Campervan Electrics Crimping

[ScubaCollie]

Hi All, I've purchased a campervan and replacing the leisure battery with 2 x AGM Leisure Batteries 150Ah each wired in parallel therefore retaining the 12V (for the habitation area I. E to run the fridge, lighting, TV etc, which are all 12v appliances).

The van also has a 230V Hookup point on the side for charging the leisure batteries via a PSU/Charger and also powering 230V sockets inside the van.

Ive got all my parts I need, however the issue I have is the cable running from the load side to the battery is less than 4mm (I measured 4mm but this is including the insulation therefore probably only 3mm conductor once stripped) but i need to cut off the existing battery terminals and replace with 8mm eyelets to fit the new battery but I can't find any 8mm suitable as the load side is fitted with a 20amp fuse near the battery and the eyelets I can source are only 19amps?

Do you think that 1amp will make much of a difference?

 

[flameport]

(I measured 4mm but this is including the insulation

Measured what exactly?
Wire sizes are cross sectional area, not diameter.

 

[ericmark]

I have had a AGM battery with a shorted cell, be it series or parallel you need some method to protect the second battery, the faulty one is clearly scrap, but you don't want it to take the good battery down with it. Be it an over load or fuse, or even simple isolator, it needs considering.

People like Batt cables do give sizes

example here current on extra low voltage can be rather high, 13 amp at 230 volt = 250 amp at 12 volt, I found welding cables good, as tend to be more flexible.

VRLA or AGM batteries the voltage is critical. Many battery chargers are not suitable, my caravan 230 volt to 12 volt unit floated at around 14.2 volt, the idea is when there is a load the voltage will dip, and easy enough to top up a flooded cell when required, but with AGM in a car the engine management controls battery charging. So you need some form of smart battery charger to ensure not over charged.

In storage my charger raises the volts to 14.4 then switches off until it drops to 12.8 so in practice it gets a pulse every so often, at a charge rate of 0.8 amps. In the main we use stage chargers or other smart charger

a battery to battery charger is not cheap Read more here the problem is speed, a motor caravan may travel for just 5 hours, even with a narrow boat travelling for 8 hours it is hard to maintain the battery. In the main we need solar panels, wind chargers, or electric hook-up.

A fridge uses between 8 and 12 amp, all the time, there are models with compressors which use less, but 300/12 = one day only, using electric while travelling OK, but once stopped need to use gas or mains. Need around 670 mm x 1020 mm solar panel to produce 10 amp, since not being used at night twice that size, you would need to cover the roof of the motor home with solar panels if not using gas.

 

[ScubaCollie]

I have had a AGM battery with a shorted cell, View attachment 255086 be it series or parallel you need some method to protect the second battery, the faulty one is clearly scrap, but you don't want it to take the good battery down with it. Be it an over load or fuse, or even simple isolator, it needs considering.

People like Batt cables do give sizes

example here current on extra low voltage can be rather high, 13 amp at 230 volt = 250 amp at 12 volt, I found welding cables good, as tend to be more flexible.

VRLA or AGM batteries the voltage is critical. Many battery chargers are not suitable, my caravan 230 volt to 12 volt unit floated at around 14.2 volt, the idea is when there is a load the voltage will dip, and easy enough to top up a flooded cell when required, but with AGM in a car the engine management controls battery charging. So you need some form of smart battery charger to ensure not over charged.

In storage my charger raises the volts to 14.4 then switches off until it drops to 12.8 so in practice it gets a pulse every so often, at a charge rate of 0.8 amps. In the main we use stage chargers or other smart charger View attachment 255087 a battery to battery charger is not cheap Read more here the problem is speed, a motor caravan may travel for just 5 hours, even with a narrow boat travelling for 8 hours it is hard to maintain the battery. In the main we need solar panels, wind chargers, or electric hook-up.

A fridge uses between 8 and 12 amp, all the time, there are models with compressors which use less, but 300/12 = one day only, using electric while travelling OK, but once stopped need to use gas or mains. Need around 670 mm x 1020 mm solar panel to produce 10 amp, since not being used at night twice that size, you would need to cover the roof of the motor home with solar panels if not using gas.

Hi Mate ive got the Autotrail Vline Sport 635.

Ive just purchased 2 x
12v 150ah Expedition Plus Agm Deep Cycle Leisure Battery (EXP12-150)

Also purchased the Victron Smart Charger to give it an additional charge up once per month as per the suppliers recommendation as my onboard charger/PSU only outputs max 13.8V.

Therefore I need to find a way to crimp the existing loom cable to this new battery (the old one had posts and the new one has M8 bolts, do you have any recommendations on crimped eyelets? As mentioned the o/d with calipers is 4mm but this is with the insulation on as I havent removed the old batter yet.

I therefore need sometning suitable to crimp the approx 3mm cable and also be rated to around 20amps as the fuse leading away from the existing battery is 20amps.

 

[ericmark]

I have crimp pliers

10 mm to 120 mm uninsulated, and a smaller set 1.5 to 6 mm

there are variations including very cheap

and technically the crimp pliers with insulated crimps should match the crimps being used, one firm I worked for GEC Large steam turbines would not allow use of multi size crimp pliers we had a set for orange, red, blue and yellow and they were sent once a year for calibration, but not had this anywhere else.

For larger terminals like 240 mm² used hydraulic type, in the main hired.

The other option is to solder the crimp.

 

[ScubaCollie]

Many

I have crimp pliers View attachment 25512510 mm to 120 mm uninsulated, and a smaller set 1.5 to 6 mm View attachment 255129 there are variations including very cheap View attachment 255130 and technically the crimp pliers with insulated crimps should match the crimps being used, one firm I worked for GEC Large steam turbines would not allow use of multi size crimp pliers we had a set for orange, red, blue and yellow and they were sent once a year for calibration, but not had this anywhere else.

For larger terminals like 240 mm² used hydraulic type, in the main hired.

The other option is to solder the crimp.

Many Thanks Eric, is it OK for example to crimp 3mm wires in a 10mm crimp? As the problem I have is trying to find a crimp with the power rating I. E 20amps in a 3mm crimp....

 

[ericmark]

Never seen 3 mm² crimps or cable. It goes 1, 1.5, 2.5, 4, 6, 10, 16, 25 mm² etc. A crimp

is marked size of cable and size of hole, for 2.5 mm² cable you use a 2.5 mm² crimp, simple.

 

[ScubaCollie]

Never seen 3 mm² crimps or cable. It goes 1, 1.5, 2.5, 4, 6, 10, 16, 25 mm² etc. A crimp

is marked size of cable and size of hole, for 2.5 mm² cable you use a 2.5 mm² crimp, simple.

Hi Eric, I haven't disconnected the battery and stripped the insulation yet, however the od with the insulation on is 4mm, therefore probably 2.5mm cable. However I can't find a crimp for 2.5 wiring rated at 20 amps?

Therefore I was going to use a larger lug like you've posted above and crimp it into that and then heatshrink it? But they are probably for 10mm wires....would it be OK to go bigger as long as the crimp is held firmly??

 

[ericmark]

4 mm = π x 2² = 12.5 mm, piR² simple school maths. So if insulation is 0.6 mm thick it is 6 mm² if 0.2 mm thick then 10 mm² latter seems most likely, so likely easy way out is solder the lug on.