Do I need new batteries?

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RobYorkshire
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Do I need new batteries?

Post: # 17300Post RobYorkshire
March 23rd, 2017, 1:37 pm

I've recently purchased a Suntrekker demountable (another topic on that later), and I'm looking for some advice regarding the batteries.

At the moment there are two 75Ah batteries - unsure of make as I can't see any labels without removing all the wires and lifting them out which I've not got round to doing yet.

There's a solar panel on the roof which I'm told is 80w.

There's also a Durite split-charge system mounted in the engine bay. All of this is tied in with a Steca Solsum 8.8F charge controller.

Now, when the truck is running the voltmeter shows 14v so at least I know the split charge is working.

After a good run in the truck, the voltmeter shows 12.5V but soon drops down to just over 12V, with no load.

Limited use of lights (LED), water pump etc will keep it at around 12V. I haven't yet turned on the compressor fridge for a long period to see how this effects the levels - if I left the fridge on and the batteries drained would this cause any negative effects to the fridge? I'm not sure of the make / model of the fridge to check power consumption.

The Solsum is showing an amber light which according to the manual means "battery weak, loads are on".

Occasionally it'll flash amber which means "LVD reconnection setpoint has not yet been reached, loads still disconnected".

So my question is do I need new batteries? I'm presuming they're charging OK (showing 14V when truck running) but as they're so quick to go down they won't hold that charge with an adequate load on them? I don't want to go away and find they're shot, so would like to replace them in advance. I could leave the fridge on and see how they do, as that'll be the only thing on constant?
Ford Ranger 2.5TD Super Cab 4x4 & Suntrekker Demountable
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zildjian
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Re: Do I need new batteries?

Post: # 17321Post zildjian
March 24th, 2017, 10:36 pm

Short answer Rob is I think as you suspect YES
typically I swap out batteries every three years and in pairs as a single bad one rapidly drags down a fresh new one pretty rapidly,
normally you'd expect to see around 13.8/14V on a running motor and yes drop rapidly to 12v by itself
you aren't using so much by the sound of it, but a fridge or TV would make a dent in it pretty quick

could you fit one of these in?

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RobYorkshire
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Re: Do I need new batteries?

Post: # 17377Post RobYorkshire
April 1st, 2017, 10:51 am

No plans to install a TV, the fridge will be electric but from what I gather the compressor fridges use very little. It's an Indel B Cruise 42L which going on their brochure, uses 0.222 kWh/24h.

I'll definitely be replacing as a pair, I understand it's always better to go for the biggest batteries you can fit but after the purchase of the truck and camper funds are on the low side, plus 2x 75AH should be more than sufficient.

Does anyone here have experience of Numax batteries? The LV22MF comes in at less than £120 for a pair, I wasn't expecting much but reviews seem favourable?

https://www.tayna.co.uk/Numax-LV22MF-Se ... 672-1.html

Before installing the new batteries I'll have to give the wiring a check over, I've noticed if you wiggle one of the wires going into the solar controller, the LED switches from amber to flashing red "deep discharge protection active (LVD), loads disconnected".
Ford Ranger 2.5TD Super Cab 4x4 & Suntrekker Demountable
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zildjian
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Re: Do I need new batteries?

Post: # 17381Post zildjian
April 1st, 2017, 3:48 pm

"I'll have to give the wiring a check over, I've noticed if you wiggle one of the wires going into the solar controller, the LED switches from amber to flashing red"
that would be worth a closer look sure Rob,

also I've posted this up again on our FB page for bit more exposure, as its something a few people here will be wondering about right now as they dust off campers for another season's use and find batteries have possibly failed

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rubberrat
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Location: North Norfolk - Near the coast

Re: Do I need new batteries?

Post: # 17382Post rubberrat
April 1st, 2017, 3:57 pm

Although vehicle electrics are my Achilles heel. I will vouch for Tayna batteries being the 'go to' place to buy.
There are of course better batteries than NuMax..but nothing wrong with them at all at the price. I think I have bought six over the last ten years for various applications.
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earthman
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Re: Do I need new batteries?

Post: # 17383Post earthman
April 1st, 2017, 4:38 pm

It's certainly worth checking wiring/connectors first, I had a similar red to green LED flashing occurrence on my motorcycle battery charger, turned out that one of the terminals inside the plastic housing were the problem.

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sabconsulting
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Re: Do I need new batteries?

Post: # 17387Post sabconsulting
April 1st, 2017, 7:56 pm

Yes, your batteries are dead.

With your batteries disconnected (and left to settle for a while) you should see these voltages for the related state of charge:

12.65v = 100% charge
12.45v = 75% charge
12.24% = 50% charge

There are several types of batteries available. Standard car batteries are probably the least desirable. You can buy "leisure batteries" - they are pretty much standard car batteries, but with slightly thicker plates to allow for the battery to be discharged more. After that you get onto the really expensive batteries, e.g. AGM. They are 3 to 4 times the price and need special charging equipment, but are superior. You probably don't want to go for that at this stage.

The problem with car batteries (and similarly leisure batteries) is that they are mainly designed for starting an engine - they can give a brief burst of high amps, but don't get discharged much. Maybe 10%. They are not like your phone battery which you can discharge to empty each time. In fact, don't expect to be able to reliably discharge a car or even leisure battery to 50% more than a couple of dozen times without killing the battery. In comparison, expensive AGM batteries may allow you to discharge down to 20% hundreds of times. Don't even contemplate letting your lead acid batteries drop below 50% state of charge if you want them to last any time at all. So if you have 2 x 75 amp hours that is actually only 75 amp hours maximum you can consume, and you should aim to consume less than that.

Also bear in mind that the 80w solar panel is going to struggle to recharge that - think of it more as an assistance and for keeping the batteries topped up. If you used 50% of your battery power that would need roughly 1000w of power to recharge it in an hour. Given your 80w panel won't be 100% efficient, and at best they will deliver the rated power at mid-day on the equator, in the sun - it could take a couple of days or more for the solar panel to recharge the batteries assuming you had turned off the fridge and all other electrics during that time. Also, the truck alternator will recharge the battery, but bear in mind the thickness and length of the wire from there to the battery will affect the amount of charging it supplies.

So replace your batteries, but don't feel too bad about having to. Ideally consider what loads you have on the batteries - the compressor fridge is quite a big load.

Do check the wiring on your solar charge controller and make sure that is working - it is good you have it, and it is a proper multi-stage one so you should be able to expect it to maintain the charge of your battery when the vehicle is not being used.

They are around £100 for a good one, but I recommend wiring in a battery meter like a Victron. The problem with reading the voltage to work out state of charge is that you really need to disconnect everything (including solar) and leave it disconnected for a while to settle, and then take the voltage - rather inconvenient if camping. A Victron or similar measures voltage and current and once programmed with the size of the batteries will sum up the current as it goes in and out of the batteries to work out their current state of charge (you can also view instantaneous current and voltage). That way you can keep an eye on the state of charge and if you appear to be using too much power overnight (e.g. fridge) then you could turn it off to save your batteries and turn it back on in the morning when you have sun and will be running the truck. Maybe adding one of these could be a future project.

You have two batteries - when you replace them make sure you replace them at the same time with identical new batteries (i.e. don't replace them one at a time or replace them with 2 batteries of differing sizes of types).

Steve
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RobYorkshire
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Re: Do I need new batteries?

Post: # 17388Post RobYorkshire
April 1st, 2017, 9:28 pm

Thanks for the replies.

There must be some life in the batteries as I've been running the water, having lights on and charging phones etc whilst I've been in there working, although I suppose the real test is a heavy load such as the fridge being on for a few hours. It's hard to tell the exact voltage as it's an analogue meter. Electrics aren't my forte, even less so when it's someone elses work / potential bodge jobs!

Good to see a thumbs up for the Numax, appreciate they're not the best brand but I'm just after something to get me up and running, and then I can look at switching them out to something a bit better next year if I decide on keeping the camper, perhaps with a new / additional solar panel and the battery meter too.

I've read up a little about the discharging to 50% thing, as mentioned the only real load on the batteries will be the fridge. Without doing all the calculations I think 2x 75aH batteries should be OK to run that for a few days at a time, bearing in mind if I'm not travelling to my next destination I'll be running about the local area, so they'll get a little charge from the vehicle (good point about cable length / thickness, hadn't considered that).

I'll run through the existing system next week and check the wiring, I think I'll have to open up the Solsum box and check the wires going into that and see what's causing the LEDs to switch to red.

It's worth noting that sometimes I'll look and the INFO light will be green, with an additional amber light which means battery low, but sometimes the amber light will be flashing, which means "LVD reconnection setpoint has not yet been reached, loads still disconnected" - ???
Ford Ranger 2.5TD Super Cab 4x4 & Suntrekker Demountable
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sabconsulting
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Location: High Wycombe

Re: Do I need new batteries?

Post: # 17389Post sabconsulting
April 1st, 2017, 9:37 pm

The thing about setpoint not reached, loads disconnected could be to do with a function some of these solar controllers have - which is that when the battery is fully charged they can divert their power to a separate "load" to run that, e.g. a water heater.

Not a feature I've used.

Steve.
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