Is an 85A relay big enough for a split charger in my TD5 90?

[vtrdaz]

I've got an 85A relay and wondered if it would be big enough to cope with a split charger on my td5 90 (will be powering an optima yellow top)

Cheers

Darren

[Terranosaurus]

How bigs you're alternator - if it's under 85A then the 85A relay will be fine.

[vtrdaz]

think it's 120A on a td5 - does this mean it charges the battery at 120A?

[wizard]

No this means that the maximum current (or load ) you can put on it is 120amps.
A totally flat battery will draw about 30amps until it begins to charge then the current will drop steadely down untill fully charged.
A 85 amp relay will be more than fine for most split charge applications.

wizard :twisted:

[vtrdaz]

Thanks wizard - much appreciated!.
The solenoid won't be used for anything heavy - just running a fridge and a few other low power things - just wasn't sure whether the 120A meant alternator output or what it could be loaded up to , so as you say - the 85A solenoid is probably more than enough.

All cleared up now - cheers!

Darren

[Terranosaurus]

But if you're running a winch off you're second battery with the engine running it will draw every last bit it can from the alternator, thus you really need a 120amp relay, some of the 120amp available will be usedby the vehicle but this gives you a small safety margin on the relay.

[SteveG]

I would fit a larger relay. You can get one from the likes of X-Eng,  http://x-eng.co.uk/X-Charge.asp, or buy and build yourself

Cheers

Steve

[vtrdaz]

Thanks chaps
I wont ever be fitting a winch - it's only going to be used for charging the second battery which will run a fridge and a few other low power stuff like phone chargers , so it should be fine.

Darren

[jjsaul]

anyone know what the rating is on a standard rangie 3.5 alternator?

i want to fit a split charge on my offroader but will be running a 9000lb winch off it...

[solihull-mick]

All the split charge systems ive fitted i use a standard 70amp 4 pin relay, you can tell these by pins 30 and 87 are the large type spades, many cars use them for heated screens and such like, i get them of the net for about a fiver, made by durite, never had one fail yet, think its vehicle wiring products, or somthing like that :D