Connecting a second leisure battery.

Wild Brambles

Wild Brambles

Free Member
Joined
Nov 11, 2019
Posts
431
Likes collected
1,687
Location
Hampshire
Funster No
66,761
MH
Van conversion
Exp
2 years
I have a second leisure battery, and recharge this by removing it from the van, and using a mains supply. One item I connect to it is a 1500 watt inverter. I use some heavy duty battery clamps to connect this to the battery. I get get a substantial spark when I make the second connection, and this happens regardless of the order of connection. The inverter is switched off at the time of connection. I'm concerned that I may be damaging the inverter, and I'm thinking of installing a switch on the positive side. Do you think this is a good idea, and will it solve the problem? This is the switch I am thinking of buying -
Amazon product ASIN B01E6Z3O0M
 
Unsafe and never a good idea to use croc clips for any connection. The sparking is due the inverter being in standby and it never completely turns off that is why it is always advisable to fit an isolator switch in the circuit.
Why do you need to remove it to charge why not use the existing charger, you could switch it to your charger using battery isolator like you have suggested.
Rather than croc clips it would be better to permanently fit it with battery terminals or use something like an Anderson connector.
Also a single battery is not going to last long with a 1500W inverter at full chat it will draw over 130 amps and will soon knacker the battery, you really need a bank of of 3 or 4 batteries to share the load (assuming batteries around 100a/h)

Anderson Connectors for sale | eBay

Find great deals on eBay for Anderson Connectors. Shop with confidence.
www.ebay.co.uk
 
This site contains affiliate links for which MHF may be compensated.
I've got a larger battery that I need to connect via a splitter. I only use the smaller battery for odd things like my computer printer, and I might want to use that outside the van. I'm also going to use it for a bit of experimentation with small solar panels. I only paid a fiver for it, and I thought that was a good price for a second hand leisure battery in good condition.

I'm still learning about motor home living, so much of the things I do are educational rather than permanent. I'm starting to realise how little I do know, and how one has to be multi-skilled if one wants to be self-sufficient. I had a greenhouse on the dashboard for a while, and that was a failure, and, no. I'm not going to put one on a roof rack. :)
 
When you first connect it, you should touch a 25w 30 ohm resistor between one cable end and its connection point to charge the capacitors then take the resistor away and clamp the cable onto the terminal straight after.
one of these. £1.50

www.bluearan.co.uk

Convair Electronics :: Convair Electronics SQP330C £1.57 - IN STOCK (25 Feb 2025)

Convair Electronics :: Resistors :: Cement Resistor 30W 33 Ohm (axial) :: Cement Resistor 30W 33 Ohm (axial) - 1.57. Cement Resistor 30W 33 Ohm (axial)
www.bluearan.co.uk www.bluearan.co.uk
 
Thanks for posting that. You started me on an investigation into why the spark is created, and I think I understand the problem. The resistor is an interesting solution.

They are in Southampton. I might see if I can collect one.

Subscribers  do not see these advertisements

 
Last edited:
Lenny HB said:
Unsafe and never a good idea to use croc clips for any connection. The sparking is due the inverter being in standby and it never completely turns off that is why it is always advisable to fit an isolator switch in the circuit.
Why do you need to remove it to charge why not use the existing charger, you could switch it to your charger using battery isolator like you have suggested.
Rather than croc clips it would be better to permanently fit it with battery terminals or use something like an Anderson connector.
Also a single battery is not going to last long with a 1500W inverter at full chat it will draw over 130 amps and will soon knacker the battery, you really need a bank of of 3 or 4 batteries to share the load (assuming batteries around 100a/h)

Anderson Connectors for sale | eBay

Find great deals on eBay for Anderson Connectors. Shop with confidence.
www.ebay.co.uk
Click to expand...
I had a second battery fitted, by a Funster Dealer who connected the second battery using a crocodile clip.. TheCaller pointed it out to me, got it fixed asap..Cheers Simon...
 
This site contains affiliate links for which MHF may be compensated.
I fitted one of these in line when I used an Inverter.

D3EDD12B-145A-4522-97CE-CE6E845D83AB.jpeg
 
I suspect they are all pretty much the same thing. I've had no problem with a 200 amp one in my last vehicle.
Oh and Wild Brambles... Saw this just now and thought of you and this thread..

Subscribers  do not see these advertisements

 
Wild Brambles said:
That looks great, a much better idea than the switch I was gong to use. I found this one on Amazon - do you think it is any good?
Amazon product ASIN B07GP5WHWX
Click to expand...
This is where I bought mine from, just make sure you buy one with the correct load rating.

www.12voltplanet.co.uk

Waterproof, Switchable, Surface Mount Circuit Breakers

IP67 circuit breakers for protecting & isolating circuits up to 200A. Re-settable and ignition protected. Ideal for use in engine compartments and bilges.
www.12voltplanet.co.uk
 
Thanks guys. I've just bought the 100 amp one, and it is being delivered to Morrisons tomorrow. What did we do before Amazon. I feel bad using them, but they are perfect for digital nomads.
 
Many thanks for the help and advice, and now that the breaker thingy ( is that the correct technical term ? ) has arrived, I thought I would post the plan before I get out the screwdriver. Please remember that this is only a temp. solution for the winter, and it is really just to allow me to use the ink jet printer, and another couple of appliances ( nothing over 600 watts ). It is to be stand alone, and I will recharge the battery in various cafes using a deep cycle charger. I will screw the inverter and breaker onto the wood panel behind the driver's seat. To use it, I assume that I press reset before connecting or disconnecting the battery, and just push the lever over to use the power. Here is a pic of the bits I will use. I'll dig out another couple of short cables to go from the inverter to the breaker.

secondary-battery.jpg
 
Wild Brambles said:
I will recharge the battery in various cafes using a deep cycle charger.
Click to expand...


What size battery have you bought (amp hours?)
What charger are you getting?

The reason I ask.. That sounds like it might be one hell of a coffee break

Subscribers  do not see these advertisements

 
The battery is an 85 amp deep cycle, and the charger is a Halford's smart charger. I have got a larger leisure battery, but the 85A one is easier to carry into a cafe. I use McD as an office,and I can be there for 8 hours or more if they aren't busy.
 
Wild Brambles said:
The battery is an 85 amp deep cycle, and the charger is a Halford's smart charger. I have got a larger leisure battery, but the 85A one is easier to carry into a cafe. I use McD as an office,and I can be there for 8 hours or more if they aren't busy.
Click to expand...

Which brand of rucksack do you use to carry the battery? It must be a good one.

Or do you use a trolley?

Ian
 
Wild Brambles said:
I have a second leisure battery, and recharge this by removing it from the van, and using a mains supply. One item I connect to it is a 1500 watt inverter. I use some heavy duty battery clamps to connect this to the battery. I get get a substantial spark when I make the second connection, and this happens regardless of the order of connection. The inverter is switched off at the time of connection. I'm concerned that I may be damaging the inverter, and I'm thinking of installing a switch on the positive side. Do you think this is a good idea, and will it solve the problem? This is the switch I am thinking of buying -
Amazon product ASIN B01E6Z3O0M
Click to expand...
this is what I fitted to my 1500w inverter
Amazon product ASIN B07TRLNFH1
 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Join us

Log in

Already a member? Log in here.

Latest journal entries

Back
Top