Duel battery low voltage issue

[scotty83]

Excuse my bad spelling. Dual battery. Can't change it from taptalk

I have a redarc 100amp isolator and have been throw 2 deep cycle batteries. In 4 years. The last battery has only been in there for 2-3 months and won't charge above 7.5 volts. I have only run the engel fridge from it for one weekender in that period.

I have checked the voltage when charging and it is always above 13volts.
Given this is a 3l the battery sits quite lose to the turbo with no shielding. Is this likely to be killing them.

I have not tried charging this new battery with a 240volt charger but the old one didn't recover.

Any ideas??

[rottodiver]

heya Scotty,
i am no expert in this field but i do have a little knowledge, my concern is the battery is getting below 7.5 volts to start with... this will kill them, although i have had my batteries get really low i do have quite expensive batteries and maybe also a bit of luck that they were not destroyed. i would look at putting a cut off so they dont get anywhere near that low, that will extend the life... i am happy to be told i am wrong but this is what i understand about batteries!!

Scotty

p.s nice name

[scotty83]

This was my understanding too and I thought the engel had one but apparently not. Also concerned that the compressor in the fridge can not have been liking it either.

[rottodiver]

my engel also seems happy to drain the voltage to nothing..... doesnt seem to worry the engel.... my waeco has a cut off but for some reason engel would rather sell the swithch as a seperate part to make more money i guess!!!

[pearcey]

Scotty I run 3 expensive deep cycle batteries but I never let them get below 10-5 volts and I Charge them as per the battery makers spec`s
As Rottodiver says get a low voltage cut out, and get the shot batterys checked out professionally as if they can be recovered your charging equipment more than likely will not be ably to do the job. Some deep cycle batterys need to be charged quite differently to recover them when they they are in a low state of charge. Best of luck, hope they can be saved.

[markmclauchlin]

The heat from the turbo will kill them. So I found out today.


---
I am here: http://maps.google.com/maps?ll=-32.722177,115.671768

[the evil twin]

Why no shielding on the Turbo?... that sort of heat is bad Juju for batteries certainly but if shielded should be fine.
You can add a shield to the battery as well if concerned.

A bit confused about "only run the engel fridge from it for one weekender in that period" and " I thought the engel had one but apparently not. Also concerned that the compressor in the fridge can not have been liking it either"

If the frig was only "on for a weekender" that battery should have handled it easily under normal conditions. Did you leave the fridge on or is there something else connected?

What i mean is there are 100's of dual setups just like you describe (including mine) that have no issues so something doesn't quite make sense

[scotty83]

Hi twin the comments were in relation to rotto's about the cut off switch.
I used the setup for a weekender and it was all fine.
The turbo has a cover but the battery doesn't. Eg no metal side plate shield as you see on most battery trays.

I going to disconnect it until i get home and sourt it out. Any ideas would be helpful though.

[the evil twin]

Hi twin the comments were in relation to rotto's about the cut off switch.
I used the setup for a weekender and it was all fine.
The turbo has a cover but the battery doesn't. Eg no metal side plate shield as you see on most battery trays.

I going to disconnect it until i get home and sourt it out. Any ideas would be helpful though.

Aaaahhhh.. OK... if it was the Engel that killed the Battery such is life unfortunately. I doubt that anything will resurrect the battery from 7.5 volts but a top line multi stage Charger like a Ctek just might.

Even then I don't think the battery will get back to full capacity as there will have been significant sulphation so don't be fooled by a healthy voltage reading as the capacity might be greatly reduced.

If you do get it back up then a lot of places will do a battery test for free so that is something I would do as well otherwise next use it may drop it's bundle after just a few hours or during the night and you are back to square one and with warm beer to boot.

The vehicle charging voltage at the terminals should be 13.8 to 14.4 nominal, usually 13.9 to 14.1 so if you are seeing "above 13" then the Redarc is OK and it plus the Alternator are supplying a charging voltage but the battery is not having a bar of accepting any of it.

Have fiddle and let us know how it turns out.

[bundy4127]

Hi Scotty. Sounds like you have the same setup as I do. I have run an engel for a couple of days with no problem.

It was recommended to me to use only Wet cell deep cycle batteries under the bonnet, due to the heat. The gell or agm batteries don't handle the heat that well apparently.

I have also made a heat shield as well. Not sure if it necessary, but I figure it can't hurt.

[Robo]

batteries hate heat and cold, full stop.
Are you using deep cycle bat to start car, they don't like this at all, can and will kill em.
get alternator checked and clean your earth's up.
you may simply be using more power than your alternator can replace also, alt upgrade maybe on the cards.
cheers

[Robo]

Batralite can get rid of sulfation on the plates.
bat needs to be the NON calcium wet cell type, read directions on bottle.
would not waste on older bat as they tend to fall apart internally when treated.
look inside bat, if its dirty looking or grey scum floating around properly waste of time also.

This can work and does but it all depends on things you cant physically see entirely.
I've been treating my cars wet cell bats with this for along time now and always get 5+ yrs from a battery ,so far touch wood.
It's just a chemical that dissolves sulfation on the plates and as far as I can tell nothing else.
also have recovered a couple of old bats a couple times now and got another year outta em.
so recon it works.
think Apollo give extra warranty if used from new, sometimes as a bonus but haven't seen that advertised for a while.
Jaycar are the cheapest for this I've seen.

[Aquarian51]

Hi ET

Don't want to hijack the thread, but have a question that your answer may assist others. I have a dual battery setup (crank battery and a deep cycle) with a Redarc isolator. Have since bought a solar panel and was wondering whether to get a multi stage smart charger like Ctek or Redarc. Is it necessary or just preferable? Please advise. Thanks

[stock patrol]

Hi Guys,
This thread has been going for some time now. So thought I'd put a little input of my own. As one of the previous posters quoted, if the deep cycle is being used to start, they certainly won't last long under that strain. Know nothing about the Redarc isolator but have a TJM dual battery solinoid on my trol. It seems to be working fine. I have a Ctek in my truck and have the fridge in there all week with no worries. However the life of the deep cycle under this pressure lasts between 12-18 months,depending on how low the voltage gets. The battery world guy near me tells me a deep cycle battery has so many cycles. A cycle is when it goes from full charge to a lower voltage say 11 volts for example. That is 1 cycle. A 100 amp deep will give for memory about 100 or so cycles. In my truck the fridge will for 4-5 days without being charged before the low voltage cut out on the fridge cuts in.
Hope this sheds some light on the thread.