Samlex DC-DC converter operation

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MTPinz
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Samlex DC-DC converter operation

Post by MTPinz »

My 710 came with a Samlex converter and I was curious how it was supposed to function. Having never dealt with a converter (or a 24v system before) I was wondering if there is always supposed to be 12v on the output side, or only when there is a draw.
As of now, I'm getting 24v on the input side but nothing from the 12 volt output side. The 12v side feeds a few receptacles but they are so corroded that nothing will make a connection to supply a load to check and see if it kicks on. The 15amp fuse looks fine.
Any suggestions?
Samlex
Samlex
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rmel
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Re: Samlex DC-DC converter operation

Post by rmel »

With 24v in you should see 12v out — assuming the fuse is good.
Likely has given up the ghost.
Puller: 71' 710K 2.7L EFI aka Mozo
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VinceAtReal4x4s
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Re: Samlex DC-DC converter operation

Post by VinceAtReal4x4s »

It looks a little weathered. Water may have gotten in there or enough mist/fog to corrode something. Luckily new ones are only about $100
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MTPinz
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Re: Samlex DC-DC converter operation

Post by MTPinz »

The whole truck is a bit weathered!
It's not surprising that a 20year old converter is kaput but once it stops raining (thankfully) I'll poke around a bit more and then if need be get a fresh one coming.
So 12v should be coming out with no load on it? I'll do some searching, but are these units still relevant?

Thanks gents!
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rmel
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Re: Samlex DC-DC converter operation

Post by rmel »

Yes, 24V IN and 12V OUT -- with Zero load to full load.
The Samlex is HOT ON. If there were an overload situation
the output voltage would drop below spec limit, and a
short at the output would result in current limit and blow
the input fuse if the short persisted.

BTW Samlex converters are pretty decent BUT ---

If your going to be in areas where your converter is exposed
to Dust and Moisture then get a converter that is convection
cooled (no fan) and has a decent IP rating (Ingress Protection).
e.g. IP43 or better.

Here's a recent thread on a similar topic: http://real4x4forums.com/PinzgauerBBS/v ... 9&start=15
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
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Texas710
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Re: Samlex DC-DC converter operation

Post by Texas710 »

The Samlex converters are not known for lasting that long. I had to replace mine pretty quickly after getting my truck, am fixing to install my 3rd converter but to #2 taking a dump on me. Listen to Rmel when he says to stay away from one's with a fan... Lesson learned.

One of the things I learned about the Samlex, if your batteries are not charged, or failing, the converter will not work right, just FYI before you tear into this much.

Overall, easy fix with the right equipment. Spend some time thinking about whats you want to use the 12v system for and that will help you design a good replacement.
MTPinz
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Re: Samlex DC-DC converter operation

Post by MTPinz »

Thanks guys that helps a lot. Makes sense that having a fan isn't the most desirable...I'll look into other options. I use a Victron solar controller for one of my Vanagons and haven't had any issues with it over the years so maybe I'll try one of theirs instead of the Samlex. I don't plan on using a ton of 12v stuff, just a charger for the phone really...maybe some LED driving lights...probably less than 10amps total. I'll probably just rock a BT speaker for the tunes.
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Re: Samlex DC-DC converter operation

Post by VinceAtReal4x4s »

A lot of the LED driving lights are multi-voltage by the way.
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MTPinz
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Re: Samlex DC-DC converter operation

Post by MTPinz »

Bringing this back around...

What's the difference between the Victron IP67 converters and the Orion style ones. The IP67, which seems like what I want in an open top rig, is waaay cheaper than the equivalent Orion counterpart. Why? What am I missing here?

https://www.victronenergy.com/dc-dc-converters
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rmel
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Re: Samlex DC-DC converter operation

Post by rmel »

It's a matter of the tradeoff your willing to take.

IP67 is a very high rating, Dust tight, and a degree of protection if immersed under water for a short period of time.
IP43 will prevent any particles from ingress if 1mm or larger, and resistance to water spray.

IMHO, IP43 is just fine if the unit won't be exposed to water, and as far as dust goes, being convention
cooled there's nothing to "Draw" dust inside the unit.

For more details on the IP ratings, look here https://www.iec.ch/ip-ratings
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q
MTPinz
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Re: Samlex DC-DC converter operation

Post by MTPinz »

Thanks Ron, good info there. I had no idea what the specifics of the IP ratings were, or even what IP stood for honestly, other than the higher the number(s) the better the protection.
As my requirements for amperage draw are so low and insignificant, I think I'll go with the fully potted IP67 20 amp converter and see how it goes.
1609414511_upload_documents_1600_640_q90-ORI241220260_Orion IP67 24_12-20A (front).png
1609414511_upload_documents_1600_640_q90-ORI241220260_Orion IP67 24_12-20A (front).png (897.06 KiB) Viewed 232 times
I'll update once it's up and running.
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