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crank avatar image
crank asked

Dual 12v lead acid. Orion tr or tr smart

Hi.

I have a Smart Solar MPPT 75/15 connected to my main battery. I'm planning to connect a second battery for auxiliary stuff outside the wagon. It is second hand batteries, so I'm not too conserned about them. The main battery are getting good charge every day, and will be able to provide charge for the second one. I'm hoping to connect them so that when the main battery are on/close to full, the second one will be charged. I do not want the main battery to be flattened due to charging the secondary.

Will the Orion-Tr 12/12- 9A, 110W do the job, or do I have to pay the double for the Orion-Tr Smart 12/12-18A (220W) Isolated DC-DC charger?

The lower chargecurrent is no issue.


Regards

Sven

battery charging
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crank avatar image crank commented ·

Or should I use the Cyrix Battery Combiner instead?

Only thing is, I believe I won't be able to control the chargecurrent with that one, and there will be a 10m distance between main and secondary battery. And to my knowledge, I would then need some massive cables.

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2 Answers
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tilo answered ·

You can connect the remote on/off input of the Orion-Tr 12/12- 9A, 110W to the load output of the Smartsolar 75/15, and switch it on when the battery is full and being charged, let´s say 14V, and switch off at 13,2V.

If you use a Cyrix, and just have small consumers on the second battery, you can use a 4 mm2 cable with a 30A fuse or breaker for your 10 meters. The voltage drop in the cable will reduce the charge current, and after a few seconds the voltage difference and charge current is further reduced. Only if the second battery is completely discharged and you start the engine with higher revolutions, the initial current might blow the fuse.

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JohnC avatar image
JohnC answered ·

Hi @Crank

The 'straight' Orion, as distinct from the Smart model, has only a pot to adjust it's output V. But that's fine, you could set it to (say) 13.5V and switch like tilo mentioned, or manually.

I use a 48/12-20 and switch from a Multiplus to do the same job. Works fine, and I don't need the Smart model.

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