Leisure battery help, for garage use

[Blanco92]

Hi all,

I'm looking to add a leisure battery to my T6 PV. My usage is not for camping, instead it's to provide off-grid mains power for use in my garage/man cave/workshop.

My expected power requirements will only be for a handful of hours at a time, running perhaps a site lamp and the odd power tool (think angle grinder etc). Doesn't seem so onerous?!

The complication is all this smart battery stuff I've read about on the T6. I think on my old T5 my power requirements could have been met by a simple SCR, (1000w?) inverter and high capacity leisure battery. But does this smart battery pretty much force me into use of a B2B setup? Or in my use case is a SCR setup likely to be sufficient?

In all honesty I was hoping to keep the setup to a budget circa £300, if possible. I'm comfortable doing the install myself, just need some advice on what setup is the best way forward.

Many thanks in advance for any assistance!

 

[Skyliner33]

Would it not be easier just to run mains to the garage? It would certainly be more convenient to use.

As for what you ant to do, I would think you are going to go over that budget. You have only mentioned getting an inverter and a battery (what size do you call high capacity?). How are you planning to charge the battery?

 

[DaveD]

running perhaps a site lamp and the odd power tool (think angle grinder etc).

I'd consider buying all cordless power tools instead, only the batteries need go indoors then to recharge.
Alternatively I'd buy a petrol inverter generator. Both options give you a great deal of flexibility.

 

[RayF]

If you want to run a battery/inverter system to provide mains power, you need to see how much power you want to draw. What are your lights and power tools rated at in watts? When you specify an inverter you’ll need to over specify so you’re not taking it to the limit. The next thing is the battery or batteries needed. Depending on the power tool, some can draw as much 1400w at 240v or 6 amps. That will equate to about 132 amps being drawn from batteries. If any of your power tools draw that kind of power you’d need an inverter that is rated around 2000VA and that will give you around 1600watts of useable power. If you’re using cordless tools and you only need to charge their batteries then you can have a smaller inverter.

Going back to the batteries for the inverter, if you are using mains power tools, a single battery will not last very long at that sort of power draw. Also make sure you use the right size battery cables. You may find these websites useful in working out power requirements and cable sizes.

Inverter AC to DC Amperage Conversion Calculator | Battery Stuff

Learn how to convert AC amps to DC amps through an inverter with our amperage conversion calculator, from Battery Stuff!

www.batterystuff.com

Cable Size Calculator - Cable sizing and selection | 12 Volt Planet

Cable Size Calculator - Read our guide to selecting cable of the correct type and size for your automotive, marine or leisure wiring application. Auto and Marine Electrical Components from 12 Volt Planet

www.12voltplanet.co.uk

By the way, I live on a narrowboat with full off grid battery and mains power. I have a max limit of about 2600 watts from an inverter rated at 3000 VA and I have 4 lithium batteries rated at 100AH each. Total 400AH. Bear in mind that most batteries only have 50% useable power drain so, for me, that 200AH. Once I’ve drawn that much power the batteries will be at about 50% discharge and need recharging. If you had one battery rated at say 110AH you’d only have 55AH of useable power. Basically you could 55 amps for one hour and the battery would be at 50% discharge.

 

[RayF]

I'd consider buying all cordless power tools instead, only the batteries need go indoors then to recharge.
Alternatively I'd buy a petrol inverter generator. Both options give you a great deal of flexibility.

That will probably be the best option, use a generator. Far less grief.

 

[Blanco92]

Would it not be easier just to run mains to the garage? It would certainly be more convenient to use.

Running mains is made difficult due to both the garage, and the property the mains feed would run from being rented. Therefore any changes made would ideally be reversible. The garage is across a residential road from the property. I should have said before, but I also have a garage elsewhere (where I don’t own or rent a property) so therefore I prefer a mobile solution.

Alternatively I'd buy a petrol inverter generator.

Could be the way. Perhaps I’m guilty of making a big job of this!

If you want to run a battery/inverter system to provide mains power, you need to see how much power you want to draw. What are your lights and power tools rated at in watts?

From memory I think the most power hungry stuff would be in the region of 1000w +/-200w or so. I’ll go away, check the ratings on the tools and work out the maths.

If you had one battery rated at say 110AH you’d only have 55AH of useable power. Basically you could 55 amps for one hour and the battery would be at 50% discharge.

Fair point, although (possibly a site lamp aside) I wouldn’t have much prolonged current draw in my use requirements. It would be short term (minutes) usage of a power tool here and there, so as long as the battery could handle the peak power requirements for short term use that kind of endurance mentioned would be acceptable.

I wouldn’t be hammering any of these power tools for hours on the end, much of my work in the garage is vehicle related so most of the time it’s working with hand tools and not powered ones. It would just be great to have the convenience to plug a power tool in now and again to make life easier when needed.

 

[Skyliner33]

Another option is a battery box. @Dellmassive is the forum guru and would be able to help far more than I.

 

[Pete C]

All you need is here:

Solar Sheds & Other Non-t6 Solar Projects - How We Done It -

Solar Sheds & Other Non-T6 Solar Projects - How We Done It - @Pete C requested it, so here it is . . . . . Dell, What do the batteries in your shed power ? I too have a solar powered shed - perhaps we should have a separate thread for sheds :) Pete Lets Post here any NON - T6 related ECO...

www.t6forum.com

 

[Blanco92]

Hi guys,

After a bit of reflection, I've decided what I want to do. I'm dropping the idea of using mains power tools. I want a setup in the van that can cope with running 3x LED fluorescent tubes from a mains plug. The only other use would be to charge some battery operated tools if I'm in a pinch.

Using the above calculator, my fluorescents at 230v and 180mA will be using ~40w each at 3.8A DC each.

Would the following spec be suitable do you think?
- 110 Ah AGM leisure battery
- 12v 20A B2B charger (like this)
- Wiring kit
- 500w inverter (like this?)

Would a pure sine inverter by necessary for running LED fluorescents?

I know it could be done with solar panels, but I'd rather use the van as a mobile solution because I'd prefer not to have to install solar at 2 different locations.

 

[RayF]

Hi guys,

After a bit of reflection, I've decided what I want to do. I'm dropping the idea of using mains power tools. I want a setup in the van that can cope with running 3x LED fluorescent tubes from a mains plug. The only other use would be to charge some battery operated tools if I'm in a pinch.

Using the above calculator, my fluorescents at 230v and 180mA will be using ~40w each at 3.8A DC each.

Would the following spec be suitable do you think?
- 110 Ah AGM leisure battery
- 12v 20A B2B charger (like this)
- Wiring kit
- 500w inverter (like this?)

Would a pure sine inverter by necessary for running LED fluorescents?

I know it could be done with solar panels, but I'd rather use the van as a mobile solution because I'd prefer not to have to install solar at 2 different locations.

I would make sure your inverter is pure sine wave as that will give as good if not better frequency as house mains. Modified sine wave inverters don’t give the 50 hertz AC frequency which will likely result in either the lights flickering or not working at all.