Translators may insert a paragraph break here as in Revised Standard Version.

When Judas saw that his army had slipped away: We know from the previous verse that not all the Jewish soldiers deserted. So we may translate “When Judas saw that most of his soldiers had deserted him.”

And the battle was imminent may be rendered “and the fighting was about to start” (similarly Contemporary English Version) or “and the enemy was about to attack them.”

He was crushed in spirit: Good News Bible says “he was worried,” but this is not quite strong enough for the Greek expression here. A better rendering is “he was terribly discouraged.”

For he had no time to assemble them: Good News Bible has a helpful model here.

An alternative model for this verse is:

• When Judas saw that most of his men had deserted [or, left him] and that the battle was about to begin, he was terribly discouraged, because there was not enough time to bring his army back together.

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 1-2 Maccabees. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here.