12v to 24v trickle charger

[charlieaarons]

Does anyone know of a reliable trickle charger/battery maintainer that will charge 24v batteries (small) off a 12v system (generally kept up with solar, or else by being plugged in).
Sterling’s 12-24v trickle charger is exceedingly unreliable, have been through several. All that’s needed is 1A or even less at 24v.
A physically small unit is preferable (maybe fit inside battery box). NOT looking for something that runs off 110v AC.
Thanks.

 

[Ramdough]

I think Victron makes one. I may be wrong…..It would be under Dc to Dc chargers. No experience with them, but that is a place to look.

Good luck.


Sent from my iPhone using Tapatalk

 

[broncobowsher]

I am going to say Victron as well. Saw a lot of that stuff while looking for solar charge controllers and related hardware.

 

[DaveInDenver]

The Victron Orion TR 12/24-10

Orion-Tr DC-DC Converters Isolated - Victron Energy

Provide a stable DC output voltage using the, easy to install, Orion DC-DC Inverter from Victron Energy. Find a dealer near you.

www.victronenergy.com

It's not cheap. Typically about $250 and over kill for your criteria (it's capable of a charge up to 10A @ 24V).

There's not a ton of options going from 12V input to 24V output. Your best option is to look for chargers designed to maintain wheelchair batteries, which are usually 24V, in vehicles. This is just an example, a more modest $75 but also limited to 2.5A, which when you say 1A trickle (float) is obviously sufficient. I have no idea about reliability to offer, though.

Mobility Electronics 24v Wheelchair Charger with Car Adapter MC24EX

Vehicle to Mobility 12 volt input, 24 volt output smart charger. FOR LEAD ACID BATTERIES ONLY. This includes AGM, Flooded and Gel.

www.batterystuff.com

 

[Joe917]

The other option is a small solar panel and 24v charge controller. However this will not work if covered in Alaskan snow or parked inside. Just throwing in ideas.

 

[charlieaarons]

What about using a charge controller for a 24v battery system using the 12v system as input instead of the small solar panel? Are there any such solar panels that actually increase voltage (and decrease current proportionately of course), rather than the other way around?
The wheelchair charger is a good idea but it says in the description “charges for 2.5 hours unless input battery voltage drops first” [which it won’t]. Need to call technical line on Monday and find out if that means it shuts down for good at 2.5 hours unless unplugged and reconnected. That won’t be possible if I am on the other side of the planet.

 

[charlieaarons]

Amazon.com: PowerEZ 24Volt 10 Watts Solar Battery Charger for Trolling Motor,Boat, RV & Marine, 0.28 Amp Trickle Solar Charger, Self Regulating-No Experience Plug & Play Design, Dimension:16.14 X 9.13x0.31inch : Patio, Lawn & Garden

Buy PowerEZ 24Volt 10 Watts Solar Battery Charger for Trolling Motor,Boat, RV & Marine, 0.28 Amp Trickle Solar Charger, Self Regulating-No Experience Plug & Play Design, Dimension:16.14 X 9.13x0.31inch: Solar Panels - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Another idea: leave inside cab in the winter. Even the tiny amount of power generated in December (maybe 10-20 mA for 5-6 hours/day) will probably be enough; how much do AGM batteries self discharge/day? They’re 18Ah. At 2%/month, that’s 12mAh/day, so solar power output of 3mA for 5h/day should be enough, about 1% of rated output.
All I’ll need to do is keep the very spacious U500 windshield mostly clear. And put the panel on the dash.

 

[DaveInDenver]

It's theoretically possible to boost voltage but that's not going to be typical with solar for various reasons. Mostly it's going to add cost and complexity for a niche use. For example doing a voltage boost eliminates a simple PWM controller as an option. Instead of $50 controller you end up with a $200 controller where it would have been cheaper and easier to have bought a 24V panel instead.

 

[charlieaarons]

http://oldclimate.gi.alaska.edu/ResearchProjects/Dissing1998.pdf

At solstice 10W/sq m = 1W onto panel. Average over 24h. Should get
100mW output = 3.5mA. Enough to compensate for 14%/month self discharge rate. Which is much higher than actual.