12V split charge system ideas

[normspanners]

you can have the thick cables already plumbed in on a manual switch or electrical relay, for emergencies etc but charge the second battery with a type of Battery-To-Battery charger( you can get them cheaper) and the second battery is then always at full charge and safe from deterioration.

 

[123hotchef]

wow they aint cheap!

 

[normspanners]

A mate of mine who is a well respected auto sparks has his breakdown van with adual charging set up and has 12v and 24v battery banks in the back ready for a breakdown situation for either 12 or 24 v trucks
I many years ago poo pooed all this type of info he was giving me (as per some of the advise on here of just connecting them together etc ) believing I knew better, untill I started suffering it for real and then started to listen to him and do my own research into it and realise how complex the issue really is.

 

[normspanners]

wow they aint cheap!

they can be sourced cheaper BTW

 

[123hotchef]

I just want to run my aux stuff of another battery so i dont have a flat main battery again

 

[ajlelectronics]

I just want to run my aux stuff of another battery so i dont have a flat main battery again

Just follow established caravan power designs and don't worry about re-inventing the wheel.

 

[123hotchef]

indeed

 

[normspanners]

https://www.roadpro.co.uk/catalogue/02d-dc-dc-battery-chargers

http://www.mdsbattery.co.uk/shop/productprofile.asp?ProductGroupID=8808

 

[normspanners]

Just follow established caravan power designs and don't worry about re-inventing the wheel.

We are Not reinventing the wheel, this is a problem that is real and always has been

 

[normspanners]

Whilst I respect other peoples views on this, and was at one time of the same opinion I am afraid technology and battery tech has moved on greatly in the last few years and we have to embrace this and understand where we have been going wrong, I know full well it has cost me a fortune in batteries with my various recovery trucks, what with heavy 12v winching hydraulic packs etc etc over the years, by not listening

 

[armalites]

These are pretty good if you are going down the VSR route, they sense both batteries and decide whether to leave contacts open or closed, they also give the option to parallel the batteries so you can jump start yourself if you need. The parallel function can be locally or remotely from the dash. I've seen a twin battery setup on a Discovery 2 using an earlier version on the web

http://www.ecs-marine-equipment.co....emergency-parallel-rating-275-item-33088.html

 

[123hotchef]

ive gone for this http://www.ebay.co.uk/itm/Voltage-S...bb5e81f&pid=100005&rk=1&rkt=6&sd=222341120194

 

[8ob]

Her in doors has got some fancy gizmo in her horse box that split charges the auxiliary batteries off the alternator and when you hook up to mains disconnects that circuit and takes over, no switches or other trickery involved. There is also a big clunker of a battery switch that can be used to jump start the trucks main batteries if flat.

Bob

 

[123hotchef]

Her in doors has got some fancy gizmo in her horse box that split charges the auxiliary batteries off the alternator and when you hook up to mains disconnects that circuit and takes over, no switches or other trickery involved. There is also a big clunker of a battery switch that can be used to jump start the trucks main batteries if flat.

Bob

what kind of box it that @8ob ? i guess that is like what the winniebago type thingies have too

 

[8ob]

what kind of box it that @8ob ? i guess that is like what the winniebago type thingies have too

Its got a load of living space so I would imagine the leccy side is probably along the lines of a motorhome, will dig about in the lockers and take a snap of it tomorrow.

No the Vets not mine

Bob

 

[Justme]

well i am going to get this Voltage Sensing Relay Control Unit http://www.ebay.co.uk/itm/322320802315 and make my own system

The down side to those is that it only senses one side.

Ok if you only have one charge source like an alt. If you also have solar it can be helpful to sense both sides.

 

[123hotchef]

Its got a load of living space so I would imagine the leccy side is probably along the lines of a motorhome, will dig about in the lockers and take a snap of it tomorrow.

No the Vets not mine

Bob

nice box thats a serious bit of kit mate

 

[123hotchef]

The down side to those is that it only senses one side.

Ok if you only have one charge source like an alt. If you also have solar it can be helpful to sense both sides.

no solar for me just the alt for charging so that should do me

 

[wookie]

If you go onto boating forums charging extra batteries is a major problem and people spend thousands to get over those problems I have gone through this double battery scenario many times if you speak with specialist in the subject it is VERY complex.

To be honest as soon as it's for a boat the price goes up, that's not to say it isn't expensive kit to begin with but to make it suitable for the marine environment does ramp the cost up quite considerably.

Believe what you will, all I know is twin battery setups do not work effectively and end up costing batteries,

I work in marine electronics and recently we replaced the domestic battery bank on a catamaran, it had 4 12v 180Ah batteries all connected in parallel with 50mm2 cables. Even though they were all in parallel 1 battery had got out of sync with the other 3 and the result was that battery boiled itself while the other 3 didn't get fully charged, it was the one nearest the load that suffered. We replaced all the batteries and upgraded the cables to 95mm2 with the end result being the battery voltages remained within a couple of millivolts of each other as they either charged or discharged. His new battery bank cost 3k just in batteries.

 

[normspanners]

Even though they were all in parallel 1 battery had got out of sync with the other 3 and the result was that battery boiled itself while the other 3 didn't get fully charged,

yep thats some of the problems that can occur possibly caused by the batteries not having an equalising charge often enough, end cells usually cop it the most. But battery terminals can cause big problems the slightest bad connection starts the rot to set in.