RE: MRC Super Brain 989
Are you charging 6 cell packs or 8 cell packs? The 989 has a "boost" circuit, which allows it to charge a high voltage pack from a 12 volt source. So even if you're charging an 8 cell pack, the 989 should have no problem providing at least 5-6 amps to the pack from a 12 volt source. Also consider this, the AGM battery is approximately 95Ah right? You're charging 4200 mah and 2200 mah batteries, right? You can charge about 22 of the 4200, or about 43 of the 2200 before you would kill the AGM. If you can spare it, you can even run 2 AGMs in parallel to double your capacity.