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Redarc dc-dc charger says no breaker?

Batvette

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I have the redarc 12v 50a dc dc charger I have used for a couple of years on an older honda odyssey, planning on transferring it to my newer odyssey. On both setups I hook the dc right to the hondas alternator output.(redarc insisted to only attach to the vehicle battery, I thought that was pointless as it limits output to what the small oem charge wire can carry, I wanted full 1/0 all the way Anyway the odysseys battery + and alt out posts are electrically equal, there is no relay or fusible link. On the old ody the redarcs dc feed is fused with an anl fuse mounted on a uniframe box rail about a foot from the alternator. On my newer ody I want protection in the same spot only I really want to use a dc automotive circuit breaker, so I can easily switch off all added accessories. Its like this only 100a.






5155cJIMotL._AC_SY1000_.jpg
So im getting ready to start putting holes in my new ody and happen to notice (as Im carefully filing the redarc manual where I usually put such things after a quick glance, the trash can) specifically states to not use a dc circuit breaker because of the heat generated in charging. Is that right? So are we to take it that this circuit breaker isnt rated for any kind of continuous duty? Or is redarc just being silly? I went ahead and bought another anl holder so have both ready to use, i just dont want to have to pop out another 40 bucks for a switch and I have used similar breakers in the past in hi power car audio...which dealt with plenty of amplifier current but is less continuous because its music not battery charging.
FWIW this redarc unit is pretty badass build quality, was over $500 with shipping and tax but well worth it. Love its small size and that the internals are potted.

It seems to me continuous current is continuous current and theres a lot of these out there used as such.
 
Because of the heat generated in charging? I would throw the manual in the bin.

Expect that the current needed to make 50a at the aux battery is 62.5 at the alternator assuming it works at 85% efficiency (my personal rule of thumb) then size the breaker to 125% of 62.5 = 78.125 so an 80 ampere thermal protected breaker is right on the MONEY!

FWIW redarc will be my next dc-dc charger, they are solid units ...
 
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I run mine through two 120amp breakers and have no problems, I have them connected to the second truck battery just after the factory fuse and the negative as well. This is on a diesel truck so it is the secondary battery. My 50 amp Redarcs (I will be running two on the truck and one in the camper) draw 50 amps from the truck and output about 47 amps using 1/0 DLO rated at 260 amps. I have had it charging for hours and the breakers have never tripped.
 
Because of the heat generated in charging? I would throw the manual in the bin.

Expect that the current needed to make 50a at the aux battery is 62.5 at the alternator assuming it works at 85% efficiency (my personal rule of thumb) then size the breaker to 125% of 62.5 = 78.125 so an 80 ampere thermal protected breaker is right on the MONEY!

FWIW redarc will be my next dc-dc charger, they are solid units ...
The most charging input the JBD BMS on my 280a lifepo4 has displayed is brief moments of 46a in the morning. This is probably the limit of what excess my Odysseys alternator has to give it. Thats okay running components at less than 100% rating isnt a drawback IMO.
Your figure of 62.5 is of course dead on, but that would require an HO alternator to achieve and the one in it is a nippondenso rebuilt only about 7 months old. Also quite a chore to replace.
Im sure when installed in my 2016, the setup will see similar numbers. Even though 9 years and a generation apart, both vans have J35 engines and are equipped with alternators rated at 130a.
When the (still OEM) 2016 alternator quits, and thats a when not if, theres a rebuilder out of LA that sells on ebay Ive used before that has 200a models not much more costly than a standard rebuilt.
IIRC from car stereo competitions, 250a or more rebuilds actually have less output at idle.

I think the question is, is redarc implying that circuit breakers generate heat under load, and fuses do not? Im not sure that isnt a valid assertion, as fuses have no moving parts or contacts that might develop carbon deposits, but breakers do, dont they?

This may still be irrelevant if the breaker is being operated under its design parameters.

Its as if redarc is claiming our product has some kind of voodoo going on, you cant protect it with a device that no one else has problems with.

Or maybe its a matter of heat within the breaker causing resistance changes which messes with the redarcs computerized sensors.

For clarity Id better find the exact statement made by redarc and go from there.
 
Is the breaker a thermal magnetic trip type. If so, and you put it in a hot engine compartment, the thermal overload and trip can be effected by the engine compartment higher ambient temp.
And I would not use that breaker if I were to use one outside of the engine compartment. Get one from Blue Sea, get a Buss MRCB series 187 breaker. There are a lot of counterfeit breakers out there, and they are cheap.

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20220214_031734.jpgthis is the actual breaker I planned to use. The one in the OP was just a picture I found of something close. I did plan to use it in the engine compartment but its not near any exhaust components.
 
It is always best to ignore the instructions of the equipment manufacturer.

Just use two friking fuses sized to protect the wire.
 
It is always best to ignore the instructions of the equipment manufacturer.

Just use two friking fuses sized to protect the wire.
Yeah thats what I did on the previous setup, but I wanted the breaker so I could have a switch to seperate the accessory circuit from the vehicle system if necessary.
 
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Yeah thats what I did on the previous setup, but I wanted the breaker so I could have a switch to seperate the accessory circuit from the vehicle system if necessary.
What did you end up doing? I was wondering if a BlueSeas switch would work?
 
Is the breaker a thermal magnetic trip type. If so, and you put it in a hot engine compartment, the thermal overload and trip can be effected by the engine compartment higher ambient temp.
And I would not use that breaker if I were to use one outside of the engine compartment. Get one from Blue Sea, get a Buss MRCB series 187 breaker. There are a lot of counterfeit breakers out there, and they are cheap.

1644711013648.png
 
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