Split charge diodes

Aethelric · Post by **Aethelric** » Fri Mar 07, 2008 10:51 pm

Has anyone actually tried using these:-

http://www.marcleleisure.co.uk/Sterling ... e%20Diodes

There were a few posts a year or so ago, but I could not find anything conclusive. They now have a 130amp unit available.

Dave

moonshine · Post by **moonshine** » Fri Mar 07, 2008 11:15 pm

Not actually used them, but if they've got round the problem usually associated with blocking diodes i.e voltage drop, then they should be ok. One of the main advantages of diodes is that there are no moving parts or contacts to wear out, unlike relays. The main disadvantage was the inevitable voltage drop meant that neither battery got a full charge.

Aethelric · Post by **Aethelric** » Sat Mar 08, 2008 12:31 am

moonshine wrote:Not actually used them, but if they've got round the problem usually associated with blocking diodes i.e voltage drop, then they should be ok. One of the main advantages of diodes is that there are no moving parts or contacts to wear out, unlike relays. The main disadvantage was the inevitable voltage drop meant that neither battery got a full charge.

Yeah but is not like for like.
Diodes are non-linear and you get about .6V at virtually no current at up to 1.2V at maximum current.
MOS FETS tend to look resistive, the voltage drop is proportional to the current and the 40mV drop must be at some particular current. I can't find out what it is from the specs.

corblimey · Post by **corblimey** » Sat Mar 08, 2008 8:22 am

They're the Sterling Power ones aren't they?

Have you found this page http://www.sterling-power.com/products-diodes.htm There's more reading to be had further down the page.

I also looked at these a while back but couldn't see the advantage over voltage sensing relays plus the wiring would be a more awkward to fit because you have to get at the alternator.

Aethelric · Post by **Aethelric** » Sat Mar 08, 2008 10:46 am

corblimey wrote:They're the Sterling Power ones aren't they?

Have you found this page http://www.sterling-power.com/products-diodes.htm There's more reading to be had further down the page.

I also looked at these a while back but couldn't see the advantage over voltage sensing relays plus the wiring would be a more awkward to fit because you have to get at the alternator.

Hmm - curious - the ones on the Sterling site look like conventional diodes, but the ones on the Marcle site look like FETs. I have emailed Sterling for clarification.

They suggest taking the main feed directly from the alternator using a new additional cable. I'm not sure why, I'd be tempted to re-route the existing cable but I don't have a bongo yet to check that out (this will be remedied tomorrow!!!!)