Batteries 😶😶

[Tacitus]

Can you damage a battery leaving the trickle charger on too long?

Short answer yes, if it is not a modern smart charger that can recognise the charge of the battery and vary the supply accordingly.
Lead acid batteries, degrade mainly due to 3 factors.
Corrosion of the plates from the acid,
gassing of the plates at the end of the charging cycle that dislodges lead particles that fall to the bottom of the battery
and sulfation that happens when the battery stays with low charge, sulfur crystals form on the plates reducing the active surface. If stays discharged for long time, the crystals get hard and they are no longer reversible.
Temperature accelerates all of the above.
A smart charger detects the level of charge and floats the charge in a way that there is no gassing and no sulfation

 

[Gecko]

Can you damage a battery leaving the trickle charger on too long?

Yes!
A dumb charger on constantly will shorten the life of a lead acid battery dramatically.

As I understand it, the best life will be with a smart charger and an occasional load taking the top off the charger - eg. starting the engine.
When not in use, most of mine are connected to solar chargers (obviously not charging at night). As the panels are way over engineered, the battery will be fully charged every day. To take the top off, each set has a light the comes on at dusk and runs a few hours.

Dual batteries present an extra challenge. If one battery starts failing, it drags the other down, very important to have a solenoid connecting both batteries that disconnects when it is turned off.

Just to confirm, do you mean: 2x 12V batteries in series for a 24V system, or 2x 12V circuits eg. a boat with 12V house battery and a 12V start battery?

 

[Tacitus]

Two 12v batteries in series for a 24V system or parallel, for a 12v, either way it means two different batteries that invariably will degrade at different speed. When one battery can no longer achieve the same charge as the other, there will be a flow of current from the good one to the dodgy one.
Dual battery kits like Redarc are designed to prevent this, more common in parallel 12v then in 24v but it is the same principle

 

[Shovelhands]

I’ve never heard of the need to have any fancy systems to run two 12v batteries in parallel. I run batteries in parallel on several machines and never have any issues that I’m aware of. I do always fit new in a pairs though.

 

[Bri963]

I’ve never heard of the need to have any fancy systems to run two 12v batteries in parallel. I run batteries in parallel on several machines and never have any issues that I’m aware of. I do always fit new in a pairs though.

Likewise. I run machines on 24v in series and 2 x 12v in parallel and no issues. When a machine doesn’t want to start it’s easy enough to stick a meter across and see which battery is on the way out.

 

[JD450A]

Likewise. I run machines on 24v in series and 2 x 12v in parallel and no issues. When a machine doesn’t want to start it’s easy enough to stick a meter across and see which battery is on the way out.

I'm going out on a limb and saying that considering pretty much every manufacturer of a lorry over 7t and plant over 10t run 24v systems and I've never seen one put a relay or isolator between the batteries I'm breaking my silence and calling bull...... Arrgh, the broom, not the broom ooofh ahhgh, I'm off.

 

[Bri963]

Two 12v batteries in series for a 24V system or parallel, for a 12v, either way it means two different batteries that invariably will degrade at different speed.

Tell that to the two nearly 20-year old batteries on one of our machines, and some of the nearly 10-year old pairs on others.

 

[Gecko]

@Tacitus
When one battery can no longer achieve the same charge as the other, there will be a flow of current from the good one to the dodgy one.

(edited)
That's a bit simplistic.
If you've got a house battery and a start battery charged from a single source (probably an alternator), the two batteries will certainly live different lives and "shouldn't" even be the same type. The house battery should be a deep cycle while the start battery should be chosen for cranking.
The most primitive charging would connect the batteries together with a relay when the alternator has decent output. A more sophisticated management would make sure the start battery is fully charged before the house battery gets its share.

2x 12V in series for 24V can not charge one from the other without something to complete the circuit.
Battery balancers are available if it is considered necessary, but realistically, it's probably a band-aid for some other problem.

For start batteries, if one is soft, you won't be getting 24V to the starter-motor - this will reduce torque and increase heating. If this is the case, the batteries are due to be replaced (as a pair).

 

[Bri963]

I'm going out on a limb and saying that considering pretty much every manufacturer of a lorry over 7t and plant over 10t run 24v systems and I've never seen one put a relay or isolator between the batteries I'm breaking my silence and calling bull...... Arrgh, the broom, not the broom ooofh ahhgh, I'm off.

Admittedly I haven’t seen every machine in the world, but I’ve never seen a manufacturer-fitted relay or isolator between batteries, just the normal machine isolator. They may fit them on ultra-large kit, but not on anything I’m ever likely to see or operate.

 

[Bri963]

That's a bit simplistic.
If you've got a house battery and a start battery charged from a single source (probably an alternator), the two batteries will certainly live different lives and "shouldn't" even be the same type. The house battery should be a deep cycle while the start battery should be chosen for cranking.In which case you would have a split-charging set up where normally the start battery gets priority
The most primitive charging would connect the batteries together with a relay when the alternator has decent output. A more sophisticated management would make sure the start battery is fully charged before the house battery gets its share.See above

2x 12V in series for 24V can not charge one from the other without something to complete the circuit. Such as normal wiring
Battery balancers are available if it is considered necessary, but realistically, it's probably a band-aid for some other problem.
View attachment 34503
For start batteries, if they are not closely matched, you won't be getting 24V to the starter-motor - this will reduce torque and increase heating. If this is the case, the batteries are due to be replaced (as a pair).

If that was aimed at me, it’s simplistic because it is simple, I’m talking about my own experience with a good few machines over a good few years. If by “house” batteries you mean gel batteries, I don’t think anyone is even talking about them, we’re talking about normal machine installations.

More than once I’ve changed one battery of a pair for the same make and performance and they’ve lasted for several years. I’ve also fitted a 450 CCA battery next to a 850 CCA battery to get me out of trouble, and it’s worked. You still get 24volts, you just don’t get as many amps and one battery heats up a bit more if you’ve got a machine that’s a bad starter.

 

[JD450A]

Admittedly I haven’t seen every machine in the world, but I’ve never seen a manufacturer-fitted relay or isolator between batteries, just the normal machine isolator. They may fit them on ultra-large kit, but not on anything I’m ever likely to see or operate.

Simple physics says that unless there is a passable current from + to - a battery should stay charged.... No matter the voltage or setup of multiple batteries this system should remain the same (be it a 12v in parallel or a 24v on series).

Issue comes when people wire the likes of radios, cameras etc to one battery, said battery never gets its full charging load as there is a constant parisitic load taking voltage from that unit. Eventually said unit will of had enough but often on 24v systems the other battery will hide the symptoms until it's too late.

I'm off to hide again now as I can hear Old Regenald stomping along with his broom again. Trying to stop me being offensive .

 

[Shovelhands]

If that was aimed at me, it’s simplistic because it is simple, I’m talking about my own experience with a good few machines over a good few years. If by “house” batteries you mean gel batteries, I don’t think anyone is even talking about them, we’re talking about normal machine installations.

More than once I’ve changed one battery of a pair for the same make and performance and they’ve lasted for several years. I’ve also fitted a 450 CCA battery next to a 850 CCA battery to get me out of trouble, and it’s worked. You still get 24volts, you just don’t get as many amps and one battery heats up a bit more if you’ve got a machine that’s a bad starter.

I think he’s talking about a motor home or caravan with a separate battery, charged from the engine or tow vehicle which has its own separate system?

 

[Bri963]

I think he’s talking about a motor home or caravan with a separate battery, charged from the engine or tow vehicle which has its own separate system?

Possibly. I’ve fitted those gel batteries and usual thing on a 12v machine is to fit a split charger, on 24v it’s a 24-12v inverter.

 

[Gecko]

If that was aimed at me,

No it wasn't.
I'd typed it up and forgot to send it!
I'll edit it to make it clearer

If by “house” batteries you mean gel batteries, ~

No, I meant "house" to differentiate from "start" as used in a boat / camper / caravan / converted bus, where the "house" battery is for lights, TV, microwave. Regardless of what you get up to overnight, you still want your "start" battery fully juiced up in the morning.

I was trying to get a handle on what application @Tacitus was referring to.

 

[Bri963]

No it wasn't.
I'd typed it up and forgot to send it!
I'll edit it to make it clearer

No problem mate, that’s what comes of typing while you’re upside down.

 

[JD450A]

No problem mate, that’s what comes of typing while you’re upside down.

Careful, people might class that as offensive and come at you with the broom

 

[Shovelhands]

Careful, people might class that as offensive and come at you with the broom

Just because you’ve been whipped doesn’t mean everyone one needs it….

 

[Gecko]

No problem mate, that’s what comes of typing while you’re upside down.

That's the trouble - I'm used to typing upside down.
I'm currently in germany and not used to typing the right way up.

 

[Lancs Lad]

Interesting thread not followed it much as I've been busy...charging stuff
But valid points about parisitic...VW won't replace a battery under warranty if any after market accessories fitted I'm told ...I'm about to try them on it..wish me luck.

 

[Bri963]

That's the trouble - I'm used to typing upside down.
I'm currently in germany and not used to typing the right way up.

Problem with your SatNav?