DC - DC Battery Chargers

adkel53 · Member

DC - DC Battery Chargers

Peter_n_Margaret · Guru

How much solar (including portables) do you anticipate installing? Allow for as much as you can fit for future expansion.
Personally, I would use separate units for the solar regulator and the DC-DC charger for redundancy, but some prefer the combined units.
I have not used any of the ones you mention, but I have had dealings with RedArc. They are an Adelaide manufacturer (where their products are made) and have a reputation for providing excellent service and technical back up.
Cheers,
Peter

Phillipn · Guru

I installed a 12v 25amp Kickass dc dc charger yesterday in the tub to charge the battery for fridge. Check out E bay they are on special reduced $70 from Australian Direct on the Sunshine Coast. Will cost you $250.

They will charge all batteries including lithium.

T1 Terry · Guru

Projecta make a 25 amp unit called an IDC25. I think a mob called ABR Sidewinder sells a similar product but the owner/proprietor advises against using them for lithium batteries because the continuous high output causes the unit to overheat and fail. Maybe that problem has since been sorted.
We have used the CTek products in the past but after a few failures we switched to the Jaycar 40 amp unit. Sadly they no longer bring these into the country so we use either the Projecta or the Enerdrive if the customer is happy to pay the extra cost. After endless complains from customers who asked to have their Redarc unit linked into the BMS system we strongly advise against using them, but if they really want to use it we will still integrate it but mark the paperwork that we are not taking responsibility for its performance or lack of due to overheating causing the unit to dial back to virtually zero current flow. Ya gotta wonder about a product developed in Australia, not too far from were the record 49.95*C was recorded last yr, doesn't include forced cooling.

T1 Terry

Peter_n_Margaret · Guru

Can't help yourself can you Terry?
The OP has "two 100 amp AGM batteries".

Cheers,

Peter

-- Edited by Peter_n_Margaret on Tuesday 22nd of October 2019 02:04:21 PM

T1 Terry · Guru

Peter_n_Margaret wrote:
Can't help yourself can you Terry?
The OP has "two 100 amp AGM batteries".
Cheers,
Peter

-- Edited by Peter_n_Margaret on Tuesday 22nd of October 2019 02:04:21 PM

You don't think it could be possible more than just the OP is reading this thread Peter? Is it something in water supply down your way or are you just bored or something?

T1 Terry

Phillipn · Guru

T1 Terry wrote:
Projecta make a 25 amp unit called an IDC25. I think a mob called ABR Sidewinder sells a similar product but the owner/proprietor advises against using them for lithium batteries because the continuous high output causes the unit to overheat and fail. Maybe that problem has since been sorted.
We have used the CTek products in the past but after a few failures we switched to the Jaycar 40 amp unit. Sadly they no longer bring these into the country so we use either the Projecta or the Enerdrive if the customer is happy to pay the extra cost. After endless complains from customers who asked to have their Redarc unit linked into the BMS system we strongly advise against using them, but if they really want to use it we will still integrate it but mark the paperwork that we are not taking responsibility for its performance or lack of due to overheating causing the unit to dial back to virtually zero current flow. Ya gotta wonder about a product developed in Australia, not too far from were the record 49.95*C was recorded last yr, doesn't include forced cooling.

T1 Terry

ABR Sidewinder`s unit can be used to charge lithium batteries, The owner advises to set the unit on the AGM setting. My son has a Projecta 25A unit in his wagon and it works good. Projecta also have a 25A unit for lithium batteries but has no settings for other types of batteries.

iana · Guru

I use an Intervolt unit, aussie made, had no problems. Have a read about them on the net.

nomadz · Veteran Member

Gday,

I think enerdrive have a 40amp dc/dc charger with inbuilt solar reg, that I believe is independent of the dc/dc charger.

Also has various settings, including lithium.

Regards,

Ian

Izabarack · Guru

I have two dual source input DC to DC chargers. D250S is maybe 5 years old and has been faultless. Newer Powertech from Jaycar was much cheaper and is currently doing the expected job on my Lithium batteries. I stayed away from Redarc purely because of cost.

I see more and more comment on the benefits of a DC to DC charger of around 20 Amps as being well sized for Solar installations up to 350 Watts. A 20 Amp charger is also much kinder on the Alternator when charging deeply discharged AGM battery banks. The more credible comments I see are supported by technical explanations of the practical considerations.

Iza

outlaw40 · Guru

Personally have a Projecta idc25 connected to 2 -125 amp agms with 120 amp solar feeding through it. Run 2 40 litre engels , 1 as a freezer and this has performed floorlessly for approx 4 yrs now.

wasn_me · Guru

I run Ctek 250s dual in the car & van.

I have a 90 watt panel on the car. This runs engel fridge non stop.

I have 200 watt panel on the van. This runs lights, tv, charges phone, tablet, batteries. I can add a 100 watt portable panel, but rarely have the need. I bought a 1kva honda 10 years ago for backup, carried it twice & it's gathered dust in the shed since.

I pulled the useless centruion set up out of the van & put in ctek 250s dual & 10 amp ctek 240v charger & nava fuse block.

I run 105 a/h batteries in car & van.

Cheers Pete

T1 Terry · Guru

outlaw40 wrote:
Personally have a Projecta idc25 connected to 2 -125 amp agms with 120 amp solar feeding through it. Run 2 40 litre engels , 1 as a freezer and this has performed floorlessly for approx 4 yrs now.

How long have you been running the IDC as a dual function unit? Just for a bit of feed back so I know if they do the job well or not so a yes or no when people ask me what works ....

T1 Terry

JeffRae · Guru

"REDARC BCDC1225D 12V 25 A In-vehicle Battery Charger - $587"

We used this to charge 2 x 100amp battery and as solar regulator

Well worth the money, have had years of use.

Just transferred it from old vehicle to new vehicle

JeffRae

outlaw40 · Guru

T1Terry have had my system set up as stated approx 4 years now cold beer and frozen ice cream on hand at all times, no complaints here. ....

Peter_n_Margaret · Guru

Adkel53 (the OP) does not actually say what type of RV he has and that may make a significant difference to the charge methods he has available.
For a motorhome, where the house batteries are not too far from the alternator/crank battery, direct charging via a simple solenoid can be the cheapest and most effective back up to the solar.
That is what I do. I have a RedArc Voltage Sensitive Relay, but typically use it manually to charge the house batteries if I have any doubt that the solar will complete the job on its own. That way I can get much higher charge initial rates than a typical DC-DC charger and I also get any solar available, at the same time.
And in the event of a solar controller failure or the failure of the DC-DC charger, the other remains totally operational.

But (as they say), there is more.:) I can also start the engine directly from the house batteries if the crank battery fails and I can charge the crank battery from the solar if the alternator fails or the crank battery is flat. All in all, a low cost, very flexible system.

This system has been operating flawlessly now for 15 years.

Cheers,
Peter

-- Edited by Peter_n_Margaret on Wednesday 23rd of October 2019 05:33:31 PM

T1 Terry · Guru

outlaw40 wrote:
T1Terry have had my system set up as stated approx 4 years now cold beer and frozen ice cream on hand at all times, no complaints here. ....

Thank you, good to get any feed back I can on how well certain equipment works as far as the intended purposes and how long they lasts

T1 Terry

denmonkey · Senior Member

also have the projecta ID25 here . Been in for probably about the same 5 years with a single 130Ah AGM .
seen some filthy summers, which I'm sure took their toll on my battery but both are still working well.
I'm not entirely sure the solar side of it is the best and whilst I can't recall specs, it's not suitable to me to use a house panel but I'm runnin 2x120W on the pajero.
My fridge stays on 24/7 and has done for those 5 years.
plus other charging duties etc.

So Terry, very good no probs, but I reckon I could do better with a dedicated solar controller which is what I'll do later and switch to a single 250v house panel.
It's just gonna work better for my mounting needs as well.
That said, it does everything I need right now. Just want to fiddle really

cheers Brett

Whenarewethere · Guru

I'm running seperate DC-DC & MPPT. Had one DC-DC which wasn't enough so added a second one. I think I may replace them with a smart DC-DC, but other than that the seperate inputs are fine. Also replaced the MPPT 75/10 with a 100/20 as the 75/10 wasn't large enough for my 120 watt solar.

T1 Terry · Guru

denmonkey wrote:
also have the projecta ID25 here . Been in for probably about the same 5 years with a single 130Ah AGM .
seen some filthy summers, which I'm sure took their toll on my battery but both are still working well.
I'm not entirely sure the solar side of it is the best and whilst I can't recall specs, it's not suitable to me to use a house panel but I'm runnin 2x120W on the pajero.
My fridge stays on 24/7 and has done for those 5 years.
plus other charging duties etc.

So Terry, very good no probs, but I reckon I could do better with a dedicated solar controller which is what I'll do later and switch to a single 250v house panel.
It's just gonna work better for my mounting needs as well.
That said, it does everything I need right now. Just want to fiddle really

cheers Brett

If you are going to use a house panel, just be careful what brand you buy, there is a lot of garbage out there. Not sure if you saw the TV interview thing where proper solar installers were talking about the business they were getting removing the rubbish panels and installing quality panels that would actually last the 10yrs plus. Most of that stuff on Evil Bay is either so old it's not worth the effort (190w panels or similar) or simply fail at the drop of a hat or when they get wet. Junko and tri something come to mind. Tindo panel made in an Adelaide suburb are good value, so if you can find some of them second hand it will help to offset the cost of an MPPT controller to make them useful.

As far as the solar losses through a DC to DC charger trying to do a dual duty, they all suffer from the same problem because they are all basically a DC to DC charger and efficiency isn't a prime objective for them because the alternator will always supply more than they need including the losses. Unfortunately the output from a solar panel is not likely to be more than the unit can use, so inefficiency just wastes some of that solar output that could have been used to recharge the house battery. On the other hand, something is better than nothing so .......

T1 Terry