Trickle Chargers - Minimum Useful Time

[Colin747]

I am having issues with my battery slowly going flat due to lack of use with Winter/COVID-19. I have been looking at trickle chargers but I don't have a garage and I don't feel comfortable with leaving a trickle charger on 24/7 just due to having leads running outside/bonnet ajar etc.

For something like this - https://www.ctek.com/uk/products/car/mxs-5-0-uk - how long would you need to have it charging the battery to at least maintain the current level? Would 3/4 hours a day be enough to keep it topped up so it starts?

[illmonkey]

No, they have a long cycle.

What about a solar one you can keep plugged in all the time?

My MXS 5.0 stays on the car for a month at a time sometimes, it's fine...

[Colin747]

I had thought about a solar charger, are you able to completely close your bonnet with it attached?

[illmonkey]

Colin747 said:

I had thought about a solar charger, are you able to completely close your bonnet with it attached?

You can get ones that go into the cigarette lighter. Then just pop the panel on the dash.

With the CTEK ones you can leave a connected wired up to the battery. Mine is in the boot, so I put the charger in there with the extension reel and it stays connected up.

If your battery is under the bonnet, you could run a wire to the footwell?

[Colin747]

I had looked at the 12v socket ones but as far as I'm aware you need a "live" socket which I don't have. I'll take a look and see how easy it is to run a wire to the footwell.

[Scrump]

The ctek 5.0 has a series of lights and will indicate when the battery is charged and the charger has switched to a maintenance mode.
This could be as quick as 30 minutes if the battery is already topped up or could take many hours if the battery is discharged. You could take the charger off when it reaches this mode.

As for how often you would need to reattach it, that would depend on how fast your battery discharges.

I leave mine on permanently using a quick connector attached to the battery terminals and a ctek extension lead so I can run the lead out at the rear of the bonnet and down under the garage door to the charge unit which lives just inside the garage.

[illmonkey]

surely you'd be able to fit the charger and an extension under the bonnet?

Get one of these to be sure: https://www.amazon.co.uk/Mains-Extension-Outdoor-1...


The MXS 5.0 has this table:

BATTERY SIZE (Ah) TIME TO 80% CHARGED
2Ah 2h
8Ah 8h
20Ah 4h
60Ah 12h
110Ah 26h

Edited by illmonkey on Monday 21st December 11:30

[Colin747]

illmonkey said:

surely you'd be able to fit the charger and an extension under the bonnet?

Get one of these to be sure: https://www.amazon.co.uk/Mains-Extension-Outdoor-1...

Maybe I've misunderstood but in my head would the bonnet not have to be left ajar for the mains cable to get access?

[illmonkey]

Colin747 said:

illmonkey said:

surely you'd be able to fit the charger and an extension under the bonnet?

Get one of these to be sure: https://www.amazon.co.uk/Mains-Extension-Outdoor-1...

Maybe I've misunderstood but in my head would the bonnet not have to be left ajar for the mains cable to get access?

Run the cable up from the underside of the engine.

Or just run it out the bonnet, there is a flexible seal that'll have some give.

[Colin747]

illmonkey said:

Run the cable up from the underside of the engine.

Huh....slightly embarrassed I didn't think of that haha Will have to take a look at the undertrays and see if there is a handy way in

[SuperPav]

Colin747 said:

Maybe I've misunderstood but in my head would the bonnet not have to be left ajar for the mains cable to get access?

I think you're being over optimistic on the tightness of the bonnet shut/seal!
I've run extension leads under the bonnet and into the boot and closed it over the cable, and it's absolutely fine. Obviously make sure you've not put the cable where the latch or striker is.

In the case of a bonnet it's even easier as you can close it over onto the first latch, without pressing it all the way down if you're worried about the cable

[Scrump]

My bonnet has no weather seal on the rear edge, so I run the cable out that back of the bonnet.

[ruggedscotty]

be careful with the solar chargers as they can be the silent killers....

If your car has an AGM battery or modern stop start etc then thing is with the solar chargers is that the voltage can rise as it charges and the battery voltage rises, if that voltage increases beyond the maximum voltage of the battery then it can start causing issues with the battery.

need to keep a charge controller to regulate and stop your solar panel from overcharging.

A trickle charger should cover the draw on the battery when standing still so get rid of any parasitic loads, also your covering the self discharge of the battery, and ensuring that you can replenish the night time and dull day effects on the battery.

[sjg]

That's not a "trickle charger", it can deliver 5A so will give a useful boost to a low battery over a few hours. If you can leave it a full day then most batteries will be full. Leave it longer and it'll go into a lower power mode and keep it topped up.

I have a similar Optimate and have just been sticking it on via an extension lead every 4-6 weeks on the car that we've not been using.

[powerstroke]

Colin747 said:

Huh....slightly embarrassed I didn't think of that haha Will have to take a look at the undertrays and see if there is a handy way in

If you get a Noco Or other smart charger they
Come with a lead with croc clips and an additional
One with ring terminals for permanent fitting , so you just
Feed it out though the grille then just plug in when you need it ..

[Penelope Stopit]

How about one of these?


https://www.rpidesigns.com/shop/item.aspx/magnetic...

Pretty sure they're for sale at ebay

[Krikkit]

sjg said:

That's not a "trickle charger", it can deliver 5A so will give a useful boost to a low battery over a few hours. If you can leave it a full day then most batteries will be full. Leave it longer and it'll go into a lower power mode and keep it topped up.

I have a similar Optimate and have just been sticking it on via an extension lead every 4-6 weeks on the car that we've not been using.

Exactly - a couple of hours with a 5A charger like that will be more than enough to keep a battery topped up once a week or possibly two.

[Arnie Cunningham]

I have some cars that I charge up roughly monthly, give them a 24hr charge and that usually get's them back up to 100%.
But I also have a pair of batteries in the boat that I leave the MXS 5.0 permanently connected to and they're fine too.

Only caveat is some cheap chargers aren't designed to be left connected and slowly "boil" the water out - so make sure you use a charger, such as the MXS 5.0, that is designed to be left connected and you'll be fine.

[Chris32345]

SuperPav said:

I think you're being over optimistic on the tightness of the bonnet shut/seal!
I've run extension leads under the bonnet and into the boot and closed it over the cable, and it's absolutely fine. Obviously make sure you've not put the cable where the latch or striker is.

In the case of a bonnet it's even easier as you can close it over onto the first latch, without pressing it all the way down if you're worried about the cable

Most engine bay I've seen have no rubber seal and don't have s gap big enough to get a mains cables through when shut

[GreenV8S]

Chris32345 said:

Most engine bay I've seen have no rubber seal and don't have s gap big enough to get a mains cables through when shut

You may be looking at the front edge. Look at the back.