Advice on battery charging

[Cuppa]

Apologies if you've seen it before, but thought the diagram of my Redarc BCDC1240 setup might be of interest.

I removed the aux battery set up I had under the bonnet to save weight, & now charge 3 x 120ah AGM batteries (in parallel) in the pod via the BCDC from the wet crank battery. The set up gives me the ability to connect the 'house' batteries & the crank battery for winching purposes, or if I wish to charge the crank battery & house batteries all together from either solar, or from a mains charger. Although there is some weight in the heavy cables run from the pod to under the bonnet, I have no need to carry jumper leads, as I can jump start from the house batteries at the turn of a switch.
With one fixed panel (125w) on the cab roof, & the rest portable, the setup is designed so that the portables only need to be used if camping for more than a couple of nights, but to be self sufficient in power indefinitely when camped for longer periods. This runs two fridge freezers & the usual lighting etc.

Now - in terms of fuses - 100A fuse near the cranker and near the house batteries?

50amp fuses between the crank batteries & BCDC1240 & between the house batteries & BCDC1240, both as close to the batteries as possible, will be sufficient. re-settable circuit breakers would probably be better. I used something in between - re-settable fuses - essentially circuit breakers in a maxi fuse housing.

[alfonso]

sorry to hijack this thread but I have a question for cuppa .
I have 1 120 amp hour battery in the back of the ute, via a 150 amp projecta relay which does all my lights and fridge when working away . I also have a 20 amp 7 stage charger which I use nightly back at camp as the drive to jobs is very short . I also have a caravan which has 2 120 amp agm batteries with a built in 25 amp projecta 7 stage charger also have 2 b and s cable running from caravan to back of ute with 75 amp Anderson plug this works great when towing as all the batteries are fully charged before set off.
my question to you now is I am looking at solar panels 240 watt with mpps regulator connected to batteries in van. when I am charging from one of the other options ie 25 amp charger or Anderson plug will this damage mpps regulator, or
is this fine connection to solar panels will be via a 50 amp Anderson plug with 8 band s cable. I will also have a mppt regulator connected to the battery in the ute . Does this setup sound ok or have I made a balls up. Solar panel and regulators have not yet been purchased . Advice on this would also be greatly appreciated . Thanks in advance Alf

[Cuppa]

Hi Alf,
I am assuming you would connect the solar panels to either the van batteries or the ute aux battery as required to allow for usage of the ute without the van? This assumption is based on the fact that you plan to have two separate solar regs, so presumably you plan to be able to disconnect the panels, rather than having them permanently connected? There is no problem running a mains charger/alternator whilst the solar panels are connected to your battery(ies). The regulators will only be connected between the batteries & panels. Other charging sources will go direct tothe batteris (not through the regulators). Using solar panels to top up the batteries (above what the alternator will take them too) can be a reasonable alternative to a dc to dc charger if you have sufficient solar to bring the batteries up to full charge during daylight hours.
If you post a wiring diagram I would feel more confident advising you, but it sounds like you have it sussed to meet your needs.

Cuppa

[alfonso]

thanks cuppa you are spot on will be using van and camper independently I will draw a wiring diagram soon thanks for the quick reply . Ps any idea where to buy solar stuff

[threedogs]

How weird my cranker failed and I brought a new one from my battery place this time they sold me a seal battery, How bizarre, how bizarre
How have you found the Redarc system ???

[Cuppa]

. Ps any idea where to buy solar stuff

EBay is your friend for panels. For portables don't go above 120w folding panels, they get too cumbersome to move around.

Choose panels based on their dimensions (what fit's your storage space the best), plus the quality of their frames. A full frame that they 'lean on' is more secure than a single strut & can be pegged down if windy. Most likely they will be supplied with a regulator stuck on the back of the panel...... These can usually be carefully removed & thrown in the bin, together with the thin cabling supplied. Plastic corner pieces on the panel frames are good, otherwise corners can be sharp.

Back to regulators - you do tend to get what you pay for, all will work, but some work much better than others. Most cheap mppt types are unlikely to have their charging based on effective charging algorithms, & in such instances a PWM type of the same price is probably a better option. In my experience Morningstar regulators are good quality, but there are others. How much you pay for one will depend upon how many bells & whistles you want. I prefer regulators with a screen which tells you, at a minimum, the battery voltage and amps in. Many folk are happy with a couple of Led indicators, but I like to know a bit more about what is going on. One thing which is really worthwhile (much more than budget mppt) is temperature compensation, the type which has a sensor mounted on the battery, rather than just internally. Mppt is good, but expect to pay for one which lives up to it's promise. There is a reason for a difference in price between a $25 mppt reg &, for example, a a Blue Sky mppt reg costing hundreds of dollars. Many, if not all, of those cheapies supplied with the panels are a con. The only mppt thing about them is the printing on the case! (I know folk who have tested this).

Cuppa

[alfonso]

hey cuppa can you join two 120 watt portable systems together to create a 240 watt system Thanks Alf

[megatexture]

You can providing your regulator can take the 240watts and the max amp output of the panels.

[Cuppa]

You can providing your regulator can take the 240watts and the max amp output of the panels.

Hi Alf, yep, as MT says. You connect them together in parallel as you would with batteries. If you connect them together in series it'd give you a 120w 24v system (assuming you are using 12v panels). You would probably be ok with 15 amp regulators if of good quality (capable of running a bit above their nominal capacity), but certainly with 20 amp ones. If there is any possibility you will want to add further panels down the track, get regs with the capacity to suit now rather than ayer.

[alfonso]

Thanks for that fellas