Leisure battery and case options

[inapottingshed]

I'm leaning towards a leisure battery and battery box over one of the popular PowerTank units firstly because I cannot envisage using the built in lights of the latter (head torch, etc.) and the former can do double duty for camping (eventually with solar charging).

However, budget is a concern and just wondering if there are any decent plain vanilla power bricks, as well as any suggestions or recommendations for a leisure battery, box, and fittings. Hopefully I can stretch the budget.

[tomato]

There are some good threads on leisure battery box builds in the DIY section:

 

 

[inapottingshed]

Thanks. Alternately, suggestions for plain vanilla power bricks welcome.

[jambouk]

How many watts will all your kit use per hour, and how many hours do you want it to run for before you recharge? 

[inapottingshed]

Difficult to say exactly because it depends on the night and tracking vs slewing. Let's say an average of 4W for the mount plus a dew heater. The latter is going to be around 28W or so, but that's at full power so let's say 70% for a decent margin, c. 20W.  Maybe a few hours for observing and longer for imaging. For campsite use (e.g. LED lighting) I guess that might pull another 20W or so (maybe over a couple of hours per night). However, that's without considering the laptop (which would be charged but after 4 hours it would need, I don't know, let's say 40W). I think all that would be around 7AH (though unlikely it would be used all at same time) so I was looking at the Yuasa 70Ah Active Leisure and Marine battery (around £65) and a battery box with sockets, etc. That would give around 10 hours full load and practically (probably something like 3Ah) I would think 2-3 night's use. Not sure about the battery tech and discharge levels, etc. I don't want to be lugging anything too heavy so thought something like that Yuasa in a box might do. 

[inapottingshed]

I've been reviewing the specs of the Yuasa L26-70 12V 70Ah 480A Leisure Battery. It claims up to 160 cycles at 50% discharge. Practically, that's probably going to cover a few years' use. So, based on a 50% discharge I would need to overspec the battery accordingly? Looking at other 'deep cycle' batteries, e.g. Hangkook they say deep cycle but don't specify any figures (other than '100% maintenance free').

 

 

[jambouk]

I’m still unsure what your total W requirements are. If you are using a laptop that could easily be 50w / hr, so say 100W / hr in total for 4 hours a night for three nights; that’s 1200W. At 12v that is 100amp hour battery which would be 100% flat, and I’d aim for 25% discharge, so you need a 400amp hour battery...!  Clearly that’s not feasible [certainly not portable], so I think my numbers are wrong.

[inapottingshed]

I think the laptop would use a bit less, possibly around 35-40W (I've got a kilowatt meter so will stick that on it next week). It's supposed to have a 6-8 hour battery but I get nearer 4-5 hrs (probably needs a new one). Firstly I can use the built in battery, then maybe a spare battery (£25), then the leisure battery. There is probably more possibility that I will be able to charge the laptop from mains over a long weekend. I think it would be much less likely that I would be able to charge a leisure battery over the weekend. I would estimate the overall demand and W requirements closer to  700W.  That's closer to 60Ah, not counting discharge which is the limitation that bumps up the capacity requirement. Surely one of the 'deep cycle' batteries used for golf carts, etc. would be robust enough to stand more than 25% discharge?

[jambouk]

60amp hour, so at 50% discharge that is a 120 amp hour battery. That is still a beast. The less you discharge it, the longer it will last. 

[inapottingshed]

Guess I'll need a cart!

This case looks interesting. Is anyone using anything similar?

https://www.amazon.co.uk/Bison-BATTERY-CARRIER-CHARGER-BREAKER/dp/B01EJV2V1G/ref=bmx_4/261-6620813-8195700?_encoding=UTF8&pd_rd_i=B01EJV2V1G&pd_rd_r=193507d0-4f4e-45aa-88fa-829e50694fef&pd_rd_w=L5MrU&pd_rd_wg=kongW&pf_rd_p=26d9b5cc-9c88-4655-88a4-db5806d5daad&pf_rd_r=E1Q84RW3MAGA9R92YMRP&psc=1&refRID=E1Q84RW3MAGA9R92YMRP