another storage battery question,,

[Pedro_The_Swift]

I see lots of campers(including my old one) with multiple small batteries,, (N70 size)
was just wondering about larger single sizes,,
say a N150MF.
https://www.aulro.com/afvb/images/imported/2011/05/311.jpg

apart from replacement costs,,
any disadvantages?

[Blknight.aus]

weight, sometimes cost.

theres some other factors that come into play with regards to discharge rates and charge rated in relation to battery life but providing you dont go to ridiculous sized batteries you're not likely to find out about that the hard way.

[dswatts]

you get no real gain with a larger battery in that kind of application. A N150 battery is around 150 A/H, comared to a couple of N70's at around 100 A/H each= 200 A/H.
Price wise they are not that much more expensive. At work I Sell N200 SMF for around $320.

Dylan

[TerryO]

I have been asking the same questions Pedro lately because I'm deciding on what is the best all round solar system to install in our van.

This might be a bit off topic because it includes solar in the equation but it in this instance also relates to batterys and is what I have found out to date.

Our van came with two 100 amp gel battery's in it, when I started researching through Van forums what was the best solar system and number and size of batterys most of the people who seem to have good sound knowledge of what works best with solar and vans were of the opinion one large battery even if it didn't quite have the same storage capactity of two batterys was better than two. Unless your going to have a split system with one panel(s) charging one battery which feeds certain appliances and the other battery again with its own panel(s) feeding through to its own appliances/ lights etc.

The basic rule most apply with solar is its better to have to much solar charging capacity with less battery then to have marginal solar with more battery. I realise your not talking about having solar but one way or the other you will still need to charge your batterys.

When my batterys eventually fail I will replace them with one large gel battery. Hopefully that won't be any time soon though.

cheers,
Terry

[moggly73]

When I was at a cavaran and camping show, one guy I spoke to pointed out that if you have one larger battery and it fails somewhere remote you have no power, but if you have 2 smaller capacity batteries and one fails, you still have the other to fall back on by itself. Made sense to me.

[TerryO]

Re the two battery v one battery and what happens when a battery fails in a multi battery installation, again going from the collective wisdom (or floored misinformation) of the people I have been trying to quote from the many vanning forums, most reckon when one battery fails it usually stuffs the other battery it is conected to as well. So you end up having to replace both batterys not just one.

That in part is why they often recommend for caravans anyway versus most automotive battery usuages having split charging systems and supply to various applinces etc so you always have a back if required. In general if you have two or more batterys then you often have a 12/240 volt fridge and not a 3-way fridge that mainly uses gas.

I freely admit I am no expert on this but am just trying to relate (in my words) what I have found out and understand from months and months of reading lots of comments and information on a number of forums.

One thing most agree on though is that Colin Rivers or what ever his name is that often writes on topics like this and in some circles is considered an expert knows bugger all and often gives very bad advice.

cheers,
Terry

[Blknight.aus]

that format battery comes in 2 styles deep cycle and starting.

compared to an N70ZZ like I use in fozzy....

the N70ZZ I use is rated for 700cca and has a 95 minute RC at the 25 Amp rate.

compared to that battery, if it was a deep cycler it might make 600CCA (but remember its not designed to be a starting battery, using it as such will kill it) and have an RC of 160 minutes at the 25 amp rate

as a starter it might have the same 95minutes RC of the N70ZZ but would have in the order of 1000cca.

sure 2 N70ZZ's wired in parallel will have more RC and more CCA But you then have to worry about 2 batteries, if your setup was done properly one battery failure wouldnt mean the automatic death of the second battery but it would mean you would have to charge the second battery. You also have to worry about the electrical connections, securing, wieght and maintaining 2 batteries.

each setups has its own merits, the best thing about doing the smaller batteries in parallel setup is you can do the installation in stages to spread the cost, you'll get full functionality of the system straight off but will be reliant on you charging system to keep the power up so your stays away from external charging ability will be limited. As the money gets spent you can then up the solar ability and the storage capacity till you hit self sufficiency.

most times when Ive done cheapy installs for people they've gone the way of a decent pair of batteries (due to size/weight distribution) set up to jave solar installed later and relied on a DBS to charge the batteries on the move and a cheapy 240v charger to keep the batteries topped off while stationary at a van park with solar or a better charger coming in later.

on solar.

work out the max current drain you will put on the system and then get a regulator thats rated to about 150% of that. you are then in a position to add panels as you can afford them but will still get the benefit of some solar from a single panel.

the options are endless and using the word Best with any given solar/battery/DBS system is misleading as whats good in one application may not work in another.

[harlie]

The camper I’ve built was designed with a battery bay to take the biggest battery I could find. The bay is 630L 290W 300H with door on the side. When it came time to purchase the battery I could only see the 60-70KG single battery causing logistical handling problems. I have fitted a pair of 305mm long 110AH batteries.

I know I could get more capacity (260AH) with a large single and there has to be inefficiencies with 2 smaller - but the handling issue of a large single killed it for me.

[Hoges]

I bought 2 of the MRV70 All rounders from Supercharge last year for the CY trip. 760CCA and 105AH deep cycle.
With the AULRO discount was a very attractive package.

For the trip I set them in parallel as I run a humidified CPAP machine (from a 150W pure sinewave inverter). Kept them charged on the run with a magic box obtained from Traxide (SC80). also supported bushman 52 L fridge at -7degC, sundry lights, Li ion battery chargers, Laptop etc. Excellent service.

Lowest charge got to 12.4V.

Thinking about a solar panel

[drivesafe]

Hi Pedro and Terry, I have been supplying some of the motor home manufacturers with DC control panels for 16 years now and many of these vehicles have multiple battery banks.

I have found that in the vast majority of cases, when one battery fails, while it drags the other battery(s) down with it, it is rare for the other battery(s) to be damaged and as Blknight posted, you usually only need to charge the other battery(s) and your back up and running.

The situation is similar for multi battery set ups in caravans and camper trailers.

As has also been posted by harlie, handling two smaller batteries instead of one big one is much easier on your back.

And as posted by moggly, if one battery does fail, pull it out of the system and you still have power.

There is also the problem with a large battery, if it does fail and you’re away from any major centres, you may have a problem getting a similar sized battery.

Also where space may be a problem, you might find it more convenient to fill the space available with say a 100 Ah battery paralleled with a 55 Ah battery.

Or you could simply fit one battery in one location and a second ( or more ) battery else where and just wire them in parallel.

Also as posted by Blknight and something that is now quite common place, people buy a van with a single battery and then find they need more power than is available so they add battery capacity to meet there needs.