Durite voltage sensitive relay

[swift1894]

I bought one of these to go between my house and starter batteries, along with a Sterling alternator regulator, to switch over and charge the starter battery once the house batteries are full. The terminals on the relay look pretty puny though, considering the charging cable is 1AWG. Looks like I can get terminals off eBay (item number:141744538476)

Cable size 50 mm stud size 6mm. Is this the right way to do it?

Edited June 4, 2016 by swift1894

[pete.i]

Dunno what 1AWG is some american fangled stuff. But I used the stuff that came with the relay on both my boats and it works just fine.

[Tony Brooks]

If the 50mm refers to the total CONDUCTOR cross sectional area then 50 sq mm is rated at 345 amps so would be fine. 6mm OD studs seem the norm for charging relays.

 

I am not going onto ebay to look up the terminals you refer to but I would suggest that you need battery/starter eye terminals with a professional crimp. Not some half hearted attempt wit pliers or a big hammer.

[Loafer]

Am I right with this:

 

If you use a VSR to connect your starter batteries to your domestics, there COULD be a situation where the current flow through your VSR might be very high. This could be caused by short-term engine runs (e.g. to power your coffee machine) which don't bring your domestics up to the VSR trigger voltage.

 

The result of this may be that the next time you run your engine for a decent period, your starter battery may be at a low-ish SOC, having started your engine a few times without a re-charge. Now, when connected, there could be a short-term high current demand from your starter battery, all flowing through your VSR.

 

Avoid short-term engine runs!

[Chalky]

If it's the 140A device they're very good. I've used them on a couple of vehicle split charge systems and also on also on a robot. Wired it up using 50mm CSA cable and used eyelets that fitted the cable and the studs.(they're available from automotive stockists). I also fitted a 150A megafuse in the cable. I had to modify the relay case to get the cable and terminal in. Make sure the ground wire has a good solid connection - a poor one will shift the switching point and it may not charge well.

The relay closes at about 13.2v and opens at 12.6v (from memory). If your batteries are in poor condition or the charging system is not working well the voltage at the first battery wont be high enough to switch the relay and charge the second battery.

I made the terminal connections using a hydraulic hex crimping tool. 140A is a lot at current and it doesn't require much resistance to generate a lot of heat.

Edited June 4, 2016 by Chalky

[swift1894]

If it's the 140A device they're very good. I've used them on a couple of vehicle split charge systems and also on also on a robot. Wired it up using 50mm CSA cable and used eyelets that fitted the cable and the studs.(they're available from automotive stockists). I also fitted a 150A megafuse in the cable. I had to modify the relay case to get the cable and terminal in. Make sure the ground wire has a good solid connection - a poor one will shift the switching point and it may not charge well.

The relay closes at about 13.2v and opens at 12.6v (from memory). If your batteries are in poor condition or the charging system is not working well the voltage at the first battery wont be high enough to switch the relay and charge the second battery.

I made the terminal connections using a hydraulic hex crimping tool. 140A is a lot at current and it doesn't require much resistance to generate a lot of heat.

It is the 140A model. Did you connect the ground wire to the negative terminal on the alternator.