Help/Advice for wiring a battery box please

[MikeWilson]

Dear electrical experts,

I've currently got a 12V leisure battery and a 4 way cigarette lighter splitter which I use to power:

1) My HEQ5 mount (up to 5A on slew)

2) Three dew heaters (?A)

3) QHY8L Camera (2A?)

and i'd like to also power:

4) Laptop (?A)

and

5) EL flat panel (?A)

The EL flat panel and Laptop are powered via their own inverters.

At the moment, 1 + 2 + 3 work fine powered off the leisure battery. The trouble comes when I plug in my laptop (4) and then the fuses go pop. I suspect that now is a good time to revisit the electrical supply for my mobile rig and go shopping for some nice thick electrical cabling, some decent fuses that can sustain the load and solder everything together neatly.

I have a "dribox"(weatherproof electric box) which I currently use as the hub for all the USB and power connections between power & laptop and the mount.

Please could someone knowledgeable advise me on:

A) What generic wire should I buy for the above loads?

What fuses/fuse box should I buy?

C) Is there a preferred type of female cigarette socket that I can fix to the outside of the box for accessories like the EL panel (5) or a hairdryer?

D) Should I use the 'chocolate box' style connectors to splice wires together? (I have just been splicing the frayed wires together, holding them in place with solder and heat shrink tubing).

Any advice would be warmly appreciated!

All the best,

Mike

[michael8554]

I would advise you to put each device on its own separate fused outlet.

Fuse accordingly and label (eg HEQ5 5A).

To connect to the battery, Maplin sell figure-of-eight red/black cable, buy some that exceeds your total load from the battery and fuse this as well, to your total load.

Connections inside the dribox can be soldered/heatshrink or choc-block.

For specifics on fuse holders, slow or fast-blow fuses, sockets etc I would do a search in this DIY section, there have been some terrific battery boxes and power supplies described.

[Merlin66]

Miike,

The HEQ5 fully loaded with both axis slewing only takes around 2.2A Max.

The laptop, when charging the battery, can pull up to 5A @ 19V (=equivalent of 8A @12V)

I use a car computer 120W DC convertor (12V-19V) rather than an invertor (12V>240Vac>transformer>19VDc) -it's much more efficient.

[MikeWilson]

I would advise you to put each device on its own separate fused outlet.

Fuse accordingly and label (eg HEQ5 5A).

To connect to the battery, Maplin sell figure-of-eight red/black cable, buy some that exceeds your total load from the battery and fuse this as well, to your total load.

Connections inside the dribox can be soldered/heatshrink or choc-block.

For specifics on fuse holders, slow or fast-blow fuses, sockets etc I would do a search in this DIY section, there have been some terrific battery boxes and power supplies described.

Thanks Michael.

Ok - separate fuses, Maplin cable, choc-block (quicker and easier for me) and I'll do a search on the forum's DIY section for fuse suggestions. Thanks

Miike,

The HEQ5 fully loaded with both axis slewing only takes around 2.2A Max.

The laptop, when charging the battery, can pull up to 5A @ 19V (=equivalent of 8A @12V)

I use a car computer 120W DC convertor (12V-19V) rather than an invertor (12V>240Vac>transformer>19VDc) -it's much more efficient.

2.2A on the HEQ5? That's interesting. Every time mine is slewing (and connected to battery), the red power light flickers. It flickers even more furiously when the dew heaters are on.

I have a 12V-19V inverter too but when it's connected, fuses start to blow. Hence my need to wire things properly

I'll take a look around the forum for a schematic to use as a starting point.

All the best,

Mike

[Merlin66]

The red light will only flicker when the voltage drops to around 11V....

[MikeWilson]

The red light will only flicker when the voltage drops to around 11V....

Which means my battery is unable to supply the required power (W=VxA)?

Or perhaps it's the wiring? I've tested the ciggy output sockets with a multimeter and get >13V.

All the best,

Mike

[Merlin66]

Could be that or other hardware is pulling the power??

[terrym2002uk]

The red light will only flicker when the voltage drops to around 11V....

If you have your worm gears too tight, the steppers will pull more current to move the load, and can cause this. Make sure you can easily turn the worm gears by hand.

There's always a compromise between tightness and play.

[MikeWilson]

Thanks for the info, chaps. I'm using a very cheap Chinese 4 port city lighter splitter, so will renew looking into the worm gear issue another time - after the battery hub has been built into the dribox. I'm worried about breaking / messing with the gears on the HEQ5, and only have problems when per kit is connected, which seems to suggest that the battery itself isn't able to supply the demanded current.

In any case, the current problem is that the fuses I have (2A) all blow when the laptop is connected. (last time I connected the laptop in addition to the already running mount, three dew heaters and camera, there was a loud bang and lots of smoke coming from the end of the male ciggy plug that goes to my regulated power supply. It completely melted.

That's why I want to rewire and recable everything with components able to take the strain.

[Gina]

Ciggy plugs and sockets are dreadful and best replaced by a more reliable connector IMO.

[MikeWilson]

Ciggy plugs and sockets are dreadful and best replaced by a more reliable connector IMO.

What connectors would you recommend, Gina?

I'm going to wire in a few ciggy sockets but for some things (i.e. mount power, camera power), I could replace it with another type of connector. What about the DC (the pin-looking one) connectors?

All the best,

Mike

[old_eyes]

try this http://stargazerslounge.com/diy-astronomer/136104-bodged-battery-box.html

old_eyes

[MikeWilson]

^ old_eyes, that is a remarkable job and very inspiring. I think I'll do something similar. Thanks!

[Reggie]

those maplin boxes look incredibly expensive (although I do appreciate that there is some circuitry in there to keep an eye on things), I Thought you might be interested in one of these:

LARGE BLACK BATTERY BOX - BOAT - YACHT - CARAVAN | eBay

or search ebay for large battery box if that one is too small.

I'll probably end up with one of those boxes at some point in the future, just thought i'd share

Regards,

Reggie.

[MikeWilson]

Thanks Reggie,

I'm currently wondering if I prefer to have things as they are:

12V + USB ------> [bOXED HUB] ------> power out + usb out

or

12V power cables out from battery box + separate boxed hub. I suspect building a battery box would be the neatest solution as that way I wouldn't have to damage my DriBox - which could be used for other things (like 240V electric hookup).

[Merlin66]

The issue with laptop's is that during the battery charging they can pull up to 10A (@ 12V) - so, whatever else, this part of the power circuit need to be independent of the others...

[Reggie]

Hi Mike, I suspect as these things are billed as 'boat/yacht' friendly devices they're dry boxes in their own right? I think I'd think about keeping the hub seperate myself but then I have plans for probably sticking everything USB into one box if it's feasible, although seeing some of the issues with people and usb bandwidth and hubs, I'm not 100% certain that things will work as I intended.