Today, I came across a portable solar power generator that offered a battery expansion kit. And at first glance, it seemed like a really good feature. It allows you to buy the generator today that can grow in size with your needs. After all, how hard is it to add batteries to your battery bank for more capacity?
Unfortunately, it is not as simple as plugging in another battery bank. Here is a list of items you need to be aware of before you invest in an expandable solar power generator:
1) Performance – adding new batteries to an existing battery bank will automatically reduce the new battery’s performance. For example, your existing batteries may only be able to achieve a 90% state of charge due to age. Adding a new battery will cause the battery to reduce to a 90% state of charge.
2) Uneven charging/ discharging – adding new batteries will generally be done by paralleling the batteries. The number one rule when paralleling batteries is to keep the resistance in each parallel feed as equal as possible. Failure to do so causes uneven charging and discharging, which will destroy a battery bank.
3) Battery Maintenance – batteries need to be brought back up to a full charge. Adding batteries to an existing battery bank means that both your solar array and charge controller will most likely need to be upgraded.
There are more items for consideration when adding to an existing battery bank. This list is only meant to highlight some of the bigger issues that can cause more harm than good to your portable solar power generator. As always, take care of your system and it will perform for many years to come.