New dual battery isolator

[equipt]

I am looking at getting a new dual battery system, as I have been told the one that is fitted to my Nav is not very good. I already have all the wiring in place and will probably just remove the solenoid and other bits and pieces and install one of the new "intelligent" dual battery isolators.

I have had a bit of a look at 2 so far,
1)Projecta DBC100K about $90
2)Piranha DBE140 about $150

I am leaning towards the Projecta as I have had great service from them before in relation to an air compressor and would like to give them my business again.

What do you guys run/recommend ???

 

[Old.Tony]

I don't run that sort of isolator, because that system can never fully charge the battery.

I run a fused 12V line to an inverter, from the 240V I run the fridge and an intelligent charger to charge the battery.

When I stop somewhere, I've got 100% charge in the battery. I can safely use up to 50% of the battery's capacity, so I can use from 100% down to 50% or a full 25Ah.

If I was charging with an isolator, I'd only get about 70-75% charge. that leaves me with (say) 25% of usable power or just 12.5Ah. That's really not a lot of power.

 

[equipt]

So you run an inverter off your 2nd battery to which you have connected a 240v battery charger that charges your 2nd battery?

Is that like infinite power?

 

[Al]

i use the projecta, great piece of gear

 

[Old.Tony]

I run the inverter off the main battery (via a relay that activates only once the ignition is on). The inverter is therefore powered only when the vehicle is running - guaranteeing that the main battery is never drawn on by the accessories. Here's a roughly complete diagram in text:

Main batt--> fuse --> relay --> cable to tub --> inverter --> battery charger --> second battery

The relay is only active when the ignition is on. While stopped somewhere, the inverter/charger setup would isolate the second battery from the vehicle anyway, but the relay completes the task - accessories are never able to draw power from the main battery.

As an added bonus, the inverter also supplies 240V directly to the Engel which auto-switches to draw power from 240V if it's present - so there's no drain on the battery being charged.

I have used this setup in my caravan for some time now and it's brilliant. I'd never, ever go back to the old way of charging batteries.

 

[Leprechaun]

I run the inverter off the main battery (via a relay that activates only once the ignition is on). The inverter is therefore powered only when the vehicle is running - guaranteeing that the main battery is never drawn on by the accessories. Here's a roughly complete diagram in text:

Main batt--> fuse --> relay --> cable to tub --> inverter --> battery charger --> second battery

The relay is only active when the ignition is on. While stopped somewhere, the inverter/charger setup would isolate the second battery from the vehicle anyway, but the relay completes the task - accessories are never able to draw power from the main battery.

As an added bonus, the inverter also supplies 240V directly to the Engel which auto-switches to draw power from 240V if it's present - so there's no drain on the battery being charged.

I have used this setup in my caravan for some time now and it's brilliant. I'd never, ever go back to the old way of charging batteries.

I was recommended to have a smart solenoid. He said the modern cars electronics are too sensitive to run the risk using normal relays or inverters that can cause current surge.

 

[Old.Tony]

I was recommended to have a smart solenoid. He said the modern cars electronics are too sensitive to run the risk using normal relays or inverters that can cause current surge.

Since none of this is connected to the car's electronics it hardly matters. Relays - your car already has them in abundance.

I do agree that you don't want to try charging the vehicle battery with an external charger while the battery is connected, but what I'm using is completely different so there's no danger.

 

[KraftyPg]

I run the projecta as well and never had a problem with it. If you subscribe to all the theories about not charging to 100% and alternators not being smart enough to act like a 240V charger then the only real thing you need to worry about is putting a decent multi-stage 240v charger on the battery every six months or so.

I've run a 190AH aux battery in the Nav for 12 months and only put the 240v charger on the battery over night for the time I was doing fencing where the fridge was running 10 hours a day and the car was only running for about an hour a day. The rest of the time the kit of the battery, projecta 100 and self resetting fuse hasn't missed a beat.

I haven't used that Piranha but I have used other Piranhas and they don't usually have any problems either however if the 140 in the model number is 140A then I'd suggest if your system has the factory alternator your wasting your money and go for something a bit smaller, the factory alternator may spike over 100amps but even a 100amp isolator should allow spikes of up to about 30% and long term your factory alternator isnt going to put out 100amps even if thats what it's rated at.

 

[merchant]

I use the ABR Sidewinder solenoid. It charges 3 batteries when the caravan is connected and works well. And has push button override if needed.

Makes sure you install a 50amp circuit breaker between the battery and solenoid and then solenoid to 2nd battery.

 

[Bosshog]

I am using a Redarc (Home | Redarc Electronics) isolator. It works well but as already mentioned the deep cycle battery does not fully charge so I throw it on a good quality battery charger/conditioner every now and then.

 

[WoodyD40]

I have a 100amp deep cycle battery in the tub, with a 50l waeco fridge on all the time. i dont have any fancy charging systems, just really heavy duty cable and solonoid between the battery's.

so far i have not had any problems with the fridge at all - it manages to keep the drinks cold ALL the time.

i also only have a short 3k drive to / from work each day, so it does not get any real charging time on a daily basis, but i probably have at least two good drives of the car in a normal week going somewhere, so thats when it gets most of its charging top up.

the deep cycle battery is now about 4 years old, and still works fine.

 

[equipt]

I like the idea of the inverter setup, but I think having 240v in the back of my Nav with no canopy is probably a little dangerous so I think I will probably head in the direction of the Projecta unit.

 

[Chartrock]

I also use the ABR Sidewinder charging a 120AH AGM battery in the tub and a second one in the van when it's in use. It has given no problems and my fridge is always cold as well.

 

[KraftyPg]

I like the idea of the inverter setup, but I think having 240v in the back of my Nav with no canopy is probably a little dangerous so I think I will probably head in the direction of the Projecta unit.

If your that worried about the inverter in the back you can always seal it in a box, the box doesn't have to be much bigger than the unit and any ventilation can be made to be splash proof then use outdoor sockets on the box for the connectors. I assuming since you're talking D22 you're mounting the aux battery up the front so a small box for your inverter in the tub wont be a huge issue, you can mount anywhere that is relatively dry and you should be right. It won't ever like a full dunking in water but you can make these fairly resistant to water.

To my way of thinking the inverter is only a worthwhile thing if you've really got a use for it and with the amount of camp site things you can get these days that are 12v it may not be a necessity for everyone. My fridge already has one mounted in it but for the amount of times it's been used I'd be unlikely to consider replacing it if it failed because my Sat phone is the only item I can't charge on 12V or keep running for a period of time on 12V, and I could probably use an excuse to buy a new sat phone.

 

[equipt]

I already have a 2nd battery in the tub with a relay and bits and pieces under the bonnet to control it all, but when I had it at the auto elecs the other day he said that the system that is fitted is an older type and not very good for my car as it could cause some sort of spike or something and stuff the computer. It was installed by the previous owner so I have no idea about it I was just looking into something a bit simpler as there are quite a few wires on mine, I think it is also because mine has an Anderson plug on the back for a camper trailer with battery.

 

[Jason]

I am using a Redarc (Home | Redarc Electronics) isolator. It works well but as already mentioned the deep cycle battery does not fully charge so I throw it on a good quality battery charger/conditioner every now and then.

Same as Boss, I throw both batteries on the C-Tek charger every 3 months.

 

[WIR35]

240v inverter is worth it's weight in gold if you're a technician or tradesman working on a farm or remote area. If you get a big enough inverter you can run power tools, and you can certainly charge your battery drill's batteries.

 

[KraftyPg]

That's true enough I used mine to power the drill while we were fencing early this year because it was either the power drill or the battery charger to charge the battery drill but if it wasn't there we'd have quit for the day so for me it's not that useful but there is plenty who will use it. It's like anything if you want it or need it you'll pay for it if you don't it's a cost you can easily ignore.

 

[Old.Tony]

For those interested - while we're talking inverters ...

Your average 300W inverter (the ones that can surge to 600W but can handle 300W constantly) are good enough to charge your vehicle battery with a C-Tek charger as well as power your Engel chest fridge.

The Engel fridge will draw about 30W at the most while it's cycling. My Waeco inside the caravan draws about 70W - relatively thirsty!

The C-Tek MXS-7000 (good for batteries up to 225Ah) charges at 7A, about 112W at peak (the charger will try charging at 16V during one of its cycles). Call that 180W to account for the circuit in the charger. Add 180W to the 30W for the fridge - you need an inverter capable of supplying 210W. The 300W is sufficient and best of all they aren't hugely expensive, so if it takes a dunking or rattles itself to pieces it's not expensive to replace.

 

[equipt]

I manage a retail store that sells inverters and can get them fairly cheap. I don't have any real use for tools or anything like that. My only thinking is of the danger of 240v if it gets wet?? What sort of safety devices do you guys use to not get zapped if it gets wet?