Saturday, Mar 15, 2008 at 14:06
Hi Simon,
There are a few deep-cycle batteries which quote more than 70AH for an N70 size. I earlier had a Trojan 105AH, but it was very expensive, it didn't really perform, and it was pretty-
well dead after 2 years (its warranty period). Everyone reckons that it should have given a lot better performance than that; perhaps I was unlucky.
On my old Mav, I fitted two 6v 110AH Exides, and they were great. Could have squeezed them into my GU, but there was too much rearranging other bits under the bonnet.
Many people swear by AGM batteries. My only worry is that all lead-acid batteries don't like heat, and AGMs even more so. If the AGM was situated in the rear or on a CT or caravan where it's cool, then they would be the best. Fullriver is about the best value AGM.
My last choice of battery was a 70AH marine/deep-cycle, based on cost alone, and the fact that I was going to be on the road a lot rather than sitting in one place for many days. It's over 2 years old now and still going ok.
Regardless, the less you deep-discharge a lead acid battery, the longer its life, so if you can get a larger one to fit, then you're better off.
Re heat, if the battery is close to the exhaust in the engine bay, a thermal shield is a good idea. I also have a small fan which cuts in and draws fresh air from the front if the temp gets too high.
Re solar panels, I chose 3 x 42w panels coz they were ex-Govt purchase and were
well-priced! No other reason (actually, that's a great reason :-) )
Re regulators, I have an older two-stage Solarex reg. Basically it regulates at 14.2v, cutting back in at about 13v if my memory is correct. But if the battery drops below 12.2v (usually overnight), then the reg will take the battery right up to 15.0v briefly before settling back to a 14.2v float. This is good for flooded lead acid batteries, ensuring that the battery is fully charged and gassing, and helps equalise the cells. Good modern regulators are cpu controlled and do a much better job of monitoring the charge-discharge of the battery, and provide nice status displays. The cheap single-stage regs do work, but you'll get better performance and battery life using the more sophisticated reg.
Derek, from Affordable Batteries is a good resource.
Cheers,
Gerry
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