Battery Isolation \ security

[DeadBeat]

The Mrs is one of those horse types, well she is irish which should explain it!

She has decided to buy a cheap horse "lorry" which will probably be a 1990ish VW LT35 so she can drive it on her car licence. this is great for me as i have a 1990 vw also and i imagine they are mostly the same electronics wise, which will make it easier for me to upgrade for her

Ive always been pretty competent with car electronics as they're pretty easy generally, have made headlight relays and wired up total closures and such in the past.

Now to say the 1990 LT35's are basic would be an understatement, so im already planning a few upgrades to make her life easier, rearview cameras are really cheap these days, and i can fit her LED spotlights and other things that make her life easier.

One thing i would be interested in fitting would be a battery isolation switch, Horse lorrys spend a lot of time not moving, left on yards for trips every other weekend and the battery often goes flat. ive done a split charge relay before when i was into car audio. so im tempted to set her up a leisure battery for the lights and stereo and such. but in order to allow her to start the thing after a long sit at the yard and also for security, id like her to be able to completely isolate the battery.

TLR

The Isolation switches ive seen online I believe have to be situated between the battery and the rest of the system, and as such have to be situated near the battery am i correct? which would make it difficult to hide in the cab?

is it possible to have a remote isolation switch that could be hooked up to a switch nearer the cab? or would people be worried that it could be switched off while driving.

I was thinking a Relay that was big enough for cranking voltage, if such a thing exists. and a switch to open and close it in the cab.

I suppose in this instance the switch would need to be fused and if the fuse went the power would go out. hmm

any suggestions?

 

[freddiemercurystwin]

http://www.demon-tweeks.co.uk/motor...hes/autolec-fia-battery-master-cut-out-switch

 

[Jackrae]

If that one's only rated at 100A it's going to struggle when cranking a diesel engine. Maybe this one ?

http://www.gsparkplug.com/shop/heav...r-switch-with-removable-key-250-amps-24v.html

 

[Burnerman]

I think the higher current switch, just to be on the safe side......
Also, put the isolator as near to the battery as is practical (extending the battery leads a mile isn't a good idea).
I guess any extra battery would be wired in parallel with the existing one, and taking it's connection from the 'dead' side of the isolator - this should ensure that the original battery maintains it's charge......the other truck circuits would of course remain live.
However, the second battery could help start the truck up, and I've heard that leisure batteries aren't too keen on heavy discharge.
Any comments, anyone?
John

 

[Jackrae]

I'd agree that trying to crank with a leisure is a sure way of destroying it. They are only really capable of delivering C/10 and even then you're pushing them. For a 90AH battery C/10 = 9 Amps.

Also, if either the cranking battery or the leisure is relatively flat the surge current into the flat one when you parallel them up could be catastrophic.

The concept of the leisure for "social" facilities during engine stoppage is excellent so a split charge controller is a must

 

[DeadBeat]

well i think what i would do is re wire internal lamps and such to the new battery with a custom fuse box and run the second battery off a split charge relay. no need to run them together assuming i can shut the main battery down so it keeps its charge

 

[Burnerman]

Cheers for that, Jack- I haven't any personal experience of that installation.
It's maybe a bit more involved than the OP intended it to be!
John

 

[Mursal]

Split charge relay controlled off the little warning light wire on the back of the alternator. You can get it anywhere in the cab, connect it to pin 86 on the relay. Pin 85 to chassis earth. Pin 30 to the positive on the truck and Pin 87 to the positive on the leisure battery. The negative on the leisure battery will be earthed to complete the circuit. Contacts 100 Amp minimum for a long trouble free life.

Consider the little tilt cabs Man Diesel's all VW stuff and drivable on a car license.

http://www.gumtree.com/p/trucks/man-7.5ton-horsebox/1083919502

 

[DeadBeat]

That man is nice, but if you passed your test after 1997 you can only drive up to 3.5 ton not 7.5 which is stupid and annoying. have to take a test to bump it up which is quite expensive. Its more annoying because the 3.5 tonnes are now more expensive than the 7.5's as you can imagine.

might get the licence upgraded at some point, if the mrs needs a bigger lorry, but we would both have to do it as i dont want to have to drive her somewhere every weekend lol.

can anyone see an issue with the primary battery isolation switch, its mainly to protect the battery from standing which it likley will do here and there.

Id like to try and get it into the cab somewhere just so she will use it, otherwise if it isnt handy she wont bother. lol

 

[Jackrae]

Might be worth looking into what's actually causing the battery to drain - apart from old age (in which case an isolator will do nothing for you). Fixing the problem rather than developing a cure is always the better option - though not necessarily the easiest one.

If you rig up a leisure battery to the "service" facilities and use a blocking diode to prevent them using the cranking battery then there may be no need for an isolator.

 

[alan333]

How about a solar powered trickle charger? I've not used one personally so maybe do some research first. IIRC the radio is permanently live on the LT so mind and switch it iff.

 

[Belle427]

Or if you park near power rig up a decent quality battery charger with extended leads, you can run this via a plug in timer a few times a week.
Its quite easy to get hold of good quality male/female connections that you may be able to situate to plug in quickly.

 

[Astra99]

Hi

Going back to the late 1970s and early 1980s I had Crestas and Ventoras (until the maggot got them!). I had a dual battery system which used a standard starter solenoid (as used on inertia starters of that era) actuated when the starter was in operation (to get maximum current) and a 40A relay connecting the two batteries together on the accessories position of the ignition switch. Thus, both batteries were switched in during starting, and both batteries were charged while the engine was running, but were isolated when the vehicle was parked up.

HTH