Charging house batteries
Good Morning I need some expert help and think you guys are the best. My brother has a Winnebago View. I replaced the 2 house batteries with 4 Trojan T145's. I also put in a Xantrex pure sine inverte...
Forum Discussion
westend wrote:
Trojan Battery user's guide (I had to find it to see what Trojan recommends). Trojan recommends a 10-13%C charge rate for absorption cycle. For one battery, this would be around 25 amps at 7.2 V (or so).
You have four, depending on how much time you wish to run the generator, a charger of 80-100 amp output rating would seem appropriate. There is much more to the charge cycle than just the simple math above so a call to bestconverters.com would be worthwhile.
IMO there is a mix up there in the charging rate numbers. 10% on a 100AH battery would be 10 amps, so that would be 46 amps on a 460 AH bank. Using 100a on the 460 would be a 22% rate
However, that 10% is for max battery life, being "gentle" and not for RVing where you want a shorter generator run to do the recharge. So now you have a trade off.
There is not much penalty in using a higher charge rate anyway, since you won't get near the batteries' deep cycle limit in the years of ownership unless you are like Mr Wiz doing a deep cycle every day all year.
You can kick off with 30% charging rate and it all works fine. Higher than that, you get to where voltage spikes so soon that there is no constant amps stage, it tapers right away. this still works but you don't save much gen time by going from 30 to 40 like you do going from 20 to 30, as it is not linear.
