Battery charging

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TONYT25T25
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Battery charging

Post by TONYT25T25 »

Is it ok to leave a battery connected whilst trickle charging from a charger. The charger generates about 12.v volts but cannot see how this would damage any electricals. During summer months I use a small solar panel which pushes out nearly 21v and this also appears ok. The solar panel this time of year although generating about 18/19v appears to be insufficient to trickle charge the battery. Advice on both of above welcome. Tks Tony
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AngeloEvs
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Re: Battery charging

Post by AngeloEvs »

My T4 handbook stated a maximum current figure 5A or thereabouts for a trickle charger when charging with battery in situ. I have a battery isolating switch but I have trickle charged with battery in situ in the past. If you are not absolutely sure it only takes a minute or so to disconnect a terminal.
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TONYT25T25
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Re: Battery charging

Post by TONYT25T25 »

Tks, had battery checked today at Halfords and it is down on recharge capability by about 25% so even a fresh charge will only partially restore it. So will probably opt for a new one.
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bigbadbob76
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Re: Battery charging

Post by bigbadbob76 »

Your solar panel 18-19v- sounds like that's an open circuit measurement, ie: with the panel not connected to the battery. It probably won't manage that many volts on load at this time of year unless the battery is high impedance (Fecked).
your charger voltage 12v- sounds like that's an on load measurement with a partially discharged battery, if it doesn't go above 13.8v when off load (disconnected from battery) then you should be safe to leave it on trickle charge in situ.
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TONYT25T25
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Re: Battery charging

Post by TONYT25T25 »

Thanks for good advice, you learn something every day.
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bigbadbob76
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Re: Battery charging

Post by bigbadbob76 »

:ok
I've learned a lot about stuff I havn't got a clue about from the guys on here so if I can help out with stuff I do know about that's great. :D
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Re: Battery charging

Post by 123-jn »

Hope you have a charge controller on the output of your panel. I have a 60watt panel and use a 10Amp Mppt regulator/controller to feed the batteries with 14 volts. If your panel is less than 15 watts you may get away without one. Mine would constantly boil the battery in the summer without the controller. I have a second 40 watt panel which I plug in to the controller when we are pitched making 100watt in bright sunlight. My 60 watt panel cannot keep the battery up to scratch in the winter either.
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TONYT25T25
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Re: Battery charging

Post by TONYT25T25 »

Tks for response, the one I use is only 2.4watts according to the instructions which is fine in the summer to keep my leisure battery in shape as I use my radio/cd player whilst parked up. So should be fine.
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Re: Battery charging

Post by California Dreamin »

2.4 watts (maximum BTW) is 0.2 amps lol .. in theory, just about keeps up with clock drain, in reality doesn't even do that as you probably have additional radio memory drain as well as normal battery/time depletion. Absolutely no worries with charge controllers at this output.
The charger you mention should be more controlled, however, output should definitely be more than 12 volts otherwise there is no 'potential difference' i.e. battery voltage (fully charged) 12.6 - 12.8 volts where as charge voltage should be 13.9 - 14.5 volts so the PD (potential difference) should anything from 1 - 2.5 volt. To put it another way: voltage is 'pressure' the pressure on the charge side needs to be higher than battery voltage (pressure) in order to push charge in the direction of the battery...if that makes sense.
Of course a SMART charger varies its output, starting with 'bulk' (maximum charge) tapering off in stages to a trickle charge when close to fully charged and then switching to 'float or pulse' to sustain but NOT overcharge the battery (The exact function depends on the charger you have purchased of course)

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Re: Battery charging

Post by CovKid »

Tony, I can confirm what Martin says regarding those 'supposed' sub-3 watt trickle chargers. Trust me, bin it. Ghost123UK and I got the meters out on one of the brightest days and it just had enough power to light up the blue flashing LED. We worked out it would take at least 7-10 days to charge a flat mobile phone and that was on the proviso the there was 24 hour bright sunlight. They are all hype and virtually no substance. 10 watt will trickle but anything less than that is pointless.
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Re: Battery charging

Post by California Dreamin »

Not sure I would be so harsh! I would agree that as a charger they are useless, however, any activity must slow up plate 'sulphation' which is the main killer of stored batteries.

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TONYT25T25
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Re: Battery charging

Post by TONYT25T25 »

Tks to all for replies, will try and monitor when the good weather eventually returns.
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Re: Battery charging

Post by Da dan »

So, I have 140w going into a controller but I’m getting a flat battery still? Really annoyed


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bigbadbob76
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Re: Battery charging

Post by bigbadbob76 »

Ok... making some assumptions here...
If that 140W is measured from your solar panel... at 18v that's 7.8A, that's a lot of current going somewhere.
If it's going into your battery but the battery is not charging then the current is just heating up your battery, in that case your battery is fecked.
I just noticed this weekend that my battery voltage comes up to 13.8v very quickly (from 12.3v at rest) when I put it on charge, this is an immediate indication that it's fecked.
A good battery should take hours to come up to 13.8v from 12.3v. Time I bought a new one. :cry:
If your 140W is not going into the battery, it's heating up something else, either your charge controller is fecked or you have a heavy drain on your battery.
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Re: Battery charging

Post by Da dan »

That’s what I suspected so I’ve been digging and testing. I’ve managed to work out it’s not draining back to sola! Hum?!? Me thinks? Maybe batteries have seen a better day? Pop on charge tonight and see.


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