Best way to keep an idle battery healthy.

[mudnut]

G'day, All. My uncle had the misfortune to watch his Rodeo go up in flames a couple of years ago.

Fortunately, he was able to acquire an 06-07 GU TD42 ute which already had a canopy and duel battery system installed.

He runs a 60 litre Engel which is great when he goes away, for 6 months of the year, but the battery seems to run down quickly in the off season.

I had a look under the bonnet and found that the second battery is only charged via a solenoid, so there is not much of a circuit that will cause leakage.

My question is this, what would be the best way of maintaining the battery?

[BigRAWesty]

A multi stage charger plugged into 240v while the car is dormant.
Or if he uses the car weekly the a dc-dc multi stage charger.. to save unplugging all the time..

You see 7 stage chargers for about $100 these days..

But if he's getting mass voltage drop over a short period I'd say battery is near toast..

[mudnut]

Will let him know, thanks, Kallen.

[Winnie]

I just bought a ctek 3.8A smart charger for $105 to leave plugged in all the time.

[the evil twin]

Charge it at the end of the Season with a "recondition" mode charger.
Disconnect the Battery until next season.
Maybe a quick top up in the middle of the "off season"

If it loses charge that way then the Battery is toast

[lhurley]

Is leaving the battery hooked up to a solar panel (regulated obviously) going to achieve the same results as a 240v charger? I.e. Maintain/top up the battery level.

My patrol is hooked up to my solar panel and I have been wondering if I can leave it or I should unplug it then just use it to top the battery up every so often.

[Cuppa]

What has been missed so far is to ask what sort of battery it is. A 'wet' battery will behave somewhat differently to a an AGM battery. The latter were originally designed for the armed forces who wanted bateries for vehicles & equipment which were only used from time to time, sitting idle in between. Wet batteries have a much higher 'self discharge rate' & need regular charging to prevent them going 'flat' & bringing about their early demise. AGM batteries on the other hand can be fully charged & then left idle & unused for months at a time. An AGM in good condition left in this way will still be at 80% SOC (State of charge) after say 3 months, & 60+% after 12 months. I don't advise leaving one for 12 months, but charging it to 100% every 3 or 4 months would be fine.

If it's a wet battery weekly charging combined with a check of of it's fluid levels will suffice. eaving it connected to a mains or solar trickle charge will also do the job, but still wise to check the fluid regularly

[BigRAWesty]

Is leaving the battery hooked up to a solar panel (regulated obviously) going to achieve the same results as a 240v charger? I.e. Maintain/top up the battery level.

My patrol is hooked up to my solar panel and I have been wondering if I can leave it or I should unplug it then just use it to top the battery up every so often.
It would but again for best results a dc-dc multi stage charger is best..

[Cuppa]

It would but again for best results a dc-dc multi stage charger is best..

Sorry Kallen, but that just isn’t so. A solar regulator is a multi stage charger & a battery doesn’t care if it’s charge is coming from the sun, an alternaor (via dc to c charger) or from a mains powered multi stage charger. In respect to the OP’s question, the least useful would be a dc to dc charger which requires the vehicle to be used to do it’s job.

[BigRAWesty]

Sorry Kallen, but that just isn’t so. A solar regulator is a multi stage charger & a battery doesn’t care if it’s charge is coming from the sun, an alternaor (via dc to c charger) or from a mains powered multi stage charger. In respect to the OP’s question, the least useful would be a dc to dc charger which requires the vehicle to be used to do it’s job.
Sorry your right. I should have put more into the answer.. lol
I was going "best option" along the line of the solar with a dc-dc charger is more versatile, once setup it can be used anywhere..

But yes when at home if the car I'd sheded for lma long time then the 240v wins

[mudnut]

I relayed all of your replies to my uncle and he thanks you very much. It is a new AGM battery bought for this season as the problem was with the battery which came with the vehicle. Now he is leaning towards buying a small solar panel to keep the battery topped up.

[the evil twin]

Fair enuf...
Still a good idea to give it a belt with a mains charger in AGM mode at the end of each season.

[Cuppa]

I’ve always been advised that you shouldn’t use the ‘Recondition/Equalise’ mode with AGM’s. I believe some folk do, but I never have except in a last ditch attempt to revive a battery which the charger says is ‘kaput’.

[the evil twin]

Shit... my bad, meant AGM, post amended