Fitting a battery isolator and a conditioner / charger link

[Nifty]

This is not specifically for the 7 but more for the Esprit ... .though if it works I may do it for the 7 too.

 

The battery in the Esprit is tucked away in the rear corner and is a bit of a pig to get to or get in and out.

Inevitably with a 70s / 80s Lotus the electrical circuitry leaks current over time and so if left for any period the vehicle needs a jump start ... and it's a s@d to get the cables onto the battery.

 

What I'd like to do is install a battery isolator switch in the rear luggage compartment which will kill all circuitry apart from a set of leads which will be permanently attached to the battery posts with a plug at the other end (once again, readily available in the luggage compartment) to plug in a battery conditioner.

 

I understand that permanently fitted battery conditioner plugs and equipment are available so I was wondering if anyone had fitted one to a 7 (or any other car) and if so if they could give me some pointers and a brand / model number.

 

Cheers,

Nifty.

[Roger Ford]

I thought most people just used a standard cigar lighter socket - any reason that wouldn't work?

[Nifty]

Roger,

 

For the battery conditioner that would be fine, assuming I wire up the conditioner to a 12v cigar lighter plug ... though I did think there were purpose designed (and therefore more secure) plugs etc.

 

What I forgot to include in the original post was the desire to have a couple of jump terminals (connected / disconnected) via a battery isolator so in the event that a jump is required I just need to attach the cable ends to these terminals (readily accessible) with that isolator circuit closed.

 

In other words I have two isolator switches, one for the general circuit to kill all electrical flow when car parked up and one specifically to kill the jumper circuit when it is not required (to avoid accidental shorting issues ❗ ).

 

 

When I used to frequent Finland (and on the farm in Canada) we had terminals hanging down at the bumper for plugging in built-in battery conditoners and engine block warmers.

 

Edited by - Nifty on 22 Nov 2012 09:14:55

[MartinWoodham]

hey Nifty!

 

I've got a optimate conditioner and it came with two plug-on leads, one with eyelets for bolting through, and one with crocodile clips.

 

The plug they've used turns out to be standard for R/C model battery packs, albeit with the + and - the other way around if you buy the pre-wired ones...! maplin sell them cheap enough here.

 

I've already got an isolator anyway, ,so I made up a flying lead with a maplin connector on it that goes on the battery terminals upstream of the isolator and wiggled through the bulkhead to dangle under the dash.

 

Sounds like you could do similar, with an isolator in the boot - you want the leads carrying the cranking current as short as possible so I guess that rules out having the isolator switch anywhere handy!

[Shaun_E]

Nifty - most of the race cars I see with tiny batteries use Anderson connectors for jump starting. I have heard of a couple of Sevens with them as well.

Have a look here.

 

Edited by - Shaun_E on 22 Nov 2012 09:25:38

[MartinWoodham]

if you want a connector that can handle a jump-start, I've seen Anderson connectors fitted to race cars

[MartinWoodham]

snap!

[tbird]

this any help

 

Tim

[Smiffy69]

Quoting mwoodham: 

if you want a connector that can handle a jump-start, I've seen Anderson connectors fitted to race cars

 

Does anyone on BC know the cranking current ? my ammeter can't handle that level of current so I have no idea what it would be.

[tbird]

IRO 300A +/- 100A depending on engine size, compression etc

 

Tim

[Grebby]

If you make it so you can get access to the back of the isolator switch then you will have a +ve jump point. -ve can be picked up in many places.

 

I looked at fitting remote battery terminals to my 7 but it was cheaper to buy the battery master switch *confused*

[Smiffy69]

Quoting tbird: 

IRO 300A +/- 100A depending on engine size, compression etc

 

Tim

 

Ahh as I suspected it's quite high. The Anderson connectors highlighted are only rated at 50A so probably not "man" enough for jumping then.

[MartinWoodham]

175A version here, they go up to 300A or so but much bigger as the current capacity goes up

[Golf Juliet Tango]

The Anderson connectors look just like those used by the AA, so the higher rated versions will certainly do the job.

It's your call Nifty on whether you want a jump-start connection or a link to an Optimate/C-Tek type battery maintenance. Both of these come with connectors for a non-power outlet connection to the battery.

[Nifty]

Great ideas chaps *thumbup*

 

Would it be better to connect the Anderson (and therefore the jumping current) directly to the battery posts or through the isolator (battery side of course)?

Being a fibreglass car earthing points are notoriously poor in general (though obviously battery ground must be good) so would link the earth to the battery terminal.

My inclination is to place the isolator switch and the Anderson jump start plug on the righthand interior "wall" of the boot space.

If the vehicle needs a jump start, or to switch isolator on or off, I will need to unlock the engine / boot hatch ... thus it gives me security of bits and also keeps them dry / clean.

 

The battery conditioner lead I will place such that it can be "stored" safely away when not in use but can then be lowered through the engine bay to be connected up to the conditioner outside of the vehicle .. i.e I can shut and lock the engine hatch without having to shut wires in it.

Fortunately the design of the Turbo lends itself to this

 

What do you reckon ?

 

Vehicle is stored in a friend's lock up so won't be able to consider further until I am up there on Saturday but think the Anderson connector is a good idea.

Could fit similar to the 7 and then chop the leads on my battery jump pack and place a connector on the end of these .. et voila, one battery jump pack fits both cars neatly.

 

For the inevitable event, when Cathy flattens her Volvo again by leaving the lights on, I could make an extension using the removed crocodile jaws from the battery pack attached to a pair of cables (I've plenty) and an Anderson on the other end and I now have the crocodile teeth back for normal battery posts *thumbup*

 

Used in reverse I could also jump the 7 or Esprit from the Landrover battery.

 

Edited by - Nifty on 22 Nov 2012 18:46:27

[MartinWoodham]

for jump-starting, you want the connector as (electrically) close to the starter as possible, so ideally not having to go through the isolator or a long cable run, both of which will add resistance.

For trickle charging, you want the connector straight across the battery terminals, then you can trip the isolator out and have the batt being charged whilst there's no drain through any other circuit.

 

Sounds like 2 connectors - a weedy Tamiya R/C one for charging upstream of the isolator and an Anderson for jumping downstream of the isoltaor IYSWIM?!

[pugwash]

Some trickle chargers only trickle but some are full chargers. I have ctek charger fly leads permanently connected to my élan, my 7, my smart car, and am about to fit on my boat as well. The ctek chargers are great and will condition and charge the battery and tell you what is going on. Connect the fly direct to the battery or as near as poss. On my 7 it is on to the FIA isolator switch as this was a neater solution. I have never had to jump the elan in 15 years of ownership. If you get a good battery and look after it with a conditioner on it, it will last you a long time. I also had one on an Aston Martin which was notorious for flattening its battery and the ctek was great. The latest flyleads have traffic lights on the fly connector itself so you can see at a glance what the state of the battery is, although in the main when they are in the garage I keep them on the chargers.

[Nifty]

An Elan ....... 🥰 🥰 🥰

I was in the market for one a few years back when they were £5 -6K upwards .. bought another Esprit instead. Now they are £15K upwards and anything from £25-35K for a good one ... outside of my reach ☹️

 

 

Back on topic:

I think easiest solution will be to connect the Anderson either direct to battery terminals or to isolator switch. Due to the relative locations it will take a lot of chopping about or additional long lengths of cable to do anything more "bespoke", i.e fitting direct to starter.

I don't think resistance is of any real concern providing the jumping battery is charged up.

(When we have to jump start agricultural machinery you can often get the positive directly onto the starter terminal, but then resistance in the cables is often more significant due to conditions deterioating the wiring etc.)

 

On a slight aside, directions for jumping always advise connecting the neagtive to an earthed part of the chassis rather than the battery negative.

What is the reason for this ?

Is it to reduce the chances of battery overload / damage from the charging system ?

 

 

[Paul Deslandes]

My understanding was that the positive lead should be connected to the battery first, followed by connecting the negative lead to the chassis, away from the battery to ensure that sparks don't ignite any hydrogen being given off. I guess a bit of chassis resistance might limit the inrush surge as well.

[MartinWoodham]

*arrowup*I think the 'connect to chassis' advice is just to minimise loss through the cables - ie connect to chassis close to the starter.

 

*arrowup*Connect positive first/ remove it last is so that you don't get an inadvertent short - if you connect +ve on good battery to +ve on bad, any touch onto earth on the duff car won't do anything since there's no circuit. When you connect the -ves it doesn't matter if you touch earth cos that's the potential they're at anyway - so the only time you run a risk of a short is when the first +ve is connected and the other end is free, before you've attached it.

 

We should really talk properly Nifty - hope you're all keeping well?!