number-1
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| posted on 20/5/24 at 04:28 PM |
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Solar battery charger advice
Does anyone use a solar charger for keeping a battery charged in either a kit car or motor home? Ive seen the below but wanted to know if its suitable
to keep the battery charged or not? If not, what specs should i be looking for?
This
Thanks
N1
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HowardB
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| posted on 21/5/24 at 06:08 AM |
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Looks very interesting if it does all it says - clearly aimed at batteries in leisure use, as in it mentions controlling the load. Even if it trickles
a few hundred mA in that will help combat a flat battery over time.
I used a much smaller one - 300mA max on my Land Rover, that worked ok, and still today powers a bank of LED lights in the garage
£50 seems like a deal?
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again  and goes zoom)
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cliftyhanger
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| posted on 21/5/24 at 06:42 AM |
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I have 2 lockup garages with cars stored in them. So wanted solar chargers for both.
Just last week I bought 2x controllers (look to be the same as used in that kit) for under £7 each https://www.ebay.co.uk/itm/354764150871
And 2x 10w panels for a similar price https://www.ebay.co.uk/itm/285765761066
The 10W panel is overkill for trickle charging a car battery, but they will not be positioned in anything like an ideal position. For a motorhome, a
bigger charger may well be a good idea especially if it gets sporadic use or has a battery drain from equipment.
And as per my standard operating proceedure, I have been away or busy since they arrived.
I intend to add a 12v led lamp in each garage too. But that will need only work when the car is connected. Unless I buy a couple of cheap rechargeable
work floodlights (£10 each thesedays)
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sebastiaan
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| posted on 21/5/24 at 10:36 AM |
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watch out, because those solar charge controllers (and all other ones....) have a current drain of ~10-15mA from the battery when the sun doesn't
shine (i.e. at night). Which means the panel needs to be able to overcompensate for that during the day also in the darkest december days. Otherwise
you'll end up draining the battery.
Worst-case math; 20 hours discharge at 10mA = 0.12W during 20 hours. Needs at least 0.6W from the panel during the remaining "light" 4 hours
per day. Which may get close during december and a PWM solar charger. And that is only to compensate the losses from the charger, not the car itself.
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jacko
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| posted on 21/5/24 at 11:06 AM |
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The last post is this the same with house solar set up or is it completely different on houses
Thanks
G
555
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cliftyhanger
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| posted on 22/5/24 at 08:35 AM |
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quote:
Originally posted by sebastiaan
watch out, because those solar charge controllers (and all other ones....) have a current drain of ~10-15mA from the battery when the sun doesn't
shine (i.e. at night). Which means the panel needs to be able to overcompensate for that during the day also in the darkest december days. Otherwise
you'll end up draining the battery.
Worst-case math; 20 hours discharge at 10mA = 0.12W during 20 hours. Needs at least 0.6W from the panel during the remaining "light" 4 hours
per day. Which may get close during december and a PWM solar charger. And that is only to compensate the losses from the charger, not the car itself.
Thank yopu for the warning, I hadn't considered that aspect
And I hope the 10w (0.8a) charger will be enough to keep the battery and controller satisfied! Glad I didn't get the smaller 5w panel.
I reckon that controller will use 0.2ah/week from the battery at .015w draw. That needs only an hour at full output from the 10w panel (exteremely
unlikely to happen!) but even at 10% efficiency that is only 10hrs light.
Or are my calcs wrong?
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