

On price i had not nexpect to much. happy as sandboy with it.

Gives me constant bat battery voltage on LCD diplay read out, i can turn off auxillary oiypit at a ptess of a button, trad load current and dolar panel current.

Latest version has two USB sockets.

There some copies but read up, get the one with round buttons and thicker pcb tracks, back is the hear sink, cheap copies have a plastic back.

The '30' applies to the solar panels handling current, i only have a 1200 bit wil be getting a bigger one for next year.

Got carried away, your going 240 down to 12 volts, so forget the SOLAR30 .


Alan

 

[Richard.C]

Thanks for your thoughts Alan.

Force 4 here in Lymington had the eps-100 in stock at £50 so I've fitted that and we'll see how it goes. There is 4 amp fused protection to the fridge so at worst it should just stop working.

 

[Happy Dayz]

Thanks for your thoughts Alan.

Force 4 here in Lymington had the eps-100 in stock at £50 so I've fitted that and we'll see how it goes. There is 4 amp fused protection to the fridge so at worst it should just stop working.

Your welcome,
It is rare you can have to much porr ability on tap, as equipment gets upgradrd or moves on having extra capacity is a cheaper 'upgrade' in time.

Alan