I believe MIDI fuses can be slow blow. Do you have a spare to swap out and check?
Strange issue with DC-DC charger [Resolved]
- Thread starter Matt_camps
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- ctek dc - dc charger renogy
Do consult a proper auto electrician on this, but a 30A fuse seems likely to blow on a DC-DC charger with a maximum of 50A charge capacity. If your leisure battery was low, and the charger tried to deliver the full 50A from the starter / alternator, for example.
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was previously using a CTEK unit, recently swapped to the Renogy unit thinking it was the charger that was the issue but did limit this to 30A in the app before starting the engine so should be able to rule this out?
Am starting to think I’ll have to take it to an auto electrician, has anyone any recommendations in the NW area (Preston)
That you’ve limited it with the app is great, but I think that fuses are normally rated about 10% over max expected load.
Just a thought about this - worth metering the charger across NEG and ALT prior to starting the engine - voltage would be roughly the same if the fuse was to blame. Starting the engine might draw enough power to blow the fuse.
Get a helper, and put your meter across the starter battery + and the Renogy ALT, repeat the tests you already did.
Do it again from the Renogy side of the starter battery fuse to renogy ALT.
Do it again from the Renogy NEG to the starter battery -
This may show you where the 3 volts is getting lost.
I'm in Clayton-Le-Woods near Leyland if you're stuck.
Do it again from the Renogy side of the starter battery fuse to renogy ALT.
Do it again from the Renogy NEG to the starter battery -
This may show you where the 3 volts is getting lost.
I'm in Clayton-Le-Woods near Leyland if you're stuck.
When all wires are connected to the DC-DC charger the voltage is low before the engine is turned on.
As soon as the ALT wire is connected to the ALT IN terminal on the DC-DC charger the voltage drops regardless of if the engine is on/off or if the leisure battery is connected/disconnected on the output terminals. I will change the fuse regardless as i've a spare lying around, thanks again for your help with this
Ah not far away thanks for your offer of help, might take you up on that!
I tried this on the resistance setting but good shout to measure the voltage! Should be able to get someone from work to give me a hand with this today, will post results.
Issue resolved! It was not the fuse itself but a loose connection on the fuse in the engine bay on the alternator wire. Thanks everyone for your help, very much appreciated.
Now just have to decide if it’s worth keeping the new Renogy unit over the CTEK. Think I’ll keep the CTEK as a spare now the Renogy unit is in.
Now just have to decide if it’s worth keeping the new Renogy unit over the CTEK. Think I’ll keep the CTEK as a spare now the Renogy unit is in.
Superb!
Great stuff.
If It were mine, and if the wiring was suitable, and especially if the LB was lithium, I'd have a bigger fuse ready to replace that 30A. Renogy suggest 75A for the job (I fitted a 60A).
Will keep the Renogy fitted ready for future mods to the battery then I think.
Still running with a Gel one at the moment and I’m not sure what size the wiring is either, not convinced it is 16mm
As a few have mentioned your cable looks to be way underrated. The 50A Renogy needs 16mmm2 if running from starter battery to leisure battery. The manual also recommends quick blow ANL fuses. If its a long run then one at each end of the cable run. One ANL fuse holder and fuse is supplied with the Renogy unit.
Thanks for the reply, i have the Renogy unit set at 25A max charging current so shouldn't be an issue.
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