Is This A Decent Split Charge Relay? (1 Viewer)

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pappajohn

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Just a tad overkill.

You will never gaet more than a few amps via split charge never mind 160a capability and 110v cable.

For that money you could have a battery or alternator to battery charger.
A standard 30a automotive relay and decent size wiring will do the job just as well.
 
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Yorick
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Just a tad overkill.

You will never gaet more than a few amps via split charge never mind 160a capability and 110v cable.

For that money you could have a battery or alternator to battery charger.
A standard 30a automotive relay and decent size wiring will do the job just as well.
The one I previously had was a 30 amp Smartcom jobby and constantly blew the 20a fuse, so quite a few amps kicking about ?

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So it seems obvious (to me) to get a higher rated one ?


Oh, and I understand that B2B chargers trick the alternator to work harder, won't this affect fuel consumption ?
 
Jan 28, 2008
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if you have solar the durites can be a problem due to the way they sense voltage the smart coms are to small to switch the possible load weve found the best solution is to use the smartcom to sense the voltage drop and trigger a heavier relay i think mine is around a hundred amp which is overkill but as it has bolt connectors makes terminating heavy cables from battery to battery easier
we still use the fridge terminal on the smartcom for our three way fridge ours is five years old and no problems yet i do keep meaning to buy another smartcom as im sure it will fail eventually
i disagree with john regarding only seeing a few amps a flat leisure battery can draw a lot of current when you start the van and relay kicks in otherwise where is the output of the alternator going?
 

scotjimland

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I understand that B2B chargers trick the alternator to work harder, won't this affect fuel consumption

as they say.. you get nowt for nowt

and B2Bs cost a lot more than sixty odd quid.. a lot more.
 
Jan 28, 2008
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this is only what i have gleaned from websites like the smbcc and here but from what i understand the durite compares voltage from both sides if solar is producing a charge voltage on the leisure battery side then the relay doesnt make even if the engine is running
the smart com works when engine side voltage rises regardless of the voltage on the leisure battery side
so on a sunny days driving with the durite you dont get the charge from the alternator
weve got 180 amps of solar and 225 ah of battery and weve not had any problems
as i say im no electical guru but it works for us
 

hilldweller

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i disagree with john regarding only seeing a few amps a flat leisure battery can draw a lot of current when you start the van and relay kicks in otherwise where is the output of the alternator going?

I suspect, just a guess, they use relatively smallish cable and it's length to ease that initial surge. But DIY and doing it by the book with big thick cables and the surge will be significant on a flat leisure battery bank.
 
Jan 28, 2008
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I suspect, just a guess, they use relatively smallish cable and it's length to ease that initial surge. But DIY and doing it by the book with big thick cables and the surge will be significant on a flat leisure battery bank.
you mean doing it properly using under sized cable to limit surge must be a fire risk

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hilldweller

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you mean doing it properly using under sized cable to limit surge must be a fire risk

Well you wouldn't make it too thin. Just lose a few volts to limit the surge. It all depends on the distance between the engine battery and the leisure battery. Ours is several metres and the circuit shows a 50A fuse.
 

pappajohn

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i disagree with john regarding only seeing a few amps a flat leisure battery can draw a lot of current when you start the van and relay kicks in otherwise where is the output of the alternator going?
Yes the alternator will kick out high current if the hab battery is flat, but only if that current can reach the battery through large cables and will diminish as the battery charges.
Don't forget, your engine battery is already fully charged and the alt senses this charge so reduces what's needed.
As for where does the excess current go if not to the battery...it doesn't go anywhere.
If the current isn't needed it simply doesn't exist in the same way there is no current in your house wiring...until you plug something in
 
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this is only what i have gleaned from websites like the smbcc and here but from what i understand the durite compares voltage from both sides if solar is producing a charge voltage on the leisure battery side then the relay doesnt make even if the engine is running
the smart com works when engine side voltage rises regardless of the voltage on the leisure battery side
so on a sunny days driving with the durite you dont get the charge from the alternator
weve got 180 amps of solar and 225 ah of battery and weve not had any problems
as i say im no electical guru but it works for us
I have a similar setup with same batteries and solar panel values, but am using a Durite, I have a switch to switch out the solar while travelling, on site we switch the solar back on. However since the charge I'm getting from the solar panel is usually sufficient, I do not bother with this routine, just leave it to the solar to do all the LB charging. I have a compressor fridge on permanently, even when it is sitting on the drive in the winter. I thus decided not to change to the Smartcom type setup. But it does make me wonder if I need a split charger at all, therefore.

I do get some rather loud clunks from the Durite with early sun-up, and also from the solar regulator. It's as if they are fighting each other.
 
Jan 28, 2008
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Yes the alternator will kick out high current if the hab battery is flat, but only if that current can reach the battery through large cables and will diminish as the battery charges.
Don't forget, your engine battery is already fully charged and the alt senses this charge so reduces what's needed.
As for where does the excess current go if not to the battery...it doesn't go anywhere.
If the current isn't needed it simply doesn't exist in the same way there is no current in your house wiring...until you plug something in
i disagree about the alternator cutting back, once that relay makes the connection the alternator will see both batteries as one
 

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