Recommendations on a new mains charger?

[charlie2]

Hi all. Got a second hand T5.1 and still learning! It's got a PMS3 and the mains charger seems to do nothing, not seeing a voltage increase in the system at all when it's turned on.

In any case, other threads have convinced me a dedicated charger is better for my lead acid battery, and I'll get more out of it.

The question is, which is the best value? I'm also interested in one that's happy with me using the 12v system while hooked up to the mains, using it as a power supply. Ideally I'd like to plug in once and forget it, and have the charger charge my battery and supply 12v to my appliances. Any ideas?

 

[charlie2]

Not sure if this is very clear, but this is a top-down diagram of my van, with the rear barn doors on the right. I'm looking to add a mains charger, shown, and run a new 240v flex cable from my PMS3 distribution board down to it.

I think I'll need a fuse box / busbar to connect all the things, as currently there are two things connected to my battery posts: my solar charger and the cables leading back to the PMS3 / relay.

Does this look sensible? I'm thinking about a Victron 15 or 20 amp mains charger.

 

[roadtripper]

Any of the Victron chargers should be happy with you consuming 12v power as they charge - the thing to double check is that you are not consuming power at a greater rate than they can charge but that seems unlikely if you are currently not having the issue with the PMS3.

Note that some chargers advertised
a "power supply mode" but this is something different. A smart multistage charger will pick a charge profile by reading the battery voltage and so won't generally do anything without being connected to a battery. The power supply mode is simply an option to force them to run without sensing a battery. Useful in a workshop but an unlikely event in leisure electrics.

 

[roadtripper]

I think I'll need a fuse box / busbar to connect all the things, as currently there are two things connected to my battery posts: my solar charger and the cables leading back to the PMS3 / relay.

Post a few pics of your current wiring will make it easier for folks to advise

You may not need the complexity of bus bars just to add a new charger. A lot of leisure batteries have twin terminals (post and bolt) which may offer options. Or there are multi way battery terminals like these

Positive Battery Terminal Clamp - 3 Stud Connection

Battery terminal clamp for positive post with 3 stud connection points (2x M6, 1x M8) and nyloc nuts. Ideal for multiple auxiliary connections.

www.12voltplanet.co.uk

 

[charlie2]

Thanks for the advice! I've totalled up the 12v stuff connected to my PMS3 and at full load they draw 11.5A. The positive cable from the relay to the battery has a 15A fuse on it. It's got blue insulation on spade connectors connecting to the battery, so I don't think it's particularly thick.

Thanks for the tip with the 3-stud terminal connectors, I didn't know they existed! Would I add an in-line fuse to the chargers (solar and the new mains one), do you think, in addition to the 15A on the positive from the relay?

 

[roadtripper]

Thanks for the tip with the 3-stud terminal connectors, I didn't know they existed! Would I add an in-line fuse to the chargers (solar and the new mains one), do you think, in addition to the 15A on the positive from the relay?

Any cable coming off the battery should have a fuse on it rated to protect the rating of the cable, and that fuse should be as close as possible to the source of power (the battery) as practical - they're there to protect against the wiring shorting in a fault and setting fire to your van.

It's not super cheap but this could make a neat way of combining the charger feeds and fusing them, mounted either on a panel by the battery or you could consider some self adhesive velcro and mounting it on top of the battery at a pinch. Just make sure that cable between the positive battery post and the distribution block is short so it cannot drop on to the chassis metal or negative post if it came loose.

Blue Sea Systems 5045 ST Blade Compact Fuse Blocks - 4 Circuits

Blue Sea Systems 5045 4-way fuse block with busbar provides a compact, safe, ignition protected fusing solution for use around fuels on boats & in vehicles.

www.12voltplanet.co.uk

They do covers for the multi way battery clamps too, don't forget to get some if you go that route as normal one won't fit.

 

[charlie2]

Just finished the job, got a Victron 20A mains charger with a small blade fuse box with positive busbar, and the battery terminal clamps you recommended. Here's a couple of pictures: