Thread: Solar controllers

Originally Posted by trout1105

That doesn't make sense.
Why would you put a 70A fuse between a 40A charger and the load/batteries?

Because you don't fuse the panels on a camper as there aren't enough to exceed your fuse rating making it a moot point.

You fuse the load to prevent the dcdc unit feeding a short if something happens to the load and to protect the batteries if the dcdc unit cocks up and the batteries back feed into it.

that unit is rated at 45V input 850 Watts (Solar) so that's only 20 amps input from the panels so never gonna blow the fuse if you put one in the panel wiring..

I just went on the enerdrive site and you might want to do the same.

DC2DC - In Vehicle Installation (enerdrive.com.au)

Originally Posted by DiscoMick

.......................................... Also recommends 70amp fuses both ends of the vehicle-caravan Anderson plugs connection.

When the Anderson plug falls out and drags along the road shorting out (or other cabling failure) the fuses protect the cabling, battery(s), alternator and charge in BOTH batterys

How do I know this ? "been there done that"

Deano

Originally Posted by DiscoMick

.................................. Enerdrive recommends using 70amp fuses with its 40 amp DC-DC charger and unregulated solar panels.

This is because the 'Enerdrive DC2DC+ ePower Charger' charger already has its own inbuilt MPPT solar controller.

It is a very, very bad idea to connect solar panels directly to a battery without a solar regulator/controller. Voc of a nominal 12v panel is around 21v and can(will) destroy the battery.

Similarly it is a bad idea to connect a solar reg into another solar reg to charge your battery. It won't destroy the battery by overcharging (no solar reg) but will undercharge (battery never reaches capacity) perhaps leading to sulphation and further loss of capacity if a lead acid battery.
This is exactly what I found a couple of years ago in a very expensive high end camper. The owner stated the battery voltage had never got above 12.x volts in the 3 years he had owned it (from new). I re-configured the solar correctly and all was good
Being Australias' most expensive/futuristic camper van (at the Time) didn't guarantee the people that designed/fitted and tested it had a clue about setting up the electrics.

Deano

Originally Posted by johnp38

Because you don't fuse the panels on a camper as there aren't enough to exceed your fuse rating making it a moot point.

You fuse the load to prevent the dcdc unit feeding a short if something happens to the load and to protect the batteries if the dcdc unit cocks up and the batteries back feed into it.

that unit is rated at 45V input 850 Watts (Solar) so that's only 20 amps input from the panels so never gonna blow the fuse if you put one in the panel wiring..

I just went on the enerdrive site and you might want to do the same.

DC2DC - In Vehicle Installation (enerdrive.com.au)

With any 12v/24v solar setup on a van/vehicle I cant see any value in adding a fuse between the panel and the regulator.
With the enerdrive units I can't fathom why with say a 40A unit they recommend a 70A fuse between the battery/load and the unit when common sense tells me that a fuse less than the 40A rating for that application seems more appropriate.

The only fuses I use on my 12v solar sytem are located AFTER the battery and I haven't had any dramas with this setup over the many years that I have been using them.
With the exception of the winch circuit breakers on my 4WD's and boats the largest fuses I have used are 30A which allows plenty of current to run my fridges, compressor or whatever other 12v appliance I want to use, 70A seems rather excessive for this application as does running 70A fuses on the rear anderson plugs as the vast majority of anderson plugs fitted are only rated at 50A.

Originally Posted by trout1105

With any 12v/24v solar setup on a van/vehicle I cant see any value in adding a fuse between the panel and the regulator.
With the enerdrive units I can't fathom why with say a 40A unit they recommend a 70A fuse between the battery/load and the unit when common sense tells me that a fuse less than the 40A rating for that application seems more appropriate.

The only fuses I use on my 12v solar sytem are located AFTER the battery and I haven't had any dramas with this setup over the many years that I have been using them.
With the exception of the winch circuit breakers on my 4WD's and boats the largest fuses I have used are 30A which allows plenty of current to run my fridges, compressor or whatever other 12v appliance I want to use, 70A seems rather excessive for this application as does running 70A fuses on the rear anderson plugs as the vast majority of anderson plugs fitted are only rated at 50A.

Solar regulator went short, wiring between reg and battery fried, very lucky it didn’t set camper alight. This was wiring already installed when camper was purchased.
Lesson learnt, a battery can provide 100s of amps, any input or output should be fused if possible. Admittedly starter motors and alternators usually aren’t fused due to the very high current involved.

Originally Posted by Geedublya

Solar regulator went short, wiring between reg and battery fried, very lucky it didn’t set camper alight. This was wiring already installed when camper was purchased.
Lesson learnt, a battery can provide 100s of amps, any input or output should be fused if possible. Admittedly starter motors and alternators usually aren’t fused due to the very high current involved.

A 70A fuse for a 40A regulator won't provide much protection either.
I have never had a solar regulater fry itself even the ones on my portable panels in the rain havent failed, A loose wire on your failed regulator perhaps?

Originally Posted by trout1105

A 70A fuse for a 40A regulator won't provide much protection either.
I have never had a solar regulater fry itself even the ones on my portable panels in the rain havent failed, A loose wire on your failed regulator perhaps?

It will protect the flatteries if the regulator shorts internally, the batteries will provide more than 70 amps and blow the fuse.

You're looking at it from the regulator end as the source and batteries as load, look at it from the batteries perspective as the source and the regulator as the load and suddenly the 70 amp fuse between the dcdc 40 amp unit and batteries has a purpose.

But yes a 50 amp fuse would suffice.

Of course if the regulator drops dead but turns into a load that only draws 20 amps out of the batteries that fuse becomes useless.

DC auto wiring is easy - [ power source +ve / fuse / switch / load / power source -ve ] - will get most things done. Even the complicated circuits can be broken down into simple individual runs if you spend a little time to understand what you're looking at.

Old school positive earth is the same except the negative battery terminal is the source and the positive terminal goes to chassis.

I like to run my trailer sockets and anderson connectors back to an earth bus bar near the battery.

Originally Posted by johnp38

It will protect the flatteries if the regulator shorts internally, the batteries will provide more than 70 amps and blow the fuse.

You're looking at it from the regulator end as the source and batteries as load, look at it from the batteries perspective as the source and the regulator as the load and suddenly the 70 amp fuse between the dcdc 40 amp unit and batteries has a purpose.

But yes a 50 amp fuse would suffice.

Of course if the regulator drops dead but turns into a load that only draws 20 amps out of the batteries that fuse becomes useless.

DC auto wiring is easy - [ power source +ve / fuse / switch / load / power source -ve ] - will get most things done. Even the complicated circuits can be broken down into simple individual runs if you spend a little time to understand what you're looking at.

Old school positive earth is the same except the negative battery terminal is the source and the positive terminal goes to chassis.

I like to run my trailer sockets and anderson connectors back to an earth bus bar near the battery.

It is my understanding that MPPT controllers are fitted with a fuse for the battery output internally.

Designed-MPPT-solar-charge-controller.jpg